CVE-2022-49062
Published: 26 February 2025
Description
In the Linux kernel, the following vulnerability has been resolved: cachefiles: Fix KASAN slab-out-of-bounds in cachefiles_set_volume_xattr Use the actual length of volume coherency data when setting the xattr to avoid the following KASAN report. BUG: KASAN: slab-out-of-bounds in cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles] Write of size 4 at addr ffff888101e02af4 by task kworker/6:0/1347 CPU: 6 PID: 1347 Comm: kworker/6:0 Kdump: loaded Not tainted 5.18.0-rc1-nfs-fscache-netfs+ #13 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-4.fc34 04/01/2014 Workqueue: events fscache_create_volume_work [fscache] Call Trace: <TASK> dump_stack_lvl+0x45/0x5a print_report.cold+0x5e/0x5db ? __lock_text_start+0x8/0x8 ? cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles] kasan_report+0xab/0x120 ? cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles] kasan_check_range+0xf5/0x1d0 memcpy+0x39/0x60 cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles] cachefiles_acquire_volume+0x2be/0x500 [cachefiles] ? __cachefiles_free_volume+0x90/0x90 [cachefiles] fscache_create_volume_work+0x68/0x160 [fscache] process_one_work+0x3b7/0x6a0 worker_thread+0x2c4/0x650 ? process_one_work+0x6a0/0x6a0 kthread+0x16c/0x1a0 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30 </TASK> Allocated by task 1347: kasan_save_stack+0x1e/0x40 __kasan_kmalloc+0x81/0xa0 cachefiles_set_volume_xattr+0x76/0x350 [cachefiles] cachefiles_acquire_volume+0x2be/0x500 [cachefiles] fscache_create_volume_work+0x68/0x160 [fscache] process_one_work+0x3b7/0x6a0 worker_thread+0x2c4/0x650 kthread+0x16c/0x1a0 ret_from_fork+0x22/0x30 The buggy address belongs to the object at ffff888101e02af0 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 4 bytes inside of 8-byte region [ffff888101e02af0, ffff888101e02af8) The buggy address belongs to the physical page: page:00000000a2292d70 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x101e02 flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff) raw: 0017ffffc0000200 0000000000000000 dead000000000001 ffff888100042280 raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888101e02980: fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc ffff888101e02a00: 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 >ffff888101e02a80: fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 04 fc ^ ffff888101e02b00: fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc ffff888101e02b80: fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc ==================================================================
Security Summary
CVE-2022-49062 is a slab-out-of-bounds write vulnerability in the Linux kernel's cachefiles module, specifically within the cachefiles_set_volume_xattr function. The issue arises when setting an extended attribute (xattr) for volume coherency data, where an incorrect length is used, leading to a KASAN-detected out-of-bounds write of 4 bytes beyond an 8-byte kmalloc-8 slab allocation. This affects Linux kernels with the cachefiles and fscache subsystems enabled, as observed in kernel version 5.18.0-rc1 during fscache_create_volume_work execution.
A local attacker with low privileges (PR:L) can exploit this vulnerability with low attack complexity (AC:L) and no user interaction (UI:N). Successful exploitation enables high-impact confidentiality, integrity, and availability violations (C:H/I:H/A:H), potentially allowing arbitrary kernel memory corruption, code execution, or system crashes, as indicated by the CVSS v3.1 base score of 7.8 and CWE-787 classification.
The provided patch references detail the fix: commits at https://git.kernel.org/stable/c/09a5df1b88c8f126c8ff9938edf160edd4e92f42 and https://git.kernel.org/stable/c/7b2f6c306601240635c72caa61f682e74d4591b2 modify cachefiles_set_volume_xattr to use the actual length of the volume coherency data, preventing the out-of-bounds access during xattr operations. Security practitioners should apply these stable kernel updates to mitigate the issue.
Details
- CWE(s)