CVE-2021-47566 (GCVE-0-2021-47566)

Vulnerability from cvelistv5 – Published: 2024-05-24 15:12 – Updated: 2026-05-11 13:57
VLAI
Title
proc/vmcore: fix clearing user buffer by properly using clear_user()
Summary
In the Linux kernel, the following vulnerability has been resolved: proc/vmcore: fix clearing user buffer by properly using clear_user() To clear a user buffer we cannot simply use memset, we have to use clear_user(). With a virtio-mem device that registers a vmcore_cb and has some logically unplugged memory inside an added Linux memory block, I can easily trigger a BUG by copying the vmcore via "cp": systemd[1]: Starting Kdump Vmcore Save Service... kdump[420]: Kdump is using the default log level(3). kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/ kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/ kdump[465]: saving vmcore-dmesg.txt complete kdump[467]: saving vmcore BUG: unable to handle page fault for address: 00007f2374e01000 #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867 Oops: 0003 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014 RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86 Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 <49> c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81 RSP: 0018:ffffc9000073be08 EFLAGS: 00010212 RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000 RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008 RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50 R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000 R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8 FS: 00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0 Call Trace: read_vmcore+0x236/0x2c0 proc_reg_read+0x55/0xa0 vfs_read+0x95/0x190 ksys_read+0x4f/0xc0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Some x86-64 CPUs have a CPU feature called "Supervisor Mode Access Prevention (SMAP)", which is used to detect wrong access from the kernel to user buffers like this: SMAP triggers a permissions violation on wrong access. In the x86-64 variant of clear_user(), SMAP is properly handled via clac()+stac(). To fix, properly use clear_user() when we're dealing with a user buffer.
Severity
No CVSS data available.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < a9e164bd160be8cbee1df70acb379129e3cd2e7c (git)
Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 33a7d698f30fa0b99d50569e9909d3baa65d8f6a (git)
Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 99d348b82bcb36171f24411d3f1a15706a2a937a (git)
Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 9ef384ed300d1bcfb23d0ab0b487d544444d4b52 (git)
Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < fd7974c547abfb03072a4ee706d3a6f182266f89 (git)
Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < a8a917058faf4abaec9fb614bb6d5f8fe3529ec6 (git)
Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1 (git)
Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < c1e63117711977cc4295b2ce73de29dd17066c82 (git)
Create a notification for this product.
Linux Linux Affected: 3.0
Unaffected: 0 , < 3.0 (semver)
Unaffected: 4.4.294 , ≤ 4.4.* (semver)
Unaffected: 4.9.292 , ≤ 4.9.* (semver)
Unaffected: 4.14.257 , ≤ 4.14.* (semver)
Unaffected: 4.19.219 , ≤ 4.19.* (semver)
Unaffected: 5.4.163 , ≤ 5.4.* (semver)
Unaffected: 5.10.83 , ≤ 5.10.* (semver)
Unaffected: 5.15.6 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47566",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-06-12T19:44:25.541373Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-12T19:44:36.617Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:39:59.769Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/proc/vmcore.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a9e164bd160be8cbee1df70acb379129e3cd2e7c",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            },
            {
              "lessThan": "33a7d698f30fa0b99d50569e9909d3baa65d8f6a",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            },
            {
              "lessThan": "99d348b82bcb36171f24411d3f1a15706a2a937a",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            },
            {
              "lessThan": "9ef384ed300d1bcfb23d0ab0b487d544444d4b52",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            },
            {
              "lessThan": "fd7974c547abfb03072a4ee706d3a6f182266f89",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            },
            {
              "lessThan": "a8a917058faf4abaec9fb614bb6d5f8fe3529ec6",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            },
            {
              "lessThan": "7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            },
            {
              "lessThan": "c1e63117711977cc4295b2ce73de29dd17066c82",
              "status": "affected",
              "version": "997c136f518c5debd63847e78e2a8694f56dcf90",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/proc/vmcore.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.0"
            },
            {
              "lessThan": "3.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.4.*",
              "status": "unaffected",
              "version": "4.4.294",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.9.*",
              "status": "unaffected",
              "version": "4.9.292",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.14.*",
              "status": "unaffected",
              "version": "4.14.257",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.19.*",
              "status": "unaffected",
              "version": "4.19.219",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.163",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.83",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.16",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.4.294",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.9.292",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.14.257",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "4.19.219",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.163",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.83",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.6",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.16",
                  "versionStartIncluding": "3.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nproc/vmcore: fix clearing user buffer by properly using clear_user()\n\nTo clear a user buffer we cannot simply use memset, we have to use\nclear_user().  With a virtio-mem device that registers a vmcore_cb and\nhas some logically unplugged memory inside an added Linux memory block,\nI can easily trigger a BUG by copying the vmcore via \"cp\":\n\n  systemd[1]: Starting Kdump Vmcore Save Service...\n  kdump[420]: Kdump is using the default log level(3).\n  kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\n  kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\n  kdump[465]: saving vmcore-dmesg.txt complete\n  kdump[467]: saving vmcore\n  BUG: unable to handle page fault for address: 00007f2374e01000\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x0003) - permissions violation\n  PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867\n  Oops: 0003 [#1] PREEMPT SMP NOPTI\n  CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86\n  Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 \u003c49\u003e c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81\n  RSP: 0018:ffffc9000073be08 EFLAGS: 00010212\n  RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000\n  RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008\n  RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50\n  R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000\n  R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8\n  FS:  00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0\n  Call Trace:\n   read_vmcore+0x236/0x2c0\n   proc_reg_read+0x55/0xa0\n   vfs_read+0x95/0x190\n   ksys_read+0x4f/0xc0\n   do_syscall_64+0x3b/0x90\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nSome x86-64 CPUs have a CPU feature called \"Supervisor Mode Access\nPrevention (SMAP)\", which is used to detect wrong access from the kernel\nto user buffers like this: SMAP triggers a permissions violation on\nwrong access.  In the x86-64 variant of clear_user(), SMAP is properly\nhandled via clac()+stac().\n\nTo fix, properly use clear_user() when we\u0027re dealing with a user buffer."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T13:57:06.193Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c"
        },
        {
          "url": "https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a"
        },
        {
          "url": "https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a"
        },
        {
          "url": "https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52"
        },
        {
          "url": "https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89"
        },
        {
          "url": "https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6"
        },
        {
          "url": "https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1"
        },
        {
          "url": "https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82"
        }
      ],
      "title": "proc/vmcore: fix clearing user buffer by properly using clear_user()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47566",
    "datePublished": "2024-05-24T15:12:53.432Z",
    "dateReserved": "2024-05-24T15:11:00.728Z",
    "dateUpdated": "2026-05-11T13:57:06.193Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-47566",
      "date": "2026-06-19",
      "epss": "0.00229",
      "percentile": "0.13461"
    },
    "fkie_nvd": {
      "descriptions": "[{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nproc/vmcore: fix clearing user buffer by properly using clear_user()\\n\\nTo clear a user buffer we cannot simply use memset, we have to use\\nclear_user().  With a virtio-mem device that registers a vmcore_cb and\\nhas some logically unplugged memory inside an added Linux memory block,\\nI can easily trigger a BUG by copying the vmcore via \\\"cp\\\":\\n\\n  systemd[1]: Starting Kdump Vmcore Save Service...\\n  kdump[420]: Kdump is using the default log level(3).\\n  kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\\n  kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\\n  kdump[465]: saving vmcore-dmesg.txt complete\\n  kdump[467]: saving vmcore\\n  BUG: unable to handle page fault for address: 00007f2374e01000\\n  #PF: supervisor write access in kernel mode\\n  #PF: error_code(0x0003) - permissions violation\\n  PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867\\n  Oops: 0003 [#1] PREEMPT SMP NOPTI\\n  CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6\\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014\\n  RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86\\n  Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 \u003c49\u003e c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81\\n  RSP: 0018:ffffc9000073be08 EFLAGS: 00010212\\n  RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000\\n  RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008\\n  RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50\\n  R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000\\n  R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8\\n  FS:  00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000\\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\\n  CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0\\n  Call Trace:\\n   read_vmcore+0x236/0x2c0\\n   proc_reg_read+0x55/0xa0\\n   vfs_read+0x95/0x190\\n   ksys_read+0x4f/0xc0\\n   do_syscall_64+0x3b/0x90\\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\\n\\nSome x86-64 CPUs have a CPU feature called \\\"Supervisor Mode Access\\nPrevention (SMAP)\\\", which is used to detect wrong access from the kernel\\nto user buffers like this: SMAP triggers a permissions violation on\\nwrong access.  In the x86-64 variant of clear_user(), SMAP is properly\\nhandled via clac()+stac().\\n\\nTo fix, properly use clear_user() when we\u0027re dealing with a user buffer.\"}, {\"lang\": \"es\", \"value\": \"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: proc/vmcore: corrige el borrado del b\\u00fafer del usuario usando correctamente clear_user() Para borrar un b\\u00fafer de usuario no podemos simplemente usar memset, tenemos que usar clear_user(). Con un dispositivo virtio-mem que registra un vmcore_cb y tiene algo de memoria l\\u00f3gicamente desconectada dentro de un bloque de memoria de Linux agregado, puedo desencadenar f\\u00e1cilmente un ERROR copiando el vmcore a trav\\u00e9s de \\\"cp\\\": systemd[1]: Iniciando el servicio Kdump Vmcore Save. . kdump[420]: Kdump est\\u00e1 utilizando el nivel de registro predeterminado (3). kdump[453]: guardar en /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/ kdump[458]: guardar vmcore-dmesg.txt en /sysroot/var/crash/127.0 .0.1-2021-11-11-14:59:22/ kdump[465]: guardar vmcore-dmesg.txt completo kdump[467]: guardar vmcore ERROR: no se puede manejar el error de p\\u00e1gina para la direcci\\u00f3n: 00007f2374e01000 #PF: escritura del supervisor acceso en modo kernel #PF: error_code(0x0003) - violaci\\u00f3n de permisos PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867 Ups: 0003 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 468 Comm: p No contaminado 5.15.0+ # 6 Nombre del hardware: PC est\\u00e1ndar QEMU (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 01/04/2014 RIP: 0010:read_from_oldmem.part.0.cold+0x1d/ 0x86 C\\u00f3digo: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 \u0026lt;49\u0026gt; c7 45 00 00 00 00 00 49 C7 44 05 F8 00 00 00 00 48 83 E7 F81 RSP: 0018: FFFFFC9000073BE08 EFLAGS: 00010212 RAX: 00000000000000001000 RBX: 000000002FD000 RCX: 00007F2374E RSI: 000000000000FFFFDFFF RDI: 00007F2374E01008 RBP: 000000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50 R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000 R13: 00007f2374e01000 R14: 0000000000000000 R15: 88807bd421e8 FS: 00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2 : 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0 Seguimiento de llamadas: read_vmcore+0x236/0x2c0 proc_reg_read+0x55/0xa0 vfs_read+0x95/0x190 do_syscall_64+0x3b/0x90 Entry_SYSCALL_64_after_hwframe+0x44/0xae Algunas CPU x86-64 tienen una funci\\u00f3n de CPU llamada \\\"Prevenci\\u00f3n de acceso en modo supervisor (SMAP)\\\", que se utiliza para detectar accesos incorrectos desde el kernel a los b\\u00faferes de usuario como este: SMAP desencadena una violaci\\u00f3n de permisos en caso de acceso incorrecto. En la variante x86-64 de clear_user(), SMAP se maneja correctamente mediante clac()+stac(). Para solucionarlo, utilice correctamente clear_user() cuando estemos tratando con un b\\u00fafer de usuario.\"}]",
      "id": "CVE-2021-47566",
      "lastModified": "2024-11-21T06:36:34.270",
      "published": "2024-05-24T15:15:21.637",
      "references": "[{\"url\": \"https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89\", \"source\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}, {\"url\": \"https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}, {\"url\": \"https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\"}]",
      "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "vulnStatus": "Awaiting Analysis"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-47566\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-05-24T15:15:21.637\",\"lastModified\":\"2025-09-18T15:41:41.317\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nproc/vmcore: fix clearing user buffer by properly using clear_user()\\n\\nTo clear a user buffer we cannot simply use memset, we have to use\\nclear_user().  With a virtio-mem device that registers a vmcore_cb and\\nhas some logically unplugged memory inside an added Linux memory block,\\nI can easily trigger a BUG by copying the vmcore via \\\"cp\\\":\\n\\n  systemd[1]: Starting Kdump Vmcore Save Service...\\n  kdump[420]: Kdump is using the default log level(3).\\n  kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\\n  kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\\n  kdump[465]: saving vmcore-dmesg.txt complete\\n  kdump[467]: saving vmcore\\n  BUG: unable to handle page fault for address: 00007f2374e01000\\n  #PF: supervisor write access in kernel mode\\n  #PF: error_code(0x0003) - permissions violation\\n  PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867\\n  Oops: 0003 [#1] PREEMPT SMP NOPTI\\n  CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6\\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014\\n  RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86\\n  Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 \u003c49\u003e c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81\\n  RSP: 0018:ffffc9000073be08 EFLAGS: 00010212\\n  RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000\\n  RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008\\n  RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50\\n  R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000\\n  R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8\\n  FS:  00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000\\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\\n  CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0\\n  Call Trace:\\n   read_vmcore+0x236/0x2c0\\n   proc_reg_read+0x55/0xa0\\n   vfs_read+0x95/0x190\\n   ksys_read+0x4f/0xc0\\n   do_syscall_64+0x3b/0x90\\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\\n\\nSome x86-64 CPUs have a CPU feature called \\\"Supervisor Mode Access\\nPrevention (SMAP)\\\", which is used to detect wrong access from the kernel\\nto user buffers like this: SMAP triggers a permissions violation on\\nwrong access.  In the x86-64 variant of clear_user(), SMAP is properly\\nhandled via clac()+stac().\\n\\nTo fix, properly use clear_user() when we\u0027re dealing with a user buffer.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: proc/vmcore: corrige el borrado del b\u00fafer del usuario usando correctamente clear_user() Para borrar un b\u00fafer de usuario no podemos simplemente usar memset, tenemos que usar clear_user(). Con un dispositivo virtio-mem que registra un vmcore_cb y tiene algo de memoria l\u00f3gicamente desconectada dentro de un bloque de memoria de Linux agregado, puedo desencadenar f\u00e1cilmente un ERROR copiando el vmcore a trav\u00e9s de \\\"cp\\\": systemd[1]: Iniciando el servicio Kdump Vmcore Save. . kdump[420]: Kdump est\u00e1 utilizando el nivel de registro predeterminado (3). kdump[453]: guardar en /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/ kdump[458]: guardar vmcore-dmesg.txt en /sysroot/var/crash/127.0 .0.1-2021-11-11-14:59:22/ kdump[465]: guardar vmcore-dmesg.txt completo kdump[467]: guardar vmcore ERROR: no se puede manejar el error de p\u00e1gina para la direcci\u00f3n: 00007f2374e01000 #PF: escritura del supervisor acceso en modo kernel #PF: error_code(0x0003) - violaci\u00f3n de permisos PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867 Ups: 0003 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 468 Comm: p No contaminado 5.15.0+ # 6 Nombre del hardware: PC est\u00e1ndar QEMU (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 01/04/2014 RIP: 0010:read_from_oldmem.part.0.cold+0x1d/ 0x86 C\u00f3digo: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 \u0026lt;49\u0026gt; c7 45 00 00 00 00 00 49 C7 44 05 F8 00 00 00 00 48 83 E7 F81 RSP: 0018: FFFFFC9000073BE08 EFLAGS: 00010212 RAX: 00000000000000001000 RBX: 000000002FD000 RCX: 00007F2374E RSI: 000000000000FFFFDFFF RDI: 00007F2374E01008 RBP: 000000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50 R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000 R13: 00007f2374e01000 R14: 0000000000000000 R15: 88807bd421e8 FS: 00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2 : 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0 Seguimiento de llamadas: read_vmcore+0x236/0x2c0 proc_reg_read+0x55/0xa0 vfs_read+0x95/0x190 do_syscall_64+0x3b/0x90 Entry_SYSCALL_64_after_hwframe+0x44/0xae Algunas CPU x86-64 tienen una funci\u00f3n de CPU llamada \\\"Prevenci\u00f3n de acceso en modo supervisor (SMAP)\\\", que se utiliza para detectar accesos incorrectos desde el kernel a los b\u00faferes de usuario como este: SMAP desencadena una violaci\u00f3n de permisos en caso de acceso incorrecto. En la variante x86-64 de clear_user(), SMAP se maneja correctamente mediante clac()+stac(). Para solucionarlo, utilice correctamente clear_user() cuando estemos tratando con un b\u00fafer de usuario.\"}],\"metrics\":{\"cvssMetricV31\":[{\"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}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-787\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"3.0\",\"versionEndExcluding\":\"4.4.294\",\"matchCriteriaId\":\"B35C423A-CD8B-48D2-8C0F-200B888B53F3\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.5\",\"versionEndExcluding\":\"4.9.292\",\"matchCriteriaId\":\"DB7F6C04-42D3-48A3-892D-2487383B9B6E\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.10\",\"versionEndExcluding\":\"4.14.257\",\"matchCriteriaId\":\"7080D941-9847-42F5-BA50-0A03CFB61FD1\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.15\",\"versionEndExcluding\":\"4.19.219\",\"matchCriteriaId\":\"B9EF0575-6BF6-4AD9-B9A0-5C8D7D71710C\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.20\",\"versionEndExcluding\":\"5.4.163\",\"matchCriteriaId\":\"80E8F086-C9B9-4987-8B2E-B4A16D1DA7BA\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.5\",\"versionEndExcluding\":\"5.10.83\",\"matchCriteriaId\":\"D4843826-EA9A-472B-82EC-B9E4FD4149AD\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11\",\"versionEndExcluding\":\"5.15.6\",\"matchCriteriaId\":\"990C08FB-0121-4296-896F-556312F8FF3B\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"357AA433-37E8-4323-BFB2-3038D6E4B414\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:39:59.769Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-47566\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-06-12T19:44:25.541373Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-06-12T19:44:32.297Z\"}}], \"cna\": {\"title\": \"proc/vmcore: fix clearing user buffer by properly using clear_user()\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"a9e164bd160b\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"33a7d698f30f\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"99d348b82bcb\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"9ef384ed300d\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"fd7974c547ab\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"a8a917058faf\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"7b3a34f08d11\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"997c136f518c\", \"lessThan\": \"c1e631177119\", \"versionType\": \"git\"}], \"programFiles\": [\"fs/proc/vmcore.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"3.0\", \"versionType\": \"custom\"}, {\"status\": \"unaffected\", \"version\": \"4.4.294\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"4.4.*\"}, {\"status\": \"unaffected\", \"version\": \"4.9.292\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"4.9.*\"}, {\"status\": \"unaffected\", \"version\": \"4.14.257\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"4.14.*\"}, {\"status\": \"unaffected\", \"version\": \"4.19.219\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"4.19.*\"}, {\"status\": \"unaffected\", \"version\": \"5.4.163\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"5.4.*\"}, {\"status\": \"unaffected\", \"version\": \"5.10.83\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.15.6\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"5.16\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"fs/proc/vmcore.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/a9e164bd160be8cbee1df70acb379129e3cd2e7c\"}, {\"url\": \"https://git.kernel.org/stable/c/33a7d698f30fa0b99d50569e9909d3baa65d8f6a\"}, {\"url\": \"https://git.kernel.org/stable/c/99d348b82bcb36171f24411d3f1a15706a2a937a\"}, {\"url\": \"https://git.kernel.org/stable/c/9ef384ed300d1bcfb23d0ab0b487d544444d4b52\"}, {\"url\": \"https://git.kernel.org/stable/c/fd7974c547abfb03072a4ee706d3a6f182266f89\"}, {\"url\": \"https://git.kernel.org/stable/c/a8a917058faf4abaec9fb614bb6d5f8fe3529ec6\"}, {\"url\": \"https://git.kernel.org/stable/c/7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1\"}, {\"url\": \"https://git.kernel.org/stable/c/c1e63117711977cc4295b2ce73de29dd17066c82\"}], \"x_generator\": {\"engine\": \"bippy-a5840b7849dd\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nproc/vmcore: fix clearing user buffer by properly using clear_user()\\n\\nTo clear a user buffer we cannot simply use memset, we have to use\\nclear_user().  With a virtio-mem device that registers a vmcore_cb and\\nhas some logically unplugged memory inside an added Linux memory block,\\nI can easily trigger a BUG by copying the vmcore via \\\"cp\\\":\\n\\n  systemd[1]: Starting Kdump Vmcore Save Service...\\n  kdump[420]: Kdump is using the default log level(3).\\n  kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\\n  kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/\\n  kdump[465]: saving vmcore-dmesg.txt complete\\n  kdump[467]: saving vmcore\\n  BUG: unable to handle page fault for address: 00007f2374e01000\\n  #PF: supervisor write access in kernel mode\\n  #PF: error_code(0x0003) - permissions violation\\n  PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867\\n  Oops: 0003 [#1] PREEMPT SMP NOPTI\\n  CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6\\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014\\n  RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86\\n  Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 \u003c49\u003e c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81\\n  RSP: 0018:ffffc9000073be08 EFLAGS: 00010212\\n  RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000\\n  RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008\\n  RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50\\n  R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000\\n  R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8\\n  FS:  00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000\\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\\n  CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0\\n  Call Trace:\\n   read_vmcore+0x236/0x2c0\\n   proc_reg_read+0x55/0xa0\\n   vfs_read+0x95/0x190\\n   ksys_read+0x4f/0xc0\\n   do_syscall_64+0x3b/0x90\\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\\n\\nSome x86-64 CPUs have a CPU feature called \\\"Supervisor Mode Access\\nPrevention (SMAP)\\\", which is used to detect wrong access from the kernel\\nto user buffers like this: SMAP triggers a permissions violation on\\nwrong access.  In the x86-64 variant of clear_user(), SMAP is properly\\nhandled via clac()+stac().\\n\\nTo fix, properly use clear_user() when we\u0027re dealing with a user buffer.\"}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2024-05-29T05:10:14.234Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-47566\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2024-08-04T05:39:59.769Z\", \"dateReserved\": \"2024-05-24T15:11:00.728Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-05-24T15:12:53.432Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.