{"id":"AZL-53630","summary":"CVE-2024-50279 affecting package kernel for versions less than 5.15.173.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: fix out-of-bounds access to the dirty bitset when resizing\n\ndm-cache checks the dirty bits of the cache blocks to be dropped when\nshrinking the fast device, but an index bug in bitset iteration causes\nout-of-bounds access.\n\nReproduce steps:\n\n1. create a cache device of 1024 cache blocks (128 bytes dirty bitset)\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 131072 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 oflag=direct\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. shrink the fast device to 512 cache blocks, triggering out-of-bounds\n   access to the dirty bitset (offset 0x80)\n\ndmsetup suspend cache\ndmsetup reload cdata --table \"0 65536 linear /dev/sdc 8192\"\ndmsetup resume cdata\ndmsetup resume cache\n\nKASAN reports:\n\n  BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0\n  Read of size 8 at addr ffffc900000f3080 by task dmsetup/131\n\n  (...snip...)\n  The buggy address belongs to the virtual mapping at\n   [ffffc900000f3000, ffffc900000f5000) created by:\n   cache_ctr+0x176a/0x35f0\n\n  (...snip...)\n  Memory state around the buggy address:\n   ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n   ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  \u003effffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n                     ^\n   ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n   ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n\nFix by making the index post-incremented.","modified":"2026-04-01T05:16:35.428293Z","published":"2024-11-19T02:16:30Z","upstream":["CVE-2024-50279"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-50279"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:2","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.15.173.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-53630.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"}]}