ghsa-3ffg-5vr4-3v59
Vulnerability from github
Published
2024-08-26 12:31
Modified
2024-09-12 21:32
Details

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

f2fs: fix to cover read extent cache access with lock

syzbot reports a f2fs bug as below:

BUG: KASAN: slab-use-after-free in sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46 Read of size 4 at addr ffff8880739ab220 by task syz-executor200/5097

CPU: 0 PID: 5097 Comm: syz-executor200 Not tainted 6.9.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46 do_read_inode fs/f2fs/inode.c:509 [inline] f2fs_iget+0x33e1/0x46e0 fs/f2fs/inode.c:560 f2fs_nfs_get_inode+0x74/0x100 fs/f2fs/super.c:3237 generic_fh_to_dentry+0x9f/0xf0 fs/libfs.c:1413 exportfs_decode_fh_raw+0x152/0x5f0 fs/exportfs/expfs.c:444 exportfs_decode_fh+0x3c/0x80 fs/exportfs/expfs.c:584 do_handle_to_path fs/fhandle.c:155 [inline] handle_to_path fs/fhandle.c:210 [inline] do_handle_open+0x495/0x650 fs/fhandle.c:226 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

We missed to cover sanity_check_extent_cache() w/ extent cache lock, so, below race case may happen, result in use after free issue.

  • f2fs_iget
  • do_read_inode
  • f2fs_init_read_extent_tree : add largest extent entry in to cache - shrink - f2fs_shrink_read_extent_tree - __shrink_extent_tree - __detach_extent_node : drop largest extent entry
  • sanity_check_extent_cache : access et->largest w/o lock

let's refactor sanity_check_extent_cache() to avoid extent cache access and call it before f2fs_init_read_extent_tree() to fix this issue.

Show details on source website


{
  "affected": [],
  "aliases": [
    "CVE-2024-44941"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-08-26T12:15:06Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to cover read extent cache access with lock\n\nsyzbot reports a f2fs bug as below:\n\nBUG: KASAN: slab-use-after-free in sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46\nRead of size 4 at addr ffff8880739ab220 by task syz-executor200/5097\n\nCPU: 0 PID: 5097 Comm: syz-executor200 Not tainted 6.9.0-rc6-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:488\n kasan_report+0x143/0x180 mm/kasan/report.c:601\n sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46\n do_read_inode fs/f2fs/inode.c:509 [inline]\n f2fs_iget+0x33e1/0x46e0 fs/f2fs/inode.c:560\n f2fs_nfs_get_inode+0x74/0x100 fs/f2fs/super.c:3237\n generic_fh_to_dentry+0x9f/0xf0 fs/libfs.c:1413\n exportfs_decode_fh_raw+0x152/0x5f0 fs/exportfs/expfs.c:444\n exportfs_decode_fh+0x3c/0x80 fs/exportfs/expfs.c:584\n do_handle_to_path fs/fhandle.c:155 [inline]\n handle_to_path fs/fhandle.c:210 [inline]\n do_handle_open+0x495/0x650 fs/fhandle.c:226\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nWe missed to cover sanity_check_extent_cache() w/ extent cache lock,\nso, below race case may happen, result in use after free issue.\n\n- f2fs_iget\n - do_read_inode\n  - f2fs_init_read_extent_tree\n  : add largest extent entry in to cache\n\t\t\t\t\t- shrink\n\t\t\t\t\t - f2fs_shrink_read_extent_tree\n\t\t\t\t\t  - __shrink_extent_tree\n\t\t\t\t\t   - __detach_extent_node\n\t\t\t\t\t   : drop largest extent entry\n  - sanity_check_extent_cache\n  : access et-\u003elargest w/o lock\n\nlet\u0027s refactor sanity_check_extent_cache() to avoid extent cache access\nand call it before f2fs_init_read_extent_tree() to fix this issue.",
  "id": "GHSA-3ffg-5vr4-3v59",
  "modified": "2024-09-12T21:32:00Z",
  "published": "2024-08-26T12:31:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-44941"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/263df78166d3a9609b97d28c34029bd01874cbb8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/323ef20b5558b9d9fd10c1224327af6f11a8177d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d7409b05a64f212735f0d33f5f1602051a886eab"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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