ghsa-fp64-r8jf-r586
Vulnerability from github
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] _kasankmalloc+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] ...
{
"affected": [],
"aliases": [
"CVE-2022-50067"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-06-18T11:15:35Z",
"severity": null
},
"details": "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 ...",
"id": "GHSA-fp64-r8jf-r586",
"modified": "2025-06-18T12:30:46Z",
"published": "2025-06-18T12:30:46Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-50067"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5d741afed0bac206640cc64d77b97853283cf719"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/78f8c2370e3d33e35f23bdc648653d779aeacb6e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/85f02d6c856b9f3a0acf5219de6e32f58b9778eb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8e546674031fc1576da501e27a8fd165222e5a37"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b60e862e133f646f19023ece1d476d630a660de1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dcb11fe0a0a9cca2b7425191b9bf30dc29f2ad0f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ff0e8ed8dfb584575cffc1561f17a1d094e8565b"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
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