ghsa-6fxv-v3gm-9m2r
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
dm cache: fix potential out-of-bounds access on the first resume
Out-of-bounds access occurs if the fast device is expanded unexpectedly before the first-time resume of the cache table. This happens because expanding the fast device requires reloading the cache table for cache_create to allocate new in-core data structures that fit the new size, and the check in cache_preresume is not performed during the first resume, leading to the issue.
Reproduce steps:
- prepare component devices:
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 oflag=direct
- load a cache table of 512 cache blocks, and deliberately expand the fast device before resuming the cache, making the in-core data structures inadequate.
dmsetup create cache --notable dmsetup reload cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" dmsetup reload cdata --table "0 131072 linear /dev/sdc 8192" dmsetup resume cdata dmsetup resume cache
- suspend the cache to write out the in-core dirty bitset and hint array, leading to out-of-bounds access to the dirty bitset at offset 0x40:
dmsetup suspend cache
KASAN reports:
BUG: KASAN: vmalloc-out-of-bounds in is_dirty_callback+0x2b/0x80 Read of size 8 at addr ffffc90000085040 by task dmsetup/90
(...snip...) The buggy address belongs to the virtual mapping at [ffffc90000085000, ffffc90000087000) created by: cache_ctr+0x176a/0x35f0
(...snip...) Memory state around the buggy address: ffffc90000084f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90000084f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
ffffc90000085000: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90000085080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90000085100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
Fix by checking the size change on the first resume.
{ "affected": [], "aliases": [ "CVE-2024-50278" ], "database_specific": { "cwe_ids": [ "CWE-125" ], "github_reviewed": false, "github_reviewed_at": null, "nvd_published_at": "2024-11-19T02:16:30Z", "severity": "HIGH" }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: fix potential out-of-bounds access on the first resume\n\nOut-of-bounds access occurs if the fast device is expanded unexpectedly\nbefore the first-time resume of the cache table. This happens because\nexpanding the fast device requires reloading the cache table for\ncache_create to allocate new in-core data structures that fit the new\nsize, and the check in cache_preresume is not performed during the\nfirst resume, leading to the issue.\n\nReproduce steps:\n\n1. prepare component devices:\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 oflag=direct\n\n2. load a cache table of 512 cache blocks, and deliberately expand the\n fast device before resuming the cache, making the in-core data\n structures inadequate.\n\ndmsetup create cache --notable\ndmsetup reload cache --table \"0 524288 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\ndmsetup reload cdata --table \"0 131072 linear /dev/sdc 8192\"\ndmsetup resume cdata\ndmsetup resume cache\n\n3. suspend the cache to write out the in-core dirty bitset and hint\n array, leading to out-of-bounds access to the dirty bitset at offset\n 0x40:\n\ndmsetup suspend cache\n\nKASAN reports:\n\n BUG: KASAN: vmalloc-out-of-bounds in is_dirty_callback+0x2b/0x80\n Read of size 8 at addr ffffc90000085040 by task dmsetup/90\n\n (...snip...)\n The buggy address belongs to the virtual mapping at\n [ffffc90000085000, ffffc90000087000) created by:\n cache_ctr+0x176a/0x35f0\n\n (...snip...)\n Memory state around the buggy address:\n ffffc90000084f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n ffffc90000084f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n \u003effffc90000085000: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8\n ^\n ffffc90000085080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n ffffc90000085100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n\nFix by checking the size change on the first resume.", "id": "GHSA-6fxv-v3gm-9m2r", "modified": "2024-11-27T18:34:01Z", "published": "2024-11-19T03:31:08Z", "references": [ { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-50278" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/036dd6e3d2638103e0092864577ea1d091466b86" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/13ed3624c6ef283acefa4cc42cc8ae54fd4391a4" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/2222b0929d00e2d13732b799b63be391b5de4492" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/483b7261b35a9d369082ab298a6670912243f0be" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/c0ade5d98979585d4f5a93e4514c2e9a65afa08d" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/c52ec00cb2f9bebfada22edcc0db385b910a1cdb" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/e492f71854ce03474d49e87fd98b8df1f7cd1d2d" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/fdef3b94dfebd57e3077a578b6e309a2bb6fa688" } ], "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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