linux-kernel - [PATCH] squashfs: Fix invalid pointer dereference in squashfs_cache

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250306132855.2030-1-zhiyuzhang999@gmail.com>
Date: Thu,  6 Mar 2025 21:28:55 +0800
From: Zhiyu Zhang <zhiyuzhang999@...il.com>
To: phillip@...ashfs.org.uk,
	akpm@...ux-foundation.org
Cc: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Zhiyu Zhang <zhiyuzhang999@...il.com>
Subject: [PATCH] squashfs: Fix invalid pointer dereference in squashfs_cache_delete

When mounting a squashfs fails, squashfs_cache_init() may return an error
pointer (e.g., -ENOMEM) instead of NULL. However, squashfs_cache_delete()
only checks for a NULL cache, and attempts to dereference the invalid
pointer. This leads to a kernel crash (BUG: unable to handle kernel paging
request in squashfs_cache_delete).

This patch fixes the issue by checking IS_ERR(cache) before accessing it.

Fixes: 49ff29240ebb ("squashfs: make squashfs_cache_init() return ERR_PTR(-ENOMEM)")
Reported-by: Zhiyu Zhang <zhiyuzhang999@...il.com>
Closes: https://lore.kernel.org/linux-fsdevel/CALf2hKvaq8B4u5yfrE+BYt7aNguao99mfWxHngA+=o5hwzjdOg@mail.gmail.com/
Tested-by: Zhiyu Zhang <zhiyuzhang999@...il.com>
Signed-off-by: Zhiyu Zhang <zhiyuzhang999@...il.com>
---
 fs/squashfs/cache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/squashfs/cache.c b/fs/squashfs/cache.c
index 4db0d2b0aab8..181260e72680 100644
--- a/fs/squashfs/cache.c
+++ b/fs/squashfs/cache.c
@@ -198,7 +198,7 @@ void squashfs_cache_delete(struct squashfs_cache *cache)
 {
 	int i, j;
 
-	if (cache == NULL)
+	if (IS_ERR(cache) || cache == NULL)
 		return;
 
 	for (i = 0; i < cache->entries; i++) {
-- 
2.34.1