[PATCH v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()

[PATCH v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()

[Dmitry Antipov]

In tcp_bpf_sendmsg(), the value returned by sk_msg_memcopy_from_iter()
is checked for error but not propagated to 'out_err' label, so error
handling may not work as expected. Fix this by assigning error value
to 'err', thus making sure that error won't be silently ignored.

Reported-by: Sashiko <shodan.ai@mcst.ru>
Fixes: 5153a75ef34b ("tcp_bpf: Fix copied value in tcp_bpf_sendmsg")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
---
v2: more descriptive commit message
---
 net/ipv4/tcp_bpf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 2e234d155b5e..0ce583f68d3b 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -581,6 +581,7 @@ static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 					       copy);
 		if (ret < 0) {
 			sk_msg_trim(sk, msg_tx, osize);
+			err = ret;
 			goto out_err;
 		}
 
-- 
2.56.0

Re: [PATCH v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.

Re: [PATCH v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()

[Kuniyuki Iwashima]

On Mon, 19 Oct 2026 11:22:14 +0300, Dmitry Antipov wrote:
> In tcp_bpf_sendmsg(), the value returned by sk_msg_memcopy_from_iter()
> is checked for error but not propagated to 'out_err' label, so error
> handling may not work as expected. Fix this by assigning error value
> to 'err', thus making sure that error won't be silently ignored.
> 
> Reported-by: Sashiko <shodan.ai@mcst.ru>
> Fixes: 5153a75ef34b ("tcp_bpf: Fix copied value in tcp_bpf_sendmsg")
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>

Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>

Re: [PATCH v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()

[Jason Xing]

On Mon, Oct 19, 2026 at 4:27 PM Dmitry Antipov <dmantipov@yandex.ru> wrote:
>
> In tcp_bpf_sendmsg(), the value returned by sk_msg_memcopy_from_iter()
> is checked for error but not propagated to 'out_err' label, so error
> handling may not work as expected. Fix this by assigning error value
> to 'err', thus making sure that error won't be silently ignored.
>
> Reported-by: Sashiko <shodan.ai@mcst.ru>
> Fixes: 5153a75ef34b ("tcp_bpf: Fix copied value in tcp_bpf_sendmsg")
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>

Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>

Re: [PATCH v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()

[Eric Dumazet]

Le mar. 20 oct. 2026 à 08:23, Jason Xing <kerneljasonxing@gmail.com> a écrit :
>
> On Mon, Oct 19, 2026 at 4:27 PM Dmitry Antipov <dmantipov@yandex.ru> wrote:
> >
> > In tcp_bpf_sendmsg(), the value returned by sk_msg_memcopy_from_iter()
> > is checked for error but not propagated to 'out_err' label, so error
> > handling may not work as expected. Fix this by assigning error value
> > to 'err', thus making sure that error won't be silently ignored.
> >
> > Reported-by: Sashiko <shodan.ai@mcst.ru>
> > Fixes: 5153a75ef34b ("tcp_bpf: Fix copied value in tcp_bpf_sendmsg")
> > Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
>
> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>

Reviewed-by: Eric Dumazet <edumazet@kernel.org>

Re: [PATCH v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()

[patchwork-bot+netdevbpf]

Hello:

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

On Mon, 19 Oct 2026 11:22:14 +0300 you wrote:
> In tcp_bpf_sendmsg(), the value returned by sk_msg_memcopy_from_iter()
> is checked for error but not propagated to 'out_err' label, so error
> handling may not work as expected. Fix this by assigning error value
> to 'err', thus making sure that error won't be silently ignored.
> 
> Reported-by: Sashiko <shodan.ai@mcst.ru>
> Fixes: 5153a75ef34b ("tcp_bpf: Fix copied value in tcp_bpf_sendmsg")
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
> 
> [...]

Here is the summary with links:
  - [v2] tcp_bpf: propagate error code in tcp_bpf_sendmsg()
    https://git.kernel.org/netdev/net/c/82e31923c055

You are awesome, thank you!
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