From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934291AbdBVXo6 (ORCPT ); Wed, 22 Feb 2017 18:44:58 -0500 Received: from namei.org ([65.99.196.166]:34785 "EHLO namei.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933823AbdBVXot (ORCPT ); Wed, 22 Feb 2017 18:44:49 -0500 Date: Thu, 23 Feb 2017 10:44:44 +1100 (AEDT) From: James Morris To: Linus Torvalds cc: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, Kees Cook Subject: [GIT PULL] security: seccomp bugfix Message-ID: User-Agent: Alpine 2.20 (LRH 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Please pull this fix for a regression in the seccomp code (it was supposed to be in the first pull req but I had it queued in the wrong branch). The following changes since commit 37c85961c3f87f2141c84e53df31e59db072fd2e: Merge tag 'tty-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty (2017-02-22 12:17:25 -0800) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git for-linus Kees Cook (1): seccomp: Only dump core when single-threaded kernel/seccomp.c | 13 ++++++++----- 1 files changed, 8 insertions(+), 5 deletions(-) --- commit d7276e321ff8a53106a59c85ca46d03e34288893 Author: Kees Cook Date: Tue Feb 7 15:18:51 2017 -0800 seccomp: Only dump core when single-threaded 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 Acked-by: Andrei Vagin Signed-off-by: James Morris diff --git a/kernel/seccomp.c b/kernel/seccomp.c index f8f88eb..e15185c 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); } }