ghsa-q6w5-274c-4fj8
Vulnerability from github
Published
2025-01-19 12:31
Modified
2025-02-02 12:30
Details

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:

  1. 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"

  1. 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

  1. 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

Show details on source website

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{
   affected: [],
   aliases: [
      "CVE-2024-57929",
   ],
   database_specific: {
      cwe_ids: [],
      github_reviewed: false,
      github_reviewed_at: null,
      nvd_published_at: "2025-01-19T12:15:27Z",
      severity: null,
   },
   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>/dev/null | hexdump -e '1/8 \"%u\\n\"')\nablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \\\n2>/dev/null | hexdump -e '1/8 \"%u\\n\"')\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 <KERNEL_DIR>",
   id: "GHSA-q6w5-274c-4fj8",
   modified: "2025-02-02T12:30:25Z",
   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",
      },
   ],
   schema_version: "1.4.0",
   severity: [],
}


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