High · published June 24, 2024
In the Linux kernel, the following vulnerability has been resolved:
f2fs: compress: don't allow unaligned truncation on released compress inode
f2fs image may be corrupted after below testcase:
- mkfs.f2fs -O extra_attr,compression -f /dev/vdb
- mount /dev/vdb /mnt/f2fs
- touch /mnt/f2fs/file
- f2fs_io setflags compression /mnt/f2fs/file
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=4
- f2fs_io release_cblocks /mnt/f2fs/file
- truncate -s 8192 /mnt/f2fs/file
- umount /mnt/f2fs
- fsck.f2fs /dev/vdb
[ASSERT] (fsck_chk_inode_blk:1256) --> ino: 0x5 has i_blocks: 0x00000002, but has 0x3 blocks
[FSCK] valid_block_count matching with CP [Fail] [0x4, 0x5]
[FSCK] other corrupted bugs [Fail]
The reason is: partial truncation assume compressed inode has reserved
blocks, after partial truncation, valid block count may change w/o
.i_blocks and .total_valid_block_count update, result in corruption.
This patch only allow cluster size aligned truncation on released
compress inode for fixing.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 5.14, < 5.15.161 | 5.15.161 |
| linux/linux_kernel | ≥ 5.16, < 6.1.93 | 6.1.93 |
| linux/linux_kernel | ≥ 6.2, < 6.6.33 | 6.6.33 |
| linux/linux_kernel | ≥ 6.7, < 6.9.4 | 6.9.4 |