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* [PATCH net] sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb
@ 2021-09-23  4:05 Xin Long
  2021-09-24  1:52 ` Marcelo Ricardo Leitner
  2021-09-24  9:40 ` patchwork-bot+netdevbpf
  0 siblings, 2 replies; 3+ messages in thread
From: Xin Long @ 2021-09-23  4:05 UTC (permalink / raw)
  To: network dev, davem, kuba, linux-sctp; +Cc: Marcelo Ricardo Leitner

We should always check if skb_header_pointer's return is NULL before
using it, otherwise it may cause null-ptr-deref, as syzbot reported:

  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:sctp_rcv_ootb net/sctp/input.c:705 [inline]
  RIP: 0010:sctp_rcv+0x1d84/0x3220 net/sctp/input.c:196
  Call Trace:
  <IRQ>
   sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1109
   ip6_protocol_deliver_rcu+0x2e9/0x1ca0 net/ipv6/ip6_input.c:422
   ip6_input_finish+0x62/0x170 net/ipv6/ip6_input.c:463
   NF_HOOK include/linux/netfilter.h:307 [inline]
   NF_HOOK include/linux/netfilter.h:301 [inline]
   ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472
   dst_input include/net/dst.h:460 [inline]
   ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
   NF_HOOK include/linux/netfilter.h:307 [inline]
   NF_HOOK include/linux/netfilter.h:301 [inline]
   ipv6_rcv+0x28c/0x3c0 net/ipv6/ip6_input.c:297

Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
Reported-by: syzbot+581aff2ae6b860625116@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/sctp/input.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/input.c b/net/sctp/input.c
index 5ef86fdb1176..1f1786021d9c 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -702,7 +702,7 @@ static int sctp_rcv_ootb(struct sk_buff *skb)
 		ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch);
 
 		/* Break out if chunk length is less then minimal. */
-		if (ntohs(ch->length) < sizeof(_ch))
+		if (!ch || ntohs(ch->length) < sizeof(_ch))
 			break;
 
 		ch_end = offset + SCTP_PAD4(ntohs(ch->length));
-- 
2.27.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH net] sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb
  2021-09-23  4:05 [PATCH net] sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb Xin Long
@ 2021-09-24  1:52 ` Marcelo Ricardo Leitner
  2021-09-24  9:40 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: Marcelo Ricardo Leitner @ 2021-09-24  1:52 UTC (permalink / raw)
  To: Xin Long; +Cc: network dev, davem, kuba, linux-sctp

On Thu, Sep 23, 2021 at 12:05:04AM -0400, Xin Long wrote:
> We should always check if skb_header_pointer's return is NULL before
> using it, otherwise it may cause null-ptr-deref, as syzbot reported:
> 
>   KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
>   RIP: 0010:sctp_rcv_ootb net/sctp/input.c:705 [inline]
>   RIP: 0010:sctp_rcv+0x1d84/0x3220 net/sctp/input.c:196
>   Call Trace:
>   <IRQ>
>    sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1109
>    ip6_protocol_deliver_rcu+0x2e9/0x1ca0 net/ipv6/ip6_input.c:422
>    ip6_input_finish+0x62/0x170 net/ipv6/ip6_input.c:463
>    NF_HOOK include/linux/netfilter.h:307 [inline]
>    NF_HOOK include/linux/netfilter.h:301 [inline]
>    ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472
>    dst_input include/net/dst.h:460 [inline]
>    ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
>    NF_HOOK include/linux/netfilter.h:307 [inline]
>    NF_HOOK include/linux/netfilter.h:301 [inline]
>    ipv6_rcv+0x28c/0x3c0 net/ipv6/ip6_input.c:297
> 
> Fixes: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
> Reported-by: syzbot+581aff2ae6b860625116@syzkaller.appspotmail.com
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH net] sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb
  2021-09-23  4:05 [PATCH net] sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb Xin Long
  2021-09-24  1:52 ` Marcelo Ricardo Leitner
@ 2021-09-24  9:40 ` patchwork-bot+netdevbpf
  1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-09-24  9:40 UTC (permalink / raw)
  To: Xin Long; +Cc: netdev, davem, kuba, linux-sctp, marcelo.leitner

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Thu, 23 Sep 2021 00:05:04 -0400 you wrote:
> We should always check if skb_header_pointer's return is NULL before
> using it, otherwise it may cause null-ptr-deref, as syzbot reported:
> 
>   KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
>   RIP: 0010:sctp_rcv_ootb net/sctp/input.c:705 [inline]
>   RIP: 0010:sctp_rcv+0x1d84/0x3220 net/sctp/input.c:196
>   Call Trace:
>   <IRQ>
>    sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1109
>    ip6_protocol_deliver_rcu+0x2e9/0x1ca0 net/ipv6/ip6_input.c:422
>    ip6_input_finish+0x62/0x170 net/ipv6/ip6_input.c:463
>    NF_HOOK include/linux/netfilter.h:307 [inline]
>    NF_HOOK include/linux/netfilter.h:301 [inline]
>    ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472
>    dst_input include/net/dst.h:460 [inline]
>    ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
>    NF_HOOK include/linux/netfilter.h:307 [inline]
>    NF_HOOK include/linux/netfilter.h:301 [inline]
>    ipv6_rcv+0x28c/0x3c0 net/ipv6/ip6_input.c:297
> 
> [...]

Here is the summary with links:
  - [net] sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb
    https://git.kernel.org/netdev/net/c/f7e745f8e944

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-09-24  9:40 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-09-23  4:05 [PATCH net] sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb Xin Long
2021-09-24  1:52 ` Marcelo Ricardo Leitner
2021-09-24  9:40 ` patchwork-bot+netdevbpf

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