FAILED: patch "[PATCH] nfsd: validate sockaddr length per family in listener_set" failed to apply to 6.12-stable tree

PATCH New [email protected] 2 participants 3 messages Sep 3 – Sep 5

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[email protected]

author maintainer

2026-09-03 13:18 UTC #0 lore raw

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x bdcc85c2b05a9378d8bd2d65f9fc41440a3cf464
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090327-bully-unsightly-dc1a@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From bdcc85c2b05a9378d8bd2d65f9fc41440a3cf464 Mon Sep 17 00:00:00 2001
From: Jeff Layton <[email protected]>
Date: Mon, 15 Jun 2026 14:31:25 -0400
Subject: [PATCH] nfsd: validate sockaddr length per family in listener_set

nfsd_sock_nl_policy declares NFSD_A_SOCK_ADDR as a bare NLA_BINARY attribute with no minimum length. A CAP_NET_ADMIN caller can send a 16-byte NFSD_A_SOCK_ADDR with sa_family=AF_INET6, causing a 12-byte OOB read across three consumers (rpc_cmp_addr_port, svc_find_listener, kernel_bind).

nfsd_nl_listener_set_doit() also parsed and validated each listener entry inline in two separate loops, interleaved with mutating the running listener configuration. The validation was duplicated, used an open-coded "nla_len < sizeof(struct sockaddr)" check that was too short for AF_INET6, and handled a malformed entry inconsistently depending on which loop noticed it.

Add an nfsd_nl_validate_listeners() helper that walks the entire list once and confirms each entry parses, carries both an address and a transport name, and is long enough for its address family (sizeof(struct sockaddr_in) for AF_INET, sizeof(struct sockaddr_in6) for AF_INET6, -EAFNOSUPPORT otherwise). Call it before taking nfsd_mutex or creating the serv, so a malformed request fails cleanly with no side effects.

Since every entry is known valid by the time the two existing loops run, drop the redundant presence and per-family length checks from both, leaving only the nla_parse_nested() call needed to extract the data.

Fixes 16a471177496 ("NFSD: add listener-{set,get} netlink command")

Cc [email protected]

Assisted-by Claude:claude-opus-4-8

Signed-off-by Jeff Layton <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Chuck Lever <[email protected]>

fs/nfsd/nfsctl.c +65 ~~-12~~

index f1ecbb13f642..caf59421f8f4 100644
@@ -1971,6 +1971,60 @@ int nfsd_nl_version_get_doit(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+/**
+ * nfsd_nl_validate_listeners - sanity-check the listener list from userland
+ * @info: netlink metadata and command arguments
+ *
+ * Walk every NFSD_A_SERVER_SOCK_ADDR attribute and confirm that each entry
+ * is well-formed: it parses against the policy, carries both an address and
+ * a transport name, and the address is long enough for its family. Doing
+ * this up front lets the callers below assume every entry is valid and
+ * guarantees we make no changes when the request is malformed.
+ *
+ * Return: 0 if every entry is valid, or a negative errno otherwise.
+ */
+static int nfsd_nl_validate_listeners(struct genl_info *info)
+{
+	const struct nlattr *attr;
+	int rem;
+
+	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,
+				 GENL_HDRLEN, rem) {
+		struct nlattr *tb[NFSD_A_SOCK_MAX + 1];
+		struct sockaddr *sa;
+		int err;
+
+		err = nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
+				       nfsd_sock_nl_policy, info->extack);
+		if (err < 0)
+			return err;
+
+		if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
+			return -EINVAL;
+
+		sa = nla_data(tb[NFSD_A_SOCK_ADDR]);
+		if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(sa->sa_family))
+			return -EINVAL;
+
+		switch (sa->sa_family) {
+		case AF_INET:
+			if (nla_len(tb[NFSD_A_SOCK_ADDR]) <
+			    sizeof(struct sockaddr_in))
+				return -EINVAL;
+			break;
+		case AF_INET6:
+			if (nla_len(tb[NFSD_A_SOCK_ADDR]) <
+			    sizeof(struct sockaddr_in6))
+				return -EINVAL;
+			break;
+		default:
+			return -EAFNOSUPPORT;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * nfsd_nl_listener_set_doit - set the nfs running sockets
  * @skb: reply buffer

@@ -1989,6 +2043,15 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 	bool delete = false;
 	int err, rem;
 
+	/*
+	 * Validate the entire listener list before making any changes, so a
+	 * malformed request fails cleanly without creating a serv or touching
+	 * the existing listeners.
+	 */
+	err = nfsd_nl_validate_listeners(info);
+	if (err)
+		return err;
+
 	mutex_lock(&nfsd_mutex);
 
 	err = nfsd_create_serv(net);

@@ -2015,16 +2078,11 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 		const char *xcl_name;
 		struct sockaddr *sa;
 
+		/* validated up front in nfsd_nl_validate_listeners() */
 		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
 				     nfsd_sock_nl_policy, info->extack) < 0)
 			continue;
 
-		if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
-			continue;
-
-		if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(*sa))
-			continue;
-
 		xcl_name = nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]);
 		sa = nla_data(tb[NFSD_A_SOCK_ADDR]);

@@ -2076,16 +2134,11 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 		struct sockaddr *sa;
 		int ret;
 
+		/* validated up front in nfsd_nl_validate_listeners() */
 		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
 				     nfsd_sock_nl_policy, info->extack) < 0)
 			continue;
 
-		if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
-			continue;
-
-		if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(*sa))
-			continue;
-
 		xcl_name = nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]);
 		sa = nla_data(tb[NFSD_A_SOCK_ADDR]);

Sasha Levin

maintainer

2026-09-05 02:26 UTC #1 lore raw

PATCH 1/2 netlink: introduce type-checking attribute iteration for nlmsg

From: Carolina Jubran <[email protected]>

[ Upstream commit 42401c42389622424f2973ec57414f033ae6be8f ]

Add the nlmsg_for_each_attr_type() macro to simplify iteration over attributes of a specific type in a Netlink message.

Convert existing users in vxlan and nfsd to use the new macro.

Signed-off-by Carolina Jubran <[email protected]>

Signed-off-by Mark Bloch <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Jakub Kicinski <[email protected]>

Stable-dep-of: bdcc85c2b05a ("nfsd: validate sockaddr length per family in listener_set")

Signed-off-by Sasha Levin <[email protected]>

---
 drivers/net/vxlan/vxlan_vnifilter.c | 13 ++++-------
 fs/nfsd/nfsctl.c                    | 36 +++++++++++------------------
 include/net/netlink.h               | 14 +++++++++++
 3 files changed, 32 insertions(+), 31 deletions(-)

drivers/net/vxlan/vxlan_vnifilter.c +4 -9

index 272fa31ef0745..4f2e2e84c9599 100644
@@ -980,15 +980,10 @@ static int vxlan_vnifilter_process(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (!(vxlan->cfg.flags & VXLAN_F_VNIFILTER))
 		return -EOPNOTSUPP;
 
-	nlmsg_for_each_attr(attr, nlh, sizeof(*tmsg), rem) {
-		switch (nla_type(attr)) {
-		case VXLAN_VNIFILTER_ENTRY:
-			err = vxlan_process_vni_filter(vxlan, attr,
-						       nlh->nlmsg_type, extack);
-			break;
-		default:
-			continue;
-		}
+	nlmsg_for_each_attr_type(attr, VXLAN_VNIFILTER_ENTRY, nlh,
+				 sizeof(*tmsg), rem) {
+		err = vxlan_process_vni_filter(vxlan, attr, nlh->nlmsg_type,
+					       extack);
 		vnis++;
 		if (err)
 			break;

fs/nfsd/nfsctl.c +14 ~~-22~~

index 7b0a6beee96ed..7854573e90009 100644
@@ -1679,10 +1679,9 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
 		return -EINVAL;
 
 	/* count number of SERVER_THREADS values */
-	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {
-		if (nla_type(attr) == NFSD_A_SERVER_THREADS)
-			nrpools++;
-	}
+	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_THREADS, info->nlhdr,
+				 GENL_HDRLEN, rem)
+		nrpools++;
 
 	mutex_lock(&nfsd_mutex);

@@ -1693,12 +1692,11 @@ int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	i = 0;
-	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {
-		if (nla_type(attr) == NFSD_A_SERVER_THREADS) {
-			nthreads[i++] = nla_get_u32(attr);
-			if (i >= nrpools)
-				break;
-		}
+	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_THREADS, info->nlhdr,
+				 GENL_HDRLEN, rem) {
+		nthreads[i++] = nla_get_u32(attr);
+		if (i >= nrpools)
+			break;
 	}
 
 	if (info->attrs[NFSD_A_SERVER_GRACETIME] ||

@@ -1839,14 +1837,12 @@ int nfsd_nl_version_set_doit(struct sk_buff *skb, struct genl_info *info)
 	for (i = 0; i <= NFSD_SUPPORTED_MINOR_VERSION; i++)
 		nfsd_minorversion(nn, i, NFSD_CLEAR);
 
-	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {
+	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_PROTO_VERSION, info->nlhdr,
+				 GENL_HDRLEN, rem) {
 		struct nlattr *tb[NFSD_A_VERSION_MAX + 1];
 		u32 major, minor = 0;
 		bool enabled;
 
-		if (nla_type(attr) != NFSD_A_SERVER_PROTO_VERSION)
-			continue;
-
 		if (nla_parse_nested(tb, NFSD_A_VERSION_MAX, attr,
 				     nfsd_version_nl_policy, info->extack) < 0)
 			continue;

@@ -1997,14 +1993,12 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 	 * Walk the list of server_socks from userland and move any that match
 	 * back to sv_permsocks
 	 */
-	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {
+	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,
+				 GENL_HDRLEN, rem) {
 		struct nlattr *tb[NFSD_A_SOCK_MAX + 1];
 		const char *xcl_name;
 		struct sockaddr *sa;
 
-		if (nla_type(attr) != NFSD_A_SERVER_SOCK_ADDR)
-			continue;
-
 		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
 				     nfsd_sock_nl_policy, info->extack) < 0)
 			continue;

@@ -2059,15 +2053,13 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 		svc_xprt_destroy_all(serv, net);
 
 	/* walk list of addrs again, open any that still don't exist */
-	nlmsg_for_each_attr(attr, info->nlhdr, GENL_HDRLEN, rem) {
+	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,
+				 GENL_HDRLEN, rem) {
 		struct nlattr *tb[NFSD_A_SOCK_MAX + 1];
 		const char *xcl_name;
 		struct sockaddr *sa;
 		int ret;
 
-		if (nla_type(attr) != NFSD_A_SERVER_SOCK_ADDR)
-			continue;
-
 		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
 				     nfsd_sock_nl_policy, info->extack) < 0)
 			continue;

include/net/netlink.h +14 -0

index db6af207287c8..bcc1ad092b515 100644
@@ -68,6 +68,8 @@
  *   nlmsg_for_each_msg()		loop over all messages
  *   nlmsg_validate()			validate netlink message incl. attrs
  *   nlmsg_for_each_attr()		loop over all attributes
+ *   nlmsg_for_each_attr_type()		loop over all attributes with the
+ *					given type
  *
  * Misc:
  *   nlmsg_report()			report back to application?

@@ -940,6 +942,18 @@ static inline u32 nlmsg_seq(const struct nlmsghdr *nlh)
 	nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
 			  nlmsg_attrlen(nlh, hdrlen), rem)
 
+/**
+ * nlmsg_for_each_attr_type - iterate over a stream of attributes
+ * @pos: loop counter, set to the current attribute
+ * @type: required attribute type for @pos
+ * @nlh: netlink message header
+ * @hdrlen: length of the family specific header
+ * @rem: initialized to len, holds bytes currently remaining in stream
+ */
+#define nlmsg_for_each_attr_type(pos, type, nlh, hdrlen, rem) \
+	nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
+		if (nla_type(pos) == type)
+
 /**
  * nlmsg_put - Add a new netlink message to an skb
  * @skb: socket buffer to store message in

Signature · 1 line

2.53.0

Sasha Levin

maintainer

2026-09-05 02:26 UTC #2 lore raw

PATCH 2/2 nfsd: validate sockaddr length per family in listener_set

From: Jeff Layton <[email protected]>

[ Upstream commit bdcc85c2b05a9378d8bd2d65f9fc41440a3cf464 ]

Fixes 16a471177496 ("NFSD: add listener-{set,get} netlink command")

Cc [email protected]

Assisted-by Claude:claude-opus-4-8

Signed-off-by Jeff Layton <[email protected]>

Link https://patch.msgid.link/[email protected] open here

Signed-off-by Chuck Lever <[email protected]>

Signed-off-by Sasha Levin <[email protected]>

---
 fs/nfsd/nfsctl.c | 77 ++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 65 insertions(+), 12 deletions(-)

fs/nfsd/nfsctl.c +65 ~~-12~~

index 7854573e90009..15c4397f09dfc 100644
@@ -1955,6 +1955,60 @@ int nfsd_nl_version_get_doit(struct sk_buff *skb, struct genl_info *info)
 	return err;
 }
 
+/**
+ * nfsd_nl_validate_listeners - sanity-check the listener list from userland
+ * @info: netlink metadata and command arguments
+ *
+ * Walk every NFSD_A_SERVER_SOCK_ADDR attribute and confirm that each entry
+ * is well-formed: it parses against the policy, carries both an address and
+ * a transport name, and the address is long enough for its family. Doing
+ * this up front lets the callers below assume every entry is valid and
+ * guarantees we make no changes when the request is malformed.
+ *
+ * Return: 0 if every entry is valid, or a negative errno otherwise.
+ */
+static int nfsd_nl_validate_listeners(struct genl_info *info)
+{
+	const struct nlattr *attr;
+	int rem;
+
+	nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr,
+				 GENL_HDRLEN, rem) {
+		struct nlattr *tb[NFSD_A_SOCK_MAX + 1];
+		struct sockaddr *sa;
+		int err;
+
+		err = nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
+				       nfsd_sock_nl_policy, info->extack);
+		if (err < 0)
+			return err;
+
+		if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
+			return -EINVAL;
+
+		sa = nla_data(tb[NFSD_A_SOCK_ADDR]);
+		if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(sa->sa_family))
+			return -EINVAL;
+
+		switch (sa->sa_family) {
+		case AF_INET:
+			if (nla_len(tb[NFSD_A_SOCK_ADDR]) <
+			    sizeof(struct sockaddr_in))
+				return -EINVAL;
+			break;
+		case AF_INET6:
+			if (nla_len(tb[NFSD_A_SOCK_ADDR]) <
+			    sizeof(struct sockaddr_in6))
+				return -EINVAL;
+			break;
+		default:
+			return -EAFNOSUPPORT;
+		}
+	}
+
+	return 0;
+}
+
 /**
  * nfsd_nl_listener_set_doit - set the nfs running sockets
  * @skb: reply buffer

@@ -1973,6 +2027,15 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 	bool delete = false;
 	int err, rem;
 
+	/*
+	 * Validate the entire listener list before making any changes, so a
+	 * malformed request fails cleanly without creating a serv or touching
+	 * the existing listeners.
+	 */
+	err = nfsd_nl_validate_listeners(info);
+	if (err)
+		return err;
+
 	mutex_lock(&nfsd_mutex);
 
 	err = nfsd_create_serv(net);

@@ -1999,16 +2062,11 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 		const char *xcl_name;
 		struct sockaddr *sa;
 
+		/* validated up front in nfsd_nl_validate_listeners() */
 		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
 				     nfsd_sock_nl_policy, info->extack) < 0)
 			continue;
 
-		if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
-			continue;
-
-		if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(*sa))
-			continue;
-
 		xcl_name = nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]);
 		sa = nla_data(tb[NFSD_A_SOCK_ADDR]);

@@ -2060,16 +2118,11 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info)
 		struct sockaddr *sa;
 		int ret;
 
+		/* validated up front in nfsd_nl_validate_listeners() */
 		if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr,
 				     nfsd_sock_nl_policy, info->extack) < 0)
 			continue;
 
-		if (!tb[NFSD_A_SOCK_ADDR] || !tb[NFSD_A_SOCK_TRANSPORT_NAME])
-			continue;
-
-		if (nla_len(tb[NFSD_A_SOCK_ADDR]) < sizeof(*sa))
-			continue;
-
 		xcl_name = nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]);
 		sa = nla_data(tb[NFSD_A_SOCK_ADDR]);

Signature · 1 line

2.53.0