From: Oleg Nesterov <oleg@redhat.com>
To: Kees Cook <kees@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@kernel.org>, Will Drewry <wad@chromium.org>,
Eric Paris <eparis@redhat.com>,
Kusaram Devineni <kusaram@devineni.in>,
Max Ver <dudududumaxver@gmail.com>,
Paul Moore <paul@paul-moore.com>,
audit@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 2/2] seccomp: drop syscall exit events for rejected syscalls
Date: Tue, 21 Apr 2026 20:59:13 +0200 [thread overview]
Message-ID: <aefJAYnzZT-zhif5@redhat.com> (raw)
In-Reply-To: <202604210951.7FFD917D@keescook>
On 04/21, Kees Cook wrote:
>
> On Sun, Apr 19, 2026 at 05:53:25PM +0200, Oleg Nesterov wrote:
> > seccomp_nack_syscall() calls syscall_rollback(), which means that the
> > syscall exit path sees the original syscall number as the return value.
> >
> > This confuses audit_syscall_exit(), trace_syscall_exit(), and ptrace,
> > causing them to report completely bogus syscall exit events.
> >
> > Add a new SYSCALL_WORK_SECCOMP_EXIT flag set by seccomp_nack_syscall(),
> > and change syscall_exit_work() to return early if this flag is set. After
> > all, this syscall was never actually executed.
>
> I think this looks good.
Great,
> I'd like to cover the non-generic syscall
> paths, though, too?
OK, I'll try to make the "extended" V2 soon.
> (Otherwise we immediately have a behavioral
> difference between e.g. x86 and arm64.)
Yes, yes, agreed, I even mentioned this in 0/2.
Thanks!
Oleg.
prev parent reply other threads:[~2026-04-21 18:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-19 15:52 [RFC PATCH 0/2] seccomp: drop syscall exit events for rejected syscalls Oleg Nesterov
2026-04-19 15:53 ` [RFC PATCH 1/2] seccomp: introduce seccomp_nack_syscall() helper Oleg Nesterov
2026-04-19 15:53 ` [RFC PATCH 2/2] seccomp: drop syscall exit events for rejected syscalls Oleg Nesterov
2026-04-21 16:52 ` Kees Cook
2026-04-21 18:59 ` Oleg Nesterov [this message]
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