{"api_version":"1","generated_at":"2026-09-03T16:14:06+00:00","cve":"CVE-2022-50488","urls":{"html":"https://cve.report/CVE-2022-50488","api":"https://cve.report/api/cve/CVE-2022-50488.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2022-50488","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2022-50488"},"summary":{"title":"block, bfq: fix possible uaf for 'bfqq->bic'","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix possible uaf for 'bfqq->bic'\n\nOur test report a uaf for 'bfqq->bic' in 5.10:\n\n==================================================================\nBUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30\n\nCPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014\nCall Trace:\n bfq_select_queue+0x378/0xa30\n bfq_dispatch_request+0xe8/0x130\n blk_mq_do_dispatch_sched+0x62/0xb0\n __blk_mq_sched_dispatch_requests+0x215/0x2a0\n blk_mq_sched_dispatch_requests+0x8f/0xd0\n __blk_mq_run_hw_queue+0x98/0x180\n __blk_mq_delay_run_hw_queue+0x22b/0x240\n blk_mq_run_hw_queue+0xe3/0x190\n blk_mq_sched_insert_requests+0x107/0x200\n blk_mq_flush_plug_list+0x26e/0x3c0\n blk_finish_plug+0x63/0x90\n __iomap_dio_rw+0x7b5/0x910\n iomap_dio_rw+0x36/0x80\n ext4_dio_read_iter+0x146/0x190 [ext4]\n ext4_file_read_iter+0x1e2/0x230 [ext4]\n new_sync_read+0x29f/0x400\n vfs_read+0x24e/0x2d0\n ksys_read+0xd5/0x1b0\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x61/0xc6\n\nCommit 3bc5e683c67d (\"bfq: Split shared queues on move between cgroups\")\nchanges that move process to a new cgroup will allocate a new bfqq to\nuse, however, the old bfqq and new bfqq can point to the same bic:\n\n1) Initial state, two process with io in the same cgroup.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |  Λ            |  Λ\n  |  |            |  |\n  V  |            V  |\n  bfqq1           bfqq2\n\n2) bfqq1 is merged to bfqq2.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |               |\n   \\-------------\\|\n                  V\n  bfqq1           bfqq2(coop)\n\n3) Process 1 exit, then issue new io(denoce IOA) from Process 2.\n\n (BIC2)\n  |  Λ\n  |  |\n  V  |\n  bfqq2(coop)\n\n4) Before IOA is completed, move Process 2 to another cgroup and issue io.\n\nProcess 2\n (BIC2)\n   Λ\n   |\\--------------\\\n   |                V\n  bfqq2           bfqq3\n\nNow that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.\nIf all the requests are completed, and Process 2 exit, BIC2 will be\nfreed while there is no guarantee that bfqq2 will be freed before BIC2.\n\nFix the problem by clearing bfqq->bic while bfqq is detached from bic.","state":"PUBLISHED","assigner":"Linux","published_at":"2025-10-04 16:15:45","updated_at":"2026-08-04 10:18:17"},"problem_types":["CWE-416"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/64dc8c732f5c2b406cc752e6aaa1bd5471159cab","name":"https://git.kernel.org/stable/c/64dc8c732f5c2b406cc752e6aaa1bd5471159cab","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/761564d93c8265f65543acf0a576b32d66bfa26a","name":"https://git.kernel.org/stable/c/761564d93c8265f65543acf0a576b32d66bfa26a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b22fd72bfebda3956efc4431b60ddfc0a51e03e0","name":"https://git.kernel.org/stable/c/b22fd72bfebda3956efc4431b60ddfc0a51e03e0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a","name":"https://git.kernel.org/stable/c/5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/094f3d9314d67691cb21ba091c1b528f6e3c4893","name":"https://git.kernel.org/stable/c/094f3d9314d67691cb21ba091c1b528f6e3c4893","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2022-50488","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2022-50488","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4dfc12f8c94c8052e975060f595938f75e8b7165 5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 81b7d0c717a487ec50e2924a773ff501ee40f0d5 094f3d9314d67691cb21ba091c1b528f6e3c4893 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3bc5e683c67d94bd839a1da2e796c15847b51b69 b22fd72bfebda3956efc4431b60ddfc0a51e03e0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3bc5e683c67d94bd839a1da2e796c15847b51b69 761564d93c8265f65543acf0a576b32d66bfa26a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3bc5e683c67d94bd839a1da2e796c15847b51b69 64dc8c732f5c2b406cc752e6aaa1bd5471159cab git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 31326bf551269fb9bafa84ca99172b8340e5d8f8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 43c51b86dbe551cff5d39b88aa2f41d29479f9c4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8615f6c0c9e7cf0ca90b6b5408784d797cbe5621 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.10.121 5.10.175 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15.46 5.15.86 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.4.198 5.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.17.14 5.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.18.3 5.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.19","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.175 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.86 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.0.16 6.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.2 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2022","cve_id":"50488","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"linux","cpe5":"linux_kernel","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["block/bfq-iosched.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a","status":"affected","version":"4dfc12f8c94c8052e975060f595938f75e8b7165","versionType":"git"},{"lessThan":"094f3d9314d67691cb21ba091c1b528f6e3c4893","status":"affected","version":"81b7d0c717a487ec50e2924a773ff501ee40f0d5","versionType":"git"},{"lessThan":"b22fd72bfebda3956efc4431b60ddfc0a51e03e0","status":"affected","version":"3bc5e683c67d94bd839a1da2e796c15847b51b69","versionType":"git"},{"lessThan":"761564d93c8265f65543acf0a576b32d66bfa26a","status":"affected","version":"3bc5e683c67d94bd839a1da2e796c15847b51b69","versionType":"git"},{"lessThan":"64dc8c732f5c2b406cc752e6aaa1bd5471159cab","status":"affected","version":"3bc5e683c67d94bd839a1da2e796c15847b51b69","versionType":"git"},{"status":"affected","version":"31326bf551269fb9bafa84ca99172b8340e5d8f8","versionType":"git"},{"status":"affected","version":"43c51b86dbe551cff5d39b88aa2f41d29479f9c4","versionType":"git"},{"status":"affected","version":"8615f6c0c9e7cf0ca90b6b5408784d797cbe5621","versionType":"git"},{"lessThan":"5.10.175","status":"affected","version":"5.10.121","versionType":"semver"},{"lessThan":"5.15.86","status":"affected","version":"5.15.46","versionType":"semver"},{"lessThan":"5.5","status":"affected","version":"5.4.198","versionType":"semver"},{"lessThan":"5.18","status":"affected","version":"5.17.14","versionType":"semver"},{"lessThan":"5.19","status":"affected","version":"5.18.3","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["block/bfq-iosched.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.19"},{"lessThan":"5.19","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.175","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.86","versionType":"semver"},{"lessThanOrEqual":"6.0.*","status":"unaffected","version":"6.0.16","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.2","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.175","versionStartIncluding":"5.10.121","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.86","versionStartIncluding":"5.15.46","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.0.16","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.2","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.2","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.198","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.17.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18.3","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix possible uaf for 'bfqq->bic'\n\nOur test report a uaf for 'bfqq->bic' in 5.10:\n\n==================================================================\nBUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30\n\nCPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014\nCall Trace:\n bfq_select_queue+0x378/0xa30\n bfq_dispatch_request+0xe8/0x130\n blk_mq_do_dispatch_sched+0x62/0xb0\n __blk_mq_sched_dispatch_requests+0x215/0x2a0\n blk_mq_sched_dispatch_requests+0x8f/0xd0\n __blk_mq_run_hw_queue+0x98/0x180\n __blk_mq_delay_run_hw_queue+0x22b/0x240\n blk_mq_run_hw_queue+0xe3/0x190\n blk_mq_sched_insert_requests+0x107/0x200\n blk_mq_flush_plug_list+0x26e/0x3c0\n blk_finish_plug+0x63/0x90\n __iomap_dio_rw+0x7b5/0x910\n iomap_dio_rw+0x36/0x80\n ext4_dio_read_iter+0x146/0x190 [ext4]\n ext4_file_read_iter+0x1e2/0x230 [ext4]\n new_sync_read+0x29f/0x400\n vfs_read+0x24e/0x2d0\n ksys_read+0xd5/0x1b0\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x61/0xc6\n\nCommit 3bc5e683c67d (\"bfq: Split shared queues on move between cgroups\")\nchanges that move process to a new cgroup will allocate a new bfqq to\nuse, however, the old bfqq and new bfqq can point to the same bic:\n\n1) Initial state, two process with io in the same cgroup.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |  Λ            |  Λ\n  |  |            |  |\n  V  |            V  |\n  bfqq1           bfqq2\n\n2) bfqq1 is merged to bfqq2.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |               |\n   \\-------------\\|\n                  V\n  bfqq1           bfqq2(coop)\n\n3) Process 1 exit, then issue new io(denoce IOA) from Process 2.\n\n (BIC2)\n  |  Λ\n  |  |\n  V  |\n  bfqq2(coop)\n\n4) Before IOA is completed, move Process 2 to another cgroup and issue io.\n\nProcess 2\n (BIC2)\n   Λ\n   |\\--------------\\\n   |                V\n  bfqq2           bfqq3\n\nNow that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.\nIf all the requests are completed, and Process 2 exit, BIC2 will be\nfreed while there is no guarantee that bfqq2 will be freed before BIC2.\n\nFix the problem by clearing bfqq->bic while bfqq is detached from bic."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-08-04T09:09:13.135Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/5533742c7cb1bc9b1f0bf401cc397d44a3a9e07a"},{"url":"https://git.kernel.org/stable/c/094f3d9314d67691cb21ba091c1b528f6e3c4893"},{"url":"https://git.kernel.org/stable/c/b22fd72bfebda3956efc4431b60ddfc0a51e03e0"},{"url":"https://git.kernel.org/stable/c/761564d93c8265f65543acf0a576b32d66bfa26a"},{"url":"https://git.kernel.org/stable/c/64dc8c732f5c2b406cc752e6aaa1bd5471159cab"}],"title":"block, bfq: fix possible uaf for 'bfqq->bic'","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2022-50488","datePublished":"2025-10-04T15:43:42.352Z","dateReserved":"2025-10-04T15:13:33.468Z","dateUpdated":"2026-08-04T09:09:13.135Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-10-04 16:15:45","lastModifiedDate":"2026-08-04 10:18:17","problem_types":["CWE-416"],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.198","versionEndExcluding":"5.5","matchCriteriaId":"81CDA30E-0E3B-47FD-A824-FDDFD9CA4E3C"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.121","versionEndExcluding":"5.10.175","matchCriteriaId":"EE96C02B-0E0C-4E77-AAE6-4628568068A7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.46","versionEndExcluding":"5.15.86","matchCriteriaId":"491345B8-FB6A-428B-9FBF-F040E1C45FF1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.17.14","versionEndExcluding":"5.18","matchCriteriaId":"53441672-E856-4C9B-92DD-20B8133BE921"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18.3","versionEndExcluding":"6.0.16","matchCriteriaId":"A4D8B69F-9B92-4C7C-8014-D16B7A22B0AA"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.1.2","matchCriteriaId":"77239F4B-6BB2-4B9E-A654-36A52396116C"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2022","CveId":"50488","Ordinal":"1","Title":"block, bfq: fix possible uaf for 'bfqq->bic'","CVE":"CVE-2022-50488","Year":"2022"},"notes":[{"CveYear":"2022","CveId":"50488","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix possible uaf for 'bfqq->bic'\n\nOur test report a uaf for 'bfqq->bic' in 5.10:\n\n==================================================================\nBUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30\n\nCPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014\nCall Trace:\n bfq_select_queue+0x378/0xa30\n bfq_dispatch_request+0xe8/0x130\n blk_mq_do_dispatch_sched+0x62/0xb0\n __blk_mq_sched_dispatch_requests+0x215/0x2a0\n blk_mq_sched_dispatch_requests+0x8f/0xd0\n __blk_mq_run_hw_queue+0x98/0x180\n __blk_mq_delay_run_hw_queue+0x22b/0x240\n blk_mq_run_hw_queue+0xe3/0x190\n blk_mq_sched_insert_requests+0x107/0x200\n blk_mq_flush_plug_list+0x26e/0x3c0\n blk_finish_plug+0x63/0x90\n __iomap_dio_rw+0x7b5/0x910\n iomap_dio_rw+0x36/0x80\n ext4_dio_read_iter+0x146/0x190 [ext4]\n ext4_file_read_iter+0x1e2/0x230 [ext4]\n new_sync_read+0x29f/0x400\n vfs_read+0x24e/0x2d0\n ksys_read+0xd5/0x1b0\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x61/0xc6\n\nCommit 3bc5e683c67d (\"bfq: Split shared queues on move between cgroups\")\nchanges that move process to a new cgroup will allocate a new bfqq to\nuse, however, the old bfqq and new bfqq can point to the same bic:\n\n1) Initial state, two process with io in the same cgroup.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |  Λ            |  Λ\n  |  |            |  |\n  V  |            V  |\n  bfqq1           bfqq2\n\n2) bfqq1 is merged to bfqq2.\n\nProcess 1       Process 2\n (BIC1)          (BIC2)\n  |               |\n   \\-------------\\|\n                  V\n  bfqq1           bfqq2(coop)\n\n3) Process 1 exit, then issue new io(denoce IOA) from Process 2.\n\n (BIC2)\n  |  Λ\n  |  |\n  V  |\n  bfqq2(coop)\n\n4) Before IOA is completed, move Process 2 to another cgroup and issue io.\n\nProcess 2\n (BIC2)\n   Λ\n   |\\--------------\\\n   |                V\n  bfqq2           bfqq3\n\nNow that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.\nIf all the requests are completed, and Process 2 exit, BIC2 will be\nfreed while there is no guarantee that bfqq2 will be freed before BIC2.\n\nFix the problem by clearing bfqq->bic while bfqq is detached from bic.","Type":"Description","Title":"block, bfq: fix possible uaf for 'bfqq->bic'"}]}}}