On Tue, 17 Jun 2014 16:05:08 -0400 Neil Horman <[email protected]> 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 <[email protected]> > Signed-off-by: Neil Horman <[email protected]> > CC: Zhang Rui <[email protected]> > CC: Jacob Pan <[email protected]> > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
