First published: Sun Jan 19 2025(Updated: )
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 $262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 dmsetup create cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. wipe the second array block offline dmsteup remove cache cmeta cdata corig mapping_root=$(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 3. 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 <KERNEL_DIR>
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Software | Affected Version | How to fix |
---|---|---|
Red Hat Kernel-devel | ||
debian/linux | <=5.10.223-1 | 5.10.234-1 6.1.129-1 6.1.128-1 6.12.21-1 |
debian/linux-6.1 | 6.1.129-1~deb11u1 |
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CVE-2024-57929 is classified as a low severity vulnerability in the Linux kernel.
To fix CVE-2024-57929, update to the latest version of the Linux kernel where the vulnerability has been patched.
CVE-2024-57929 affects various versions of the Linux kernel.
CVE-2024-57929 exploits issues related to the dm_array_cursor_end function, specifically when dm_bm_read_lock() fails.
No, CVE-2024-57929 is no longer exploitable if the relevant patches have been applied.