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| author | Deepanshu Kartikey <kartikey406@gmail.com> | 2025-10-21 09:12:17 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-29 14:00:01 +0100 |
| commit | 4954d297c91d292630ab43ba4d195dc371ce65d3 (patch) | |
| tree | b865478c029411791b39a342029ff25eb7adffe5 | |
| parent | 301c668d5e21e261b3e2602c6fcb958626868638 (diff) | |
| download | linux-4954d297c91d292630ab43ba4d195dc371ce65d3.tar.gz linux-4954d297c91d292630ab43ba4d195dc371ce65d3.tar.bz2 linux-4954d297c91d292630ab43ba4d195dc371ce65d3.zip | |
ext4: detect invalid INLINE_DATA + EXTENTS flag combination
[ Upstream commit 1d3ad183943b38eec2acf72a0ae98e635dc8456b ]
syzbot reported a BUG_ON in ext4_es_cache_extent() when opening a verity
file on a corrupted ext4 filesystem mounted without a journal.
The issue is that the filesystem has an inode with both the INLINE_DATA
and EXTENTS flags set:
EXT4-fs error (device loop0): ext4_cache_extents:545: inode #15:
comm syz.0.17: corrupted extent tree: lblk 0 < prev 66
Investigation revealed that the inode has both flags set:
DEBUG: inode 15 - flag=1, i_inline_off=164, has_inline=1, extents_flag=1
This is an invalid combination since an inode should have either:
- INLINE_DATA: data stored directly in the inode
- EXTENTS: data stored in extent-mapped blocks
Having both flags causes ext4_has_inline_data() to return true, skipping
extent tree validation in __ext4_iget(). The unvalidated out-of-order
extents then trigger a BUG_ON in ext4_es_cache_extent() due to integer
underflow when calculating hole sizes.
Fix this by detecting this invalid flag combination early in ext4_iget()
and rejecting the corrupted inode.
Cc: stable@kernel.org
Reported-and-tested-by: syzbot+038b7bf43423e132b308@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=038b7bf43423e132b308
Suggested-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Message-ID: <20250930112810.315095-1-kartikey406@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[ Adjust context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/ext4/inode.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 2eec365f182a..98f09beca90b 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5077,6 +5077,14 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, } ei->i_flags = le32_to_cpu(raw_inode->i_flags); ext4_set_inode_flags(inode); + /* Detect invalid flag combination - can't have both inline data and extents */ + if (ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA) && + ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + ext4_error_inode(inode, function, line, 0, + "inode has both inline data and extents flags"); + ret = -EFSCORRUPTED; + goto bad_inode; + } inode->i_blocks = ext4_inode_blocks(raw_inode, ei); ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo); if (ext4_has_feature_64bit(sb)) |