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From: mwilck@suse.com
To: Christophe Varoqui <christophe.varoqui@opensvc.com>,
	Benjamin Marzinski <bmarzins@redhat.com>
Cc: lixiaokeng@huawei.com, dm-devel@redhat.com,
	Martin Wilck <mwilck@suse.com>
Subject: [dm-devel] [PATCH v2 22/29] multipath: fix leaks in check_path_valid()
Date: Fri, 16 Oct 2020 12:44:54 +0200
Message-ID: <20201016104501.8700-23-mwilck@suse.com> (raw)
In-Reply-To: <20201016104501.8700-1-mwilck@suse.com>

From: Martin Wilck <mwilck@suse.com>

There were two leaks in check_path_valid(): if path status was
successfully determined before calling store_pathvec(), free_path()
wasn't called. Also, if an error exit occured, neither cleanup
function was called.

This patch fixes both, at the cost of using "static" for the pp and
pathvec variables.

Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Martin Wilck <mwilck@suse.com>
---
 multipath/main.c | 55 +++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 43 insertions(+), 12 deletions(-)

diff --git a/multipath/main.c b/multipath/main.c
index 049a36f..9974993 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -93,7 +93,7 @@ void rcu_register_thread_memb(void) {}
 void rcu_unregister_thread_memb(void) {}
 
 static int
-filter_pathvec (vector pathvec, char * refwwid)
+filter_pathvec (vector pathvec, const char *refwwid)
 {
 	int i;
 	struct path * pp;
@@ -592,12 +592,37 @@ out:
 	return r;
 }
 
+static void cleanup_pathvec(__attribute__((unused)) int dummy, void *arg)
+{
+	vector *ppv = arg;
+
+	if (ppv && *ppv) {
+		free_pathvec(*ppv, FREE_PATHS);
+		*ppv = NULL;
+	}
+}
+
+static void cleanup_path(__attribute__((unused)) int dummy, void *arg)
+{
+	struct path **ppp = arg;
+
+	if (ppp && *ppp) {
+		free_path(*ppp);
+		*ppp = NULL;
+	}
+}
+
 static int
 check_path_valid(const char *name, struct config *conf, bool is_uevent)
 {
 	int fd, r = PATH_IS_ERROR;
-	struct path *pp = NULL;
-	vector pathvec = NULL;
+	static struct path *pp = NULL;
+	static vector pathvec = NULL;
+	const char *wwid;
+
+	/* register these as exit handlers in case we exit irregularly */
+	on_exit(cleanup_path, &pp);
+	on_exit(cleanup_pathvec, &pathvec);
 
 	pp = alloc_path();
 	if (!pp)
@@ -667,13 +692,17 @@ check_path_valid(const char *name, struct config *conf, bool is_uevent)
 	if (store_path(pathvec, pp) != 0) {
 		free_path(pp);
 		goto fail;
+	} else {
+		/* make sure path isn't freed twice */
+		wwid = pp->wwid;
+		pp = NULL;
 	}
 
 	/* For find_multipaths = SMART, if there is more than one path
 	 * matching the refwwid, then the path is valid */
 	if (path_discovery(pathvec, DI_SYSFS | DI_WWID) < 0)
 		goto fail;
-	filter_pathvec(pathvec, pp->wwid);
+	filter_pathvec(pathvec, wwid);
 	if (VECTOR_SIZE(pathvec) > 1)
 		r = PATH_IS_VALID;
 	else
@@ -681,21 +710,23 @@ check_path_valid(const char *name, struct config *conf, bool is_uevent)
 
 out:
 	r = print_cmd_valid(r, pathvec, conf);
-	free_pathvec(pathvec, FREE_PATHS);
 	/*
 	 * multipath -u must exit with status 0, otherwise udev won't
 	 * import its output.
 	 */
 	if (!is_uevent && r == PATH_IS_NOT_VALID)
-		return RTVL_FAIL;
-	return RTVL_OK;
+		r = RTVL_FAIL;
+	else
+		r = RTVL_OK;
+	goto cleanup;
 
 fail:
-	if (pathvec)
-		free_pathvec(pathvec, FREE_PATHS);
-	else
-		free_path(pp);
-	return RTVL_FAIL;
+	r = RTVL_FAIL;
+
+cleanup:
+	cleanup_path(0, &pp);
+	cleanup_pathvec(0, &pathvec);
+	return r;
 }
 
 static int
-- 
2.28.0


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  parent reply index

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-16 10:44 [dm-devel] [PATCH v2 00/29] libmultipath: improve cleanup on exit mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 01/29] multipathd: uxlsnr: avoid deadlock " mwilck
2020-10-20 19:04   ` Benjamin Marzinski
2020-10-16 10:44 ` [dm-devel] [PATCH v2 02/29] multipathd: Fix liburcu memory leak mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 03/29] multipathd: move handling of io_err_stat_attr into libmultipath mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 04/29] multipathd: move vecs desctruction into cleanup function mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 05/29] multipathd: make some globals static mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 06/29] multipathd: move threads destruction into separate function mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 07/29] multipathd: move conf " mwilck
2020-10-19 18:56   ` Benjamin Marzinski
2020-10-16 10:44 ` [dm-devel] [PATCH v2 08/29] multipathd: move pid " mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 09/29] multipathd: close pidfile on exit mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 10/29] multipathd: add helper for systemd notification at exit mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 11/29] multipathd: child(): call cleanups in failure case, too mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 12/29] multipathd: unwatch_all_dmevents: check if waiter is initialized mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 13/29] multipathd: print error message if config can't be loaded mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 14/29] libmultipath: add libmp_dm_exit() mwilck
2020-10-19 19:07   ` Benjamin Marzinski
2020-10-16 10:44 ` [dm-devel] [PATCH v2 15/29] multipathd: fixup libdm deinitialization mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 16/29] libmultipath: log_thread_stop(): check if logarea is initialized mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 17/29] multipathd: add cleanup_child() exit handler mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 18/29] libmultipath: fix log_thread startup and teardown mwilck
2020-10-19 20:00   ` Benjamin Marzinski
2020-10-26 13:58     ` Martin Wilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 19/29] multipathd: move cleanup_{prio, checkers, foreign} to libmultipath_exit mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 20/29] multipath: use atexit() for cleanup handlers mwilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 21/29] mpathpersist: " mwilck
2020-10-16 10:44 ` mwilck [this message]
2020-10-16 10:44 ` [dm-devel] [PATCH v2 23/29] multipath-tools: mpath-tools.supp: file with valgrind suppressions mwilck
2020-10-19 20:01   ` Benjamin Marzinski
2020-10-16 10:44 ` [dm-devel] [PATCH v2 24/29] libmultipath: use libmp_verbosity to track verbosity mwilck
2020-10-19 20:38   ` Benjamin Marzinski
2020-10-26 14:47     ` Martin Wilck
2020-10-16 10:44 ` [dm-devel] [PATCH v2 25/29] libmultipath: introduce symbolic values for logsink mwilck
2020-10-16 20:13   ` Benjamin Marzinski
2020-10-16 10:44 ` [dm-devel] [PATCH v2 26/29] libmultipath: simplify dlog() mwilck
2020-10-19 21:07   ` Benjamin Marzinski
2020-10-16 10:44 ` [dm-devel] [PATCH v2 27/29] multipathd: common code for "-k" and command args mwilck
2020-10-19 21:51   ` Benjamin Marzinski
2020-10-16 10:45 ` [dm-devel] [PATCH v2 28/29] multipathd: sanitize uxsock_listen() mwilck
2020-10-19 23:33   ` Benjamin Marzinski
2020-10-26 13:54     ` Martin Wilck
2020-10-16 10:45 ` [dm-devel] [PATCH v2 29/29] libmultipath: fix race between log_safe and log_thread_stop() mwilck
2020-10-20  2:20   ` Benjamin Marzinski
2020-10-26 16:22     ` Martin Wilck
2020-10-26 17:24       ` Martin Wilck
2020-11-03  0:11         ` Benjamin Marzinski
2020-11-04 12:36           ` Martin Wilck
2020-11-04 15:46             ` Benjamin Marzinski

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