{ "data_version": "4.0", "data_type": "CVE", "data_format": "MITRE", "CVE_data_meta": { "ID": "CVE-2021-47375", "ASSIGNER": "cve@kernel.org", "STATE": "PUBLIC" }, "description": { "description_data": [ { "lang": "eng", "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." } ] }, "problemtype": { "problemtype_data": [ { "description": [ { "lang": "eng", "value": "n/a" } ] } ] }, "affects": { "vendor": { "vendor_data": [ { "vendor_name": "Linux", "product": { "product_data": [ { "product_name": "Linux", "version": { "version_data": [ { "version_affected": "<", "version_name": "c71a89615411", "version_value": "488da313edf3" }, { "version_value": "not down converted", "x_cve_json_5_version_data": { "versions": [ { "version": "2.6.30", "status": "affected" }, { "version": "0", "lessThan": "2.6.30", "status": "unaffected", "versionType": "custom" }, { "version": "4.4.286", "lessThanOrEqual": "4.4.*", "status": "unaffected", "versionType": "custom" }, { "version": "4.9.285", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "custom" }, { "version": "4.14.249", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "custom" }, { "version": "4.19.209", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.4.150", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.10.70", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.14.9", "lessThanOrEqual": "5.14.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.15", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ], "defaultStatus": "affected" } } ] } } ] } } ] } }, "references": { "reference_data": [ { "url": "https://git.kernel.org/stable/c/488da313edf3abea7f7733efe011c96b23740ab5", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/488da313edf3abea7f7733efe011c96b23740ab5" }, { "url": "https://git.kernel.org/stable/c/dacfd5e4d1142bfb3809aab3634a375f6f373269", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/dacfd5e4d1142bfb3809aab3634a375f6f373269" }, { "url": "https://git.kernel.org/stable/c/d56171d9360c0170c5c5f8f7e2362a2e999eca40", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/d56171d9360c0170c5c5f8f7e2362a2e999eca40" }, { "url": "https://git.kernel.org/stable/c/677e362ba807f3aafe6f405c07e0b37244da5222", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/677e362ba807f3aafe6f405c07e0b37244da5222" }, { "url": "https://git.kernel.org/stable/c/ebb8d26d93c3ec3c7576c52a8373a2309423c069", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/ebb8d26d93c3ec3c7576c52a8373a2309423c069" }, { "url": "https://git.kernel.org/stable/c/3815fe7371d2411ce164281cef40d9fc7b323dee", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/3815fe7371d2411ce164281cef40d9fc7b323dee" }, { "url": "https://git.kernel.org/stable/c/a5f8e86192612d0183047448d8bbe7918b3f1a26", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/a5f8e86192612d0183047448d8bbe7918b3f1a26" }, { "url": "https://git.kernel.org/stable/c/5afedf670caf30a2b5a52da96eb7eac7dee6a9c9", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/5afedf670caf30a2b5a52da96eb7eac7dee6a9c9" } ] }, "generator": { "engine": "bippy-a5840b7849dd" } }