linux-kernel - [PATCH 1/4] erofs: fix incorrect early exits for invalid metabox-enabled images

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Message-ID: <20251229092949.2316075-1-hsiangkao@linux.alibaba.com>
Date: Mon, 29 Dec 2025 17:29:46 +0800
From: Gao Xiang <hsiangkao@...ux.alibaba.com>
To: linux-erofs@...ts.ozlabs.org
Cc: LKML <linux-kernel@...r.kernel.org>,
	Gao Xiang <hsiangkao@...ux.alibaba.com>
Subject: [PATCH 1/4] erofs: fix incorrect early exits for invalid metabox-enabled images

Crafted EROFS images with metadata compression enabled can trigger
incorrect early returns, leading to folio reference leaks.

However, this does not cause system crashes or other severe issues.

Fixes: 414091322c63 ("erofs: implement metadata compression")
Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
---
 fs/erofs/super.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 937a215f626c..2e4d0ea2ffa1 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -330,12 +330,13 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 	sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
 	if (erofs_sb_has_metabox(sbi)) {
+		ret = -EFSCORRUPTED;
 		if (sbi->sb_size <= offsetof(struct erofs_super_block,
 					     metabox_nid))
-			return -EFSCORRUPTED;
+			goto out;
 		sbi->metabox_nid = le64_to_cpu(dsb->metabox_nid);
 		if (sbi->metabox_nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT))
-			return -EFSCORRUPTED;	/* self-loop detection */
+			goto out;		/* self-loop detection */
 	}
 	sbi->inos = le64_to_cpu(dsb->inos);
 
-- 
2.43.5