From 048d795bb5b3d9c5701b4855f5e74bcf6849bf5e Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard@nod.at>
Date: Fri, 2 Aug 2024 22:05:09 +0200
Subject: [PATCH] squashfs: Fix heap corruption in sqfs_search_dir()

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@nod.at>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 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 af7ff80a7bdf..b9314019b1bc 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;
