From: Deepanshu Kartikey <kartikey406@gmail.com> stable inclusion from stable-v6.6.114 commit cb6039b68efa547b676a8a10fc4618d9d1865c23 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID6BAP CVE: CVE-2025-40167 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 1d3ad183943b38eec2acf72a0ae98e635dc8456b upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/ext4/inode.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 045a7213d6b6..f09c64c5c76c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5528,6 +5528,14 @@ 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, true); + /* 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)) -- 2.46.1