From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754484AbbAGSMo (ORCPT ); Wed, 7 Jan 2015 13:12:44 -0500 Received: from mail-pa0-f48.google.com ([209.85.220.48]:49011 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754353AbbAGSMl (ORCPT ); Wed, 7 Jan 2015 13:12:41 -0500 From: John Stultz To: lkml Cc: Sasha Levin , Thomas Gleixner , Ingo Molnar , stable , Andy Lutomirski , John Stultz Subject: [PATCH 2/2] time: adjtimex: Validate the ADJ_FREQUENCY values Date: Wed, 7 Jan 2015 10:12:20 -0800 Message-Id: <1420654340-3009-3-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 Verify that the frequency value from userspace is valid and makes sense. Unverified values can cause overflows later on. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: stable Cc: Andy Lutomirski Signed-off-by: Sasha Levin [jstultz: Fix up bug for negative values and drop redunent cap check] Signed-off-by: John Stultz --- kernel/time/ntp.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 87a346f..28bf91c 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -633,6 +633,13 @@ int ntp_validate_timex(struct timex *txc) if ((txc->modes & ADJ_SETOFFSET) && (!capable(CAP_SYS_TIME))) return -EPERM; + if (txc->modes & ADJ_FREQUENCY) { + if (LONG_MIN / PPM_SCALE > txc->freq) + return -EINVAL; + if (LONG_MAX / PPM_SCALE < txc->freq) + return -EINVAL; + } + return 0; } -- 1.9.1