From: Kees Cook <kees@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@kernel.org>, Will Drewry <wad@chromium.org>,
Kusaram Devineni <kusaram@devineni.in>,
Max Ver <dudududumaxver@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 2/2] seccomp: defer syscall_rollback() to get_signal()
Date: Tue, 14 Apr 2026 10:27:07 -0700 [thread overview]
Message-ID: <202604141026.4BEA64A4@keescook> (raw)
In-Reply-To: <ad5v1J7bosR88z7b@redhat.com>
On Tue, Apr 14, 2026 at 06:48:20PM +0200, Oleg Nesterov wrote:
> Currently, seccomp_nack_syscall() calls syscall_rollback() immediately.
> Because this restores the original registers, the syscall exit path sees
> the original syscall number as the return value.
>
> This confuses audit_syscall_exit(), trace_syscall_exit(), and ptrace.
>
> Change seccomp_nack_syscall() to call syscall_set_return_value(-EINTR),
> and add the new check_force_sig_seccomp() helper called by get_signal()
> which does syscall_rollback() if the signal was sent by seccomp.
>
> Note that the si_code == SYS_SECCOMP check in check_force_sig_seccomp()
> is not 100% reliable, see the comment in check_force_sig_seccomp(), but
> I hope we don't really care.
>
> Reported-by: Max Ver <dudududumaxver@gmail.com>
> Closes: https://lore.kernel.org/all/CABjJbFJO+p3jA1r0gjUZrCepQb1Fab3kqxYhc_PSfoqo21ypeQ@mail.gmail.com/
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Can we also add a new selftest for this case? I'd like to be sure we
don't regress when we make changes in the future...
-Kees
--
Kees Cook
next prev parent reply other threads:[~2026-04-14 17:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-14 16:47 [RFC PATCH 0/2] seccomp: defer syscall_rollback() to get_signal() Oleg Nesterov
2026-04-14 16:48 ` [RFC PATCH 1/2] seccomp: introduce seccomp_nack_syscall() helper Oleg Nesterov
2026-04-14 16:48 ` [RFC PATCH 2/2] seccomp: defer syscall_rollback() to get_signal() Oleg Nesterov
2026-04-14 17:27 ` Kees Cook [this message]
2026-04-14 17:41 ` Oleg Nesterov
2026-04-15 15:50 ` Kees Cook
2026-04-15 16:08 ` Oleg Nesterov
2026-04-15 10:44 ` [RFC PATCH 0/2] " Oleg Nesterov
2026-04-15 16:07 ` Kees Cook
2026-04-15 19:21 ` Kees Cook
2026-04-16 14:07 ` Oleg Nesterov
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