CVE-2024-33847

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 extraattr,compression -f /dev/vdb - mount /dev/vdb /mnt/f2fs - touch /mnt/f2fs/file - f2fsio setflags compression /mnt/f2fs/file - dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=4 - f2fsio releasecblocks /mnt/f2fs/file - truncate -s 8192 /mnt/f2fs/file - umount /mnt/f2fs - fsck.f2fs /dev/vdb

[ASSERT] (fsckchkinodeblk:1256) --> ino: 0x5 has iblocks: 0x00000002, but has 0x3 blocks [FSCK] validblockcount 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 .iblocks and .totalvalidblockcount update, result in corruption.

This patch only allow cluster size aligned truncation on released compress inode for fixing.