[PATCH net v2 1/1] af_unix: Reject SIOCATMARK on non-stream sockets

[PATCH net v2 1/1] af_unix: Reject SIOCATMARK on non-stream sockets

[Ren Wei]

From: Jiexun Wang <wangjiexun2025@gmail.com>

SIOCATMARK reports whether the receive queue is at the urgent mark for
MSG_OOB.

In AF_UNIX, MSG_OOB is supported only for SOCK_STREAM sockets.
SOCK_DGRAM and SOCK_SEQPACKET reject MSG_OOB in sendmsg() and recvmsg(),
so they should not support SIOCATMARK either.

Return -EOPNOTSUPP for non-stream sockets before checking the receive
queue.

Fixes: 314001f0bf92 ("af_unix: Add OOB support")
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Tested-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Jiexun Wang <wangjiexun2025@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
---
Changes in v2:
- Rework the fix based on maintainer feedback.
- Drop the receive-queue locking approach and reject SIOCATMARK on
  non-stream sockets instead, since it is only meaningful for MSG_OOB.
- V1 link: https://lore.kernel.org/netdev/f6cbbc8da90e95584847b5ceb60aae830d1631c2.1775731983.git.wangjiexun2025@gmail.com/

 net/unix/af_unix.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index b23c33df8b46..09d43b4813b1 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -3300,6 +3300,9 @@ static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 			struct sk_buff *skb;
 			int answ = 0;
 
+			if (sk->sk_type != SOCK_STREAM)
+				return -EOPNOTSUPP;
+
 			mutex_lock(&u->iolock);
 
 			skb = skb_peek(&sk->sk_receive_queue);
-- 
2.34.1

Re: [PATCH net v2 1/1] af_unix: Reject SIOCATMARK on non-stream sockets

[Kuniyuki Iwashima]

On Mon, Apr 13, 2026 at 5:29 AM Ren Wei <n05ec@lzu.edu.cn> wrote:
>
> From: Jiexun Wang <wangjiexun2025@gmail.com>
>
> SIOCATMARK reports whether the receive queue is at the urgent mark for
> MSG_OOB.
>
> In AF_UNIX, MSG_OOB is supported only for SOCK_STREAM sockets.
> SOCK_DGRAM and SOCK_SEQPACKET reject MSG_OOB in sendmsg() and recvmsg(),
> so they should not support SIOCATMARK either.
>
> Return -EOPNOTSUPP for non-stream sockets before checking the receive
> queue.
>
> Fixes: 314001f0bf92 ("af_unix: Add OOB support")
> Reported-by: Yifan Wu <yifanwucs@gmail.com>
> Reported-by: Juefei Pu <tomapufckgml@gmail.com>
> Co-developed-by: Yuan Tan <yuantan098@gmail.com>
> Signed-off-by: Yuan Tan <yuantan098@gmail.com>
> Suggested-by: Xin Liu <bird@lzu.edu.cn>

Please read this guideline again.
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by

Co-developed-by is not where you mention someone who
developed a tool to find a bug, and Suggested-by is not where
you mention someone who funds your research.
https://lore.kernel.org/netdev/7c26a74d-90c5-4520-a10a-22f06e098b86@gmail.com/

When you just copy my fix and modify the commit message,
the two tags are inappropriate.


> Tested-by: Ren Wei <enjou1224z@gmail.com>
> Signed-off-by: Jiexun Wang <wangjiexun2025@gmail.com>
> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
> ---
> Changes in v2:
> - Rework the fix based on maintainer feedback.
> - Drop the receive-queue locking approach and reject SIOCATMARK on
>   non-stream sockets instead, since it is only meaningful for MSG_OOB.
> - V1 link: https://lore.kernel.org/netdev/f6cbbc8da90e95584847b5ceb60aae830d1631c2.1775731983.git.wangjiexun2025@gmail.com/
>
>  net/unix/af_unix.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index b23c33df8b46..09d43b4813b1 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -3300,6 +3300,9 @@ static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
>                         struct sk_buff *skb;
>                         int answ = 0;
>
> +                       if (sk->sk_type != SOCK_STREAM)
> +                               return -EOPNOTSUPP;
> +
>                         mutex_lock(&u->iolock);
>
>                         skb = skb_peek(&sk->sk_receive_queue);
> --
> 2.34.1
>

Re: [PATCH net v2 1/1] af_unix: Reject SIOCATMARK on non-stream sockets

[Yuan Tan]

On 4/13/2026 10:33 PM, Kuniyuki Iwashima wrote:
> On Mon, Apr 13, 2026 at 5:29 AM Ren Wei <n05ec@lzu.edu.cn> wrote:
>> From: Jiexun Wang <wangjiexun2025@gmail.com>
>>
>> SIOCATMARK reports whether the receive queue is at the urgent mark for
>> MSG_OOB.
>>
>> In AF_UNIX, MSG_OOB is supported only for SOCK_STREAM sockets.
>> SOCK_DGRAM and SOCK_SEQPACKET reject MSG_OOB in sendmsg() and recvmsg(),
>> so they should not support SIOCATMARK either.
>>
>> Return -EOPNOTSUPP for non-stream sockets before checking the receive
>> queue.
>>
>> Fixes: 314001f0bf92 ("af_unix: Add OOB support")
>> Reported-by: Yifan Wu <yifanwucs@gmail.com>
>> Reported-by: Juefei Pu <tomapufckgml@gmail.com>
>> Co-developed-by: Yuan Tan <yuantan098@gmail.com>
>> Signed-off-by: Yuan Tan <yuantan098@gmail.com>
>> Suggested-by: Xin Liu <bird@lzu.edu.cn>
> Please read this guideline again.
> https://www.kernel.org/doc/html/latest/process/submitting-patches.html#when-to-use-acked-by-cc-and-co-developed-by
>
> Co-developed-by is not where you mention someone who
> developed a tool to find a bug, and Suggested-by is not where
> you mention someone who funds your research.
> https://lore.kernel.org/netdev/7c26a74d-90c5-4520-a10a-22f06e098b86@gmail.com/
>
> When you just copy my fix and modify the commit message,
> the two tags are inappropriate.
>
We sincerely apologize for the misuse of the tags and the incorrect
crediting in our previous submission. We are still learning the
community's process and appreciate your patience.

Would you allow us to add:
Suggested-by: Kuniyuki Iwashima <kuniyu@google.com>
Or
Co-developed-by: Kumiki Iwashima <kuniyu@google.com>
in this patch?

In future patches, if a maintainer provides specific code suggestions,
we will first ask if a Suggested-by or Co-developed-by tag is needed
before sending a new version.

If a maintainer doesn't provide specific code, but points out errors in
our patch, explains how to fix the bug correctly, or mentions similar
paths that could be fixed together, I am not quite sure if a
Suggested-by tag is required. Maybe we can send an email first when we
are uncertain to avoid this happening again.

If the following tags are the correct way, we will update the v3 patch
like this:

Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yihan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Co-developed-by or Suggested-by? : Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Jiexun Wang <wangjiexun2025@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>


One more thing: my understanding is that non-maintainers can also
provide Reviewed-by tags, right? While I will be less involved in direct
development and mentoring, I will still review every report and patch
from our team before submission to ensure quality.


>> Tested-by: Ren Wei <enjou1224z@gmail.com>
>> Signed-off-by: Jiexun Wang <wangjiexun2025@gmail.com>
>> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
>> ---
>> Changes in v2:
>> - Rework the fix based on maintainer feedback.
>> - Drop the receive-queue locking approach and reject SIOCATMARK on
>>   non-stream sockets instead, since it is only meaningful for MSG_OOB.
>> - V1 link: https://lore.kernel.org/netdev/f6cbbc8da90e95584847b5ceb60aae830d1631c2.1775731983.git.wangjiexun2025@gmail.com/
>>
>>  net/unix/af_unix.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
>> index b23c33df8b46..09d43b4813b1 100644
>> --- a/net/unix/af_unix.c
>> +++ b/net/unix/af_unix.c
>> @@ -3300,6 +3300,9 @@ static int unix_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
>>                         struct sk_buff *skb;
>>                         int answ = 0;
>>
>> +                       if (sk->sk_type != SOCK_STREAM)
>> +                               return -EOPNOTSUPP;
>> +
>>                         mutex_lock(&u->iolock);
>>
>>                         skb = skb_peek(&sk->sk_receive_queue);
>> --
>> 2.34.1
>>