BUG: unable to handle kernel paging request in smc_ib_remember_port_attr

PATCH In review syzbot 3 participants 3 messages Mar 26, 2018 – May 14, 2018

Subsystems (4)

Networking Network drivers s390 Shared memory communications (SMC) sockets

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author syzbot

2018-03-26 00:01 UTC #0 lore raw

Hello,

syzbot hit the following crash on upstream commit bcfc1f4554662d8f2429ac8bd96064a59c149754 (Sat Mar 24 16:50:12 2018 +0000)
Merge tag 'pinctrl-v4.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=5cd61039dc9b8bfa6e47

So far this crash happened 5 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=4566822275776512
syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=5414431521505280
Raw console output: https://syzkaller.appspot.com/x/log.txt?id=5642358322364416
Kernel config: https://syzkaller.appspot.com/x/.config?id=-5034017172441945317
compiler: gcc (GCC) 7.1.1 20170620

IMPORTANT: if you fix the bug, please add the following tag to the commit:

Reported-by [email protected]

It will help syzbot understand when the bug is fixed. See footer for details. If you forward the report, please keep this part and the footer.

BUG: unable to handle kernel paging request at fffffc0000000000

IP: bytes_is_nonzero mm/kasan/kasan.c:166 [inline]
IP: memory_is_nonzero mm/kasan/kasan.c:184 [inline]
IP: memory_is_poisoned_n mm/kasan/kasan.c:210 [inline]
IP: memory_is_poisoned mm/kasan/kasan.c:241 [inline]
IP: check_memory_region_inline mm/kasan/kasan.c:257 [inline]
IP: check_memory_region+0x83/0x190 mm/kasan/kasan.c:267 PGD 0 P4D 0

Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 4138 Comm: syzkaller407129 Not tainted 4.16.0-rc6+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bytes_is_nonzero mm/kasan/kasan.c:166 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/kasan.c:184 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/kasan.c:210 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/kasan.c:241 [inline]
RIP: 0010:check_memory_region_inline mm/kasan/kasan.c:257 [inline]
RIP: 0010:check_memory_region+0x83/0x190 mm/kasan/kasan.c:267
RSP: 0018:ffff8801b8c472e0 EFLAGS: 00010282
RAX: fffffc0000000000 RBX: 0000000000000017 RCX: ffffffff85a53701
RDX: 0000000000000001 RSI: 0000000000000040 RDI: ffffffffffffffd8
RBP: ffff8801b8c472f0 R08: fffffc0000000001 R09: dffffc0000000003
R10: e000000000000008 R11: dffffc0000000002 R12: dffffc0000000003
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffffffffffd8
FS:  0000000000a75880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffc0000000000 CR3: 00000001ceb8a001 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 memset+0x23/0x40 mm/kasan/kasan.c:285
 memset include/linux/string.h:330 [inline]
 smc_ib_remember_port_attr+0x91/0x340 net/smc/smc_ib.c:419
 smc_pnet_add+0xb43/0xde0 net/smc/smc_pnet.c:354
 genl_family_rcv_msg+0x7b7/0xfb0 net/netlink/genetlink.c:599
 genl_rcv_msg+0xb2/0x140 net/netlink/genetlink.c:624
 netlink_rcv_skb+0x14b/0x380 net/netlink/af_netlink.c:2444
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:635
 netlink_unicast_kernel net/netlink/af_netlink.c:1308 [inline]
 netlink_unicast+0x4c4/0x6b0 net/netlink/af_netlink.c:1334
 netlink_sendmsg+0xa4a/0xe60 net/netlink/af_netlink.c:1897
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:640
 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046
 __sys_sendmsg+0xe5/0x210 net/socket.c:2080
 SYSC_sendmsg net/socket.c:2091 [inline]
 SyS_sendmsg+0x2d/0x50 net/socket.c:2087
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x43fda9
RSP: 002b:00007ffd35aa5268 EFLAGS: 00000213 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fda9
RDX: 0000000000040004 RSI: 0000000020a87fc8 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000213 R12: 00000000004016d0
R13: 0000000000401760 R14: 0000000000000000 R15: 0000000000000000
Code: fa 10 7f 3d 4d 85 d2 74 33 41 80 39 00 75 21 48 b8 01 00 00 00 00 fc ff df 4d 01 d1 49 01 c0 4d 39 c1 4c 89 c0 74 15 49 83 c0 01 <80> 38 00 74 ef 48 85 c0 49 89 c0 0f 85 89 00 00 00 5b 41 5c 5d
RIP: bytes_is_nonzero mm/kasan/kasan.c:166 [inline] RSP: ffff8801b8c472e0
RIP: memory_is_nonzero mm/kasan/kasan.c:184 [inline] RSP: ffff8801b8c472e0
RIP: memory_is_poisoned_n mm/kasan/kasan.c:210 [inline] RSP: ffff8801b8c472e0
RIP: memory_is_poisoned mm/kasan/kasan.c:241 [inline] RSP: ffff8801b8c472e0
RIP: check_memory_region_inline mm/kasan/kasan.c:257 [inline] RSP: ffff8801b8c472e0
RIP: check_memory_region+0x83/0x190 mm/kasan/kasan.c:267 RSP: ffff8801b8c472e0
CR2: fffffc0000000000
---[ end trace 327b8c6e0903b0d7 ]---

---
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Eric Biggers

2018-05-14 00:01 UTC #1 lore raw

PATCH 1/1 net/smc: check for missing nlattrs in SMC_PNETID messages

From: Eric Biggers <[email protected]>

It's possible to crash the kernel in several different ways by sending messages to the SMC_PNETID generic netlink family that are missing the expected attributes:

- Missing SMC_PNETID_NAME => null pointer dereference when comparing names.
- Missing SMC_PNETID_ETHNAME => null pointer dereference accessing smc_pnetentry::ndev.
- Missing SMC_PNETID_IBNAME => null pointer dereference accessing smc_pnetentry::smcibdev.
- Missing SMC_PNETID_IBPORT => out of bounds array access to smc_ib_device::pattr[-1].

Fix it by validating that all expected attributes are present and that SMC_PNETID_IBPORT is nonzero.

Reported-by [email protected]

Fixes 6812baabf24d ("smc: establish pnet table management")

Cc <[email protected]> # v4.11+

Signed-off-by Eric Biggers <[email protected]>

---
 net/smc/smc_pnet.c | 71 ++++++++++++++++++++++++++--------------------
 1 file changed, 40 insertions(+), 31 deletions(-)

net/smc/smc_pnet.c +40 ~~-31~~

index 74568cdbca708..d7b88b2d1b224 100644
@@ -245,40 +245,45 @@ static struct smc_ib_device *smc_pnet_find_ib(char *ib_name)
 static int smc_pnet_fill_entry(struct net *net, struct smc_pnetentry *pnetelem,
 			       struct nlattr *tb[])
 {
-	char *string, *ibname = NULL;
-	int rc = 0;
+	char *string, *ibname;
+	int rc;
 
 	memset(pnetelem, 0, sizeof(*pnetelem));
 	INIT_LIST_HEAD(&pnetelem->list);
-	if (tb[SMC_PNETID_NAME]) {
-		string = (char *)nla_data(tb[SMC_PNETID_NAME]);
-		if (!smc_pnetid_valid(string, pnetelem->pnet_name)) {
-			rc = -EINVAL;
-			goto error;
-		}
-	}
-	if (tb[SMC_PNETID_ETHNAME]) {
-		string = (char *)nla_data(tb[SMC_PNETID_ETHNAME]);
-		pnetelem->ndev = dev_get_by_name(net, string);
-		if (!pnetelem->ndev)
-			return -ENOENT;
-	}
-	if (tb[SMC_PNETID_IBNAME]) {
-		ibname = (char *)nla_data(tb[SMC_PNETID_IBNAME]);
-		ibname = strim(ibname);
-		pnetelem->smcibdev = smc_pnet_find_ib(ibname);
-		if (!pnetelem->smcibdev) {
-			rc = -ENOENT;
-			goto error;
-		}
-	}
-	if (tb[SMC_PNETID_IBPORT]) {
-		pnetelem->ib_port = nla_get_u8(tb[SMC_PNETID_IBPORT]);
-		if (pnetelem->ib_port > SMC_MAX_PORTS) {
-			rc = -EINVAL;
-			goto error;
-		}
-	}
+
+	rc = -EINVAL;
+	if (!tb[SMC_PNETID_NAME])
+		goto error;
+	string = (char *)nla_data(tb[SMC_PNETID_NAME]);
+	if (!smc_pnetid_valid(string, pnetelem->pnet_name))
+		goto error;
+
+	rc = -EINVAL;
+	if (!tb[SMC_PNETID_ETHNAME])
+		goto error;
+	rc = -ENOENT;
+	string = (char *)nla_data(tb[SMC_PNETID_ETHNAME]);
+	pnetelem->ndev = dev_get_by_name(net, string);
+	if (!pnetelem->ndev)
+		goto error;
+
+	rc = -EINVAL;
+	if (!tb[SMC_PNETID_IBNAME])
+		goto error;
+	rc = -ENOENT;
+	ibname = (char *)nla_data(tb[SMC_PNETID_IBNAME]);
+	ibname = strim(ibname);
+	pnetelem->smcibdev = smc_pnet_find_ib(ibname);
+	if (!pnetelem->smcibdev)
+		goto error;
+
+	rc = -EINVAL;
+	if (!tb[SMC_PNETID_IBPORT])
+		goto error;
+	pnetelem->ib_port = nla_get_u8(tb[SMC_PNETID_IBPORT]);
+	if (pnetelem->ib_port < 1 || pnetelem->ib_port > SMC_MAX_PORTS)
+		goto error;
+
 	return 0;
 
 error:

@@ -307,6 +312,8 @@ static int smc_pnet_get(struct sk_buff *skb, struct genl_info *info)
 	void *hdr;
 	int rc;
 
+	if (!info->attrs[SMC_PNETID_NAME])
+		return -EINVAL;
 	pnetelem = smc_pnet_find_pnetid(
 				(char *)nla_data(info->attrs[SMC_PNETID_NAME]));
 	if (!pnetelem)

@@ -359,6 +366,8 @@ static int smc_pnet_add(struct sk_buff *skb, struct genl_info *info)
 
 static int smc_pnet_del(struct sk_buff *skb, struct genl_info *info)
 {
+	if (!info->attrs[SMC_PNETID_NAME])
+		return -EINVAL;
 	return smc_pnet_remove_by_pnetid(
 				(char *)nla_data(info->attrs[SMC_PNETID_NAME]));
 }

Signature · 1 line

2.17.0

David Miller

maintainer

2018-05-14 20:41 UTC #2 lore raw

Re: [PATCH] net/smc: check for missing nlattrs in SMC_PNETID messages

From: Eric Biggers <[email protected]>
Date: Sun, 13 May 2018 17:01:30 -0700

Quoted 15 lines

From: Eric Biggers <[email protected]>
It's possible to crash the kernel in several different ways by sending messages to the SMC_PNETID generic netlink family that are missing the expected attributes:
- Missing SMC_PNETID_NAME => null pointer dereference when comparing names.
- Missing SMC_PNETID_ETHNAME => null pointer dereference accessing smc_pnetentry::ndev.
- Missing SMC_PNETID_IBNAME => null pointer dereference accessing smc_pnetentry::smcibdev.
- Missing SMC_PNETID_IBPORT => out of bounds array access to smc_ib_device::pattr[-1].

Quoted 7 lines

Fix it by validating that all expected attributes are present and that SMC_PNETID_IBPORT is nonzero.
Reported-by [email protected]
Fixes 6812baabf24d ("smc: establish pnet table management")
Cc <[email protected]> # v4.11+
Signed-off-by Eric Biggers <[email protected]>

Applied and queued up for -stable, thanks.