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authorNeil Horman <nhorman@tuxdriver.com>2014-06-17 16:05:08 -0400
committerZhang Rui <rui.zhang@intel.com>2014-07-01 22:00:38 +0800
commit951fda3d8c644597a1d5cdae14cab31567e754a1 (patch)
tree7d705c9a9c0208e8b94b4c683377865c182f0af5
parent6b533269fb2513a1281a878e316bb920fc54db31 (diff)
tmon: Check log file for common secuirty issues
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. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
-rw-r--r--tools/thermal/tmon/tmon.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/tools/thermal/tmon/tmon.c b/tools/thermal/tmon/tmon.c
index b30f531173e4..059e0becb386 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 */