Re: [PATCH] seccomp: Unconditionally allow accept(2) even if accept4(2) is present

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Jan 02, 2025 at 11:02:23PM +0100, Stefano Brivio wrote:
> On Alpine Linux 3.21, passt aborts right away as soon as QEMU connects
> to it.
> 
> Most likely, this has always been the case with musl, because since
> musl commit dc01e2cbfb29 ("add fallback emulation for accept4 on old
> kernels"), accept4() without flags is implemented using accept().
> 
> However, I guess that nobody realised earlier because it's typically
> pasta(1) being used on musl-based distributions, and the only place
> where we call accept4() without flags is tap_listen_handler().
> 
> Add accept() to the list of allowed system calls regardless of the
> presence of accept4().
> 
> Reported-by: NN708
> Link: https://bugs.passt.top/show_bug.cgi?id=106
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  passt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/passt.c b/passt.c
> index 957f3d0..1a0c404 100644
> --- a/passt.c
> +++ b/passt.c
> @@ -180,7 +180,7 @@ void exit_handler(int signal)
>   * #syscalls socket getsockopt setsockopt s390x:socketcall i686:socketcall close
>   * #syscalls bind connect recvfrom sendto shutdown
>   * #syscalls arm:recv ppc64le:recv arm:send ppc64le:send
> - * #syscalls accept4|accept listen epoll_ctl epoll_wait|epoll_pwait epoll_pwait
> + * #syscalls accept4 accept listen epoll_ctl epoll_wait|epoll_pwait epoll_pwait
>   * #syscalls clock_gettime arm:clock_gettime64 i686:clock_gettime64
>   */
>  int main(int argc, char **argv)

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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