From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965277AbaFQVNJ (ORCPT ); Tue, 17 Jun 2014 17:13:09 -0400 Received: from mga01.intel.com ([192.55.52.88]:23419 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965215AbaFQVNH (ORCPT ); Tue, 17 Jun 2014 17:13:07 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,496,1400050800"; d="scan'208";a="557026021" Date: Tue, 17 Jun 2014 14:13:02 -0700 From: Jacob Pan To: Neil Horman Cc: linux-kernel@vger.kernel.org, Zhang Rui Subject: Re: [PATCH 1/2] tmon: Check log file for common secuirty issues Message-ID: <20140617141302.7f5b0434@ultegra> In-Reply-To: <1403035509-31815-2-git-send-email-nhorman@tuxdriver.com> References: <1403035509-31815-1-git-send-email-nhorman@tuxdriver.com> <1403035509-31815-2-git-send-email-nhorman@tuxdriver.com> Organization: OTC X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.17; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Jun 2014 16:05:08 -0400 Neil Horman wrote: > The tmon logging system blindly opens its log file on a static path, > making it very easy for someone to redirect that log information to > inappropriate places or overwrite other users data. Do some easy > checking to make sure we're not logging to a symlink or a file owned > by another user. > Acked-by: Jacob Pan > Signed-off-by: Neil Horman > CC: Zhang Rui > CC: Jacob Pan > --- > tools/thermal/tmon/tmon.c | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/tools/thermal/tmon/tmon.c b/tools/thermal/tmon/tmon.c > index b30f531..059e0be 100644 > --- a/tools/thermal/tmon/tmon.c > +++ b/tools/thermal/tmon/tmon.c > @@ -142,6 +142,7 @@ static void start_syslog(void) > static void prepare_logging(void) > { > int i; > + struct stat logstat; > > if (!logging) > return; > @@ -152,6 +153,29 @@ static void prepare_logging(void) > return; > } > > + if (lstat(TMON_LOG_FILE, &logstat) < 0) { > + syslog(LOG_ERR, "Unable to stat log file %s\n", > TMON_LOG_FILE); > + fclose(tmon_log); > + tmon_log = NULL; > + return; > + } > + > + /* The log file must be a regular file owned by us */ > + if (S_ISLNK(logstat.st_mode)) { > + syslog(LOG_ERR, "Log file is a symlink. Will not > log\n"); > + fclose(tmon_log); > + tmon_log = NULL; > + return; > + } > + > + if (logstat.st_uid != getuid()) { > + syslog(LOG_ERR, "We don't own the log file. Not > logging\n"); > + fclose(tmon_log); > + tmon_log = NULL; > + return; > + } > + > + > fprintf(tmon_log, "#----------- THERMAL SYSTEM CONFIG > -------------\n"); for (i = 0; i < ptdata.nr_tz_sensor; i++) { > char binding_str[33]; /* size of long + 1 */ [Jacob Pan] -- Thanks, Jacob