block, bfq: fix possible uaf for 'bfqq->bic'

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2022-50488
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-10-04 16:15:45 UTC
Updated2026-08-04 10:18:17 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: block, bfq: fix possible uaf for 'bfqq->bic' Our test report a uaf for 'bfqq->bic' in 5.10: ================================================================== BUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30 CPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014 Call Trace: bfq_select_queue+0x378/0xa30 bfq_dispatch_request+0xe8/0x130 blk_mq_do_dispatch_sched+0x62/0xb0 __blk_mq_sched_dispatch_requests+0x215/0x2a0 blk_mq_sched_dispatch_requests+0x8f/0xd0 __blk_mq_run_hw_queue+0x98/0x180 __blk_mq_delay_run_hw_queue+0x22b/0x240 blk_mq_run_hw_queue+0xe3/0x190 blk_mq_sched_insert_requests+0x107/0x200 blk_mq_flush_plug_list+0x26e/0x3c0 blk_finish_plug+0x63/0x90 __iomap_dio_rw+0x7b5/0x910 iomap_dio_rw+0x36/0x80 ext4_dio_read_iter+0x146/0x190 [ext4] ext4_file_read_iter+0x1e2/0x230 [ext4] new_sync_read+0x29f/0x400 vfs_read+0x24e/0x2d0 ksys_read+0xd5/0x1b0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x61/0xc6 Commit 3bc5e683c67d ("bfq: Split shared queues on move between cgroups") changes that move process to a new cgroup will allocate a new bfqq to use, however, the old bfqq and new bfqq can point to the same bic: 1) Initial state, two process with io in the same cgroup. Process 1 Process 2 (BIC1) (BIC2) | Λ | Λ | | | | V | V | bfqq1 bfqq2 2) bfqq1 is merged to bfqq2. Process 1 Process 2 (BIC1) (BIC2) | | \-------------\| V bfqq1 bfqq2(coop) 3) Process 1 exit, then issue new io(denoce IOA) from Process 2. (BIC2) | Λ | | V | bfqq2(coop) 4) Before IOA is completed, move Process 2 to another cgroup and issue io. Process 2 (BIC2) Λ |\--------------\ | V bfqq2 bfqq3 Now that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2. If all the requests are completed, and Process 2 exit, BIC2 will be freed while there is no guarantee that bfqq2 will be freed before BIC2. Fix the problem by clearing bfqq->bic while bfqq is detached from bic.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem Types: CWE-416

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 4dfc12f8c94c8052e975060f595938f75e8b7165 5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a git Not specified
CNA Linux Linux affected 81b7d0c717a487ec50e2924a773ff501ee40f0d5 094f3d9314d67691cb21ba091c1b528f6e3c4893 git Not specified
CNA Linux Linux affected 3bc5e683c67d94bd839a1da2e796c15847b51b69 b22fd72bfebda3956efc4431b60ddfc0a51e03e0 git Not specified
CNA Linux Linux affected 3bc5e683c67d94bd839a1da2e796c15847b51b69 761564d93c8265f65543acf0a576b32d66bfa26a git Not specified
CNA Linux Linux affected 3bc5e683c67d94bd839a1da2e796c15847b51b69 64dc8c732f5c2b406cc752e6aaa1bd5471159cab git Not specified
CNA Linux Linux affected 31326bf551269fb9bafa84ca99172b8340e5d8f8 git Not specified
CNA Linux Linux affected 43c51b86dbe551cff5d39b88aa2f41d29479f9c4 git Not specified
CNA Linux Linux affected 8615f6c0c9e7cf0ca90b6b5408784d797cbe5621 git Not specified
CNA Linux Linux affected 5.10.121 5.10.175 semver Not specified
CNA Linux Linux affected 5.15.46 5.15.86 semver Not specified
CNA Linux Linux affected 5.4.198 5.5 semver Not specified
CNA Linux Linux affected 5.17.14 5.18 semver Not specified
CNA Linux Linux affected 5.18.3 5.19 semver Not specified
CNA Linux Linux affected 5.19 Not specified
CNA Linux Linux unaffected 5.19 semver Not specified
CNA Linux Linux unaffected 5.10.175 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.86 5.15.* semver Not specified
CNA Linux Linux unaffected 6.0.16 6.0.* semver Not specified
CNA Linux Linux unaffected 6.1.2 6.1.* semver Not specified
CNA Linux Linux unaffected 6.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/64dc8c732f5c2b406cc752e6aaa1bd5471159cab 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/761564d93c8265f65543acf0a576b32d66bfa26a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/b22fd72bfebda3956efc4431b60ddfc0a51e03e0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/094f3d9314d67691cb21ba091c1b528f6e3c4893 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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