ghsa-q6w5-274c-4fj8
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
dm array: fix releasing a faulty array block twice in dm_array_cursor_end
When dm_bm_read_lock() fails due to locking or checksum errors, it releases the faulty block implicitly while leaving an invalid output pointer behind. The caller of dm_bm_read_lock() should not operate on this invalid dm_block pointer, or it will lead to undefined result. For example, the dm_array_cursor incorrectly caches the invalid pointer on reading a faulty array block, causing a double release in dm_array_cursor_end(), then hitting the BUG_ON in dm-bufio cache_put().
Reproduce steps:
- initialize a cache device
dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc $262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
- wipe the second array block offline
dmsteup remove cache cmeta cdata corig mapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \ 2>/dev/null | hexdump -e '1/8 "%u\n"') ablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \ 2>/dev/null | hexdump -e '1/8 "%u\n"') dd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock
- try reopen the cache device
dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc $262144" dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
Kernel logs:
(snip) device-mapper: array: array_block_check failed: blocknr 0 != wanted 10 device-mapper: block manager: array validator check failed for block 10 device-mapper: array: get_ablock failed device-mapper: cache metadata: dm_array_cursor_next for mapping failed ------------[ cut here ]------------ kernel BUG at drivers/md/dm-bufio.c:638!
Fix by setting the cached block pointer to NULL on errors.
In addition to the reproducer described above, this fix can be verified using the "array_cursor/damaged" test in dm-unit: dm-unit run /pdata/array_cursor/damaged --kernel-dir
{
"affected": [],
"aliases": [
"CVE-2024-57929"
],
"database_specific": {
"cwe_ids": [
"CWE-672"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-01-19T12:15:27Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm array: fix releasing a faulty array block twice in dm_array_cursor_end\n\nWhen dm_bm_read_lock() fails due to locking or checksum errors, it\nreleases the faulty block implicitly while leaving an invalid output\npointer behind. The caller of dm_bm_read_lock() should not operate on\nthis invalid dm_block pointer, or it will lead to undefined result.\nFor example, the dm_array_cursor incorrectly caches the invalid pointer\non reading a faulty array block, causing a double release in\ndm_array_cursor_end(), then hitting the BUG_ON in dm-bufio cache_put().\n\nReproduce steps:\n\n1. initialize a cache device\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 65536 linear /dev/sdc 8192\"\ndmsetup create corig --table \"0 524288 linear /dev/sdc $262144\"\ndd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1\ndmsetup create cache --table \"0 524288 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\n\n2. wipe the second array block offline\n\ndmsteup remove cache cmeta cdata corig\nmapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \\\n2\u003e/dev/null | hexdump -e \u00271/8 \"%u\\n\"\u0027)\nablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \\\n2\u003e/dev/null | hexdump -e \u00271/8 \"%u\\n\"\u0027)\ndd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock\n\n3. try reopen the cache device\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 65536 linear /dev/sdc 8192\"\ndmsetup create corig --table \"0 524288 linear /dev/sdc $262144\"\ndmsetup create cache --table \"0 524288 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\n\nKernel logs:\n\n(snip)\ndevice-mapper: array: array_block_check failed: blocknr 0 != wanted 10\ndevice-mapper: block manager: array validator check failed for block 10\ndevice-mapper: array: get_ablock failed\ndevice-mapper: cache metadata: dm_array_cursor_next for mapping failed\n------------[ cut here ]------------\nkernel BUG at drivers/md/dm-bufio.c:638!\n\nFix by setting the cached block pointer to NULL on errors.\n\nIn addition to the reproducer described above, this fix can be\nverified using the \"array_cursor/damaged\" test in dm-unit:\n dm-unit run /pdata/array_cursor/damaged --kernel-dir \u003cKERNEL_DIR\u003e",
"id": "GHSA-q6w5-274c-4fj8",
"modified": "2025-11-03T21:32:14Z",
"published": "2025-01-19T12:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-57929"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/017c4470bff53585370028fec9341247bad358ff"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6002bec5354f86d1a2df21468f68e3ec03ede9da"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/738994872d77e189b2d13c501a1d145e95d98f46"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9c7c03d0e926762adf3a3a0ba86156fb5e19538b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e477021d252c007f0c6d45b5d13d341efed03979"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f2893c0804d86230ffb8f1c8703fdbb18648abc8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fc1ef07c3522e257e32702954f265debbcb096a7"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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