CVE-2024-44942 f2fs: fix to do sanity check on F2FS_INLINE_DATA flag in inode during GC

2024-08-2611:20:46

Linux

www.cve.org

linux kernel

vulnerability resolution

f2fs

sanity check

inode

bug

blkaddr migration

f2fs_bug_on

dirty page writeback

cve-2024-44942

EPSS

Percentile

5.0%

JSON

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to do sanity check on F2FS_INLINE_DATA flag in inode during GC

syzbot reports a f2fs bug as below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/inline.c:258!
CPU: 1 PID: 34 Comm: kworker/u8:2 Not tainted 6.9.0-rc6-syzkaller-00012-g9e4bc4bcae01 #0
RIP: 0010:f2fs_write_inline_data+0x781/0x790 fs/f2fs/inline.c:258
Call Trace:
f2fs_write_single_data_page+0xb65/0x1d60 fs/f2fs/data.c:2834
f2fs_write_cache_pages fs/f2fs/data.c:3133 [inline]
__f2fs_write_data_pages fs/f2fs/data.c:3288 [inline]
f2fs_write_data_pages+0x1efe/0x3a90 fs/f2fs/data.c:3315
do_writepages+0x35b/0x870 mm/page-writeback.c:2612
__writeback_single_inode+0x165/0x10b0 fs/fs-writeback.c:1650
writeback_sb_inodes+0x905/0x1260 fs/fs-writeback.c:1941
wb_writeback+0x457/0xce0 fs/fs-writeback.c:2117
wb_do_writeback fs/fs-writeback.c:2264 [inline]
wb_workfn+0x410/0x1090 fs/fs-writeback.c:2304
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa12/0x17c0 kernel/workqueue.c:3335
worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
kthread+0x2f2/0x390 kernel/kthread.c:388
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The root cause is: inline_data inode can be fuzzed, so that there may
be valid blkaddr in its direct node, once f2fs triggers background GC
to migrate the block, it will hit f2fs_bug_on() during dirty page
writeback.

Let’s add sanity check on F2FS_INLINE_DATA flag in inode during GC,
so that, it can forbid migrating inline_data inode’s data block 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/gc.c"
    ],
    "versions": [
      {
        "version": "1da177e4c3f4",
        "lessThan": "ae00e6536a2d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "26c07775fb5d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "fc01008c92f4",
        "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/gc.c"
    ],
    "versions": [
      {
        "version": "6.6.47",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.10.6",
        "lessThanOrEqual": "6.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.11",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]