From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754704AbbBQC33 (ORCPT ); Mon, 16 Feb 2015 21:29:29 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33804 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752036AbbBQBu6 (ORCPT ); Mon, 16 Feb 2015 20:50:58 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Ingo Molnar" , "John Stultz" , "Sasha Levin" , "Thomas Gleixner" Date: Tue, 17 Feb 2015 01:46:53 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 089/152] time: settimeofday: Validate the values of tv from user In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.67-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sasha Levin commit 6ada1fc0e1c4775de0e043e1bd3ae9d065491aa5 upstream. An unvalidated user input is multiplied by a constant, which can result in an undefined behaviour for large values. While this is validated later, we should avoid triggering undefined behaviour. Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Sasha Levin [jstultz: include trivial milisecond->microsecond correction noticed by Andy] Signed-off-by: John Stultz [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- include/linux/time.h | 13 +++++++++++++ kernel/time.c | 4 ++++ 2 files changed, 17 insertions(+) --- a/include/linux/time.h +++ b/include/linux/time.h @@ -138,6 +138,19 @@ static inline bool timespec_valid_strict return true; } +static inline bool timeval_valid(const struct timeval *tv) +{ + /* Dates before 1970 are bogus */ + if (tv->tv_sec < 0) + return false; + + /* Can't have more microseconds then a second */ + if (tv->tv_usec < 0 || tv->tv_usec >= USEC_PER_SEC) + return false; + + return true; +} + extern void read_persistent_clock(struct timespec *ts); extern void read_boot_clock(struct timespec *ts); extern int update_persistent_clock(struct timespec now); --- a/kernel/time.c +++ b/kernel/time.c @@ -192,6 +192,10 @@ SYSCALL_DEFINE2(settimeofday, struct tim if (tv) { if (copy_from_user(&user_tv, tv, sizeof(*tv))) return -EFAULT; + + if (!timeval_valid(&user_tv)) + return -EINVAL; + new_ts.tv_sec = user_tv.tv_sec; new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC; }