[PATCH 4.16 015/279] isofs: fix potential memory leak in mount option parsing

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chengguang Xu <cgxu519@xxxxxxx>

[ Upstream commit 4f34a5130a471f32f2fe7750769ab4057dc3eaa0 ]

When specifying string type mount option (e.g., iocharset)
several times in a mount, current option parsing may
cause memory leak. Hence, call kfree for previous one
in this case. Meanwhile, check memory allocation result
for it.

Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/isofs/inode.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -394,7 +394,10 @@ static int parse_options(char *options,
 			break;
 #ifdef CONFIG_JOLIET
 		case Opt_iocharset:
+			kfree(popt->iocharset);
 			popt->iocharset = match_strdup(&args[0]);
+			if (!popt->iocharset)
+				return 0;
 			break;
 #endif
 		case Opt_map_a: