CVE-2021-47375

{"id": "CVE-2021-47375", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.2, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 3.6, "exploitabilityScore": 2.5}]}, "published": "2024-05-21T15:15:23.290", "references": [{"url": "https://git.kernel.org/stable/c/3815fe7371d2411ce164281cef40d9fc7b323dee", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/488da313edf3abea7f7733efe011c96b23740ab5", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/5afedf670caf30a2b5a52da96eb7eac7dee6a9c9", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/677e362ba807f3aafe6f405c07e0b37244da5222", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/a5f8e86192612d0183047448d8bbe7918b3f1a26", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d56171d9360c0170c5c5f8f7e2362a2e999eca40", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/dacfd5e4d1142bfb3809aab3634a375f6f373269", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ebb8d26d93c3ec3c7576c52a8373a2309423c069", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/3815fe7371d2411ce164281cef40d9fc7b323dee", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/488da313edf3abea7f7733efe011c96b23740ab5", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/5afedf670caf30a2b5a52da96eb7eac7dee6a9c9", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/677e362ba807f3aafe6f405c07e0b37244da5222", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/a5f8e86192612d0183047448d8bbe7918b3f1a26", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/d56171d9360c0170c5c5f8f7e2362a2e999eca40", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/dacfd5e4d1142bfb3809aab3634a375f6f373269", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/ebb8d26d93c3ec3c7576c52a8373a2309423c069", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-416"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblktrace: Fix uaf in blk_trace access after removing by sysfs\n\nThere is an use-after-free problem triggered by following process:\n\n P1(sda)\t\t\t\tP2(sdb)\n\t\t\techo 0 > /sys/block/sdb/trace/enable\n\t\t\t blk_trace_remove_queue\n\t\t\t synchronize_rcu\n\t\t\t blk_trace_free\n\t\t\t relay_close\nrcu_read_lock\n__blk_add_trace\n trace_note_tsk\n (Iterate running_trace_list)\n\t\t\t relay_close_buf\n\t\t\t\t relay_destroy_buf\n\t\t\t\t kfree(buf)\n trace_note(sdb's bt)\n relay_reserve\n buf->offset <- nullptr deference (use-after-free) !!!\nrcu_read_unlock\n\n[ 502.714379] BUG: kernel NULL pointer dereference, address:\n0000000000000010\n[ 502.715260] #PF: supervisor read access in kernel mode\n[ 502.715903] #PF: error_code(0x0000) - not-present page\n[ 502.716546] PGD 103984067 P4D 103984067 PUD 17592b067 PMD 0\n[ 502.717252] Oops: 0000 [#1] SMP\n[ 502.720308] RIP: 0010:trace_note.isra.0+0x86/0x360\n[ 502.732872] Call Trace:\n[ 502.733193] __blk_add_trace.cold+0x137/0x1a3\n[ 502.733734] blk_add_trace_rq+0x7b/0xd0\n[ 502.734207] blk_add_trace_rq_issue+0x54/0xa0\n[ 502.734755] blk_mq_start_request+0xde/0x1b0\n[ 502.735287] scsi_queue_rq+0x528/0x1140\n...\n[ 502.742704] sg_new_write.isra.0+0x16e/0x3e0\n[ 502.747501] sg_ioctl+0x466/0x1100\n\nReproduce method:\n ioctl(/dev/sda, BLKTRACESETUP, blk_user_trace_setup[buf_size=127])\n ioctl(/dev/sda, BLKTRACESTART)\n ioctl(/dev/sdb, BLKTRACESETUP, blk_user_trace_setup[buf_size=127])\n ioctl(/dev/sdb, BLKTRACESTART)\n\n echo 0 > /sys/block/sdb/trace/enable &\n // Add delay(mdelay/msleep) before kernel enters blk_trace_free()\n\n ioctl$SG_IO(/dev/sda, SG_IO, ...)\n // Enters trace_note_tsk() after blk_trace_free() returned\n // Use mdelay in rcu region rather than msleep(which may schedule out)\n\nRemove blk_trace from running_list before calling blk_trace_free() by\nsysfs if blk_trace is at Blktrace_running state."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: blktrace: corrige uaf en el acceso a blk_trace despu\u00e9s de eliminarlo mediante sysfs. Hay un problema de use after free desencadenado por el siguiente proceso: P1(sda) P2(sdb) echo 0 &gt; /sys /block/sdb/trace/enable blk_trace_remove_queue sincronizar_rcu blk_trace_free rel\u00e9_cerrar rcu_read_lock __blk_add_trace trace_note_tsk (Iterar running_trace_list) rel\u00e9_close_buf rel\u00e9_destroy_buf kfree(buf) trace_note(sdb's bt) rel\u00e9_reserve buf-&gt;offset &lt;- deferencia nullptr (uso-despu\u00e9s) -gratis) !!! rcu_read_unlock [502.714379] ERROR: desreferencia del puntero NULL del kernel, direcci\u00f3n: 0000000000000010 [502.715260] #PF: acceso de lectura de supervisor en modo kernel [502.715903] #PF: error_code(0x0000) - p\u00e1gina no presente [502.716546] PGD 103984067 P4D 103984067 PUD 17592b067 PMD 0 [ 502.717252] Vaya: 0000 [#1] SMP [ 502.720308] RIP: 0010:trace_note.isra.0+0x86/0x360 [ 502.732872] Seguimiento de llamadas: [ 502.733193] 0x1a3 [502.733734] blk_add_trace_rq+ 0x7b/0xd0 [ 502.734207] blk_add_trace_rq_issue+0x54/0xa0 [ 502.734755] blk_mq_start_request+0xde/0x1b0 [ 502.735287] scsi_queue_rq+0x528/0x1140 ... [ 502.7427 04] sg_new_write.isra.0+0x16e/0x3e0 [ 502.747501] sg_ioctl+0x466/0x1100 M\u00e9todo de reproducci\u00f3n: ioctl(/dev/sda, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sda, BLKTRACESTART) ioctl(/dev/sdb, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sdb , BLKTRACESTART) echo 0 &gt; /sys/block/sdb/trace/enable &amp; // Agrega retraso(mdelay/msleep) antes de que el kernel entre blk_trace_free() ioctl$SG_IO(/dev/sda, SG_IO, ...) // Entra trace_note_tsk() despu\u00e9s de que blk_trace_free() regresara // Utilice mdelay en la regi\u00f3n rcu en lugar de msleep (que puede programarse) Elimine blk_trace de running_list antes de llamar a blk_trace_free() mediante sysfs si blk_trace est\u00e1 en el estado Blktrace_running."}], "lastModified": "2025-04-02T14:53:06.550", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "157EDB40-6A7D-4DA4-8B53-B0E1B429365E", "versionEndExcluding": "4.4.286", "versionStartIncluding": "2.6.30"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "531DC051-E22F-4355-A06F-BE9AF2124AA3", "versionEndExcluding": "4.9.285", "versionStartIncluding": "4.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "9DFC8239-9F26-43B2-A340-8EFC6BC6BDA8", "versionEndExcluding": "4.14.249", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "21C23429-F802-4256-B3C2-9EEA76AC11FF", "versionEndExcluding": "4.19.209", "versionStartIncluding": "4.15"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "87771E47-210D-48FA-95BC-48A86225B30F", "versionEndExcluding": "5.4.150", "versionStartIncluding": "4.20"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A2A50090-4483-4F44-9147-BF0B012FBF7E", "versionEndExcluding": "5.10.70", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1B31D6C1-A751-438D-906B-0C56B789D498", "versionEndExcluding": "5.14.9", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E46C74C6-B76B-4C94-A6A4-FD2FFF62D644"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "60134C3A-06E4-48C1-B04F-2903732A4E56"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}