ghsa-67hq-69g7-2v5w
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix bug_on ext4_mb_use_inode_pa
Hulk Robot reported a BUG_ON:
kernel BUG at fs/ext4/mballoc.c:3211! [...] RIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f [...] Call Trace: ext4_mb_new_blocks+0x9df/0x5d30 ext4_ext_map_blocks+0x1803/0x4d80 ext4_map_blocks+0x3a4/0x1a10 ext4_writepages+0x126d/0x2c30 do_writepages+0x7f/0x1b0 __filemap_fdatawrite_range+0x285/0x3b0 file_write_and_wait_range+0xb1/0x140 ext4_sync_file+0x1aa/0xca0 vfs_fsync_range+0xfb/0x260 do_fsync+0x48/0xa0 [...] ==================================================================
Above issue may happen as follows:
do_fsync vfs_fsync_range ext4_sync_file file_write_and_wait_range __filemap_fdatawrite_range do_writepages ext4_writepages mpage_map_and_submit_extent mpage_map_one_extent ext4_map_blocks ext4_mb_new_blocks ext4_mb_normalize_request >>> start + size <= ac->ac_o_ex.fe_logical ext4_mb_regular_allocator ext4_mb_simple_scan_group ext4_mb_use_best_found ext4_mb_new_preallocation ext4_mb_new_inode_pa ext4_mb_use_inode_pa >>> set ac->ac_b_ex.fe_len <= 0 ext4_mb_mark_diskspace_used >>> BUG_ON(ac->ac_b_ex.fe_len <= 0);
we can easily reproduce this problem with the following commands:
fallocate -l100M disk
mkfs.ext4 -b 1024 -g 256 disk
mount disk /mnt
fsstress -d /mnt -l 0 -n 1000 -p 1
The size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP. Therefore, "start + size <= ac->ac_o_ex.fe_logical" may occur when the size is truncated. So start should be the start position of the group where ac_o_ex.fe_logical is located after alignment. In addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP is very large, the value calculated by start_off is more accurate.
{
"affected": [],
"aliases": [
"CVE-2022-49708"
],
"database_specific": {
"cwe_ids": [
"CWE-617"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-26T07:01:46Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix bug_on ext4_mb_use_inode_pa\n\nHulk Robot reported a BUG_ON:\n==================================================================\nkernel BUG at fs/ext4/mballoc.c:3211!\n[...]\nRIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f\n[...]\nCall Trace:\n ext4_mb_new_blocks+0x9df/0x5d30\n ext4_ext_map_blocks+0x1803/0x4d80\n ext4_map_blocks+0x3a4/0x1a10\n ext4_writepages+0x126d/0x2c30\n do_writepages+0x7f/0x1b0\n __filemap_fdatawrite_range+0x285/0x3b0\n file_write_and_wait_range+0xb1/0x140\n ext4_sync_file+0x1aa/0xca0\n vfs_fsync_range+0xfb/0x260\n do_fsync+0x48/0xa0\n[...]\n==================================================================\n\nAbove issue may happen as follows:\n-------------------------------------\ndo_fsync\n vfs_fsync_range\n ext4_sync_file\n file_write_and_wait_range\n __filemap_fdatawrite_range\n do_writepages\n ext4_writepages\n mpage_map_and_submit_extent\n mpage_map_one_extent\n ext4_map_blocks\n ext4_mb_new_blocks\n ext4_mb_normalize_request\n \u003e\u003e\u003e start + size \u003c= ac-\u003eac_o_ex.fe_logical\n ext4_mb_regular_allocator\n ext4_mb_simple_scan_group\n ext4_mb_use_best_found\n ext4_mb_new_preallocation\n ext4_mb_new_inode_pa\n ext4_mb_use_inode_pa\n \u003e\u003e\u003e set ac-\u003eac_b_ex.fe_len \u003c= 0\n ext4_mb_mark_diskspace_used\n \u003e\u003e\u003e BUG_ON(ac-\u003eac_b_ex.fe_len \u003c= 0);\n\nwe can easily reproduce this problem with the following commands:\n\t`fallocate -l100M disk`\n\t`mkfs.ext4 -b 1024 -g 256 disk`\n\t`mount disk /mnt`\n\t`fsstress -d /mnt -l 0 -n 1000 -p 1`\n\nThe size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP.\nTherefore, \"start + size \u003c= ac-\u003eac_o_ex.fe_logical\" may occur\nwhen the size is truncated. So start should be the start position of\nthe group where ac_o_ex.fe_logical is located after alignment.\nIn addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP\nis very large, the value calculated by start_off is more accurate.",
"id": "GHSA-67hq-69g7-2v5w",
"modified": "2025-10-24T18:30:57Z",
"published": "2025-10-24T18:30:57Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49708"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5707d721d1819db57dba57b1d4623034fcb32047"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6880fb2e64331b9fdc85d3f32b1d7e81ad8703f1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6fdaf31ad5f3d3afab744dfd9a8b0d9142aa881f"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/887a3e9ad4b8309a2266bce7ae749b2bf1f7a687"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/90f0f9d45dff0128c0fca0d2358c4153b024afa6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a08f789d2ab5242c07e716baf9a835725046be89"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a37c1359714da42517dd19d36fc3c4d17edba832"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a6b31616e5afe1d3972cb0682a373e50597faf5c"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
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