From: Hui Peng <benquike@gmail.com>
To: slava@dubeyko.com, glaubitz@physik.fu-berlin.de,
frank.li@vivo.com, brauner@kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] hfs: validate drAlBlkSiz and fs_ablocks in hfs_mdb_get()
Date: Sat, 19 Sep 2026 22:26:05 +0000 [thread overview]
Message-ID: <20260919222605.3794529-1-benquike@gmail.com> (raw)
In hfs_mdb_get() (fs/hfs/mdb.c), reject images with allocation block
size (drAlBlkSiz) of 0 or not a multiple of HFS_SECTOR_SIZE (512), or
with fs_ablocks == 0, preventing a divide-by-zero trap and out-of-bounds
bitmap scans on crafted HFS images.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Assisted-by: LLM
Signed-off-by: Hui Peng <benquike@gmail.com>
---
diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c
index 277de712f9d4..9e78c561a3f1 100644
--- a/fs/hfs/mdb.c
+++ b/fs/hfs/mdb.c
@@ -204,6 +204,11 @@ int hfs_mdb_get(struct super_block *sb)
/* These parameters are read from the MDB, and never written */
HFS_SB(sb)->part_start = part_start;
HFS_SB(sb)->fs_ablocks = be16_to_cpu(mdb->drNmAlBlks);
+ if (!HFS_SB(sb)->fs_ablocks) {
+ brelse(bh);
+ HFS_SB(sb)->mdb_bh = NULL;
+ return -EINVAL;
+ }
HFS_SB(sb)->fs_div = HFS_SB(sb)->alloc_blksz >> sb->s_blocksize_bits;
HFS_SB(sb)->clumpablks = be32_to_cpu(mdb->drClpSiz) /
HFS_SB(sb)->alloc_blksz;
reply other threads:[~2026-09-19 22:26 UTC|newest]
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