diff mbox series

[net] ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action()

Message ID 20240507163145.835254-1-edumazet@google.com (mailing list archive)
State Accepted
Commit d101291b2681e5ab938554e3e323f7a7ee33e3aa
Delegated to: Netdev Maintainers
Headers show
Series [net] ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action() | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 926 this patch: 926
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 6 maintainers
netdev/build_clang success Errors and warnings before: 937 this patch: 937
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 937 this patch: 937
netdev/checkpatch warning WARNING: Possible repeated word: 'Google'
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-05-08--03-00 (tests: 1005)

Commit Message

Eric Dumazet May 7, 2024, 4:31 p.m. UTC 
syzbot is able to trigger the following crash [1],
caused by unsafe ip6_dst_idev() use.

Indeed ip6_dst_idev() can return NULL, and must always be checked.

[1]

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 31648 Comm: syz-executor.0 Not tainted 6.9.0-rc4-next-20240417-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
 RIP: 0010:__fib6_rule_action net/ipv6/fib6_rules.c:237 [inline]
 RIP: 0010:fib6_rule_action+0x241/0x7b0 net/ipv6/fib6_rules.c:267
Code: 02 00 00 49 8d 9f d8 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f9 32 bf f7 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e0 32 bf f7 4c 8b 03 48 89 ef 4c
RSP: 0018:ffffc9000fc1f2f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1a772f98c8186700
RDX: 0000000000000003 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f9760
RBP: ffff8880673fb980 R08: ffffffff8fac15ef R09: 1ffffffff1f582bd
R10: dffffc0000000000 R11: fffffbfff1f582be R12: dffffc0000000000
R13: 0000000000000080 R14: ffff888076509000 R15: ffff88807a029a00
FS:  00007f55e82ca6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31d23000 CR3: 0000000022b66000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
  fib_rules_lookup+0x62c/0xdb0 net/core/fib_rules.c:317
  fib6_rule_lookup+0x1fd/0x790 net/ipv6/fib6_rules.c:108
  ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline]
  ip6_route_output_flags+0x38e/0x610 net/ipv6/route.c:2649
  ip6_route_output include/net/ip6_route.h:93 [inline]
  ip6_dst_lookup_tail+0x189/0x11a0 net/ipv6/ip6_output.c:1120
  ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1250
  sctp_v6_get_dst+0x792/0x1e20 net/sctp/ipv6.c:326
  sctp_transport_route+0x12c/0x2e0 net/sctp/transport.c:455
  sctp_assoc_add_peer+0x614/0x15c0 net/sctp/associola.c:662
  sctp_connect_new_asoc+0x31d/0x6c0 net/sctp/socket.c:1099
  __sctp_connect+0x66d/0xe30 net/sctp/socket.c:1197
  sctp_connect net/sctp/socket.c:4819 [inline]
  sctp_inet_connect+0x149/0x1f0 net/sctp/socket.c:4834
  __sys_connect_file net/socket.c:2048 [inline]
  __sys_connect+0x2df/0x310 net/socket.c:2065
  __do_sys_connect net/socket.c:2075 [inline]
  __se_sys_connect net/socket.c:2072 [inline]
  __x64_sys_connect+0x7a/0x90 net/socket.c:2072
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: 5e5f3f0f8013 ("[IPV6] ADDRCONF: Convert ipv6_get_saddr() to ipv6_dev_get_saddr().")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv6/fib6_rules.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Simon Horman May 8, 2024, 1:46 p.m. UTC | #1 
On Tue, May 07, 2024 at 04:31:45PM +0000, Eric Dumazet wrote:
> syzbot is able to trigger the following crash [1],
> caused by unsafe ip6_dst_idev() use.
> 
> Indeed ip6_dst_idev() can return NULL, and must always be checked.
> 
> [1]
> 
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 0 PID: 31648 Comm: syz-executor.0 Not tainted 6.9.0-rc4-next-20240417-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
>  RIP: 0010:__fib6_rule_action net/ipv6/fib6_rules.c:237 [inline]
>  RIP: 0010:fib6_rule_action+0x241/0x7b0 net/ipv6/fib6_rules.c:267
> Code: 02 00 00 49 8d 9f d8 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f9 32 bf f7 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e0 32 bf f7 4c 8b 03 48 89 ef 4c
> RSP: 0018:ffffc9000fc1f2f0 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1a772f98c8186700
> RDX: 0000000000000003 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f9760
> RBP: ffff8880673fb980 R08: ffffffff8fac15ef R09: 1ffffffff1f582bd
> R10: dffffc0000000000 R11: fffffbfff1f582be R12: dffffc0000000000
> R13: 0000000000000080 R14: ffff888076509000 R15: ffff88807a029a00
> FS:  00007f55e82ca6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b31d23000 CR3: 0000000022b66000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>   fib_rules_lookup+0x62c/0xdb0 net/core/fib_rules.c:317
>   fib6_rule_lookup+0x1fd/0x790 net/ipv6/fib6_rules.c:108
>   ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline]
>   ip6_route_output_flags+0x38e/0x610 net/ipv6/route.c:2649
>   ip6_route_output include/net/ip6_route.h:93 [inline]
>   ip6_dst_lookup_tail+0x189/0x11a0 net/ipv6/ip6_output.c:1120
>   ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1250
>   sctp_v6_get_dst+0x792/0x1e20 net/sctp/ipv6.c:326
>   sctp_transport_route+0x12c/0x2e0 net/sctp/transport.c:455
>   sctp_assoc_add_peer+0x614/0x15c0 net/sctp/associola.c:662
>   sctp_connect_new_asoc+0x31d/0x6c0 net/sctp/socket.c:1099
>   __sctp_connect+0x66d/0xe30 net/sctp/socket.c:1197
>   sctp_connect net/sctp/socket.c:4819 [inline]
>   sctp_inet_connect+0x149/0x1f0 net/sctp/socket.c:4834
>   __sys_connect_file net/socket.c:2048 [inline]
>   __sys_connect+0x2df/0x310 net/socket.c:2065
>   __do_sys_connect net/socket.c:2075 [inline]
>   __se_sys_connect net/socket.c:2072 [inline]
>   __x64_sys_connect+0x7a/0x90 net/socket.c:2072
>   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>   do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Fixes: 5e5f3f0f8013 ("[IPV6] ADDRCONF: Convert ipv6_get_saddr() to ipv6_dev_get_saddr().")
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Simon Horman <horms@kernel.org>
David Ahern May 8, 2024, 3:02 p.m. UTC | #2 
On 5/7/24 10:31 AM, Eric Dumazet wrote:
> syzbot is able to trigger the following crash [1],
> caused by unsafe ip6_dst_idev() use.
> 
> Indeed ip6_dst_idev() can return NULL, and must always be checked.
> 
> [1]
> 
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 0 PID: 31648 Comm: syz-executor.0 Not tainted 6.9.0-rc4-next-20240417-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
>  RIP: 0010:__fib6_rule_action net/ipv6/fib6_rules.c:237 [inline]
>  RIP: 0010:fib6_rule_action+0x241/0x7b0 net/ipv6/fib6_rules.c:267
> Code: 02 00 00 49 8d 9f d8 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 f9 32 bf f7 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 e0 32 bf f7 4c 8b 03 48 89 ef 4c
> RSP: 0018:ffffc9000fc1f2f0 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1a772f98c8186700
> RDX: 0000000000000003 RSI: ffffffff8bcac4e0 RDI: ffffffff8c1f9760
> RBP: ffff8880673fb980 R08: ffffffff8fac15ef R09: 1ffffffff1f582bd
> R10: dffffc0000000000 R11: fffffbfff1f582be R12: dffffc0000000000
> R13: 0000000000000080 R14: ffff888076509000 R15: ffff88807a029a00
> FS:  00007f55e82ca6c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000001b31d23000 CR3: 0000000022b66000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>   fib_rules_lookup+0x62c/0xdb0 net/core/fib_rules.c:317
>   fib6_rule_lookup+0x1fd/0x790 net/ipv6/fib6_rules.c:108
>   ip6_route_output_flags_noref net/ipv6/route.c:2637 [inline]
>   ip6_route_output_flags+0x38e/0x610 net/ipv6/route.c:2649
>   ip6_route_output include/net/ip6_route.h:93 [inline]
>   ip6_dst_lookup_tail+0x189/0x11a0 net/ipv6/ip6_output.c:1120
>   ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1250
>   sctp_v6_get_dst+0x792/0x1e20 net/sctp/ipv6.c:326
>   sctp_transport_route+0x12c/0x2e0 net/sctp/transport.c:455
>   sctp_assoc_add_peer+0x614/0x15c0 net/sctp/associola.c:662
>   sctp_connect_new_asoc+0x31d/0x6c0 net/sctp/socket.c:1099
>   __sctp_connect+0x66d/0xe30 net/sctp/socket.c:1197
>   sctp_connect net/sctp/socket.c:4819 [inline]
>   sctp_inet_connect+0x149/0x1f0 net/sctp/socket.c:4834
>   __sys_connect_file net/socket.c:2048 [inline]
>   __sys_connect+0x2df/0x310 net/socket.c:2065
>   __do_sys_connect net/socket.c:2075 [inline]
>   __se_sys_connect net/socket.c:2072 [inline]
>   __x64_sys_connect+0x7a/0x90 net/socket.c:2072
>   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>   do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Fixes: 5e5f3f0f8013 ("[IPV6] ADDRCONF: Convert ipv6_get_saddr() to ipv6_dev_get_saddr().")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
>  net/ipv6/fib6_rules.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>
patchwork-bot+netdevbpf@kernel.org May 9, 2024, 2 a.m. UTC | #3 
Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue,  7 May 2024 16:31:45 +0000 you wrote:
> syzbot is able to trigger the following crash [1],
> caused by unsafe ip6_dst_idev() use.
> 
> Indeed ip6_dst_idev() can return NULL, and must always be checked.
> 
> [1]
> 
> [...]

Here is the summary with links:
  - [net] ipv6: fib6_rules: avoid possible NULL dereference in fib6_rule_action()
    https://git.kernel.org/netdev/net/c/d101291b2681

You are awesome, thank you!
diff mbox series

Patch

diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 52c04f0ac498123becfdc30af5a90f1b2291934d..9e254de7462fb86bb053353dfaa2715a369a7994 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -233,8 +233,12 @@  static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
 	rt = pol_lookup_func(lookup,
 			     net, table, flp6, arg->lookup_data, flags);
 	if (rt != net->ipv6.ip6_null_entry) {
+		struct inet6_dev *idev = ip6_dst_idev(&rt->dst);
+
+		if (!idev)
+			goto again;
 		err = fib6_rule_saddr(net, rule, flags, flp6,
-				      ip6_dst_idev(&rt->dst)->dev);
+				      idev->dev);
 
 		if (err == -EAGAIN)
 			goto again;