[PATCH] squashfs: Fix heap corruption in sqfs_search_dir()

[Richard Weinberger]

res needs to be large enough to store both strings rem and target,
plus the path separator and the terminator.
Currently the space for the path separator is not accounted, so
the heap is corrupted by one byte.

Signed-off-by: Richard Weinberger <richard at nod.at>
---
 fs/squashfs/sqfs.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/squashfs/sqfs.c b/fs/squashfs/sqfs.c
index af7ff80a7b..b9314019b1 100644
--- a/fs/squashfs/sqfs.c
+++ b/fs/squashfs/sqfs.c
@@ -567,8 +567,11 @@ static int sqfs_search_dir(struct squashfs_dir_stream *dirs, char **token_list,
 				ret = -ENOMEM;
 				goto out;
 			}
-			/* Concatenate remaining tokens and symlink's target */
-			res = malloc(strlen(rem) + strlen(target) + 1);
+			/*
+			 * Concatenate remaining tokens and symlink's target.
+			 * Allocate enough space for rem, target, '/' and '\0'.
+			 */
+			res = malloc(strlen(rem) + strlen(target) + 2);
 			if (!res) {
 				ret = -ENOMEM;
 				goto out;
-- 
2.35.3