CVE-2024-33847 f2fs: compress: don't allow unaligned truncation on released compress inode

2024-06-2413:56:48

Linux

www.cve.org

linux kernel

f2fs

compression

inode

corruption

vulnerability fix

0.0004 Low

EPSS

Percentile

10.4%

JSON

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.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/f2fs/file.c"
    ],
    "versions": [
      {
        "version": "8e1651cd667c",
        "lessThan": "b8962cf98595",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c61404153eb6",
        "lessThan": "8acae0472150",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c61404153eb6",
        "lessThan": "3ccf5210dc94",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c61404153eb6",
        "lessThan": "9f9341064a9b",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c61404153eb6",
        "lessThan": "5268241b41b1",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c61404153eb6",
        "lessThan": "29ed2b5dd521",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/f2fs/file.c"
    ],
    "versions": [
      {
        "version": "5.14",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.14",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.161",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.93",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.33",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9.4",
        "lessThanOrEqual": "6.9.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10-rc1",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]