From: Andrei Vagin <avagin@virtuozzo.com>
To: Kees Cook <keescook@chromium.org>
Cc: James Morris <james.l.morris@oracle.com>,
Mike Frysinger <vapier@gentoo.org>,
Paul Moore <paul@paul-moore.com>,
Tyler Hicks <tyhicks@canonical.com>,
Andy Lutomirski <luto@amacapital.net>,
Will Drewry <wad@chromium.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] seccomp: Only dump core when single-threaded
Date: Mon, 13 Feb 2017 22:37:26 -0800 [thread overview]
Message-ID: <20170214063724.GA9021@outlook.office365.com> (raw)
In-Reply-To: <20170207231851.GA129818@beast>
On Tue, Feb 07, 2017 at 03:18:51PM -0800, Kees Cook wrote:
> The SECCOMP_RET_KILL filter return code has always killed the current
> thread, not the entire process. Changing this as a side-effect of dumping
> core isn't a safe thing to do (a few test suites have already flagged this
> behavioral change). Instead, restore the RET_KILL semantics, but still
> dump core when a RET_KILL delivers SIGSYS to a single-threaded process.
>
> Fixes: b25e67161c29 ("seccomp: dump core when using SECCOMP_RET_KILL")
> Signed-off-by: Kees Cook <keescook@chromium.org>
All CRIU tests passed with this patch. Thanks!
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
> ---
> kernel/seccomp.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/seccomp.c b/kernel/seccomp.c
> index f8f88ebcb3ba..e15185c28de5 100644
> --- a/kernel/seccomp.c
> +++ b/kernel/seccomp.c
> @@ -643,11 +643,14 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
> default: {
> siginfo_t info;
> audit_seccomp(this_syscall, SIGSYS, action);
> - /* Show the original registers in the dump. */
> - syscall_rollback(current, task_pt_regs(current));
> - /* Trigger a manual coredump since do_exit skips it. */
> - seccomp_init_siginfo(&info, this_syscall, data);
> - do_coredump(&info);
> + /* Dump core only if this is the last remaining thread. */
> + if (get_nr_threads(current) == 1) {
> + /* Show the original registers in the dump. */
> + syscall_rollback(current, task_pt_regs(current));
> + /* Trigger a manual coredump since do_exit skips it. */
> + seccomp_init_siginfo(&info, this_syscall, data);
> + do_coredump(&info);
> + }
> do_exit(SIGSYS);
> }
> }
> --
> 2.7.4
>
>
> --
> Kees Cook
> Pixel Security
next prev parent reply other threads:[~2017-02-14 6:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-07 23:18 [PATCH] seccomp: Only dump core when single-threaded Kees Cook
2017-02-14 6:37 ` Andrei Vagin [this message]
2017-02-14 19:09 ` Kees Cook
2017-02-14 22:34 ` James Morris
2017-02-22 23:35 ` Andrei Vagin
2017-02-23 0:01 ` Kees Cook
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