[v1] atm: clip: Fix NULL pointer dereference in vcc_sendmsg()

[PATCH] atm: clip: Fix NULL pointer dereference in vcc_sendmsg()

Posted by Yue Haibing 7 months, 1 week ago

BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000d3cf778 EFLAGS: 00010246
RAX: 1ffffffff1910dd1 RBX: 00000000000000c0 RCX: dffffc0000000000
RDX: ffffc9000dc82000 RSI: ffff88803e4c4640 RDI: ffff888052cd0000
RBP: ffffc9000d3cf8d0 R08: ffff888052c9143f R09: 1ffff1100a592287
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff92001a79f00
R13: ffff888052cd0000 R14: ffff88803e4c4640 R15: ffffffff8c886e88
FS:  00007fbc762566c0(0000) GS:ffff88808d6c2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000041f1b000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vcc_sendmsg+0xa10/0xc50 net/atm/common.c:644
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 ____sys_sendmsg+0x52d/0x830 net/socket.c:2566
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
 __sys_sendmmsg+0x227/0x430 net/socket.c:2709
 __do_sys_sendmmsg net/socket.c:2736 [inline]
 __se_sys_sendmmsg net/socket.c:2733 [inline]
 __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2733
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

atmarpd_dev_ops does not implement the send method, which may cause crash
as above.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+e34e5e6b5eddb0014def@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/682f82d5.a70a0220.1765ec.0143.GAE@google.com/T
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
---
 net/atm/clip.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/atm/clip.c b/net/atm/clip.c
index b234dc3bcb0d..c02ba9d64bc3 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -616,8 +616,15 @@ static void atmarpd_close(struct atm_vcc *vcc)
 	module_put(THIS_MODULE);
 }
 
+static int atmarpd_send(struct atm_vcc *vcc, struct sk_buff *skb)
+{
+	dev_kfree_skb_any(skb);
+	return 0;
+}
+
 static const struct atmdev_ops atmarpd_dev_ops = {
-	.close = atmarpd_close
+	.close = atmarpd_close,
+	.send = atmarpd_send
 };
 
 
-- 
2.34.1

Re: [PATCH] atm: clip: Fix NULL pointer dereference in vcc_sendmsg()

Posted by Kuniyuki Iwashima 7 months, 1 week ago

Please specify 'net' in subject:

  [PATCH net v2] atm: clip: ...

From: Yue Haibing <yuehaibing@huawei.com>
Date: Fri, 4 Jul 2025 10:39:14 +0800
> BUG: kernel NULL pointer dereference, address: 0000000000000000
> PGD 0 P4D 0
> Oops: Oops: 0010 [#1] SMP KASAN NOPTI
> CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
> RIP: 0010:0x0
> Code: Unable to access opcode bytes at 0xffffffffffffffd6.
> RSP: 0018:ffffc9000d3cf778 EFLAGS: 00010246
> RAX: 1ffffffff1910dd1 RBX: 00000000000000c0 RCX: dffffc0000000000
> RDX: ffffc9000dc82000 RSI: ffff88803e4c4640 RDI: ffff888052cd0000
> RBP: ffffc9000d3cf8d0 R08: ffff888052c9143f R09: 1ffff1100a592287
> R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff92001a79f00
> R13: ffff888052cd0000 R14: ffff88803e4c4640 R15: ffffffff8c886e88
> FS:  00007fbc762566c0(0000) GS:ffff88808d6c2000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: ffffffffffffffd6 CR3: 0000000041f1b000 CR4: 0000000000352ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  vcc_sendmsg+0xa10/0xc50 net/atm/common.c:644
>  sock_sendmsg_nosec net/socket.c:712 [inline]
>  __sock_sendmsg+0x219/0x270 net/socket.c:727
>  ____sys_sendmsg+0x52d/0x830 net/socket.c:2566
>  ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
>  __sys_sendmmsg+0x227/0x430 net/socket.c:2709
>  __do_sys_sendmmsg net/socket.c:2736 [inline]
>  __se_sys_sendmmsg net/socket.c:2733 [inline]
>  __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2733
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> atmarpd_dev_ops does not implement the send method, which may cause crash
> as above.

Please move commit message before the splat.


> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Reported-by: syzbot+e34e5e6b5eddb0014def@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/all/682f82d5.a70a0220.1765ec.0143.GAE@google.com/T
> Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
> ---
>  net/atm/clip.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/net/atm/clip.c b/net/atm/clip.c
> index b234dc3bcb0d..c02ba9d64bc3 100644
> --- a/net/atm/clip.c
> +++ b/net/atm/clip.c
> @@ -616,8 +616,15 @@ static void atmarpd_close(struct atm_vcc *vcc)
>  	module_put(THIS_MODULE);
>  }
>  
> +static int atmarpd_send(struct atm_vcc *vcc, struct sk_buff *skb)
> +{
> +	dev_kfree_skb_any(skb);

This is not enough, see:

commit 7851263998d4269125fd6cb3fdbfc7c6db853859
Author: Kuniyuki Iwashima <kuniyu@google.com>
Date:   Mon Jun 16 18:21:15 2025

    atm: Revert atm_account_tx() if copy_from_iter_full() fails.


> +	return 0;
> +}
> +
>  static const struct atmdev_ops atmarpd_dev_ops = {
> -	.close = atmarpd_close
> +	.close = atmarpd_close,
> +	.send = atmarpd_send
>  };
>  
>  
> -- 
> 2.34.1

Re: [PATCH] atm: clip: Fix NULL pointer dereference in vcc_sendmsg()

Posted by Yue Haibing 7 months, 1 week ago

On 2025/7/4 14:53, Kuniyuki Iwashima wrote:
> Please specify 'net' in subject:
> 
>   [PATCH net v2] atm: clip: ...
> 
> From: Yue Haibing <yuehaibing@huawei.com>
> Date: Fri, 4 Jul 2025 10:39:14 +0800
[...]
>> as above.
> 
> Please move commit message before the splat.

ok
> 
> 
>>
>> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
>> Reported-by: syzbot+e34e5e6b5eddb0014def@syzkaller.appspotmail.com
>> Closes: https://lore.kernel.org/all/682f82d5.a70a0220.1765ec.0143.GAE@google.com/T
>> Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
>> ---
>>  net/atm/clip.c | 9 ++++++++-
>>  1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/atm/clip.c b/net/atm/clip.c
>> index b234dc3bcb0d..c02ba9d64bc3 100644
>> --- a/net/atm/clip.c
>> +++ b/net/atm/clip.c
>> @@ -616,8 +616,15 @@ static void atmarpd_close(struct atm_vcc *vcc)
>>  	module_put(THIS_MODULE);
>>  }
>>  
>> +static int atmarpd_send(struct atm_vcc *vcc, struct sk_buff *skb)
>> +{
>> +	dev_kfree_skb_any(skb);
> 
> This is not enough, see:

Thanks, will check this and rework.

> commit 7851263998d4269125fd6cb3fdbfc7c6db853859
> Author: Kuniyuki Iwashima <kuniyu@google.com>
> Date:   Mon Jun 16 18:21:15 2025
> 
>     atm: Revert atm_account_tx() if copy_from_iter_full() fails.
> 
> 
>> +	return 0;
>> +}
>> +
>>  static const struct atmdev_ops atmarpd_dev_ops = {
>> -	.close = atmarpd_close
>> +	.close = atmarpd_close,
>> +	.send = atmarpd_send
>>  };
>>  
>>  
>> -- 
>> 2.34.1