{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "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."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "kernel/trace/blktrace.c"
               ],
               "versions": [
                  {
                     "version": "c71a89615411",
                     "lessThan": "488da313edf3",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c71a89615411",
                     "lessThan": "dacfd5e4d114",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c71a89615411",
                     "lessThan": "d56171d9360c",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c71a89615411",
                     "lessThan": "677e362ba807",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c71a89615411",
                     "lessThan": "ebb8d26d93c3",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c71a89615411",
                     "lessThan": "3815fe7371d2",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c71a89615411",
                     "lessThan": "a5f8e8619261",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "c71a89615411",
                     "lessThan": "5afedf670caf",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "kernel/trace/blktrace.c"
               ],
               "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"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/488da313edf3abea7f7733efe011c96b23740ab5"
            },
            {
               "url": "https://git.kernel.org/stable/c/dacfd5e4d1142bfb3809aab3634a375f6f373269"
            },
            {
               "url": "https://git.kernel.org/stable/c/d56171d9360c0170c5c5f8f7e2362a2e999eca40"
            },
            {
               "url": "https://git.kernel.org/stable/c/677e362ba807f3aafe6f405c07e0b37244da5222"
            },
            {
               "url": "https://git.kernel.org/stable/c/ebb8d26d93c3ec3c7576c52a8373a2309423c069"
            },
            {
               "url": "https://git.kernel.org/stable/c/3815fe7371d2411ce164281cef40d9fc7b323dee"
            },
            {
               "url": "https://git.kernel.org/stable/c/a5f8e86192612d0183047448d8bbe7918b3f1a26"
            },
            {
               "url": "https://git.kernel.org/stable/c/5afedf670caf30a2b5a52da96eb7eac7dee6a9c9"
            }
         ],
         "title": "blktrace: Fix uaf in blk_trace access after removing by sysfs",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2021-47375",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}