6.1.183-rc1 review

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Yi Cong <[email protected]>

commit 1f428e30947395d9b9aacee03e25a4e6cfcad7a4 upstream.

When the interface has NETIF_F_SG enabled and skb_linearize() fails in ax88179_tx_fixup(), the function returns NULL without freeing the skb.

usbnet_start_xmit() treats a NULL return from tx_fixup() as a drop (info->flags does not set FLAG_MULTI_PACKET for this driver), jumping to the "drop" label where it does if (skb) dev_kfree_skb_any(skb). Because tx_fixup() returned NULL, the local skb variable in usbnet_start_xmit() is NULL, so the original skb is never freed — a memory leak on every TX frame whose linearization fails (i.e. under memory pressure).

Free the skb before returning, matching the error handling already used for the pskb_expand_head() failure path in the same function.

---
 drivers/net/usb/ax88179_178a.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -1491,8 +1491,10 @@ ax88179_tx_fixup(struct usbnet *dev, str
 
 	headroom = skb_headroom(skb) - 8;
 
-	if ((dev->net->features & NETIF_F_SG) && skb_linearize(skb))
+	if ((dev->net->features & NETIF_F_SG) && skb_linearize(skb)) {
+		dev_kfree_skb_any(skb);
 		return NULL;
+	}
 
 	if ((skb_header_cloned(skb) || headroom < 0) &&
 	    pskb_expand_head(skb, headroom < 0 ? 8 : 0, 0, GFP_ATOMIC)) {

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Joshua Rogers <[email protected]>

commit a7ad0034453ba4c353f9b8f810ee2569de33d283 upstream.

KDSKBMETA modifies keyboard meta mode but lacks the !perm check that all other keyboard setter ioctls in vt_k_ioctl() enforce, allowing a process to change meta mode on a non-controlling console without authorization.

---
 drivers/tty/vt/vt_ioctl.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -408,6 +408,8 @@ static int vt_k_ioctl(struct tty_struct
 	/* this could be folded into KDSKBMODE, but for compatibility
 	   reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
 	case KDSKBMETA:
+		if (!perm)
+			return -EPERM;
 		return vt_do_kdskbmeta(console, arg);
 
 	case KDGKBMETA:

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Joshua Rogers <[email protected]>

commit e25d47a526939ad44b75f778b8a7500562b84fc1 upstream.

kbd_keycode() reads vc->port.tty without acquiring a tty reference, racing against con_shutdown() which clears port.tty under a different lock. Use tty_port_tty_get()/tty_kref_put() to hold a proper reference for the duration the tty pointer is needed.

---
 drivers/tty/vt/keyboard.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

@@ -1405,7 +1405,7 @@ static void kbd_keycode(unsigned int key
 	struct keyboard_notifier_param param = { .vc = vc, .value = keycode, .down = down };
 	int rc;
 
-	tty = vc->port.tty;
+	tty = tty_port_tty_get(&vc->port);
 
 	if (tty && (!tty->driver_data)) {
 		/* No driver data? Strange. Okay we fix it then. */

@@ -1465,9 +1465,12 @@ static void kbd_keycode(unsigned int key
 		 * characters get aren't echoed locally. This makes key repeat
 		 * usable with slow applications and under heavy loads.
 		 */
+		tty_kref_put(tty);
 		return;
 	}
 
+	tty_kref_put(tty);
+
 	param.shift = shift_final = (shift_state | kbd->slockstate) ^ kbd->lockstate;
 	param.ledstate = kbd->ledflagstate;
 	key_map = key_maps[shift_final];

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dmitry Torokhov <[email protected]>

commit 90f305f2c7a30257c683e13f4bf7c798eea992a0 upstream.

In evdev_pass_values(), the input_event structure is allocated on the kernel stack and populated field-by-field. However, it is never fully initialized. On architectures where struct input_event contains explicit or implicit padding (such as the 32-bit __pad field on SPARC64), these padding bytes are left uninitialized.

When this event structure is subsequently passed to the client buffer and later copied to userspace, the uninitialized padding bytes leak kernel stack memory, potentially exposing sensitive information.

Similar issues exist in __evdev_queue_syn_dropped and __pass_event.

Fix this by explicitly zeroing the entire event structure with memset() before populating its fields. This ensures all padding bytes are cleared before the data crosses the security boundary.

---
 drivers/input/evdev.c |   22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

@@ -149,11 +149,11 @@ static void __evdev_queue_syn_dropped(st
 	struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]);
 	struct input_event ev;
 
+	memset(&ev, 0, sizeof(ev));
 	ev.input_event_sec = ts.tv_sec;
 	ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
 	ev.type = EV_SYN;
 	ev.code = SYN_DROPPED;
-	ev.value = 0;
 
 	client->buffer[client->head++] = ev;
 	client->head &= client->bufsize - 1;

@@ -221,20 +221,20 @@ static void __pass_event(struct evdev_cl
 	client->head &= client->bufsize - 1;
 
 	if (unlikely(client->head == client->tail)) {
+		struct input_event ev;
+
+		memset(&ev, 0, sizeof(ev));
+		ev.input_event_sec = event->input_event_sec;
+		ev.input_event_usec = event->input_event_usec;
+		ev.type = EV_SYN;
+		ev.code = SYN_DROPPED;
+
 		/*
 		 * This effectively "drops" all unconsumed events, leaving
 		 * EV_SYN/SYN_DROPPED plus the newest event in the queue.
 		 */
 		client->tail = (client->head - 2) & (client->bufsize - 1);
-
-		client->buffer[client->tail] = (struct input_event) {
-			.input_event_sec = event->input_event_sec,
-			.input_event_usec = event->input_event_usec,
-			.type = EV_SYN,
-			.code = SYN_DROPPED,
-			.value = 0,
-		};
-
+		client->buffer[client->tail] = ev;
 		client->packet_head = client->tail;
 	}
 

@@ -256,6 +256,8 @@ static void evdev_pass_values(struct evd
 	if (client->revoked)
 		return;
 
+	memset(&event, 0, sizeof(event));
+
 	ts = ktime_to_timespec64(ev_time[client->clk_type]);
 	event.input_event_sec = ts.tv_sec;
 	event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Lincoln Wallace <[email protected]>

commit 5ff232d31106f45ac87c3b64e1d35a0667777797 upstream.

The digest-length check in xattr_verify() mixes int and size_t:

	if (xattr_len - sizeof(xattr_value->type) - hash_start >=
			iint->ima_hash->length)

sizeof() yields size_t, so the usual arithmetic conversions promote the whole left-hand side to unsigned 64-bit before the subtraction runs. For a truncated xattr this underflows instead of going negative:
a 1-byte IMA_XATTR_DIGEST_NG xattr (xattr_len == 1, hash_start == 1) turns "1 - 1 - 1" into SIZE_MAX, which is trivially >= ima_hash->length. The check then passes and the following memcmp() reads iint->ima_hash->length bytes starting past the end of the buffer vfs_getxattr_alloc() allocated for it.

Nothing upstream clamps xattr_len back into a safe range first:
ima_get_hash_algo() only special-cases xattr_len < 2 to pick a default algorithm, and evm_verifyxattr() returns INTEGRITY_UNKNOWN rather than failing when no HMAC key is loaded, so a truncated security.ima value reaches the length check as-is.

Rewrite the comparison so every operand stays a signed int and no implicit conversion to size_t can occur.

---
 security/integrity/ima/ima_appraise.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

@@ -301,8 +301,13 @@ static int xattr_verify(enum ima_hooks f
 		} else {
 			set_bit(IMA_DIGSIG, &iint->atomic_flags);
 		}
-		if (xattr_len - sizeof(xattr_value->type) - hash_start >=
-				iint->ima_hash->length)
+		/*
+		 * Use addition, not subtraction: sizeof() forces unsigned
+		 * math and a short xattr_len would wrap around, bypassing
+		 * this bounds check.
+		 */
+		if (xattr_len >= (int)sizeof(xattr_value->type) + hash_start +
+				(int)iint->ima_hash->length)
 			/*
 			 * xattr length may be longer. md5 hash in previous
 			 * version occupied 20 bytes in xattr, instead of 16

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Julian Anastasov <[email protected]>

commit 04d2feaed8d0103c498727191ba04001d5100e67 upstream.

Replace the inactconns dest counter with totalconns, now inactconns can be obtained from totalconns - activeconns. This reduces the atomic inc/dec ops for TCP/SCTP from 6 to 4 if the connection is established and then closed.

---
 include/net/ip_vs.h                   |   17 ++++++++++++-----
 net/netfilter/ipvs/ip_vs_conn.c       |   24 +++++++-----------------
 net/netfilter/ipvs/ip_vs_ctl.c        |   10 +++++-----
 net/netfilter/ipvs/ip_vs_lc.c         |    4 ++--
 net/netfilter/ipvs/ip_vs_proto_sctp.c |    2 --
 net/netfilter/ipvs/ip_vs_proto_tcp.c  |    2 --
 net/netfilter/ipvs/ip_vs_sync.c       |    7 ++-----
 7 files changed, 28 insertions(+), 38 deletions(-)

@@ -675,7 +675,7 @@ struct ip_vs_dest {
 
 	/* connection counters and thresholds */
 	atomic_t		activeconns;	/* active connections */
-	atomic_t		inactconns;	/* inactive connections */
+	atomic_t		totalconns;	/* total connections */
 	atomic_t		persistconns;	/* persistent connections */
 	__u32			u_threshold;	/* upper threshold */
 	__u32			l_threshold;	/* lower threshold */

@@ -1735,14 +1735,21 @@ void ip_vs_unregister_hooks(struct netns
 static inline int
 ip_vs_dest_conn_overhead(struct ip_vs_dest *dest)
 {
-	/* We think the overhead of processing active connections is 256
+	/* We think the overhead of processing active connections is 257
 	 * times higher than that of inactive connections in average. (This
-	 * 256 times might not be accurate, we will change it later) We
+	 * 257 times might not be accurate, we will change it later) We
 	 * use the following formula to estimate the overhead now:
-	 *		  dest->activeconns*256 + dest->inactconns
+	 *		  dest->activeconns*256 + dest->totalconns
 	 */
 	return (atomic_read(&dest->activeconns) << 8) +
-		atomic_read(&dest->inactconns);
+		atomic_read(&dest->totalconns);
+}
+
+static inline int
+ip_vs_dest_inactconns(const struct ip_vs_dest *dest)
+{
+	return max(atomic_read(&dest->totalconns) -
+		   atomic_read(&dest->activeconns), 0);
 }
 
 #ifdef CONFIG_IP_VS_PROTO_TCP

@@ -570,12 +570,6 @@ static inline void ip_vs_bind_xmit_v6(st
 #endif
 
 
-static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
-{
-	return atomic_read(&dest->activeconns)
-		+ atomic_read(&dest->inactconns);
-}
-
 /*
  *	Bind a connection entry with a virtual service destination
  *	Called just after a new connection entry is created.

@@ -633,8 +627,7 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, s
 		 */
 		if (!(flags & IP_VS_CONN_F_INACTIVE))
 			atomic_inc(&dest->activeconns);
-		else
-			atomic_inc(&dest->inactconns);
+		atomic_inc(&dest->totalconns);
 	} else {
 		/* It is a persistent connection/template, so increase
 		   the persistent connection counter */

@@ -642,7 +635,7 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, s
 	}
 
 	if (dest->u_threshold != 0 &&
-	    ip_vs_dest_totalconns(dest) >= dest->u_threshold)
+	    atomic_read(&dest->totalconns) >= dest->u_threshold)
 		dest->flags |= IP_VS_DEST_F_OVERLOAD;
 }
 

@@ -724,13 +717,10 @@ static inline void ip_vs_unbind_dest(str
 
 	/* Update the connection counters */
 	if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
-		/* It is a normal connection, so decrease the inactconns
-		   or activeconns counter */
-		if (cp->flags & IP_VS_CONN_F_INACTIVE) {
-			atomic_dec(&dest->inactconns);
-		} else {
+		/* It is a normal connection, so decrease the counters */
+		if (!(cp->flags & IP_VS_CONN_F_INACTIVE))
 			atomic_dec(&dest->activeconns);
-		}
+		atomic_dec(&dest->totalconns);
 	} else {
 		/* It is a persistent connection/template, so decrease
 		   the persistent connection counter */

@@ -738,10 +728,10 @@ static inline void ip_vs_unbind_dest(str
 	}
 
 	if (dest->l_threshold != 0) {
-		if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
+		if (atomic_read(&dest->totalconns) < dest->l_threshold)
 			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 	} else if (dest->u_threshold != 0) {
-		if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
+		if (atomic_read(&dest->totalconns) * 4 < dest->u_threshold * 3)
 			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
 	} else {
 		if (dest->flags & IP_VS_DEST_F_OVERLOAD)

@@ -1011,7 +1011,7 @@ ip_vs_new_dest(struct ip_vs_service *svc
 	dest->port = udest->port;
 
 	atomic_set(&dest->activeconns, 0);
-	atomic_set(&dest->inactconns, 0);
+	atomic_set(&dest->totalconns, 0);
 	atomic_set(&dest->persistconns, 0);
 	refcount_set(&dest->refcnt, 1);
 

@@ -2225,7 +2225,7 @@ static int ip_vs_info_seq_show(struct se
 					   ip_vs_fwd_name(atomic_read(&dest->conn_flags)),
 					   atomic_read(&dest->weight),
 					   atomic_read(&dest->activeconns),
-					   atomic_read(&dest->inactconns));
+					   ip_vs_dest_inactconns(dest));
 			else
 #endif
 				seq_printf(seq,

@@ -2236,7 +2236,7 @@ static int ip_vs_info_seq_show(struct se
 					   ip_vs_fwd_name(atomic_read(&dest->conn_flags)),
 					   atomic_read(&dest->weight),
 					   atomic_read(&dest->activeconns),
-					   atomic_read(&dest->inactconns));
+					   ip_vs_dest_inactconns(dest));
 
 		}
 	}

@@ -2717,7 +2717,7 @@ __ip_vs_get_dest_entries(struct netns_ip
 			entry.u_threshold = dest->u_threshold;
 			entry.l_threshold = dest->l_threshold;
 			entry.activeconns = atomic_read(&dest->activeconns);
-			entry.inactconns = atomic_read(&dest->inactconns);
+			entry.inactconns = ip_vs_dest_inactconns(dest);
 			entry.persistconns = atomic_read(&dest->persistconns);
 			ip_vs_copy_stats(&kstats, &dest->stats);
 			ip_vs_export_stats_user(&entry.stats, &kstats);

@@ -3321,7 +3321,7 @@ static int ip_vs_genl_fill_dest(struct s
 	    nla_put_u32(skb, IPVS_DEST_ATTR_ACTIVE_CONNS,
 			atomic_read(&dest->activeconns)) ||
 	    nla_put_u32(skb, IPVS_DEST_ATTR_INACT_CONNS,
-			atomic_read(&dest->inactconns)) ||
+			ip_vs_dest_inactconns(dest)) ||
 	    nla_put_u32(skb, IPVS_DEST_ATTR_PERSIST_CONNS,
 			atomic_read(&dest->persistconns)) ||
 	    nla_put_u16(skb, IPVS_DEST_ATTR_ADDR_FAMILY, dest->af))

@@ -31,7 +31,7 @@ ip_vs_lc_schedule(struct ip_vs_service *
 
 	/*
 	 * Simply select the server with the least number of
-	 *        (activeconns<<5) + inactconns
+	 *        (activeconns*256) + totalconns
 	 * Except whose weight is equal to zero.
 	 * If the weight is equal to zero, it means that the server is
 	 * quiesced, the existing connections to the server still get

@@ -57,7 +57,7 @@ ip_vs_lc_schedule(struct ip_vs_service *
 			      IP_VS_DBG_ADDR(least->af, &least->addr),
 			      ntohs(least->port),
 			      atomic_read(&least->activeconns),
-			      atomic_read(&least->inactconns));
+			      ip_vs_dest_inactconns(least));
 
 	return least;
 }

@@ -446,12 +446,10 @@ set_sctp_state(struct ip_vs_proto_data *
 			if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 				(next_state != IP_VS_SCTP_S_ESTABLISHED)) {
 				atomic_dec(&dest->activeconns);
-				atomic_inc(&dest->inactconns);
 				cp->flags |= IP_VS_CONN_F_INACTIVE;
 			} else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 				   (next_state == IP_VS_SCTP_S_ESTABLISHED)) {
 				atomic_inc(&dest->activeconns);
-				atomic_dec(&dest->inactconns);
 				cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 			}
 		}

@@ -527,12 +527,10 @@ set_tcp_state(struct ip_vs_proto_data *p
 			if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
 			    !tcp_state_active(new_state)) {
 				atomic_dec(&dest->activeconns);
-				atomic_inc(&dest->inactconns);
 				cp->flags |= IP_VS_CONN_F_INACTIVE;
 			} else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
 				   tcp_state_active(new_state)) {
 				atomic_inc(&dest->activeconns);
-				atomic_dec(&dest->inactconns);
 				cp->flags &= ~IP_VS_CONN_F_INACTIVE;
 			}
 		}

@@ -879,13 +879,10 @@ static void ip_vs_proc_conn(struct netns
 		spin_lock_bh(&cp->lock);
 		if ((cp->flags ^ flags) & IP_VS_CONN_F_INACTIVE &&
 		    !(flags & IP_VS_CONN_F_TEMPLATE) && dest) {
-			if (flags & IP_VS_CONN_F_INACTIVE) {
+			if (flags & IP_VS_CONN_F_INACTIVE)
 				atomic_dec(&dest->activeconns);
-				atomic_inc(&dest->inactconns);
-			} else {
+			else
 				atomic_inc(&dest->activeconns);
-				atomic_dec(&dest->inactconns);
-			}
 		}
 		flags &= IP_VS_CONN_F_BACKUP_UPD_MASK;
 		flags |= cp->flags & ~IP_VS_CONN_F_BACKUP_UPD_MASK;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Julian Anastasov <[email protected]>

commit 8f843441c4e7eae8ea83491e8c203c2b192edcf5 upstream.

The upper/lower connection thresholds for dest can be changed, so use ip_vs_dest_update_overload() to properly update the dest overload flag.

The thresholds were not limited, fit them in the 0 .. INT_MAX range as already done in ipvsadm.

As the thresholds are also read when connections are created and expired, use WRITE_ONCE/READ_ONCE to access them.

As the lower threshold is optional, use (u - (u >> 2)) to calculate the 75% default value based on the upper threshold by preserving the integer rounding, as suggested by Yizhou Zhao.

Trigger flag update when totalconns reaches one of the thresholds and use dst_lock to serialize the updating.

---
 include/net/ip_vs.h             |    3 +
 net/netfilter/ipvs/ip_vs_conn.c |   27 +++++-----------
 net/netfilter/ipvs/ip_vs_ctl.c  |   67 +++++++++++++++++++++++++++++++++++-----
 3 files changed, 72 insertions(+), 25 deletions(-)

@@ -679,6 +679,7 @@ struct ip_vs_dest {
 	atomic_t		persistconns;	/* persistent connections */
 	__u32			u_threshold;	/* upper threshold */
 	__u32			l_threshold;	/* lower threshold */
+	__u32			l_threshold_val;/* used lower threshold */
 
 	/* for destination cache */
 	spinlock_t		dst_lock;	/* lock of dst_cache */

@@ -1468,6 +1469,8 @@ static inline void ip_vs_dest_put_and_fr
 		kfree(dest);
 }
 
+void ip_vs_dest_update_overload(struct ip_vs_dest *dest, int mode);
+
 /* IPVS sync daemon data and function prototypes
  * (from ip_vs_sync.c)
  */

@@ -621,22 +621,22 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, s
 
 	/* Update the connection counters */
 	if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
+		int tc;
+
 		/* It is a normal connection, so modify the counters
 		 * according to the flags, later the protocol can
 		 * update them on state change
 		 */
 		if (!(flags & IP_VS_CONN_F_INACTIVE))
 			atomic_inc(&dest->activeconns);
-		atomic_inc(&dest->totalconns);
+		tc = atomic_inc_return(&dest->totalconns);
+		if (tc == READ_ONCE(dest->u_threshold))
+			ip_vs_dest_update_overload(dest, 1);
 	} else {
 		/* It is a persistent connection/template, so increase
 		   the persistent connection counter */
 		atomic_inc(&dest->persistconns);
 	}
-
-	if (dest->u_threshold != 0 &&
-	    atomic_read(&dest->totalconns) >= dest->u_threshold)
-		dest->flags |= IP_VS_DEST_F_OVERLOAD;
 }
 
 

@@ -717,27 +717,20 @@ static inline void ip_vs_unbind_dest(str
 
 	/* Update the connection counters */
 	if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
+		int tc;
+
 		/* It is a normal connection, so decrease the counters */
 		if (!(cp->flags & IP_VS_CONN_F_INACTIVE))
 			atomic_dec(&dest->activeconns);
-		atomic_dec(&dest->totalconns);
+		tc = atomic_fetch_dec(&dest->totalconns);
+		if (tc == READ_ONCE(dest->l_threshold_val))
+			ip_vs_dest_update_overload(dest, -1);
 	} else {
 		/* It is a persistent connection/template, so decrease
 		   the persistent connection counter */
 		atomic_dec(&dest->persistconns);
 	}
 
-	if (dest->l_threshold != 0) {
-		if (atomic_read(&dest->totalconns) < dest->l_threshold)
-			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
-	} else if (dest->u_threshold != 0) {
-		if (atomic_read(&dest->totalconns) * 4 < dest->u_threshold * 3)
-			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
-	} else {
-		if (dest->flags & IP_VS_DEST_F_OVERLOAD)
-			dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
-	}
-
 	ip_vs_dest_put(dest);
 }
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Kyle Zeng <[email protected]>

commit e0ba936287dfe9783426aac27e5fd76fe35b38c9 upstream.

ip_vs_in_icmp() rebases an skb from the outer ICMP packet to the quoted original request before passing it to icmp_send(). However, IPCB(skb)->opt still describes the outer IPv4 header.

A timestamp option in the outer header can therefore leave an offset that points into the quoted transport header after the rebase. __ip_options_echo() treats a byte at that stale location as the option length and copies it into the fixed-size option storage on the __icmp_send() stack, causing a stack out-of-bounds write.

Clear the stale option metadata after resetting the network header. Keep the remaining control block fields, including the ingress interface used by the ICMP response path.

---
 net/netfilter/ipvs/ip_vs_core.c |    1 +
 1 file changed, 1 insertion(+)

@@ -1777,6 +1777,7 @@ ip_vs_in_icmp(struct netns_ipvs *ipvs, s
 		if (pskb_pull(skb, offset2) == NULL)
 			goto ignore_tunnel;
 		skb_reset_network_header(skb);
+		memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 		/* Ensure the IP header is present in headroom */
 		if (!pskb_may_pull(skb, hlen_orig))
 			goto ignore_tunnel;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Doruk Tan Ozturk <[email protected]>

commit c2707480cfbf19c7619acc9c089d17f20869821f upstream.

packet_parse_headers() resets the MAC header only for a SOCK_RAW frame whose socket did not bind a protocol. A protocol-bound SOCK_RAW socket, any SOCK_DGRAM frame, and the legacy SOCK_PACKET path therefore leave skb->mac_header unset here.

For frames sent via __dev_queue_xmit() this is harmless: it resets the MAC header unconditionally. But the packet-socket PACKET_QDISC_BYPASS path uses dev_direct_xmit(), which does not, so the frame reaches ndo_start_xmit() with the MAC header unset. A driver that reads eth_hdr(skb) on transmit then dereferences skb->head + (u16)~0, an out-of-bounds access ~64 KiB past the head -- the same class fixed for one consumer in commit f5089008f90c ("macsec: do not read an unset MAC header in macsec_encrypt()").

packet_parse_headers() runs only on the transmit path, where skb->data points at the start of the L2 header for every packet-socket type regardless of its length: SOCK_RAW and SOCK_PACKET carry a user-supplied header and SOCK_DGRAM has one built by dev_hard_header(). Reset the MAC header unconditionally, mirroring __dev_queue_xmit(), so the frame is anchored on the bypass path too.

Found by 0sec (https://0sec.ai) using automated source analysis; verified against source and matched to the macsec KASAN report in f5089008f90c. Compile-tested.

---
 net/packet/af_packet.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

@@ -1978,11 +1978,12 @@ static void packet_parse_headers(struct
 {
 	int depth;
 
+	/* On TX skb->data is the L2 header; anchor it for all socket types. */
+	skb_reset_mac_header(skb);
+
 	if ((!skb->protocol || skb->protocol == htons(ETH_P_ALL)) &&
-	    sock->type == SOCK_RAW) {
-		skb_reset_mac_header(skb);
+	    sock->type == SOCK_RAW)
 		skb->protocol = dev_parse_header_protocol(skb);
-	}
 
 	/* Move network header to the right position for VLAN tagged packets */
 	if (likely(skb->dev->type == ARPHRD_ETHER) &&

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zhiling Zou <[email protected]>

commit 5d1c224dd914579524a183a514c12b95095d12ce upstream.

ovs_flow_cmd_new() preallocates the optional reply skb before it takes ovs_mutex and before it knows which existing flow will be updated.

That is normally fine because the skb is sized from the request flow identifier. That identifier also becomes the inserted flow's identifier. For updates, however, a request with a UFID may miss the UFID lookup and then fall back to the flow key lookup. That lookup can legitimately find an existing key-identified flow. UFIDs are optional and the flow key is the primary identifier.

For echoed replies, ovs_flow_cmd_fill_info() writes the matched flow's identifier, not the request identifier used for the preallocation. A short request UFID can therefore leave too little room for the key identifier. The fill can then fail with -EMSGSIZE and hit the BUG_ON(error < 0) in the update path.

Once the update target has been resolved, reallocate the reply skb if the matched flow needs a larger reply than the request identifier allowed. Do this before replacing the actions so the request can still fail cleanly if the rare extra allocation fails.

---
 net/openvswitch/datapath.c |   29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

@@ -1060,9 +1060,8 @@ static int ovs_flow_cmd_new(struct sk_bu
 			error = -EEXIST;
 			goto err_unlock_ovs;
 		}
-		/* The flow identifier has to be the same for flow updates.
-		 * Look for any overlapping flow.
-		 */
+
+		/* Look for any overlapping flow. */
 		if (unlikely(!ovs_flow_cmp(flow, &match))) {
 			if (ovs_identifier_is_key(&flow->id))
 				flow = ovs_flow_tbl_lookup_exact(&dp->table,

@@ -1074,6 +1073,30 @@ static int ovs_flow_cmd_new(struct sk_bu
 				goto err_unlock_ovs;
 			}
 		}
+
+		if (unlikely(reply)) {
+			size_t cur, req;
+
+			cur = ovs_flow_cmd_msg_size(acts, &new_flow->id,
+						    ufid_flags);
+			req = ovs_flow_cmd_msg_size(acts, &flow->id,
+						    ufid_flags);
+			if (cur < req) {
+				struct sk_buff *resized;
+
+				resized = ovs_flow_cmd_alloc_info(acts,
+								  &flow->id,
+								  info, false,
+								  ufid_flags);
+				if (IS_ERR(resized)) {
+					error = PTR_ERR(resized);
+					goto err_unlock_ovs;
+				}
+				kfree_skb(reply);
+				reply = resized;
+			}
+		}
+
 		/* Update actions. */
 		old_acts = ovsl_dereference(flow->sf_acts);
 		rcu_assign_pointer(flow->sf_acts, acts);

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zijie Huang <[email protected]>

commit dedd34b0f2310e28c5f6d4875cfbf4b7ed821c01 upstream.

Deep qdisc hierarchies can lead to excessive recursion in qdisc tree walkers and exhaust the kernel stack. The existing loop check does not cover the create-and-graft path, so a hierarchy can still be extended by creating a new child qdisc below an already deep parent.

Store the hierarchy depth in struct Qdisc and update it when qdiscs are grafted. Reject new child qdiscs once the parent is already at the maximum allowed depth.

---
 include/net/sch_generic.h |    1 +
 net/sched/sch_api.c       |    9 +++++++++
 2 files changed, 10 insertions(+)

@@ -100,6 +100,7 @@ struct Qdisc {
 	struct hlist_node       hash;
 	u32			handle;
 	u32			parent;
+	int			depth;
 
 	struct netdev_queue	*dev_queue;
 

@@ -1063,6 +1063,9 @@ static int qdisc_graft(struct net_device
 		unsigned int i, num_q, ingress;
 		struct netdev_queue *dev_queue;
 
+		if (new)
+			new->depth = 0;
+
 		ingress = 0;
 		num_q = dev->num_tx_queues;
 		if ((q && q->flags & TCQ_F_INGRESS) ||

@@ -1160,9 +1163,15 @@ skip:
 			NL_SET_ERR_MSG(extack, "STAB not supported on a non root");
 			return -EINVAL;
 		}
+		if (new && parent->depth >= 7) {
+			NL_SET_ERR_MSG(extack, "Qdisc hierarchy is too deep");
+			return -E2BIG;
+		}
 		err = cops->graft(parent, cl, new, &old, extack);
 		if (err)
 			return err;
+		if (new)
+			new->depth = parent->depth + 1;
 		notify_and_destroy(net, skb, n, classid, old, new, extack);
 	}
 	return 0;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Sergey V. Frolov <[email protected]>

commit 7e2d693af0d4c05bddccb3541a0aabd69f4cb244 upstream.

In function otx2_get_egress_burst_cfg, when the parameter burst is 255 and the max mantissa is 255 (0xFFULL), burst_exp is set to ilog2(255) - 1, which equals 6.

This results in an unsigned wrap-around when calculating (1ULL << (*burst_exp - 7)), since *burst_exp - 7 becomes -1, which makes the shift operand 0xFFFFFFFF. This value is greater than the width of the left operand.

According to standard 6.5.7 p.3:
"The type of the result is that of the promoted left operand. If the value of the right operand is negative or is greater than or equal to the width of the promoted left operand, the behavior is undefined."

Fix the off-by-one boundary condition.

Add a WARN_ON(*burst_exp < 7) before the else branch as an explicit safeguard. This ensures that if max_mantissa ever changes in a way that reintroduces this condition, it will be immediately caught at runtime rather than silently triggering UB.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

---
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_tc.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -86,10 +86,12 @@ static void otx2_get_egress_burst_cfg(st
 	if (burst) {
 		*burst_exp = ilog2(burst) ? ilog2(burst) - 1 : 0;
 		tmp = burst - rounddown_pow_of_two(burst);
-		if (burst < max_mantissa)
+		if (burst <= max_mantissa) {
 			*burst_mantissa = tmp * 2;
-		else
+		} else {
+			WARN_ON(*burst_exp < 7);
 			*burst_mantissa = tmp / (1ULL << (*burst_exp - 7));
+		}
 	} else {
 		*burst_exp = MAX_BURST_EXPONENT;
 		*burst_mantissa = max_mantissa;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Qihang Tang <[email protected]>

commit 3b9a324e646d3657a8d9806dfbfe4f3e4066e882 upstream.

dev_validate_header() reads dev->hard_header_len directly when zero-padding short link layer headers for CAP_SYS_RAWIO holders:

    if (capable(CAP_SYS_RAWIO)) {
        memset(ll_header + len, 0, dev->hard_header_len - len);
        return true;
    }

Packet send paths call dev_validate_header() on skbs whose headroom was allocated from an earlier hard_header_len read. If the device is reconfigured so that dev->hard_header_len increases before validation, the memset writes past the reserved buffer, an out-of-bounds write.

This out-of-bounds write is masked in some SOCK_RAW paths today because the same concurrent increase can first make skb_push() exceed the reserved headroom and trigger skb_under_panic(). Remove the zero-padding branch before making those hard_header_len reads consistent, so the snapshot fixes do not turn a loud panic into a silent overwrite.

This path is only reached for variable length L2 protocols, where len < hard_header_len but len >= min_header_len. No remaining in-tree variable length L2 protocol implements header_ops->validate, and the CAP_SYS_RAWIO bypass that zero-pads and accepts short headers has no real value beyond allowing testing of intentionally malformed input.

Drop the CAP_SYS_RAWIO branch. The remaining reads of dev->hard_header_len in dev_validate_header() are comparisons only and have no memory safety impact.

---
 include/linux/netdevice.h |    5 -----
 1 file changed, 5 deletions(-)

@@ -3131,11 +3131,6 @@ static inline bool dev_validate_header(c
 	if (len < dev->min_header_len)
 		return false;
 
-	if (capable(CAP_SYS_RAWIO)) {
-		memset(ll_header + len, 0, dev->hard_header_len - len);
-		return true;
-	}
-
 	if (dev->header_ops && dev->header_ops->validate)
 		return dev->header_ops->validate(ll_header, len);
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Chengfeng Ye <[email protected]>

commit 30825970339c107bacaf7f61af90fcdb1f597ca1 upstream.

nf_log_unregister() runs after the per-net teardown so its final RCU grace period also drains readers that obtained the logger from a per-net binding. However, ebt_nflog passes an explicit ULOG log type to nf_log_packet() without holding a reference on the selected logger module, unlike the xt_NFLOG and nft_log frontends.

An ebtables nflog rule can therefore remain callable while nfnetlink_log is unloaded. The resulting interleaving is:

CPU 0 CPU 1
nfnetlink_log_fini()

    unregister_pernet_subsys()
      kfree(nfnl_log_pernet(net))
                                      ebt_nflog_tg()
                                        nf_log_packet()
                                          nfulnl_log_packet()
                                            instance_lookup_get_rcu()

The global ULOG logger is still registered at this point, so CPU 1 dereferences the per-net state after CPU 0 has freed it. KASAN reported:

  BUG: KASAN: slab-use-after-free in instance_lookup_get_rcu
  Read of size 8 at addr ff110001052e6210 by task poc/92
  Call Trace:
   instance_lookup_get_rcu+0x1ce/0x1f0 [nfnetlink_log]
   nfulnl_log_packet+0x248/0x2fb0 [nfnetlink_log]
   nf_log_packet+0x204/0x300
   ebt_nflog_tg+0x351/0x550
   ebt_do_table+0xedf/0x22b0
  Allocated by task 90:
   __kmalloc_noprof+0x186/0x470
   ops_init+0x6d/0x420
   register_pernet_operations+0x2f6/0x670
   register_pernet_subsys+0x23/0x40
  Freed by task 93:
   kfree+0x131/0x3c0
   ops_undo_list+0x3e3/0x700
   unregister_pernet_operations+0x232/0x490
   unregister_pernet_subsys+0x1c/0x30
   nfnetlink_log_fini+0x34/0x450 [nfnetlink_log]

Acquire the ULOG logger module reference when an ebt_nflog rule is validated and release it when the rule is destroyed. Request the NFLOG backend for legacy callers when needed, matching xt_NFLOG. This prevents module teardown until all ebt_nflog rules have stopped using the logger.

---
 net/bridge/netfilter/ebt_nflog.c |   17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

@@ -41,11 +41,25 @@ ebt_nflog_tg(struct sk_buff *skb, const
 static int ebt_nflog_tg_check(const struct xt_tgchk_param *par)
 {
 	struct ebt_nflog_info *info = par->targinfo;
+	int ret;
 
 	if (info->flags & ~EBT_NFLOG_MASK)
 		return -EINVAL;
 	info->prefix[EBT_NFLOG_PREFIX_SIZE - 1] = '\0';
-	return 0;
+
+	ret = nf_logger_find_get(par->family, NF_LOG_TYPE_ULOG);
+	if (ret != 0 && !par->nft_compat) {
+		request_module("%s", "nfnetlink_log");
+
+		ret = nf_logger_find_get(par->family, NF_LOG_TYPE_ULOG);
+	}
+
+	return ret;
+}
+
+static void ebt_nflog_tg_destroy(const struct xt_tgdtor_param *par)
+{
+	nf_logger_put(par->family, NF_LOG_TYPE_ULOG);
 }
 
 static struct xt_target ebt_nflog_tg_reg __read_mostly = {

@@ -54,6 +68,7 @@ static struct xt_target ebt_nflog_tg_reg
 	.family     = NFPROTO_BRIDGE,
 	.target     = ebt_nflog_tg,
 	.checkentry = ebt_nflog_tg_check,
+	.destroy    = ebt_nflog_tg_destroy,
 	.targetsize = sizeof(struct ebt_nflog_info),
 	.me         = THIS_MODULE,
 };

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Baul Lee <[email protected]>

commit 63488dba65ef91373ef616575b32eb0eb21459f4 upstream.

br_mrp_alloc_test_skb() builds MRP test frames on an skb from dev_alloc_skb(), which does not clear the linear data area. On the MRA ring-role branch the sub-option TLV header is appended with

	sub_tlv = skb_put(skb, sizeof(*sub_tlv));
	sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;

so sub_tlv->length is never written, and the two trailing alignment bytes are appended with a bare skb_put() that does not clear them either. The neighbouring oui and sub_opt regions are explicitly zeroed, so three uninitialised bytes are left in every MRA MRP_Test frame that goes out.

Put the sub-option TLV header and the alignment padding in a single skb_put_zero(), which clears both. The AUTO_MGR sub-TLV carries no payload, so the zeroed length field is already the value it should have.

---
 net/bridge/br_mrp.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

@@ -224,11 +224,9 @@ static struct sk_buff *br_mrp_alloc_test
 		sub_opt = skb_put(skb, sizeof(*sub_opt));
 		memset(sub_opt, 0x0, sizeof(*sub_opt));
 
-		sub_tlv = skb_put(skb, sizeof(*sub_tlv));
-		sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;
-
 		/* 32 bit alligment shall be ensured therefore add 2 bytes */
-		skb_put(skb, MRP_OPT_PADDING);
+		sub_tlv = skb_put_zero(skb, sizeof(*sub_tlv) + MRP_OPT_PADDING);
+		sub_tlv->type = BR_MRP_SUB_TLV_HEADER_TEST_AUTO_MGR;
 	}
 
 	br_mrp_skb_tlv(skb, BR_MRP_TLV_HEADER_END, 0x0);

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Keno Fischer <[email protected]>

commit 6d4514ca9cdf61fec4ec634cf50386f6f7e69748 upstream.

A robust futex unlock stores 0 over the whole futex value - wiping FUTEX_WAITERS - and wakes a single waiter. That wakeup is a one-shot
notification: the protocol relies on its recipient to either acquire the futex (and eventually unlock while aware of the remaining contention) or re-arm FUTEX_WAITERS before sleeping again. If the woken waiter is killed before it can do either, the kernel must jump in and wake the next task down the line.

This is a known complication of the futex protocol with a previous partial fix in commit ca16d5bee598 ("futex: Prevent robust futex exit race"). Unfortunately, that fix is insufficient.

If a third task re-acquired the futex through the uncontended fast path in the meantime, the notification is lost: robust exit processing sees that it is owned by another task and does nothing, while the new owner sees no FUTEX_WAITERS when it unlocks and wakes nobody. The remaining waiters sleep forever behind a free futex:

A owns the futex, B and C sleep in FUTEX_WAIT

                                        uval == A | FUTEX_WAITERS
  A robust unlock: store 0, FUTEX_WAKE(1) wakes B
                                        uval == 0
  D fast path acquire: cmpxchg(0 -> D)
                                        uval == D, no FUTEX_WAITERS

B killed before acting on the wakeup
B exit walk, pending op: owner D != B -> no action D unlock: no FUTEX_WAITERS -> no wake
C sleeps forever

This is clearly a shortcoming in the implementation, which fails to keep the FUTEX_WAITERS bit consistent.

Work around this by augmenting the robust list exit processing to also perform the extra wakeup if the futex word is owned by another thread but FUTEX_WAITERS is not set.

This does not fix the problem of a non-contended take over/release and free sequence, which has been discussed for years and has been addressed by commit 3ca9595d9fb6 ("futex: Add support for unlocking robust futexes") and subsequent changes, but failed to take the problem described above into account.

A more complete solution which is based on the in kernel unlock of contended robust futexes has been discussed in the context of this change and should show up in mainline sooner than later.

[ tglx: Amend change log slightly and fixup coding style ]

---
 kernel/futex/core.c | 82 +++++++++++++++++++++++++++++++--------------
 1 file changed, 56 insertions(+), 26 deletions(-)

index d4141b0547187..b370fdea7c217 100644
@@ -660,8 +660,11 @@ static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr,
 		return -1;
 
 	/*
-	 * Special case for regular (non PI) futexes. The unlock path in
-	 * user space has two race scenarios:
+	 * Special case for regular (non PI) futexes. Ordinarily, we do
+	 * not perform any processing here unless the current thread was
+	 * the owner of the futex (by the TID check below).
+	 *
+	 * However, the unlock path has three race scenarios:
 	 *
 	 * 1. The unlock path releases the user space futex value and
 	 *    before it can execute the futex() syscall to wake up

@@ -670,41 +673,68 @@ static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr,
 	 * 2. A woken up waiter is killed before it can acquire the
 	 *    futex in user space.
 	 *
-	 * In the second case, the wake up notification could be generated
-	 * by the unlock path in user space after setting the futex value
-	 * to zero or by the kernel after setting the OWNER_DIED bit below.
+	 * 3. A woken up waiter is killed in user space after another
+	 *    thread has acquired the futex, but before it can set
+	 *    FUTEX_WAITERS.
+	 *
+	 * Note that, if userspace uses the FUTEX_ROBUST_UNLOCK flag, we
+	 * will not see case 1 here.
+	 *
+	 * In the second and third case, the wake up notification could
+	 * be generated from any of:
+	 *
+	 *    i.   An ordinary futex wakeup after unlock (with or
+	 *         without FUTEX_ROBUST_UNLOCK)
+	 *    ii.  A robust wakeup from another thread's death
+	 *    iii. A previous round through this special case
+	 *
+	 * As a result, the futex world will be in one of four states:
 	 *
-	 * In both cases the TID validation below prevents a wakeup of
-	 * potential waiters which can cause these waiters to block
-	 * forever.
+	 *    A. The futex word is 0 (unlocked)
+	 *    B. The futex word is owned by another thread
+	 *       (FUTEX_WAITERS is not set)
+	 *    C. The futex word is owned by another thread
+	 *       (FUTEX_WAITERS set)
+	 *    D. The futex's owner died and OWNER_DIED is set
+	 *       (the owner part of the word is 0)
 	 *
-	 * In both cases the following conditions are met:
+	 * The key issue is that the kernel usually (at least from
+	 * sources ii. and iii. or when so requested by userspace from
+	 * source i.) only ever wakes *one* waiter at a time. If this
+	 * waiter dies before acquiring the futex (or setting the
+	 * FUTEX_WAITERS bit), the kernel *must* still wake the next
+	 * waiter down the line to uphold the futex invariants and
+	 * avoid lost wakeups. Note we do not need to handle state C,
+	 * as it does not matter to us whether *we* successfully set
+	 * the bit or a third thread did so in the meantime.
 	 *
-	 *	1) task->robust_list->list_op_pending != NULL
-	 *	   @pending_op == true
-	 *	2) The owner part of user space futex value == 0
+	 * Therefore, in these cases we must issue an additional
+	 * futex_wake(). Note however that we *must not* set OWNER_DIED
+	 * here. Our thread is *not* the owner of the futex.
+	 *
+	 * Thus to summarize, the conditions for needing the additional
+	 * futex_wake() are:
+	 *
+	 *	1) @pending_op == true (the thread has not finished the
+	 *	   mutex operation)
+	 *	2) The futex word is in one of the states A, B or D
 	 *	3) Regular futex: @pi == false
 	 *
-	 * If these conditions are met, it is safe to attempt waking up a
-	 * potential waiter without touching the user space futex value and
-	 * trying to set the OWNER_DIED bit. If the futex value is zero,
-	 * the rest of the user space mutex state is consistent, so a woken
-	 * waiter will just take over the uncontended futex. Setting the
-	 * OWNER_DIED bit would create inconsistent state and malfunction
-	 * of the user space owner died handling. Otherwise, the OWNER_DIED
-	 * bit is already set, and the woken waiter is expected to deal with
-	 * this.
+	 * Note in particular that in all of the states A-D the owner
+	 * portion of the futex word differs from our thread's TID
+	 * (unless the actual owner has the same TID in another PID
+	 * namespace, but we cannot currently distinguish that
+	 * scenario), so this can be a special-case wakeup in the bail
+	 * path of the ordinary TID check.
 	 */
 	owner = uval & FUTEX_TID_MASK;
 
-	if (pending_op && !pi && !owner) {
-		futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
+	if (owner != task_pid_vnr(curr)) {
+		if (pending_op && !pi && (!owner || !(uval & FUTEX_WAITERS)))
+			futex_wake(uaddr, 1, 1, FUTEX_BITSET_MATCH_ANY);
 		return 0;
 	}
 
-	if (owner != task_pid_vnr(curr))
-		return 0;
-
 	/*
 	 * Ok, this dying thread is truly holding a futex
 	 * of interest. Set the OWNER_DIED bit atomically

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Masahiro Yamada <[email protected]>

commit 4e9903b0861c9df3464b82db4a7025863bac1897 upstream.

There are some issues in the test_fortify Makefile code.

Problem 1: cc-disable-warning invokes compiler dozens of times

To see how many times the cc-disable-warning is evaluated, change this code:

  $(call cc-disable-warning,fortify-source)

to:

  $(call cc-disable-warning,$(shell touch /tmp/fortify-$$$$)fortify-source)

Then, build the kernel with CONFIG_FORTIFY_SOURCE=y. You will see a large number of '/tmp/fortify-<PID>' files created:

  $ ls -1 /tmp/fortify-* | wc
       80      80    1600

This means the compiler was invoked 80 times just for checking the -Wno-fortify-source flag support.

$(call cc-disable-warning,fortify-source) should be added to a simple variable instead of a recursive variable.

Problem 2: do not recompile string.o when the test code is updated

The test cases are independent of the kernel. However, when the test code is updated, $(obj)/string.o is rebuilt and vmlinux is relinked due to this dependency:

  $(obj)/string.o: $(obj)/$(TEST_FORTIFY_LOG)

always-y is suitable for building the log files.

Problem 3: redundant code

  clean-files += $(addsuffix .o, $(TEST_FORTIFY_LOGS))

... is unneeded because the top Makefile globally cleans *.o files.

This commit fixes these issues and makes the code readable.

---
 lib/.gitignore              |  2 --
 lib/Makefile                | 34 +---------------------------------
 lib/test_fortify/.gitignore |  2 ++
 lib/test_fortify/Makefile   | 28 ++++++++++++++++++++++++++++
 scripts/remove-stale-files  |  2 ++
 5 files changed, 33 insertions(+), 35 deletions(-)
 create mode 100644 lib/test_fortify/.gitignore
 create mode 100644 lib/test_fortify/Makefile

index 54596b634ecbf..101a4aa92fb53 100644
@@ -5,5 +5,3 @@
 /gen_crc32table
 /gen_crc64table
 /oid_registry_data.c
-/test_fortify.log
-/test_fortify/*.log

index 6ae66e13f3194..1081d0c161159 100644
@@ -394,36 +394,4 @@ CFLAGS_longest_symbol_kunit.o += $(call cc-disable-warning, missing-prototypes)
 
 obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o
 
-# FORTIFY_SOURCE compile-time behavior tests
-TEST_FORTIFY_SRCS = $(wildcard $(srctree)/$(src)/test_fortify/*-*.c)
-TEST_FORTIFY_LOGS = $(patsubst $(srctree)/$(src)/%.c, %.log, $(TEST_FORTIFY_SRCS))
-TEST_FORTIFY_LOG = test_fortify.log
-
-quiet_cmd_test_fortify = TEST    $@
-      cmd_test_fortify = $(CONFIG_SHELL) $(srctree)/scripts/test_fortify.sh \
-			$< $@ "$(NM)" $(CC) $(c_flags) \
-			$(call cc-disable-warning,fortify-source) \
-			-DKBUILD_EXTRA_WARN1
-
-targets += $(TEST_FORTIFY_LOGS)
-clean-files += $(TEST_FORTIFY_LOGS)
-clean-files += $(addsuffix .o, $(TEST_FORTIFY_LOGS))
-$(obj)/test_fortify/%.log: $(src)/test_fortify/%.c \
-			   $(src)/test_fortify/test_fortify.h \
-			   $(srctree)/include/linux/fortify-string.h \
-			   $(srctree)/scripts/test_fortify.sh \
-			   FORCE
-	$(call if_changed,test_fortify)
-
-quiet_cmd_gen_fortify_log = GEN     $@
-      cmd_gen_fortify_log = cat </dev/null $(filter-out FORCE,$^) 2>/dev/null > $@ || true
-
-targets += $(TEST_FORTIFY_LOG)
-clean-files += $(TEST_FORTIFY_LOG)
-$(obj)/$(TEST_FORTIFY_LOG): $(addprefix $(obj)/, $(TEST_FORTIFY_LOGS)) FORCE
-	$(call if_changed,gen_fortify_log)
-
-# Fake dependency to trigger the fortify tests.
-ifeq ($(CONFIG_FORTIFY_SOURCE),y)
-$(obj)/string.o: $(obj)/$(TEST_FORTIFY_LOG)
-endif
+subdir-$(CONFIG_FORTIFY_SOURCE) += test_fortify

new file mode 100644
index 0000000000000..c1ba37d14b50e
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+/*.log

new file mode 100644
index 0000000000000..7887e6126e79c
@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0
+
+ccflags-y := $(call cc-disable-warning,fortify-source)
+
+quiet_cmd_test_fortify = TEST    $@
+      cmd_test_fortify = $(CONFIG_SHELL) $(srctree)/scripts/test_fortify.sh \
+			$< $@ "$(NM)" $(CC) $(c_flags) -DKBUILD_EXTRA_WARN1
+
+$(obj)/%.log: $(src)/%.c $(srctree)/scripts/test_fortify.sh \
+	      $(src)/test_fortify.h \
+	      $(srctree)/include/linux/fortify-string.h \
+	      FORCE
+	$(call if_changed,test_fortify)
+
+logs = $(patsubst $(srctree)/$(src)/%.c, %.log, $(wildcard $(srctree)/$(src)/*-*.c))
+targets += $(logs)
+
+quiet_cmd_gen_fortify_log = CAT     $@
+      cmd_gen_fortify_log = cat $(or $(real-prereqs),/dev/null) > $@
+
+$(obj)/test_fortify.log: $(addprefix $(obj)/, $(logs)) FORCE
+	$(call if_changed,gen_fortify_log)
+
+always-y += test_fortify.log
+
+# Some architectures define __NO_FORTIFY if __SANITIZE_ADDRESS__ is undefined.
+# Pass CFLAGS_KASAN to avoid warnings.
+KASAN_SANITIZE := y

index ccadfa3afb2b8..c22fe4630bac0 100755
@@ -47,3 +47,5 @@ rm -f arch/riscv/purgatory/kexec-purgatory.c
 rm -f scripts/extract-cert
 
 rm -f arch/x86/purgatory/kexec-purgatory.c
+
+rm -f lib/test_fortify.log

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Nathan Chancellor <[email protected]>

commit c1f3e770eec26d6f96dd6d2ea30555ba7c09a244 upstream.

clang recently added support for -Wstringop-overread [1], which is on by default like -Wfortify-source. This breaks the usage of -Werror in the fortify tests, resulting in the following false positive warnings in the kernel build:

warning: unsafe memcmp() usage lacked '__read_overflow2' warning in lib/test_fortify/read_overflow2-memcmp.c
warning: unsafe memcmp() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memcmp.c
warning: unsafe memchr() usage lacked '__read_overflow' warning in lib/test_fortify/read_overflow-memchr.c

Examining the fortify test logs shows a warning like the following in each of the failed logs:

In file included from lib/test_fortify/read_overflow2-memcmp.c:5:
lib/test_fortify/test_fortify.h:34:2: error: 'memcmp' reading 17 bytes from a region of size 16 [-Werror,-Wstringop-overread]

     34 |         TEST;
        |         ^
  lib/test_fortify/read_overflow2-memcmp.c:3:2: note: expanded from macro 'TEST'
      3 |         memcmp(large, small, sizeof(small) + 1)
        |         ^

1 error generated.

Disable -Wstringop-overread for the fortify tests, as it defeats the purpose of testing the Linux specific implementation of fortify, like -Wfortify-source.

---
 lib/test_fortify/Makefile | 1 +
 1 file changed, 1 insertion(+)

index 7887e6126e79c..eba2ba0faeb6a 100644
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 ccflags-y := $(call cc-disable-warning,fortify-source)
+ccflags-y += $(call cc-disable-warning,stringop-overread)
 
 quiet_cmd_test_fortify = TEST    $@
       cmd_test_fortify = $(CONFIG_SHELL) $(srctree)/scripts/test_fortify.sh \

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Claudiu Beznea <[email protected]>

commit c1492da3939c89372929e062d731f328f7693f1e upstream.

The pinctrl and GPIO core code make exceptions for the -ENOTSUPP error code. One such example is gpio_set_config_with_argument_optional(), which returns success when gpio_set_config_with_argument() returns -ENOTSUPP, but reports failure for all other error codes.

Returning -EOPNOTSUPP from the pinctrl driver on the unsupported pinctrl operation may lead to boot failures when pinctrl drivers implements struct gpio_chip::set_config, the system uses GPIO hogs, and the struct gpio_chip::set_config implementation returns -EOPNOTSUPP for the unsupported operations.

Return -ENOTSUPP for the unsupported pinctrl operation.

[claudiu.beznea: fixed conflict by dropping the code not present in
v6.1 stable]

---
 drivers/pinctrl/renesas/pinctrl-rzg2l.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 1304ab0bcac1e..85bcc9bbe6770 100644
@@ -708,7 +708,7 @@ static int rzg2l_pinctrl_pinconf_set(struct pinctrl_dev *pctldev,
 		}
 
 		default:
-			return -EOPNOTSUPP;
+			return -ENOTSUPP;
 		}
 	}
 

@@ -757,7 +757,7 @@ static int rzg2l_pinctrl_pinconf_group_get(struct pinctrl_dev *pctldev,
 
 		/* Check config matching between to pin  */
 		if (i && prev_config != *config)
-			return -EOPNOTSUPP;
+			return -ENOTSUPP;
 
 		prev_config = *config;
 	}

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zhu Yanjun <[email protected]>

[ Upstream commit 35744ab3d03c5fca8c1752f53fc8fc674e14c561 ]

rxe_mmap() removes a rxe_mmap_info struct from the pending_mmaps list and releases pending_lock while the struct's kref is still at 1:

list_del_init(&ip->pending_mmaps);
spin_unlock_bh(&rxe->pending_lock); /* ref == 1, no lock held */
ret = remap_vmalloc_range(vma, ip->obj, 0); /* walks PTEs */ [...]
rxe_vma_open(vma); /* kref_get, ref → 2 */
remap_vmalloc_range_partial() walks PTEs without any lock.

A concurrent DESTROY_CQ ioctl on another CPU calls:

    kref_put(&q->ip->ref, rxe_mmap_release)   /* ref 1→0 */
    vfree(ip->obj)   /* clears vmalloc PTEs mid-walk */
    kfree(ip)        /* frees rxe_mmap_info */

This yields:

1. Kernel crash, vmalloc_to_page() returns NULL when vfree wins the per-PTE race -> vm_insert_page(NULL) → GPF in validate_page_before_insert

2. Page UAF, vmalloc_to_page() reads a stale PTE before vfree clears it. User VMA holds a PTE to a free'd page which might eventually get reallocated later by vmalloc which allows the attacker to get a clean page-level UAF.

It is worth noting that even though a page-level UAF is possible given the strong primitive, it is statistically very difficult to achieve given the very short time window (after the last insert_page and before the kref_get).

The call trace are as below:

  Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
  KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
  CPU: 0 UID: 1000 PID: 413 Comm: poc Not tainted 7.0.0-rc5-dirty #28 PREEMPT(lazy)
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
  RIP: 0010:validate_page_before_insert+0x32/0x300
  Code: e5 41 57 41 56 49 89 fe 41 55 41 54 53 48 89 f3 e8 93 b5 a3 ff 48 8d 7b 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 7b 02 00 00 4c 8b 63 08 31 ff 4d 89 e5 41 83 e5
  RSP: 0018:ffff88811b15f2f0 EFLAGS: 00000202
  RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
  RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000008
  RBP: ffff88811b15f318 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881181eee00
  R13: 0000000000000000 R14: ffff8881181eee00 R15: ffff8881181eee20
  FS:  00007b1e000f76c0(0000) GS:ffff8884268e0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007b1e00a24ac0 CR3: 0000000116eb3000 CR4: 00000000000006f0
  Call Trace:
   <TASK>
   insert_page+0x8f/0x190
   ? __pfx_insert_page+0x10/0x10
   ? kasan_save_alloc_info+0x38/0x60
   vm_insert_page+0x2e7/0x400
   remap_vmalloc_range_partial+0x212/0x3e0
   remap_vmalloc_range+0x6e/0xb0
   ? __kasan_check_write+0x14/0x30
   rxe_mmap+0x2e9/0x5d0
   ib_uverbs_mmap+0x1ad/0x2c0
   __mmap_region+0x12c2/0x2ad0
   ? __pfx___mmap_region+0x10/0x10
   ? __sanitizer_cov_trace_switch+0x58/0xb0
   ? mas_prev_slot+0x360/0x39c0
   ? __sanitizer_cov_trace_switch+0x58/0xb0
   ? mas_next_slot+0x1e5b/0x2f40
   ? __sanitizer_cov_trace_cmp8+0x18/0x30
   ? unmapped_area_topdown+0x4dd/0x610
   ? kfree+0x1b1/0x440
   ? free_cpumask_var+0x16/0x30
   ? __kasan_slab_free+0x7d/0xa0
   ? __sanitizer_cov_trace_cmp8+0x18/0x30
   mmap_region+0x2e6/0x3c0
   do_mmap+0xa3e/0x12a0
   ? __pfx_do_mmap+0x10/0x10
   ? __kasan_check_write+0x14/0x30
   ? down_write_killable+0xba/0x160
   ? __pfx_down_write_killable+0x10/0x10
   ? __sanitizer_cov_trace_cmp4+0x16/0x30
   vm_mmap_pgoff+0x2d4/0x4a0
   ? __pfx_vm_mmap_pgoff+0x10/0x10
   ? fget+0x1bf/0x270
   ksys_mmap_pgoff+0x40c/0x690
   ? __sanitizer_cov_trace_const_cmp4+0x16/0x30
   ? __pfx_ksys_mmap_pgoff+0x10/0x10
   ? __kasan_check_write+0x14/0x30
   ? _raw_spin_trylock+0xbb/0x130
   ? __pfx__raw_spin_trylock+0x10/0x10
   __x64_sys_mmap+0x135/0x1e0
   x64_sys_call+0x1c14/0x2790
   do_syscall_64+0xd2/0x1050
   ? rcu_core+0x352/0x7d0
   ? rcu_core_si+0xe/0x20
   ? handle_softirqs+0x1aa/0x650
   ? __sanitizer_cov_trace_cmp4+0x16/0x30
   ? fpregs_assert_state_consistent+0xe1/0x160
   ? irqentry_exit+0xb1/0x670
   entry_SYSCALL_64_after_hwframe+0x76/0x7e

---
 drivers/infiniband/sw/rxe/rxe_mmap.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

index 9149b60954296..2749ed48b014a 100644
@@ -93,18 +93,31 @@ int rxe_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
 	goto done;
 
 found_it:
+	/*
+	 * Increment refcount and check whether it is being freed atm while
+	 * holding lock to prevent UAF
+	 */
+	if (!kref_get_unless_zero(&ip->ref)) {
+		spin_unlock_bh(&rxe->pending_lock);
+		ret = -ENXIO;
+		goto done;
+	}
+
 	list_del_init(&ip->pending_mmaps);
 	spin_unlock_bh(&rxe->pending_lock);
 
+	vma->vm_ops = &rxe_vm_ops;
+	vma->vm_private_data = ip;
+
 	ret = remap_vmalloc_range(vma, ip->obj, 0);
 	if (ret) {
+		vma->vm_private_data = NULL;
+		vma->vm_ops = NULL;
+		kref_put(&ip->ref, rxe_mmap_release);
 		pr_err("err %d from remap_vmalloc_range\n", ret);
 		goto done;
 	}
 
-	vma->vm_ops = &rxe_vm_ops;
-	vma->vm_private_data = ip;
-	rxe_vma_open(vma);
 done:
 	return ret;
 }

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eric Biggers <[email protected]>

commit 696c030e1e3438955aba443b308ee8b6faa3983e upstream.

Change mk_users (the set of user claims to an fscrypt master key) from a 'struct key' keyring to a simple linked list.

It's still a collection of 'struct key' for quota tracking. It was originally thought to be natural that a collection of 'struct key' should be held in a 'struct key' keyring. In reality, it's just been causing problems, similar to how using 'struct key' for the filesystem keyring caused problems and was removed in commit d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key").

Commit d3a7bd420076 ("fscrypt: clear keyring before calling key_put()") fixed mk_users cleanup to be synchronous. But that apparently wasn't
enough: the keyring subsystem's redundant locking is still generating lockdep false positives due to the interaction with filesystem reclaim.

With the simple list, the redundant locking and lockdep issue goes away.

Of course, searching a linked list is linear-time whereas the 'struct key' keyring used a fancy constant-time associative array. But that's fine here, since in practice there's just one entry in the list. In fact the new code is much faster in practice, since it's much smaller and doesn't have to convert the kuid_t into a string to search for it.

---
 fs/crypto/fscrypt_private.h |  32 ++++--
 fs/crypto/keyring.c         | 212 ++++++++++++++++--------------------
 2 files changed, 113 insertions(+), 131 deletions(-)

index 88414cbd97aee..aabc3a4751df7 100644
@@ -423,6 +423,19 @@ fscrypt_is_key_prepared(struct fscrypt_prepared_key *prep_key,
 
 /* keyring.c */
 
+/*
+ * fscrypt_master_key_user - a user's claim to a master key
+ */
+struct fscrypt_master_key_user {
+	struct list_head link;
+	kuid_t uid;
+	/*
+	 * This 'struct key' contains no secret.  It exists solely to charge the
+	 * appropriate user's key quota.
+	 */
+	struct key *quota_key;
+};
+
 /*
  * fscrypt_master_key_secret - secret key material of an in-use master key
  */

@@ -513,19 +526,18 @@ struct fscrypt_master_key {
 	struct fscrypt_key_specifier		mk_spec;
 
 	/*
-	 * Keyring which contains a key of type 'key_type_fscrypt_user' for each
-	 * user who has added this key.  Normally each key will be added by just
-	 * one user, but it's possible that multiple users share a key, and in
-	 * that case we need to keep track of those users so that one user can't
-	 * remove the key before the others want it removed too.
+	 * List of user claims to this key (struct fscrypt_master_key_user).
+	 * Normally each key will be added by just one user, but it's possible
+	 * that multiple users share a key, and in that case we need to keep
+	 * track of those users so that one user can't remove the key before the
+	 * others want it removed too.
 	 *
-	 * This is NULL for v1 policy keys; those can only be added by root.
+	 * Used only for v2 policy keys.  v1 policy keys can be added only by
+	 * root, so user tracking doesn't apply to them.
 	 *
-	 * Locking: protected by ->mk_sem.  (We don't just rely on the keyrings
-	 * subsystem semaphore ->mk_users->sem, as we need support for atomic
-	 * search+insert along with proper synchronization with ->mk_secret.)
+	 * Locking: protected by ->mk_sem.
 	 */
-	struct key		*mk_users;
+	struct list_head	mk_users;
 
 	/*
 	 * List of inodes that were unlocked using this key.  This allows the

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Michal Luczaj <[email protected]>

[ Upstream commit 30581eda4a07ff15db623612cac578e81869e96f ]

Update sockmap_listen to accommodate the recent change in sockmap that rejects unbound UDP sockets.

TCP: Reject unbound and bound (unless established or listening).
UDP: Accept only bound sockets.

While at it, migrate to ASSERT_* and enforce reverse xmas tree.

---
 .../selftests/bpf/prog_tests/sockmap_listen.c | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

index cef5d35951711..2112b01a4b03a 100644
@@ -341,8 +341,8 @@ static void test_insert_invalid(int family, int sotype, int mapfd)
 static void test_insert_opened(int family, int sotype, int mapfd)
 {
 	u32 key = 0;
-	u64 value;
 	int err, s;
+	u64 value;
 
 	s = xsocket(family, sotype, 0);
 	if (s == -1)

@@ -351,11 +351,8 @@ static void test_insert_opened(int family, int sotype, int mapfd)
 	errno = 0;
 	value = s;
 	err = bpf_map_update_elem(mapfd, &key, &value, BPF_NOEXIST);
-	if (sotype == SOCK_STREAM) {
-		if (!err || errno != EOPNOTSUPP)
-			FAIL_ERRNO("map_update: expected EOPNOTSUPP");
-	} else if (err)
-		FAIL_ERRNO("map_update: expected success");
+	ASSERT_ERR(err, "map_update");
+	ASSERT_EQ(errno, EOPNOTSUPP, "errno");
 	xclose(s);
 }
 

@@ -364,8 +361,8 @@ static void test_insert_bound(int family, int sotype, int mapfd)
 	struct sockaddr_storage addr;
 	socklen_t len;
 	u32 key = 0;
-	u64 value;
 	int err, s;
+	u64 value;
 
 	init_addr_loopback(family, &addr, &len);
 

@@ -380,8 +377,12 @@ static void test_insert_bound(int family, int sotype, int mapfd)
 	errno = 0;
 	value = s;
 	err = bpf_map_update_elem(mapfd, &key, &value, BPF_NOEXIST);
-	if (!err || errno != EOPNOTSUPP)
-		FAIL_ERRNO("map_update: expected EOPNOTSUPP");
+	if (sotype == SOCK_STREAM) {
+		ASSERT_ERR(err, "map_update");
+		ASSERT_EQ(errno, EOPNOTSUPP, "errno");
+	} else {
+		ASSERT_OK(err, "map_update");
+	}
 close:
 	xclose(s);
 }

@@ -1480,7 +1481,7 @@ static void test_ops(struct test_sockmap_listen *skel, struct bpf_map *map,
 		/* insert */
 		TEST(test_insert_invalid),
 		TEST(test_insert_opened),
-		TEST(test_insert_bound, SOCK_STREAM),
+		TEST(test_insert_bound),
 		TEST(test_insert),
 		/* delete */
 		TEST(test_delete_after_insert),

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Michal Luczaj <[email protected]>

[ Upstream commit 203b06932777b9ad5085319389dea566f5c2ca63 ]

sockmap now rejects unbound UDP sockets. Adjust test_maps. While at it, check socket()'s return value.

This effectively reverts commit c39aa2159974 ("bpf, selftests: Fix test_maps now that sockmap supports UDP").

---
 tools/testing/selftests/bpf/test_maps.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

index 81cd48cc80c23..73878ec8ec7d0 100644
@@ -752,16 +752,15 @@ static void test_sockmap(unsigned int tasks, void *data)
 		goto out_sockmap;
 	}
 
-	/* Test update with unsupported UDP socket */
+	/* Test update with unsupported unbound UDP socket */
 	udp = socket(AF_INET, SOCK_DGRAM, 0);
-	i = 0;
-	err = bpf_map_update_elem(fd, &i, &udp, BPF_ANY);
-	if (err) {
-		printf("Failed socket update SOCK_DGRAM '%i:%i'\n",
-		       i, udp);
+	CHECK(udp < 0, "socket(AF_INET, SOCK_DGRAM)", "errno:%d\n", errno);
+	err = bpf_map_update_elem(fd, &(int){0}, &udp, BPF_ANY);
+	close(udp);
+	if (!err) {
+		printf("Unexpectedly succeeded unbound UDP update '0:%i'\n", udp);
 		goto out_sockmap;
 	}
-	close(udp);
 
 	/* Test update without programs */
 	for (i = 0; i < 6; i++) {

2.53.0

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zihan Xi <[email protected]>

commit 4ff9548d84945d2cbf9e4c207288063a200ea397 upstream.

fib_nlmsg_size() still estimates nexthop space as if every gateway is encoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an IPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA.

As a result, route notifications can allocate an skb that is too small. fib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the WARN_ON() that marks such failures as a fib_nlmsg_size() bug. With panic_on_warn set, this becomes a kernel panic.

Mirror the actual nexthop dump layout in fib_nlmsg_size(): account for IPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop layout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is actually present.

---
 net/ipv4/fib_semantics.c |   67 ++++++++++++++++++++++++++++++++++-------------
 1 file changed, 49 insertions(+), 18 deletions(-)

@@ -462,6 +462,34 @@ int ip_fib_check_default(__be32 gw, stru
 	return -1;
 }
 
+static size_t fib_nexthop_nlmsg_size(const struct fib_nh_common *nhc,
+				     bool skip_oif)
+{
+	size_t nhsize = 0;
+
+	switch (nhc->nhc_gw_family) {
+	case AF_INET:
+		nhsize += nla_total_size(4); /* RTA_GATEWAY */
+		break;
+	case AF_INET6:
+		nhsize += nla_total_size(sizeof(struct rtvia) +
+					 sizeof(struct in6_addr));
+		break;
+	}
+
+	if (!skip_oif && nhc->nhc_dev)
+		nhsize += nla_total_size(4); /* RTA_OIF */
+
+	if (nhc->nhc_lwtstate) {
+		/* RTA_ENCAP */
+		nhsize += lwtunnel_get_encap_size(nhc->nhc_lwtstate);
+		/* RTA_ENCAP_TYPE */
+		nhsize += nla_total_size(2);
+	}
+
+	return nhsize;
+}
+
 size_t fib_nlmsg_size(struct fib_info *fi)
 {
 	size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))

@@ -479,32 +507,35 @@ size_t fib_nlmsg_size(struct fib_info *f
 		payload += nla_total_size(4); /* RTA_NH_ID */
 
 	if (nhs) {
-		size_t nh_encapsize = 0;
-		/* Also handles the special case nhs == 1 */
-
-		/* each nexthop is packed in an attribute */
-		size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
+		size_t mpsize = 0;
 		unsigned int i;
 
-		/* may contain flow and gateway attribute */
-		nhsize += 2 * nla_total_size(4);
-
-		/* grab encap info */
 		for (i = 0; i < fib_info_num_path(fi); i++) {
 			struct fib_nh_common *nhc = fib_info_nhc(fi, i);
+			size_t nhsize;
+
+			nhsize = fib_nexthop_nlmsg_size(nhc, nhs != 1);
 
-			if (nhc->nhc_lwtstate) {
-				/* RTA_ENCAP_TYPE */
-				nh_encapsize += lwtunnel_get_encap_size(
-						nhc->nhc_lwtstate);
-				/* RTA_ENCAP */
-				nh_encapsize +=  nla_total_size(2);
+			if (nhs != 1)
+				nhsize += NLA_ALIGN(sizeof(struct rtnexthop));
+
+#ifdef CONFIG_IP_ROUTE_CLASSID
+			if (nhc->nhc_family == AF_INET) {
+				struct fib_nh *nh;
+
+				nh = container_of(nhc, struct fib_nh, nh_common);
+				if (nh->nh_tclassid)
+					nhsize += nla_total_size(4);
 			}
+#endif
+			if (nhs == 1)
+				payload += nhsize;
+			else
+				mpsize += nhsize;
 		}
 
-		/* all nexthops are packed in a nested attribute */
-		payload += nla_total_size((nhs * nhsize) + nh_encapsize);
-
+		if (nhs != 1)
+			payload += nla_total_size(mpsize);
 	}
 
 	return payload;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Chengfeng Ye <[email protected]>

commit bc5bde9ce3cc36502839dfe98e068f7303a50982 upstream.

fib_nhc_update_mtu() walks the nexthop exception table under RTNL, but RTNL does not serialize this walk with PMTU exception updates. The walk uses rcu_dereference_protected() with a constant true condition without holding fnhe_lock.

The following interleaving can therefore occur:

CPU 0 CPU 1
fib_nhc_update_mtu() update_or_create_fnhe()
load fnhe spin_lock_bh(&fnhe_lock)
fnhe_remove_oldest()
unlink fnhe kfree_rcu(fnhe, rcu)
<quiescent state>
access fnhe after grace period

KASAN reported:

  BUG: KASAN: slab-use-after-free in fib_nhc_update_mtu+0x3df/0x410
  Read of size 8 at addr ffff888107d49000 by task poc/90
  Call Trace:
   fib_nhc_update_mtu+0x3df/0x410
   fib_sync_mtu+0x7a/0xd0
   fib_netdev_event+0x229/0x3f0
   netif_set_mtu_ext+0x33a/0x570
   dev_set_mtu+0x88/0x120

The same walk updates fnhe_pmtu and fnhe_mtu_locked. These fields form a pair and other writers serialize them with fnhe_lock. RCU alone prevents reclamation, but would still allow concurrent writers to leave a mixed pair.

Walk the table under RCU and acquire fnhe_lock only while updating each exception. RCU keeps the current entry alive while the short critical section serializes its paired PMTU fields. This avoids holding the global lock while scanning all 2048 buckets for every nexthop.

---
 include/net/route.h      |    2 ++
 net/ipv4/fib_semantics.c |   34 +++++++++++-----------------------
 net/ipv4/route.c         |   29 +++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 23 deletions(-)

@@ -247,6 +247,8 @@ int fib_dump_info_fnhe(struct sk_buff *s
 		       u32 table_id, struct fib_info *fi,
 		       int *fa_index, int fa_start, unsigned int flags);
 
+void fnhe_update_pmtu(struct fib_nh_exception *fnhe, u32 new, u32 orig);
+
 static inline void ip_rt_put(struct rtable *rt)
 {
 	/* dst_release() accepts a NULL parameter.

@@ -1958,42 +1958,30 @@ static int call_fib_nh_notifiers(struct
 	return NOTIFY_DONE;
 }
 
-/* Update the PMTU of exceptions when:
- * - the new MTU of the first hop becomes smaller than the PMTU
- * - the old MTU was the same as the PMTU, and it limited discovery of
- *   larger MTUs on the path. With that limit raised, we can now
- *   discover larger MTUs
- * A special case is locked exceptions, for which the PMTU is smaller
- * than the minimal accepted PMTU:
- * - if the new MTU is greater than the PMTU, don't make any change
- * - otherwise, unlock and set PMTU
+/* Walk the exceptions of a nexthop after its first hop MTU changed. The
+ * chain is RCU protected here, while fnhe_update_pmtu() takes fnhe_lock
+ * for the update of each entry.
  */
 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
 {
 	struct fnhe_hash_bucket *bucket;
 	int i;
 
-	bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
+	rcu_read_lock();
+	bucket = rcu_dereference(nhc->nhc_exceptions);
 	if (!bucket)
-		return;
+		goto out;
 
 	for (i = 0; i < FNHE_HASH_SIZE; i++) {
 		struct fib_nh_exception *fnhe;
 
-		for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
+		for (fnhe = rcu_dereference(bucket[i].chain);
 		     fnhe;
-		     fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
-			if (fnhe->fnhe_mtu_locked) {
-				if (new <= fnhe->fnhe_pmtu) {
-					fnhe->fnhe_pmtu = new;
-					fnhe->fnhe_mtu_locked = false;
-				}
-			} else if (new < fnhe->fnhe_pmtu ||
-				   orig == fnhe->fnhe_pmtu) {
-				fnhe->fnhe_pmtu = new;
-			}
-		}
+		     fnhe = rcu_dereference(fnhe->fnhe_next))
+			fnhe_update_pmtu(fnhe, new, orig);
 	}
+out:
+	rcu_read_unlock();
 }
 
 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)

@@ -751,6 +751,35 @@ out_unlock:
 	spin_unlock_bh(&fnhe_lock);
 }
 
+/* Update the PMTU of an exception when:
+ * - the new MTU of the first hop becomes smaller than the PMTU
+ * - the old MTU was the same as the PMTU, and it limited discovery of
+ *   larger MTUs on the path. With that limit raised, we can now
+ *   discover larger MTUs
+ * A special case is locked exceptions, for which the PMTU is smaller
+ * than the minimal accepted PMTU:
+ * - if the new MTU is greater than the PMTU, don't make any change
+ * - otherwise, unlock and set PMTU
+ *
+ * fnhe_lock keeps fnhe_pmtu and fnhe_mtu_locked consistent against
+ * update_or_create_fnhe(), which sets both under the same lock.
+ */
+void fnhe_update_pmtu(struct fib_nh_exception *fnhe, u32 new, u32 orig)
+{
+	spin_lock_bh(&fnhe_lock);
+
+	if (fnhe->fnhe_mtu_locked) {
+		if (new <= fnhe->fnhe_pmtu) {
+			fnhe->fnhe_pmtu = new;
+			fnhe->fnhe_mtu_locked = false;
+		}
+	} else if (new < fnhe->fnhe_pmtu || orig == fnhe->fnhe_pmtu) {
+		fnhe->fnhe_pmtu = new;
+	}
+
+	spin_unlock_bh(&fnhe_lock);
+}
+
 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
 			     bool kill_route)
 {

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Cunhao Lu <[email protected]>

commit e2fe6a0efecbef00e3ecc2db64dd5afa8c212b41 upstream.

serial8250_release_dma() terminates RX DMA and releases the channel, but leaves rx_running set. If the port is closed while an RX transfer is active, the stale state remains while rxchan is NULL until the channel is requested again on the next open.

The DesignWare BUSY workaround added by commit a7b9ce39fbe4 ("serial: 8250_dw: Ensure BUSY is deasserted") calls serial8250_rx_dma_flush() from the LCR write path during startup. This happens before serial8250_request_dma() obtains a new RX channel. On reopen, the stale rx_running state therefore makes the flush path pass a NULL channel to dmaengine_pause(), causing a kernel Oops.

Clear rx_running after terminating RX DMA, matching the TX cleanup. Also make the flush helper return if the DMA object or RX channel is not available so startup and teardown paths cannot pass a NULL channel to the DMAengine API.

---
 drivers/tty/serial/8250/8250_dma.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

@@ -195,11 +195,12 @@ void serial8250_rx_dma_flush(struct uart
 {
 	struct uart_8250_dma *dma = p->dma;
 
-	if (dma->rx_running) {
-		dmaengine_pause(dma->rxchan);
-		__dma_rx_complete(p);
-		dmaengine_terminate_async(dma->rxchan);
-	}
+	if (!dma || !dma->rxchan || !dma->rx_running)
+		return;
+
+	dmaengine_pause(dma->rxchan);
+	__dma_rx_complete(p);
+	dmaengine_terminate_async(dma->rxchan);
 }
 EXPORT_SYMBOL_GPL(serial8250_rx_dma_flush);
 

@@ -308,6 +309,7 @@ void serial8250_release_dma(struct uart_
 
 	/* Release RX resources */
 	dmaengine_terminate_sync(dma->rxchan);
+	dma->rx_running = 0;
 	dma_free_coherent(dma->rxchan->device->dev, dma->rx_size, dma->rx_buf,
 			  dma->rx_addr);
 	dma_release_channel(dma->rxchan);

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Muhammad Bilal <[email protected]>

commit 1c3e23e78862493e8cf1adad02b10ffcb8b9921c upstream.

rtw_get_wpa_ie() reads bytes at fixed offsets into a vendor-specific information element without checking that the element is long enough, causing an out-of-bounds read for a short trailing IE.

The function locates a vendor-specific IE (EID 221) with rtw_get_ie() and then compares a 4-byte OUI+type at pbuf + 2 and reads a 2-byte version word at pbuf + 6. Those accesses require the IE body to be at least 6 bytes, but rtw_get_ie() only guarantees that the element fits within the buffer; it does not enforce a minimum body length. A vendor-specific IE whose length byte is 0 to 5, placed at the end of the buffer, therefore makes these reads run past the end of the IE and past the end of the buffer itself.

The buffer holds information elements taken from received management frames and from the IE blob passed to rtw_cfg80211_set_wpa_ie(), which is kmemdup'd to its exact length, so the read can run off the end of the allocation.

The sibling helpers rtw_get_sec_ie(), rtw_get_wapi_ie() and rtw_get_wps_ie() in this file already reject too-short vendor-specific IEs before their OUI memcmp(); rtw_get_wpa_ie() was never brought in line with them, and needs a minimum of 6 rather than 4 bytes because of the version word. Add the missing length check.

---
 drivers/staging/rtl8723bs/core/rtw_ieee80211.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -371,6 +371,9 @@ unsigned char *rtw_get_wpa_ie(unsigned c
 		pbuf = rtw_get_ie(pbuf, WLAN_EID_VENDOR_SPECIFIC, &len, limit_new);
 
 		if (pbuf) {
+			if (len < 6)
+				goto check_next_ie;
+
 			/* check if oui matches... */
 			if (memcmp((pbuf + 2), wpa_oui_type, sizeof(wpa_oui_type)))
 				goto check_next_ie;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Muhammad Bilal <[email protected]>

commit ae21407350151bddfd4fea7aa39bd0643c0ca9d3 upstream.

WMM_param_handler() copies a fixed-size WMM parameter element out of a received information element without checking that the element is long enough, causing an out-of-bounds read for a short WMM IE.

The handler reads sizeof(struct WMM_para_element) (18) bytes at pIE->data + 6, so it requires pIE->length to be at least 24 (WLAN_WMM_LEN), but it never validates the length. Two of its three callers reach it after matching only the WMM OUI: OnAssocRsp() in rtw_mlme_ext.c matches a 6-byte OUI, and join_cmd_hdl() matches a 4-byte OUI, before calling the handler. A vendor-specific IE carrying the WMM OUI but a length between 6 and 23, placed in an association response or in the IE blob handed to join_cmd_hdl(), passes the OUI check and then makes the memcmp() and memcpy() at pIE->data + 6 read past the end of the element. OnAssocRsp() parses a frame received from the AP, so this is reachable from a remote peer.

The remaining caller in rtw_wlan_util.c already guards the handler with "pIE->length == WLAN_WMM_LEN". Move the equivalent check into the handler itself so every caller is covered; the sibling IE handlers in the same parsing loop (HT_caps_handler(), HT_info_handler(), ERP_IE_handler()) likewise bound their accesses by pIE->length.

---
 drivers/staging/rtl8723bs/core/rtw_wlan_util.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -731,6 +731,9 @@ int WMM_param_handler(struct adapter *pa
 		return false;
 	}
 
+	if (pIE->length != WLAN_WMM_LEN)
+		return false;
+
 	if (!memcmp(&(pmlmeinfo->WMM_param), (pIE->data + 6), sizeof(struct WMM_para_element)))
 		return false;
 	else

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Panagiotis Petrakopoulos <[email protected]>

commit 2c56ef658ac8c6bca36bc5574715e8f717207c6c upstream.

The WEP shared-key authentication handler uses the challenge-text element's attacker-controlled length without checking it against the fixed 128-byte chg_txt buffer.

In OnAuthClient() the length from rtw_get_ie() - up to 255 - is used to perform memcpy() into the 128-byte pmlmeinfo->chg_txt, so a malicious AP sending a malformed WLAN_EID_CHALLENGE element can overflow/underfill chg_txt by up to 127 bytes. It is reachable over the air, before association, during shared-key authentication. In the case of an overflow, the driver can write out of bounds. In the case of an underfill, the driver can echo stale buffer memory.

The challenge text is defined to be exactly 128 octets, which is already provided as the WLAN_AUTH_CHALLENGE_LEN define; require the element to be exactly that length before use.

---
 drivers/staging/rtl8723bs/core/rtw_mlme_ext.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -907,7 +907,7 @@ unsigned int OnAuthClient(struct adapter
 			p = rtw_get_ie(pframe + WLAN_HDR_A3_LEN + _AUTH_IE_OFFSET_, WLAN_EID_CHALLENGE, (int *)&len,
 				pkt_len - WLAN_HDR_A3_LEN - _AUTH_IE_OFFSET_);
 
-			if (!p)
+			if (!p || len != WLAN_AUTH_CHALLENGE_LEN)
 				goto authclnt_fail;
 
 			memcpy((void *)(pmlmeinfo->chg_txt), (void *)(p + 2), len);

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Mariano Baragiola <[email protected]>

commit 6829665d050983907b560173e49dcc6c11cb2730 upstream.

rtw_cfg80211_monitor_if_xmit_entry() removes the radiotap header and then reads the 802.11 frame control field without checking that a base 802.11 header remains.

The data path also pulls the calculated 802.11, QoS and SNAP header span before confirming that the skb contains it. A truncated frame can therefore cause out-of-bounds reads or leave insufficient data for the Ethernet address writes.

Reject frames that do not contain the base 802.11 header and data frames that do not contain their complete calculated header span.

---
 drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -2075,6 +2075,8 @@ static netdev_tx_t rtw_cfg80211_monitor_
 
 	/* Skip the ratio tap header */
 	skb_pull(skb, rtap_len);
+	if (skb->len < dot11_hdr_len)
+		goto fail;
 
 	dot11_hdr = (struct ieee80211_hdr *)skb->data;
 	frame_control = le16_to_cpu(dot11_hdr->frame_control);

@@ -2087,6 +2089,8 @@ static netdev_tx_t rtw_cfg80211_monitor_
 			qos_len = 2;
 		if ((frame_control & 0x0300) == 0x0300)
 			dot11_hdr_len += 6;
+		if (skb->len < dot11_hdr_len + qos_len + snap_len)
+			goto fail;
 
 		memcpy(dst_mac_addr, dot11_hdr->addr1, sizeof(dst_mac_addr));
 		memcpy(src_mac_addr, dot11_hdr->addr2, sizeof(src_mac_addr));

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Anandu Krishnan E <[email protected]>

commit 310f7868399668c6d99d88acc9c4cf3462e69d5b upstream.

fastrpc_channel_ctx_get() is called in fastrpc_device_open() before fastrpc_session_alloc(). If session alloc fails, the error path returns -EBUSY without calling fastrpc_channel_ctx_put(), leaking the reference. Fix by adding the missing put.

---
 drivers/misc/fastrpc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -1448,7 +1448,7 @@ static int fastrpc_device_open(struct in
 		dev_err(&cctx->rpdev->dev, "No session available\n");
 		mutex_destroy(&fl->mutex);
 		kfree(fl);
-
+		fastrpc_channel_ctx_put(cctx);
 		return -EBUSY;
 	}
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Eddie Lin <[email protected]>

commit 2fae94ee14f7fea11d3f95e10383a87c01d21518 upstream.

The 'ctx_idr' is initialized but never destroyed when the channel context is freed, leading to a memory leak. Add idr_destroy() to properly clean up the IDR resources.

---
 drivers/misc/fastrpc.c |    1 +
 1 file changed, 1 insertion(+)

@@ -426,6 +426,7 @@ static void fastrpc_channel_ctx_free(str
 
 	cctx = container_of(ref, struct fastrpc_channel_ctx, refcount);
 
+	idr_destroy(&cctx->ctx_idr);
 	kfree(cctx);
 }
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hui Su <[email protected]>

commit 91542863abade2fd4f2b361991f5386ad9d19c8c upstream.

In test_ringbuffer()'s out_free cleanup loop, the check !rb_threads[cpu] only catches NULL entries and misses entries that hold an ERR_PTR.

rb_threads[] is static, so unassigned slots are NULL. But when kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or -EINTR) in rb_threads[cpu] before the creation loop jumps to out_free. That entry is non-NULL, so the old !ptr check does not break, and the cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop() then dereferences the bogus pointer, crashing the kernel during the late_initcall self-test.

crash logs:

  BUG: kernel NULL pointer dereference, address: 000000000000001c
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy)
  RIP: 0010:kthread_stop+0x2e/0x220
  RBX: fffffffffffffff4
  CR2: 000000000000001c
  Call Trace:
   <TASK>
   test_ringbuffer+0x1ec/0x650
   do_one_initcall+0x6c/0x2c0
   kernel_init_freeable+0x21d/0x420
   kernel_init+0x15/0x1c0
   ret_from_fork+0x21b/0x320
   </TASK>
  Kernel panic - not syncing: Fatal exception

---
 kernel/trace/ring_buffer.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -6089,7 +6089,7 @@ static __init int test_ringbuffer(void)
 
  out_free:
 	for_each_online_cpu(cpu) {
-		if (!rb_threads[cpu])
+		if (IS_ERR_OR_NULL(rb_threads[cpu]))
 			break;
 		kthread_stop(rb_threads[cpu]);
 	}

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Baul Lee <[email protected]>

commit 2ca1eea3cd17930daffe9e429a7c89232036ec24 upstream.

snd_us428ctls_vm_fault() turns the faulting page offset into a kernel address with no bound of any kind:

	offset = vmf->pgoff << PAGE_SHIFT;
	vaddr = (char *)(...)->us428ctls_sharedmem + offset;
	page = virt_to_page(vaddr);
	get_page(page);
	vmf->page = page;

	return 0;

snd_us428ctls_mmap() checks only the length of the mapping, never the offset, and us428ctls_sharedmem is a single page from alloc_pages_exact(). For a character device file_mmap_size_max() returns ULONG_MAX, so the mm layer imposes no ceiling either. Every page offset above zero resolves to a struct page outside the object, and the handler installs it into the caller's address space read-write; the vma is not marked read-only.

The caller picks the page frame with a single mmap() argument and gets read-write access to a page of kernel memory it does not own; an offset that lands in an unpopulated vmemmap region oopses instead.

A process that can open the hwdep node of an attached US-X2Y reaches this after loading the FPGA image through the same node; no capability check is involved.

On 7.2.0-rc5 (arm64), mmap() with a large offset:

  Unable to handle kernel paging request at virtual address fffffdffc45d5ac8
  pc : snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y]
  Call trace:
   snd_us428ctls_vm_fault+0x68/0x140 [snd_usb_usx2y]
   __do_fault
   __handle_mm_fault
   handle_mm_fault
   el0_da

Reject any offset outside the shared region. The pcm hwdep handler in usx2yhwdeppcm.c computes its address the same way and needs the same bound.

Discovered by XBOW, triaged by Baul Lee <[email protected]>

---
 sound/usb/usx2y/usX2Yhwdep.c    |    2 ++
 sound/usb/usx2y/usx2yhwdeppcm.c |    2 ++
 2 files changed, 4 insertions(+)

@@ -29,6 +29,8 @@ static vm_fault_t snd_us428ctls_vm_fault
 		   vmf->pgoff);
 
 	offset = vmf->pgoff << PAGE_SHIFT;
+	if (offset >= US428_SHAREDMEM_PAGES)
+		return VM_FAULT_SIGBUS;
 	vaddr = (char *)((struct usx2ydev *)vmf->vma->vm_private_data)->us428ctls_sharedmem + offset;
 	page = virt_to_page(vaddr);
 	get_page(page);

@@ -676,6 +676,8 @@ static vm_fault_t snd_usx2y_hwdep_pcm_vm
 	void *vaddr;
 
 	offset = vmf->pgoff << PAGE_SHIFT;
+	if (offset >= USX2Y_HWDEP_PCM_PAGES)
+		return VM_FAULT_SIGBUS;
 	vaddr = (char *)((struct usx2ydev *)vmf->vma->vm_private_data)->hwdep_pcm_shm + offset;
 	vmf->page = virt_to_page(vaddr);
 	get_page(vmf->page);

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Michael Wu <[email protected]>

commit c3730b8373bb5059d735509b9e6a00d7eb337d7c upstream.

The following sequence may leads race between event_define_fields() and update_event_fields():

 CPU0 (loads module A)                      CPU1 (loads module B)
 ===============================            ===============================
 load_module(A)                             load_module(B)
   notifier_call_chain                        notifier_call_chain
     trace_module_notify                        trace_module_notify
       mutex_lock(&event_mutex)                   trace_event_update_all()
         trace_module_add_events(A)                 down_write(&trace_event_sem)
            __register_event(call_A)
              __add_event_to_tracers(call_A)
                event_define_fields(call_A)
                  for each f:                         list_for_each_entry(field,
                    list_add(&f->link,                                    &class->fields, link)
                             &class->fields)            field = class->fields->next;

Where access to the class->fields is not protected by the event_mutex in trace_event_update_all().

This produces the following panic:

   Unable to handle kernel access ... at virtual address 0000000000000018
   pc : update_event_fields+0xf8/0x368
   Call trace:
    update_event_fields+0xf8/0x368
    trace_event_update_all+0x7c/0x2b4
    trace_module_notify+0x4c/0x1dc
    notifier_call_chain+0x84/0x168
    blocking_notifier_call_chain_robust+0x64/0xd4
    load_module+0x10c8/0x123c
    __arm64_sys_finit_module+0x230/0x31c

Fix by taking event_mutex in trace_event_update_all() before trace_event_sem.

---
 kernel/trace/trace_events.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -2904,6 +2904,7 @@ void trace_event_eval_update(struct trac
 	int last_i;
 	int i;
 
+	mutex_lock(&event_mutex);
 	down_write(&trace_event_sem);
 	list_for_each_entry_safe(call, p, &ftrace_events, list) {
 		/* events are usually grouped together with systems */

@@ -2937,6 +2938,7 @@ void trace_event_eval_update(struct trac
 		cond_resched();
 	}
 	up_write(&trace_event_sem);
+	mutex_unlock(&event_mutex);
 }
 
 static struct trace_event_file *

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Rik van Riel <[email protected]>

commit e033cbf3975a8465f879ebd5989dc35b04423a4d upstream.

bit_cursor() fetches the glyph under the cursor with

	c = scr_readw(vc_pos);
	src = vc_font.data + ((c & charmask) * w * height);

where charmask is 0x1ff when vc_hi_font_mask is set. The screen buffer value comes directly from scr_readw() and may be larger than the current font's glyph count.

Syzkaller triggers this via vcs_write(). The Call Trace shows vcs_write() in vc_screen.c writing an arbitrary 16-bit value with writev() to /dev/vcsa, which vcs_write_buf() in vc_screen.c stores via vcs_scr_writew() without checking charcount. The stored value is later read in bit_cursor() in bitblit.c.

When the font is changed from a font with 512 glyphs to a font with 256 glyphs, the screen buffer can retain characters with the high bit set from the previous mode, which could also produce the same out-of-bounds access.

  BUG: KASAN: global-out-of-bounds in soft_cursor+0x378/0x6bc drivers/video/fbdev/core/softcursor.c:70
  Read of size 16 at addr ffff800086c57970

  Call Trace:
   soft_cursor+0x378/0x6bc drivers/video/fbdev/core/softcursor.c:70
   bit_cursor+0xa90/0x1108 drivers/video/fbdev/core/bitblit.c:365
   fbcon_cursor+0x344/0x498 drivers/video/fbdev/core/fbcon.c:1427
   hide_cursor+0xdc/0x2d0 drivers/tty/vt/vt.c:883
   update_region+0x100/0x18c drivers/tty/vt/vt.c:669
   vcs_write+0x8ec/0xaf0 drivers/tty/vt/vc_screen.c:685

bit_putcs_aligned() and bit_putcs_unaligned() already clamp the glyph index to vc_font.charcount. Apply the same clamp in bit_cursor() after extracting the attribute and masking, before indexing fontdata.

The fix completes the bounds checking started in commit 18c4ef4e765a ("fbdev: bitblit: bound-check glyph index in bit_putcs*"), which missed the cursor path.

This change should be safe because the clamp reuses the existing contract from fbcon: charcount is maintained under console_lock in con_font_set() and fbcon_font_set(), and hi_font_mask is cleared when switching from 512 to 256 glyphs. When stale screen data with high bits remains after a font switch, or when vcs_write() stores an arbitrary value, clamping the index to 0 prevents the out-of-bounds read without changing cursor semantics — the same fallback bit_putcs uses.

---
 drivers/video/fbdev/core/bitblit.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

@@ -274,9 +274,14 @@ static void bit_cursor(struct vc_data *v
 	if (!vc->vc_font.data)
 		return;
 
- 	c = scr_readw((u16 *) vc->vc_pos);
+	c = scr_readw((u16 *) vc->vc_pos);
 	attribute = get_attribute(info, c);
-	src = vc->vc_font.data + ((c & charmask) * (w * vc->vc_font.height));
+	c &= charmask;
+
+	/* Clamp to font size, same as bit_putcs_aligned() */
+	if (c >= vc->vc_font.charcount)
+		c = 0;
+	src = vc->vc_font.data + (c * (w * vc->vc_font.height));
 
 	if (ops->cursor_state.image.data != src ||
 	    ops->cursor_reset) {

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Daming Li <[email protected]>

commit 5d9686af2976741bbd79b150d1c9e60b81e7f12e upstream.

smc_rx_splice() passes pages to splice_to_pipe() before taking the references that cover the lifetime of each splice entry. In the VM-backed RMB path, splice_to_pipe() may drop unqueued entries through smc_rx_spd_release(), while queued entries are released later via the pipe buffer callback.

The old post-splice accounting also derives the number of queued VM pages from an offset mutated while building the descriptor, and a multi-page splice pairs one sock_hold() with multiple sock_put() calls.

Take the page and socket references for every candidate entry before splice_to_pipe(), and drop the matching private state, page reference, and socket reference from smc_rx_spd_release() for entries that never get queued. This fixes a refcount imbalance that can underflow page refcounts and trigger a use-after-free.

---
 net/smc/smc_rx.c |   19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

@@ -146,7 +146,12 @@ static const struct pipe_buf_operations
 static void smc_rx_spd_release(struct splice_pipe_desc *spd,
 			       unsigned int i)
 {
+	struct smc_spd_priv *priv = (struct smc_spd_priv *)spd->partial[i].private;
+	struct sock *sk = &priv->smc->sk;
+
+	kfree(priv);
 	put_page(spd->pages[i]);
+	sock_put(sk);
 }
 
 static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len,

@@ -205,6 +210,10 @@ static int smc_rx_splice(struct pipe_ino
 			offset = 0;
 		}
 	}
+	for (i = 0; i < nr_pages; i++) {
+		get_page(pages[i]);
+		sock_hold(&smc->sk);
+	}
 	spd.nr_pages_max = nr_pages;
 	spd.nr_pages = nr_pages;
 	spd.pages = pages;

@@ -213,16 +222,8 @@ static int smc_rx_splice(struct pipe_ino
 	spd.spd_release = smc_rx_spd_release;
 
 	bytes = splice_to_pipe(pipe, &spd);
-	if (bytes > 0) {
-		sock_hold(&smc->sk);
-		if (!lgr->is_smcd && smc->conn.rmb_desc->is_vm) {
-			for (i = 0; i < PAGE_ALIGN(bytes + offset) / PAGE_SIZE; i++)
-				get_page(pages[i]);
-		} else {
-			get_page(smc->conn.rmb_desc->pages);
-		}
+	if (bytes > 0)
 		atomic_add(bytes, &smc->conn.splice_pending);
-	}
 	kfree(priv);
 	kfree(partial);
 	kfree(pages);

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Kyle Zeng <[email protected]>

commit 0e243671bc7b8eaf00f83dd2f4367436dc0cff98 upstream.

in6_dev_get() reads dev->ip6_ptr under RCU and then unconditionally increments its refcount. Device teardown can clear the pointer and drop the last reference between these operations. The increment then resurrects an object whose RCU free has already been queued, so callers can use it after it is freed.

Use refcount_inc_not_zero() and return NULL when the object has already reached zero. RCU keeps the memory accessible through the attempted reference acquisition, and a successful increment pins the object for the caller.

An independent run on the exact unpatched 6f5156d7a31a (v7.2-rc3) kernel reproduced the invalid reference acquisition as UID 1000:

refcount_t: addition on 0; use-after-free.
ip6_mc_source+0xef4/0x17e0

It was followed by the corresponding reference underflow in ip6_mc_source(). The supplied trace from the same unpatched revision additionally shows the access after the RCU read-side section ends:

  BUG: KASAN: slab-use-after-free in mutex_lock+0x76/0xe0
  Write of size 8 at addr ffff888015b50240 by task poc/1219

Bug found and triaged by OpenAI Security Research and validated by Trail of Bits.

---
 include/net/addrconf.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -370,8 +370,8 @@ static inline struct inet6_dev *in6_dev_
 
 	rcu_read_lock();
 	idev = rcu_dereference(dev->ip6_ptr);
-	if (idev)
-		refcount_inc(&idev->refcnt);
+	if (idev && !refcount_inc_not_zero(&idev->refcnt))
+		idev = NULL;
 	rcu_read_unlock();
 	return idev;
 }

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zhiling Zou <[email protected]>

commit d45cc8020d7c0a9f01dee42ff5c40bc14c9af72f upstream.

A bridge nftables ct zone set rule can attach a conntrack template to an skb before nf_ct_bridge_pre() sees it. For non-IPv4 and non-IPv6 EtherTypes, nf_ct_bridge_pre() currently overwrites skb->_nfct with IP_CT_UNTRACKED without releasing the existing template reference.

That makes the per-cpu template, and any temporary templates allocated for concurrent use, unreachable and leaks memory until the host runs out of slab.

Reset the skb conntrack state before marking the frame untracked so the existing template reference is dropped on the non-IP path.

---
 net/bridge/netfilter/nf_conntrack_bridge.c |    1 +
 1 file changed, 1 insertion(+)

@@ -281,6 +281,7 @@ static unsigned int nf_ct_bridge_pre(voi
 		ret = nf_ct_br_defrag6(skb, &bridge_state);
 		break;
 	default:
+		nf_reset_ct(skb);
 		nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
 		return NF_ACCEPT;
 	}

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Yangyu Chen <[email protected]>

commit 452636ea5410a96e02ebaaf80b21e3620b98e0dd upstream.

aq_vec_deinit() drains the TX rings with a single aq_ring_tx_clean() call, which frees at most AQ_CFG_TX_CLEAN_BUDGET (256) descriptors and stops at hw_head, which no longer moves once aq_vec_stop() has stopped the hardware and NAPI. Completed descriptors beyond the budget and everything still posted in [hw_head, sw_tail) keep their skb or xdp_frame when the interface goes down: aq_vec_ring_free() then frees the buffer ring and the references are lost for good.

Today this is a silent memory leak on every interface down under TX/XDP_TX load. With the conversion of the RX path to page_pool posted for net-next it becomes much more visible: XDP_TX frames carry fragment references on the RX ring's page_pool, so a single stranded frame keeps the pool's inflight count above zero forever. page_pool_destroy() then never completes, the pool is leaked together with its pages, and "page_pool_release_retry() stalled pool shutdown" is warned every 60 seconds from that point on, on every ifdown, XDP detach or ring resize under XDP_TX load.

Bring back aq_ring_tx_deinit() as it was before the removal and use it for teardown again, with one extension: TX rings can hold xdp_frames nowadays, so release those too. They are returned with xdp_return_frame() since this runs in process context.

---
 drivers/net/ethernet/aquantia/atlantic/aq_ring.c |   29 +++++++++++++++++++++++
 drivers/net/ethernet/aquantia/atlantic/aq_ring.h |    1 
 drivers/net/ethernet/aquantia/atlantic/aq_vec.c  |    2 -
 3 files changed, 31 insertions(+), 1 deletion(-)

@@ -336,6 +336,35 @@ out:
 	return !!budget;
 }
 
+void aq_ring_tx_deinit(struct aq_ring_s *self)
+{
+	if (!self)
+		return;
+
+	for (; self->sw_head != self->sw_tail;
+		self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
+		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
+		struct device *ndev = aq_nic_get_dev(self->aq_nic);
+
+		if (buff->is_mapped) {
+			if (buff->is_sop) {
+				dma_unmap_single(ndev, buff->pa, buff->len,
+						 DMA_TO_DEVICE);
+			} else {
+				dma_unmap_page(ndev, buff->pa, buff->len,
+					       DMA_TO_DEVICE);
+			}
+		}
+
+		if (buff->is_eop) {
+			if (buff->skb)
+				dev_kfree_skb_any(buff->skb);
+			else if (buff->xdpf)
+				xdp_return_frame(buff->xdpf);
+		}
+	}
+}
+
 static void aq_rx_checksum(struct aq_ring_s *self,
 			   struct aq_ring_buff_s *buff,
 			   struct sk_buff *skb)

@@ -199,6 +199,7 @@ void aq_ring_update_queue_state(struct a
 void aq_ring_queue_wake(struct aq_ring_s *ring);
 void aq_ring_queue_stop(struct aq_ring_s *ring);
 bool aq_ring_tx_clean(struct aq_ring_s *self);
+void aq_ring_tx_deinit(struct aq_ring_s *self);
 int aq_xdp_xmit(struct net_device *dev, int num_frames,
 		struct xdp_frame **frames, u32 flags);
 int aq_ring_rx_clean(struct aq_ring_s *self,

@@ -275,7 +275,7 @@ void aq_vec_deinit(struct aq_vec_s *self
 
 	for (i = 0U; self->tx_rings > i; ++i) {
 		ring = self->ring[i];
-		aq_ring_tx_clean(&ring[AQ_VEC_TX_ID]);
+		aq_ring_tx_deinit(&ring[AQ_VEC_TX_ID]);
 		aq_ring_rx_deinit(&ring[AQ_VEC_RX_ID]);
 	}
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Yangyu Chen <[email protected]>

commit e8e7471ef686b6c002218fee9671cc61992ae01a upstream.

aq_ring_rx_deinit() only walks [sw_head, sw_tail), the region posted to hardware. Since the page reuse strategy was added, a cleaned RX buffer keeps its page (and its DMA mapping) in the ring for reuse, and refill is batched: aq_ring_rx_fill() returns early until AQ_CFG_RX_REFILL_THRES slots are free. Slots that were consumed but not yet reposted therefore sit in the complementary [sw_tail, sw_head) gap with a live page, and the deinit walk never visits them: up to a refill batch worth of pages and DMA mappings leak on every interface down.

Walk the whole ring instead and release whatever is still there. Also bail out if the buffer ring is already gone: a partial aq_ptp_ring_alloc() failure frees the ring but leaves aq_nic set, so aq_ptp_ring_deinit() still gets here on the unwind path.

---
 drivers/net/ethernet/aquantia/atlantic/aq_ring.c |   22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

@@ -926,15 +926,29 @@ err_exit:
 
 void aq_ring_rx_deinit(struct aq_ring_s *self)
 {
-	if (!self)
+	unsigned int i;
+
+	if (!self || !self->buff_ring)
 		return;
 
-	for (; self->sw_head != self->sw_tail;
-		self->sw_head = aq_ring_next_dx(self, self->sw_head)) {
-		struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
+	/* Release every page still owned by the ring.
+	 *
+	 * Walking [sw_head, sw_tail) is not enough: refill is batched
+	 * (aq_ring_rx_fill() waits for AQ_CFG_RX_REFILL_THRES free slots),
+	 * so slots that were cleaned but not yet reposted accumulate in the
+	 * [sw_tail, sw_head) gap, and they keep their page for reuse. Walk
+	 * the whole ring and release whatever is left.
+	 */
+	for (i = 0; i < self->size; i++) {
+		struct aq_ring_buff_s *buff = &self->buff_ring[i];
+
+		if (!buff->rxdata.page)
+			continue;
 
 		aq_free_rxpage(&buff->rxdata, aq_nic_get_dev(self->aq_nic));
 	}
+
+	self->sw_head = self->sw_tail;
 }
 
 void aq_ring_free(struct aq_ring_s *self)

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hyunjung Ko <[email protected]>

commit 883b56ae58fe657d8497806c7059646e9ba6dbd0 upstream.

tcf_action_check_ctrlact() range checks the primary control action:

	if (!opcode)
		ret = action > TC_ACT_VALUE_MAX ? -EINVAL : 0;

TC_ACT_VALUE_MAX is TC_ACT_TRAP, so kernel-internal verdicts above it cannot be set that way. But act_gact and act_police each carry a second, independent control action supplied by user space that never reaches that helper - TCA_GACT_PROB.paction and TCA_POLICE_RESULT. Both only reject TC_ACT_GOTO_CHAIN, so any other value is stored verbatim and returned verbatim from the action.

In particular user space can store TC_ACT_CONSUMED, which is TC_ACT_VALUE_MAX + 1 and is deliberately not part of the UAPI value range. That verdict tells every caller the action took ownership of the skb, so nobody frees it: sch_handle_ingress(), sch_handle_egress() and tcf_qevent_handle() all deliberately skip the free for it. The result is one leaked sk_buff plus its data buffer per packet traversing the filter, unbounded, for all traffic on the chain including kernel-generated packets.

Both are trivially deterministic. act_gact clamps tcfg_pval to >= 1, so with pval = 1 gact_determ() returns the fallback for every packet. act_police has no mandatory rate, so rate = 0 leaves tcfp_mtu = ~0 and tcf_police_mtu_check() always passes.

TC_ACT_CONSUMED was added by commit 720f22fed81b ("net: sched: refactor reinsert action"), after both goto-chain guards were written:
commit 9469f375ab09 ("net/sched: act_gact: disallow 'goto chain' on fallback control action") and
commit c08f5ed5d625 ("net/sched: act_police: disallow 'goto chain' on fallback control action"). Neither guard was widened when the new verdict appeared.

Factor the existing range test out of tcf_action_check_ctrlact() as tcf_action_valid() and apply it to both fallbacks. The helper cannot call tcf_action_check_ctrlact() directly because that also allocates a goto_chain, which is exactly what these two sites must not do.

Reproduced on v7.2-rc6: kmemleak reports one leaked 232-byte skbuff_head_cache object plus its 704-byte data buffer per packet. With this patch both configurations are rejected with -EINVAL and kmemleak reports none.

---
 include/net/act_api.h  |   19 +++++++++++++++++++
 net/sched/act_gact.c   |    5 +++++
 net/sched/act_police.c |    6 ++++++
 3 files changed, 30 insertions(+)

@@ -267,6 +267,25 @@ int tcf_action_check_ctrlact(int action,
 struct tcf_chain *tcf_action_set_ctrlact(struct tc_action *a, int action,
 					 struct tcf_chain *newchain);
 
+/* Range check for a control action supplied by user space.
+ *
+ * This is the same test tcf_action_check_ctrlact() applies to the primary
+ * control action, factored out for the *fallback* control actions
+ * (act_gact's TCA_GACT_PROB.paction and act_police's TCA_POLICE_RESULT),
+ * which must not reach tcf_action_check_ctrlact() because they have no
+ * goto_chain to allocate.  Without it, user space can store kernel-internal
+ * verdicts such as TC_ACT_CONSUMED, which is TC_ACT_VALUE_MAX + 1 and is
+ * deliberately not part of the UAPI value range.
+ */
+static inline bool tcf_action_valid(int action)
+{
+	int opcode = TC_ACT_EXT_OPCODE(action);
+
+	if (!opcode)
+		return action <= TC_ACT_VALUE_MAX;
+	return opcode <= TC_ACT_EXT_OPCODE_MAX || action == TC_ACT_UNSPEC;
+}
+
 #ifdef CONFIG_INET
 DECLARE_STATIC_KEY_FALSE(tcf_frag_xmit_count);
 #endif

@@ -88,6 +88,11 @@ static int tcf_gact_init(struct net *net
 		p_parm = nla_data(tb[TCA_GACT_PROB]);
 		if (p_parm->ptype >= MAX_RAND)
 			return -EINVAL;
+		if (!tcf_action_valid(p_parm->paction)) {
+			NL_SET_ERR_MSG(extack,
+				       "invalid fallback control action");
+			return -EINVAL;
+		}
 		if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
 			NL_SET_ERR_MSG(extack,
 				       "goto chain not allowed on fallback");

@@ -126,6 +126,12 @@ static int tcf_police_init(struct net *n
 
 	if (tb[TCA_POLICE_RESULT]) {
 		tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
+		if (!tcf_action_valid(tcfp_result)) {
+			NL_SET_ERR_MSG(extack,
+				       "invalid fallback control action");
+			err = -EINVAL;
+			goto failure;
+		}
 		if (TC_ACT_EXT_CMP(tcfp_result, TC_ACT_GOTO_CHAIN)) {
 			NL_SET_ERR_MSG(extack,
 				       "goto chain not allowed on fallback");

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Zhiling Zou <[email protected]>

commit e48e8edbef2eb824201495daa5234560f632b23c upstream.

xdpf_clone() clones broadcast copies into a single page and sets frame_sz to PAGE_SIZE. __xdp_build_skb_from_frame() later treats that page like a normal XDP frame and expects the usual skb_shared_info tailroom at the end of the buffer.

The current check only rejects frames whose linear xdp_frame header, headroom, and packet data exceed PAGE_SIZE. A source frame backed by a larger allocation can still satisfy that check while extending into the clone's required shared-info area. When such a clone is converted back into an skb, build_skb_around() places skb_shared_info over live packet bytes and later writes can corrupt XDP return metadata.

Reject clones unless their linear area fits inside SKB_WITH_OVERHEAD(PAGE_SIZE), matching the tailroom requirement already enforced by the XDP-to-skb conversion path.

---
 net/core/xdp.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -688,7 +688,7 @@ struct xdp_frame *xdpf_clone(struct xdp_
 	headroom = xdpf->headroom + sizeof(*xdpf);
 	totalsize = headroom + xdpf->len;
 
-	if (unlikely(totalsize > PAGE_SIZE))
+	if (unlikely(totalsize > SKB_WITH_OVERHEAD(PAGE_SIZE)))
 		return NULL;
 	page = dev_alloc_page();
 	if (!page)

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Baul Lee <[email protected]>

commit b37971686ec59fb027fa4910ba16805e68fddb97 upstream.

vxlan_changelink() arms vxlan->age_timer whenever the requested ageing interval differs from the configured one:

	if (conf.age_interval != vxlan->cfg.age_interval)
		mod_timer(&vxlan->age_timer, jiffies);

There is no netif_running() test, so the timer is armed even on a device that was never brought up. The only synchronous cancel in the driver is the timer_delete_sync() in vxlan_stop(), which is .ndo_stop. netif_close_many() drops devices without IFF_UP before __dev_close_many() runs, so that cancel is skipped for such a device.

vxlan_setup() sets dev->needs_free_netdev = true and age_timer is a member of struct vxlan_dev, so free_netdev() releases the allocation the timer lives in while it is still queued on a timer_base. expire_timers() unlinks the entry before it loads timer->function, so the timer core writes through the freed object's list pointers:

  BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654
  Write of size 8 at addr ffff00001adace68 by task true/192
   __asan_store8+0x84/0xac
   __run_timers+0x208/0x654
   run_timer_softirq+0x154/0x18c
  Allocated by task 189:
   alloc_netdev_mqs+0x64/0x720
   rtnl_create_link+0x4ac/0x520
   rtnl_newlink+0x758/0xd00
  Freed by task 191:
   netdev_release+0x40/0x58
   netdev_run_todo+0x4a4/0x8c0
   rtnl_dellink+0x200/0x4e8

The rtnl operations involved are netns-scoped, so an unprivileged user can perform them in a new user and network namespace.

Arming the timer on a down device never had an effect: vxlan_cleanup() returns early on !netif_running(), and vxlan_open() arms the timer for any non-zero interval once the device is brought up. Add the missing test.

Discovered by XBOW, triaged by Baul Lee <[email protected]>

---
 drivers/net/vxlan/vxlan_core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -4330,7 +4330,7 @@ static int vxlan_changelink(struct net_d
 	if (change_igmp && vxlan_addr_multicast(&dst->remote_ip))
 		err = vxlan_multicast_leave(vxlan);
 
-	if (conf.age_interval != vxlan->cfg.age_interval)
+	if (netif_running(dev) && conf.age_interval != vxlan->cfg.age_interval)
 		mod_timer(&vxlan->age_timer, jiffies);
 
 	netdev_adjacent_change_commit(dst->remote_dev, lowerdev, dev);

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Weiming Shi <[email protected]>

commit ebac8f6b1ef0e9278afe204b8692a7479988dace upstream.

Commit bd50c5dc182b ("vsock/virtio: add support for device suspend/resume") made the *_run flags transition from false to true when restore installs replacement virtqueues. The RX, TX and event workers read their virtqueue before locking and checking the corresponding flag, so a worker delayed across freeze and restore can observe the replacement queue's running state while retaining a pointer to the deleted queue.

Read each virtqueue under its mutex after checking the run flag, keeping the pointer and state in the same queue generation.

---
 net/vmw_vsock/virtio_transport.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

@@ -257,12 +257,13 @@ static void virtio_transport_tx_work(str
 	struct virtqueue *vq;
 	bool added = false;
 
-	vq = vsock->vqs[VSOCK_VQ_TX];
 	mutex_lock(&vsock->tx_lock);
 
 	if (!vsock->tx_run)
 		goto out;
 
+	vq = vsock->vqs[VSOCK_VQ_TX];
+
 	do {
 		struct sk_buff *skb;
 		unsigned int len;

@@ -362,13 +363,13 @@ static void virtio_transport_event_work(
 		container_of(work, struct virtio_vsock, event_work);
 	struct virtqueue *vq;
 
-	vq = vsock->vqs[VSOCK_VQ_EVENT];
-
 	mutex_lock(&vsock->event_lock);
 
 	if (!vsock->event_run)
 		goto out;
 
+	vq = vsock->vqs[VSOCK_VQ_EVENT];
+
 	do {
 		struct virtio_vsock_event *event;
 		unsigned int len;

@@ -484,13 +485,13 @@ static void virtio_transport_rx_work(str
 		container_of(work, struct virtio_vsock, rx_work);
 	struct virtqueue *vq;
 
-	vq = vsock->vqs[VSOCK_VQ_RX];
-
 	mutex_lock(&vsock->rx_lock);
 
 	if (!vsock->rx_run)
 		goto out;
 
+	vq = vsock->vqs[VSOCK_VQ_RX];
+
 	do {
 		virtqueue_disable_cb(vq);
 		for (;;) {

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Weiming Shi <[email protected]>

commit a31e0ad444698d8aa7534a0f89fda543730f97a5 upstream.

Commit b917507e5ad9 ("vsock/virtio: stop workers during the .remove()") made the RX worker jump to its common exit when rx_run is clear. That exit still refills the RX queue when the buffer count is low, so work queued across virtio_vsock_vqs_del() can add buffers after the virtqueues have been deleted.

BUG: KASAN: slab-use-after-free in virtqueue_add_sgs
Read of size 4 by task kworker/0:1
Workqueue: virtio_vsock virtio_transport_rx_work
Call Trace:
 virtqueue_add_sgs (drivers/virtio/virtio_ring.c:2796)
 virtio_vsock_rx_fill (net/vmw_vsock/virtio_transport.c:332)
 virtio_transport_rx_work (net/vmw_vsock/virtio_transport.c:701)
 process_one_work (kernel/workqueue.c:3314)
 worker_thread (kernel/workqueue.c:3478)
 kthread (kernel/kthread.c:436)
 ret_from_fork (arch/x86/kernel/process.c:158)
 ret_from_fork_asm (arch/x86/entry/entry_64.S:245)
...
Freed by task 141:
 kfree (mm/slub.c:6566)
 vp_del_vq (drivers/virtio/virtio_pci_common.c:259)
 vp_del_vqs (drivers/virtio/virtio_pci_common.c:285)
 virtio_vsock_freeze (net/vmw_vsock/virtio_transport.c:912)
 virtio_device_freeze (drivers/virtio/virtio.c:658)
 virtio_pci_freeze (drivers/virtio/virtio_pci_common.c:601)
 pci_pm_freeze (drivers/pci/pci-driver.c:1098)
 device_suspend (drivers/base/power/main.c:1968)
Kernel panic - not syncing: KASAN: panic_on_warn set ...

Jump to a no-refill exit when rx_run is clear, leaving the normal exit to replenish a running queue.

---
 net/vmw_vsock/virtio_transport.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -488,7 +488,7 @@ static void virtio_transport_rx_work(str
 	mutex_lock(&vsock->rx_lock);
 
 	if (!vsock->rx_run)
-		goto out;
+		goto out_nofill;
 
 	vq = vsock->vqs[VSOCK_VQ_RX];
 

@@ -536,6 +536,7 @@ static void virtio_transport_rx_work(str
 out:
 	if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2)
 		virtio_vsock_rx_fill(vsock);
+out_nofill:
 	mutex_unlock(&vsock->rx_lock);
 }
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jun Yang <[email protected]>

commit de845981da67a6b049080c87e605130b0c30adc5 upstream.

vq->meta_iotlb[] caches the vhost_iotlb_map that backs each vring metadata region, and iotlb_access_ok() returns early on a cache hit, taking the hit as proof that the region has already been validated:

	if (vhost_vq_meta_fetch(vq, addr, len, type))
		return true;

The cache is reset on VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE, on device IOTLB (re)initialisation and on vq reset, but not when VHOST_SET_VRING_ADDR replaces vq->desc, vq->avail and vq->used, nor when VHOST_SET_VRING_NUM changes the region sizes.

With a device IOTLB attached both ioctls are accepted while the vq is live, and neither validates the addresses at ioctl time: vq_access_ok() and vq_log_used_access_ok() return true early because the addresses are GIOVAs, deferring validation to prefetch time. Once the cache has been populated that deferred validation no longer runs -- vq_meta_prefetch() hits the stale entry and returns true -- and vhost_vq_meta_fetch() keeps translating through the old mapping as

	map->addr + addr - map->start

for an address the mapping no longer covers. vhost_copy_to_user() and vhost_copy_from_user() consume the result with __copy_to_user() and __copy_from_user(), which do not check it either, so a subsequent used ring update or descriptor fetch accesses memory outside the region the IOTLB actually maps.

Reset the metadata cache whenever the vring is reconfigured, so the new addresses are pushed back through iotlb_access_ok()'s slow path.

Message-ID: <[email protected]>

---
 drivers/vhost/vhost.c |    8 ++++++++
 1 file changed, 8 insertions(+)

@@ -1587,6 +1587,14 @@ static long vhost_vring_set_num_addr(str
 		BUG();
 	}
 
+	/*
+	 * The metadata cache holds the IOTLB mapping that backed the previous
+	 * desc/avail/used addresses and vring size, both of which are being
+	 * replaced here.  iotlb_access_ok() takes a cache hit as proof that the
+	 * region was validated, so the stale entries have to go.
+	 */
+	__vhost_vq_meta_reset(vq);
+
 	mutex_unlock(&vq->mutex);
 
 	return r;

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jun Yang <[email protected]>

commit cba9ccb47e9fa4cc77692fb896cc5ab57a667882 upstream.

tipc_node_link_down() caches the link pointer before taking n->lock:

	struct tipc_link *l = le->link;		/* unlocked */

	if (!l)
		return;
	tipc_node_write_lock(n);
	if (!tipc_link_is_establishing(l)) {	/* deref l */
	...
		tipc_link_reset(l);		/* write into l */
	if (delete) {
		kfree(l);
		le->link = NULL;

The delete=true caller frees that very object under n->lock, so the lock does not protect the cached pointer against it:

- CPU A, delete=false: tipc_rcv() on TIPC_LINK_DOWN_EVT, or the link supervision timer via tipc_node_timeout(), reads l unlocked and then dereferences it under n->lock;
- CPU B, delete=true: netlink TIPC_NL_BEARER_DISABLE -> bearer_disable() -> tipc_node_delete_links() -> tipc_node_link_down(n, bearer_id, true) -> kfree(l).

The link is freed with plain kfree(), not kfree_rcu(), and for UDP bearers disable_media() only schedules the asynchronous cleanup_bearer() work, so its synchronize_net() runs after the links are already gone. An in-flight CPU A that has read l therefore dereferences freed memory once B frees it:
a use-after-free read in tipc_link_is_establishing(), and a use-after-free write via tipc_link_reset() on the establishing branch.

The following trace was captured on 7.2.0-rc5-00284-gaf39eb111ce6:

  BUG: KASAN: slab-use-after-free in tipc_link_is_establishing (net/tipc/link.c:285)
  Read of size 4 at addr ffff88802e2aa068 by task swapper/2/0
   tipc_link_is_establishing (net/tipc/link.c:285)
   tipc_node_link_down (net/tipc/node.c:1076)
   tipc_node_timeout (net/tipc/node.c:843)
  Allocated by task 9549:
   tipc_link_create (net/tipc/link.c:490)
   tipc_node_check_dest (net/tipc/node.c:1279)
   tipc_disc_rcv (net/tipc/discover.c:252)
   tipc_udp_recv (net/tipc/udp_media.c:389)
  Freed by task 9549:
   tipc_node_link_down (net/tipc/node.c:1084)
   tipc_node_delete_links (net/tipc/node.c:1320)
   bearer_disable (net/tipc/bearer.c:414)
   __tipc_nl_bearer_disable (net/tipc/bearer.c:992)

Move the le->link read inside tipc_node_write_lock(), so it is serialised against the kfree() in the delete path. A racing teardown now either has not run yet, and we see a valid link, or has already run, and we see NULL.

---
 net/tipc/node.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

@@ -1063,18 +1063,23 @@ static void __tipc_node_link_down(struct
 
 static void tipc_node_link_down(struct tipc_node *n, int bearer_id, bool delete)
 {
-	struct tipc_link_entry *le = &n->links[bearer_id];
 	struct tipc_media_addr *maddr = NULL;
-	struct tipc_link *l = le->link;
 	int old_bearer_id = bearer_id;
+	struct tipc_link_entry *le;
 	struct sk_buff_head xmitq;
-
-	if (!l)
-		return;
+	struct tipc_link *l;
 
 	__skb_queue_head_init(&xmitq);
 
+	/* Synchronize the link lookup with bearer teardown. */
 	tipc_node_write_lock(n);
+	le = &n->links[bearer_id];
+	l = le->link;
+	if (!l) {
+		tipc_node_write_unlock_fast(n);
+		return;
+	}
+
 	if (!tipc_link_is_establishing(l)) {
 		__tipc_node_link_down(n, &bearer_id, &xmitq, &maddr);
 	} else {

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Shuangpeng Bai <[email protected]>

commit 4986410316b1ae0e63c6ce418e4eb196723626e7 upstream.

cifs_try_adding_channels() takes a temporary reference to an interface before dropping iface_lock. If cifs_ses_add_channel() fails, it drops that reference and then increments iface->weight_fulfilled.

A concurrent interface list refresh can remove the list reference while channel creation is in progress. In that case, the failure-path kref_put() releases the last reference and frees iface. Updating weight_fulfilled afterward then accesses freed memory.

Increment weight_fulfilled before dropping the temporary reference, keeping iface alive for the final access.

---
 fs/smb/client/sess.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -247,9 +247,9 @@ int cifs_try_adding_channels(struct cifs
 				cifs_dbg(VFS, "failed to open extra channel on iface:%pIS rc=%d\n",
 					 &iface->sockaddr,
 					 rc);
-				kref_put(&iface->refcount, release_iface);
 				/* failure to add chan should increase weight */
 				iface->weight_fulfilled++;
+				kref_put(&iface->refcount, release_iface);
 				continue;
 			}
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Sean Christopherson <[email protected]>

commit 5ec42d57655c690234c14aece6dd3f209778c1d8 upstream.

Explicitly clear role.invalid when deriving a child shadow page's role from its parent to harden against bugs elsewhere in KVM, as violating KVM's invariant that invalid pages are NOT on the list of active MMU pages leads to use-after-free due to __kvm_mmu_prepare_zap_page() using list_add() instead of list_move() when processing an invalid shadow page, i.e. makes a bad situation far worse.

Yell loudly if the parent is invalid, as it means KVM has missed a validity check, i.e. KVM is attempting to map memory using an invalid/obsolete root, but continue on as the child is otherwise still a valid shadow page.

==================================================================

  BUG: KASAN: slab-use-after-free in __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]
  Write of size 8 at addr ff11000153dd1368 by task repro/853

  CPU: 1 UID: 1000 PID: 853 Comm: repro Not tainted 7.2.0-rc2-3aec122bdcaf-next-vm #5 PREEMPT
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  Call Trace:
   <TASK>
   dump_stack_lvl+0x4b/0x70
   print_report+0x153/0x49c
   kasan_report+0xbc/0xf0
   __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm]
   mmu_alloc_root+0x141/0x320 [kvm]
   kvm_mmu_load+0x612/0x20f0 [kvm]
   kvm_arch_vcpu_ioctl_run+0x3dd5/0x6150 [kvm]
   kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
   __x64_sys_ioctl+0x131/0x1b0
   do_syscall_64+0x67/0x5f0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
   </TASK>

  Allocated by task 853:
   kasan_save_stack+0x20/0x40
   kasan_save_track+0x14/0x30
   __kasan_slab_alloc+0x5f/0x70
   kmem_cache_alloc_noprof+0xfe/0x2e0
   __kvm_mmu_topup_memory_cache+0x135/0x530 [kvm]
   paging64_page_fault+0x318/0x1e30 [kvm]
   kvm_mmu_do_page_fault+0x21d/0x630 [kvm]
   kvm_mmu_page_fault+0x18c/0x17b0 [kvm]
   kvm_arch_vcpu_ioctl_run+0x1f35/0x6150 [kvm]
   kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
   __x64_sys_ioctl+0x131/0x1b0
   do_syscall_64+0x67/0x5f0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53

  Freed by task 853:
   kasan_save_stack+0x20/0x40
   kasan_save_track+0x14/0x30
   kasan_save_free_info+0x3b/0x60
   __kasan_slab_free+0x43/0x70
   kmem_cache_free+0xe2/0x400
   kvm_mmu_commit_zap_page.part.0+0x1e2/0x310 [kvm]
   kvm_mmu_free_roots+0x283/0x560 [kvm]
   kvm_arch_vcpu_ioctl_run+0x33c8/0x6150 [kvm]
   kvm_vcpu_ioctl+0x5e4/0x10d0 [kvm]
   __x64_sys_ioctl+0x131/0x1b0
   do_syscall_64+0x67/0x5f0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53

---
 arch/x86/kvm/mmu/mmu.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -2201,6 +2201,9 @@ static union kvm_mmu_page_role kvm_mmu_c
 	role.direct = direct;
 	role.passthrough = 0;
 
+	WARN_ON_ONCE(role.invalid);
+	role.invalid = 0;
+
 	/*
 	 * If the guest has 4-byte PTEs then that means it's using 32-bit,
 	 * 2-level, non-PAE paging. KVM shadows such guests with PAE paging

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Rafael J. Wysocki <[email protected]>

commit ff8da20b6f47c48d46e47f93f7a59e2d56ee9107 upstream.

Revert commit 030a48b0f6ce ("thermal/drivers/hwmon: Cleanup coding style a bit") that introduced a use-after-free into the error path of thermal_add_hwmon_sysfs() by removing a valid check from it.

---
 drivers/thermal/thermal_hwmon.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -209,7 +209,8 @@ int thermal_add_hwmon_sysfs(struct therm
 	if (new_hwmon_device)
 		hwmon_device_unregister(hwmon->device);
  free_mem:
-	kfree(hwmon);
+	if (new_hwmon_device)
+		kfree(hwmon);
 
 	return result;
 }

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ahmad Byagowi <[email protected]>

commit 6b69f2ef10cdb018c0b127a7cab88e590bbddba4 upstream.

The EEPROM board ID is a fixed 13-byte field and is not guaranteed to contain a NUL terminator. Passing it directly to devlink_info_version_fixed_put() treats it as a C string and may read beyond the field.

Format at most OCP_BOARD_ID_LEN bytes into the existing local buffer before reporting the ID. Use a precision limit because the snprintf() output size alone does not bound the source string scan.

---
 drivers/ptp/ptp_ocp.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -1483,9 +1483,11 @@ ptp_ocp_devlink_info_get(struct devlink
 	if (err)
 		return err;
 
+	snprintf(buf, sizeof(buf), "%.*s", OCP_BOARD_ID_LEN,
+		 (const char *)bp->board_id);
 	err = devlink_info_version_fixed_put(req,
 			DEVLINK_INFO_VERSION_GENERIC_BOARD_ID,
-			bp->board_id);
+			buf);
 	if (err)
 		return err;
 

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Tengda Wu <[email protected]>

commit f27bdc43077e4fcb5557dfc315ee8d91e741f483 upstream.

The ring_buffer_swap_cpu() function currently checks the per-CPU committing counter to determine if a buffer is actively being written to before performing the swap. However, there exists a race window where this check can be bypassed:

    ring_buffer_lock_reserve
        cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a
        rb_reserve_next_event
            rb_start_commit // inc committing
            if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
            __rb_reserve_next
                rb_move_tail
                    rb_end_commit(cpu_buffer);   // dec committing => 0
                    /* interrupt hits here, successfully swaps! */
                    local_inc(&cpu_buffer->committing);

    ring_buffer_unlock_commit
        cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b
        rb_commit
            rb_end_commit
            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
                                                // triggers warning

The committing counter can temporarily drop to 0 during a single write operation (within rb_move_tail), creating a window where swap can succeed even though the write is still in progress. This leads to inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().

Replace the committing counter check with current_context checks, which are set at the entry of ring_buffer_lock_reserve() and remain valid throughout the entire write operation, providing a reliable indicator of buffer busy state during swap.

---
 kernel/trace/ring_buffer.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

@@ -5457,7 +5457,7 @@ int ring_buffer_swap_cpu(struct trace_bu
 {
 	struct ring_buffer_per_cpu *cpu_buffer_a;
 	struct ring_buffer_per_cpu *cpu_buffer_b;
-	int ret = -EINVAL;
+	int ret = -EBUSY;
 
 	if (!cpumask_test_cpu(cpu, buffer_a->cpumask) ||
 	    !cpumask_test_cpu(cpu, buffer_b->cpumask))

@@ -5493,10 +5493,10 @@ int ring_buffer_swap_cpu(struct trace_bu
 	atomic_inc(&cpu_buffer_a->record_disabled);
 	atomic_inc(&cpu_buffer_b->record_disabled);
 
-	ret = -EBUSY;
-	if (local_read(&cpu_buffer_a->committing))
+	/* Do not swap if either buffer is in the process of writing */
+	if (cpu_buffer_a->current_context)
 		goto out_dec;
-	if (local_read(&cpu_buffer_b->committing))
+	if (cpu_buffer_b->current_context)
 		goto out_dec;
 
 	/*

6.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Yuejie Shi <[email protected]>

commit d1ad8fb2ac6a1afb71dc22d9ae8efb4dda96c824 upstream.

rt6_route_rcv() validates the Route Information option (RFC 4191) length against the prefix length, but both checks are off by one.

rinfo->length is the ND option length in units of 8 octets and it *includes* the 8-byte option header, so an option carrying N bytes of prefix has length == 1 + N/8. RFC 4191 section 2.3 requires length 3 when Prefix Length is greater than 64, and 2 or 3 when it is greater than 0. The code accepts length >= 2 and length >= 1 respectively.

ipv6_addr_prefix() then copies prefix_len/8 bytes out of rinfo->prefix, so a Router Advertisement with (prefix_len=128, length=2) or (prefix_len=64, length=1) makes the kernel read up to 8 bytes past the end of the option. Those bytes end up in the prefix of the route that gets installed, so they are visible to userspace:

# RA with a Route Information option (prefix_len=128, length=2)

  # followed by a source link-layer address option, 01 01 de ad be ef ca fe
  $ ip -6 route show
  2001:db8:dead:beef:101:dead:beef:cafe via fe80::1234 dev veth0 proto ra
                     ^^^^^^^^^^^^^^^^^^ the next option, read out of bounds

When the Route Information option is the last one in the packet, those eight bytes come from the skb tail room instead.

Reject the option lengths RFC 4191 does not allow.