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SubjectRe: [PATCH 1/2] tmon: Check log file for common secuirty issues
On Tue, 17 Jun 2014 16:05:08 -0400
Neil Horman <nhorman@tuxdriver.com> 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 <jacob.jun.pan@linux.intel.com>

> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
> CC: Zhang Rui <rui.zhang@intel.com>
> CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
> ---
> 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


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