From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754570AbbAGSNI (ORCPT ); Wed, 7 Jan 2015 13:13:08 -0500 Received: from mail-pd0-f178.google.com ([209.85.192.178]:34670 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754370AbbAGSMj (ORCPT ); Wed, 7 Jan 2015 13:12:39 -0500 From: John Stultz To: lkml Cc: Sasha Levin , Thomas Gleixner , Ingo Molnar , stable , Andy Lutomirski , John Stultz Subject: [PATCH 1/2] time: settimeofday: Validate the values of tv from user Date: Wed, 7 Jan 2015 10:12:19 -0800 Message-Id: <1420654340-3009-2-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1420654340-3009-1-git-send-email-john.stultz@linaro.org> References: <1420654340-3009-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sasha Levin 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 Cc: stable Cc: Andy Lutomirski Signed-off-by: Sasha Levin [jstultz: include trivial milisecond->microsecond correction noticed by Andy] Signed-off-by: John Stultz --- include/linux/time.h | 13 +++++++++++++ kernel/time/time.c | 4 ++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/time.h b/include/linux/time.h index 8c42cf8..5989b0e 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -99,6 +99,19 @@ static inline bool timespec_valid_strict(const struct timespec *ts) 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 struct timespec timespec_trunc(struct timespec t, unsigned gran); #define CURRENT_TIME (current_kernel_time()) diff --git a/kernel/time/time.c b/kernel/time/time.c index a9ae20f..22d5d3b 100644 --- a/kernel/time/time.c +++ b/kernel/time/time.c @@ -196,6 +196,10 @@ SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv, 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; } -- 1.9.1