From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752741AbdKHQJ5 (ORCPT ); Wed, 8 Nov 2017 11:09:57 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:35534 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751963AbdKHQJ4 (ORCPT ); Wed, 8 Nov 2017 11:09:56 -0500 To: Linus Torvalds Cc: LKLM , Colin Ian King From: John Johansen Subject: [PATCH] apparmor: fix off-by-one comparison on MAXMAPPED_SIG Organization: Canonical Message-ID: Date: Wed, 8 Nov 2017 08:09:52 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This came in yesterday, and I have verified our regression tests were missing this and it can cause an oops. Please apply. There is a an off-by-one comparision on sig against MAXMAPPED_SIG that can lead to a read outside the sig_map array if sig is MAXMAPPED_SIG. Fix this. Verified that the check is an out of bounds case that can cause an oops. Revised: add comparison fix to second case Fixes: cd1dbf76b23d ("apparmor: add the ability to mediate signals") Signed-off-by: Colin Ian King Signed-off-by: John Johansen --- security/apparmor/ipc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c index 66fb9ede9447..7ca0032e7ba9 100644 --- a/security/apparmor/ipc.c +++ b/security/apparmor/ipc.c @@ -128,7 +128,7 @@ static inline int map_signal_num(int sig) return SIGUNKNOWN; else if (sig >= SIGRTMIN) return sig - SIGRTMIN + 128; /* rt sigs mapped to 128 */ - else if (sig <= MAXMAPPED_SIG) + else if (sig < MAXMAPPED_SIG) return sig_map[sig]; return SIGUNKNOWN; } @@ -163,7 +163,7 @@ static void audit_signal_cb(struct audit_buffer *ab, void *va) audit_signal_mask(ab, aad(sa)->denied); } } - if (aad(sa)->signal <= MAXMAPPED_SIG) + if (aad(sa)->signal < MAXMAPPED_SIG) audit_log_format(ab, " signal=%s", sig_names[aad(sa)->signal]); else audit_log_format(ab, " signal=rtmin+%d", -- 2.11.0