fkie_cve-2022-50067
Vulnerability from fkie_nvd
Published
2025-06-18 11:15
Modified
2025-06-18 13:47
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: btrfs: unset reloc control if transaction commit fails in prepare_to_relocate() In btrfs_relocate_block_group(), the rc is allocated. Then btrfs_relocate_block_group() calls relocate_block_group() prepare_to_relocate() set_reloc_control() that assigns rc to the variable fs_info->reloc_ctl. When prepare_to_relocate() returns, it calls btrfs_commit_transaction() btrfs_start_dirty_block_groups() btrfs_alloc_path() kmem_cache_zalloc() which may fail for example (or other errors could happen). When the failure occurs, btrfs_relocate_block_group() detects the error and frees rc and doesn't set fs_info->reloc_ctl to NULL. After that, in btrfs_init_reloc_root(), rc is retrieved from fs_info->reloc_ctl and then used, which may cause a use-after-free bug. This possible bug can be triggered by calling btrfs_ioctl_balance() before calling btrfs_ioctl_defrag(). To fix this possible bug, in prepare_to_relocate(), check if btrfs_commit_transaction() fails. If the failure occurs, unset_reloc_control() is called to set fs_info->reloc_ctl to NULL. The error log in our fault-injection testing is shown as follows: [ 58.751070] BUG: KASAN: use-after-free in btrfs_init_reloc_root+0x7ca/0x920 [btrfs] ... [ 58.753577] Call Trace: ... [ 58.755800] kasan_report+0x45/0x60 [ 58.756066] btrfs_init_reloc_root+0x7ca/0x920 [btrfs] [ 58.757304] record_root_in_trans+0x792/0xa10 [btrfs] [ 58.757748] btrfs_record_root_in_trans+0x463/0x4f0 [btrfs] [ 58.758231] start_transaction+0x896/0x2950 [btrfs] [ 58.758661] btrfs_defrag_root+0x250/0xc00 [btrfs] [ 58.759083] btrfs_ioctl_defrag+0x467/0xa00 [btrfs] [ 58.759513] btrfs_ioctl+0x3c95/0x114e0 [btrfs] ... [ 58.768510] Allocated by task 23683: [ 58.768777] ____kasan_kmalloc+0xb5/0xf0 [ 58.769069] __kmalloc+0x227/0x3d0 [ 58.769325] alloc_reloc_control+0x10a/0x3d0 [btrfs] [ 58.769755] btrfs_relocate_block_group+0x7aa/0x1e20 [btrfs] [ 58.770228] btrfs_relocate_chunk+0xf1/0x760 [btrfs] [ 58.770655] __btrfs_balance+0x1326/0x1f10 [btrfs] [ 58.771071] btrfs_balance+0x3150/0x3d30 [btrfs] [ 58.771472] btrfs_ioctl_balance+0xd84/0x1410 [btrfs] [ 58.771902] btrfs_ioctl+0x4caa/0x114e0 [btrfs] ... [ 58.773337] Freed by task 23683: ... [ 58.774815] kfree+0xda/0x2b0 [ 58.775038] free_reloc_control+0x1d6/0x220 [btrfs] [ 58.775465] btrfs_relocate_block_group+0x115c/0x1e20 [btrfs] [ 58.775944] btrfs_relocate_chunk+0xf1/0x760 [btrfs] [ 58.776369] __btrfs_balance+0x1326/0x1f10 [btrfs] [ 58.776784] btrfs_balance+0x3150/0x3d30 [btrfs] [ 58.777185] btrfs_ioctl_balance+0xd84/0x1410 [btrfs] [ 58.777621] btrfs_ioctl+0x4caa/0x114e0 [btrfs] ...
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5d741afed0bac206640cc64d77b97853283cf719
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/78f8c2370e3d33e35f23bdc648653d779aeacb6e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/85f02d6c856b9f3a0acf5219de6e32f58b9778eb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8e546674031fc1576da501e27a8fd165222e5a37
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b60e862e133f646f19023ece1d476d630a660de1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dcb11fe0a0a9cca2b7425191b9bf30dc29f2ad0f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ff0e8ed8dfb584575cffc1561f17a1d094e8565b
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: unset reloc control if transaction commit fails in prepare_to_relocate()\n\nIn btrfs_relocate_block_group(), the rc is allocated.  Then\nbtrfs_relocate_block_group() calls\n\nrelocate_block_group()\n  prepare_to_relocate()\n    set_reloc_control()\n\nthat assigns rc to the variable fs_info-\u003ereloc_ctl. When\nprepare_to_relocate() returns, it calls\n\nbtrfs_commit_transaction()\n  btrfs_start_dirty_block_groups()\n    btrfs_alloc_path()\n      kmem_cache_zalloc()\n\nwhich may fail for example (or other errors could happen). When the\nfailure occurs, btrfs_relocate_block_group() detects the error and frees\nrc and doesn\u0027t set fs_info-\u003ereloc_ctl to NULL. After that, in\nbtrfs_init_reloc_root(), rc is retrieved from fs_info-\u003ereloc_ctl and\nthen used, which may cause a use-after-free bug.\n\nThis possible bug can be triggered by calling btrfs_ioctl_balance()\nbefore calling btrfs_ioctl_defrag().\n\nTo fix this possible bug, in prepare_to_relocate(), check if\nbtrfs_commit_transaction() fails. If the failure occurs,\nunset_reloc_control() is called to set fs_info-\u003ereloc_ctl to NULL.\n\nThe error log in our fault-injection testing is shown as follows:\n\n  [   58.751070] BUG: KASAN: use-after-free in btrfs_init_reloc_root+0x7ca/0x920 [btrfs]\n  ...\n  [   58.753577] Call Trace:\n  ...\n  [   58.755800]  kasan_report+0x45/0x60\n  [   58.756066]  btrfs_init_reloc_root+0x7ca/0x920 [btrfs]\n  [   58.757304]  record_root_in_trans+0x792/0xa10 [btrfs]\n  [   58.757748]  btrfs_record_root_in_trans+0x463/0x4f0 [btrfs]\n  [   58.758231]  start_transaction+0x896/0x2950 [btrfs]\n  [   58.758661]  btrfs_defrag_root+0x250/0xc00 [btrfs]\n  [   58.759083]  btrfs_ioctl_defrag+0x467/0xa00 [btrfs]\n  [   58.759513]  btrfs_ioctl+0x3c95/0x114e0 [btrfs]\n  ...\n  [   58.768510] Allocated by task 23683:\n  [   58.768777]  ____kasan_kmalloc+0xb5/0xf0\n  [   58.769069]  __kmalloc+0x227/0x3d0\n  [   58.769325]  alloc_reloc_control+0x10a/0x3d0 [btrfs]\n  [   58.769755]  btrfs_relocate_block_group+0x7aa/0x1e20 [btrfs]\n  [   58.770228]  btrfs_relocate_chunk+0xf1/0x760 [btrfs]\n  [   58.770655]  __btrfs_balance+0x1326/0x1f10 [btrfs]\n  [   58.771071]  btrfs_balance+0x3150/0x3d30 [btrfs]\n  [   58.771472]  btrfs_ioctl_balance+0xd84/0x1410 [btrfs]\n  [   58.771902]  btrfs_ioctl+0x4caa/0x114e0 [btrfs]\n  ...\n  [   58.773337] Freed by task 23683:\n  ...\n  [   58.774815]  kfree+0xda/0x2b0\n  [   58.775038]  free_reloc_control+0x1d6/0x220 [btrfs]\n  [   58.775465]  btrfs_relocate_block_group+0x115c/0x1e20 [btrfs]\n  [   58.775944]  btrfs_relocate_chunk+0xf1/0x760 [btrfs]\n  [   58.776369]  __btrfs_balance+0x1326/0x1f10 [btrfs]\n  [   58.776784]  btrfs_balance+0x3150/0x3d30 [btrfs]\n  [   58.777185]  btrfs_ioctl_balance+0xd84/0x1410 [btrfs]\n  [   58.777621]  btrfs_ioctl+0x4caa/0x114e0 [btrfs]\n  ..."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: btrfs: anular el control de reubicaci\u00f3n si falla el commit de la transacci\u00f3n en prepare_to_relocate(). En btrfs_relocate_block_group(), se asigna el rc. Luego, btrfs_relocate_block_group() llama a relocate_block_group() prepare_to_relocate() set_reloc_control() que asigna rc a la variable fs_info-\u0026gt;reloc_ctl. Cuando prepare_to_relocate() retorna, llama a btrfs_commit_transaction() btrfs_start_dirty_block_groups() btrfs_alloc_path() kmem_cache_zalloc() que puede fallar, por ejemplo (o podr\u00edan ocurrir otros errores). Cuando ocurre el fallo, btrfs_relocate_block_group() detecta el error y libera rc y no establece fs_info-\u0026gt;reloc_ctl en NULL. Posteriormente, en btrfs_init_reloc_root(), se recupera rc de fs_info-\u0026gt;reloc_ctl y se utiliza, lo que podr\u00eda causar un error de Use-After-Free. Este posible error se puede activar llamando a btrfs_ioctl_balance() antes de llamar a btrfs_ioctl_defrag(). Para corregir este posible error, en prepare_to_relocate(), compruebe si btrfs_commit_transaction() falla. Si falla, se llama a unset_reloc_control() para establecer fs_info-\u0026gt;reloc_ctl en NULL. El registro de errores en nuestras pruebas de inyecci\u00f3n de fallas se muestra a continuaci\u00f3n: [ 58.751070] ERROR: KASAN: use-after-free en btrfs_init_reloc_root+0x7ca/0x920 [btrfs] ... [ 58.753577] Seguimiento de llamadas: ... [ 58.755800] kasan_report+0x45/0x60 [ 58.756066] btrfs_init_reloc_root+0x7ca/0x920 [btrfs] [ 58.757304] record_root_in_trans+0x792/0xa10 [btrfs] [ 58.757748] btrfs_record_root_in_trans+0x463/0x4f0 [btrfs] [ 58.758231] start_transaction+0x896/0x2950 [btrfs] [ 58.758661] btrfs_defrag_root+0x250/0xc00 [btrfs] [ 58.759083] btrfs_ioctl_defrag+0x467/0xa00 [btrfs] [ 58.759513] btrfs_ioctl+0x3c95/0x114e0 [btrfs] ... [ 58.768510] Asignado por la tarea 23683: [ 58.768777] ____kasan_kmalloc+0xb5/0xf0 [ 58.769069] __kmalloc+0x227/0x3d0 [ 58.769325] alloc_reloc_control+0x10a/0x3d0 [btrfs] [ 58.769755] btrfs_relocate_block_group+0x7aa/0x1e20 [btrfs] [ 58.770228] btrfs_relocate_chunk+0xf1/0x760 [btrfs] [ 58.770655] __btrfs_balance+0x1326/0x1f10 [btrfs] [ 58.771071] btrfs_balance+0x3150/0x3d30 [btrfs] [ 58.771472] btrfs_ioctl_balance+0xd84/0x1410 [btrfs] [ 58.771902] btrfs_ioctl+0x4caa/0x114e0 [btrfs] ... [ 58.773337] Liberado por la tarea 23683: ... [ 58.774815] kfree+0xda/0x2b0 [ 58.775038] free_reloc_control+0x1d6/0x220 [btrfs] [ 58.775465] btrfs_relocate_block_group+0x115c/0x1e20 [btrfs] [ 58.775944] btrfs_relocate_chunk+0xf1/0x760 [btrfs] [ 58.776369] __btrfs_balance+0x1326/0x1f10 [btrfs] [ 58.776784] btrfs_balance+0x3150/0x3d30 [btrfs] [ 58.777185] btrfs_ioctl_balance+0xd84/0x1410 [btrfs] [ 58.777621] btrfs_ioctl+0x4caa/0x114e0 [btrfs] ..."
    }
  ],
  "id": "CVE-2022-50067",
  "lastModified": "2025-06-18T13:47:40.833",
  "metrics": {},
  "published": "2025-06-18T11:15:35.490",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5d741afed0bac206640cc64d77b97853283cf719"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/78f8c2370e3d33e35f23bdc648653d779aeacb6e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/85f02d6c856b9f3a0acf5219de6e32f58b9778eb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8e546674031fc1576da501e27a8fd165222e5a37"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b60e862e133f646f19023ece1d476d630a660de1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dcb11fe0a0a9cca2b7425191b9bf30dc29f2ad0f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ff0e8ed8dfb584575cffc1561f17a1d094e8565b"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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