cve-2021-46935
Vulnerability from cvelistv5
Published
2024-02-27 09:44
Modified
2024-12-19 07:32
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: binder: fix async_free_space accounting for empty parcels In 4.13, commit 74310e06be4d ("android: binder: Move buffer out of area shared with user space") fixed a kernel structure visibility issue. As part of that patch, sizeof(void *) was used as the buffer size for 0-length data payloads so the driver could detect abusive clients sending 0-length asynchronous transactions to a server by enforcing limits on async_free_size. Unfortunately, on the "free" side, the accounting of async_free_space did not add the sizeof(void *) back. The result was that up to 8-bytes of async_free_space were leaked on every async transaction of 8-bytes or less. These small transactions are uncommon, so this accounting issue has gone undetected for several years. The fix is to use "buffer_size" (the allocated buffer size) instead of "size" (the logical buffer size) when updating the async_free_space during the free operation. These are the same except for this corner case of asynchronous transactions with payloads < 8 bytes.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5daPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ffPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5daPatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ffPatch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593Patch
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901Patch
Impacted products
Vendor Product Version
Linux Linux Version: 4.14
Show details on NVD website

To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-46935",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-02-27T20:52:57.585284Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-07-05T17:22:03.611Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:17:43.010Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5da"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ff"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/android/binder_alloc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2d2df539d05205fd83c404d5f2dff48d36f9b495",
              "status": "affected",
              "version": "74310e06be4d74dcf67cd108366710dee5c576d5",
              "versionType": "git"
            },
            {
              "lessThan": "7c7064402609aeb6fb11be1b4ec10673ff17b593",
              "status": "affected",
              "version": "74310e06be4d74dcf67cd108366710dee5c576d5",
              "versionType": "git"
            },
            {
              "lessThan": "103b16a8c51f96d5fe063022869ea906c256e5da",
              "status": "affected",
              "version": "74310e06be4d74dcf67cd108366710dee5c576d5",
              "versionType": "git"
            },
            {
              "lessThan": "1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4",
              "status": "affected",
              "version": "74310e06be4d74dcf67cd108366710dee5c576d5",
              "versionType": "git"
            },
            {
              "lessThan": "17691bada6b2f1d5f1c0f6d28cd9d0727023b0ff",
              "status": "affected",
              "version": "74310e06be4d74dcf67cd108366710dee5c576d5",
              "versionType": "git"
            },
            {
              "lessThan": "cfd0d84ba28c18b531648c9d4a35ecca89ad9901",
              "status": "affected",
              "version": "74310e06be4d74dcf67cd108366710dee5c576d5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/android/binder_alloc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.14"
            },
            {
              "lessThan": "4.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.14.*",
              "status": "unaffected",
              "version": "4.14.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "4.19.*",
              "status": "unaffected",
              "version": "4.19.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.170",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.90",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.16",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbinder: fix async_free_space accounting for empty parcels\n\nIn 4.13, commit 74310e06be4d (\"android: binder: Move buffer out of area shared with user space\")\nfixed a kernel structure visibility issue. As part of that patch,\nsizeof(void *) was used as the buffer size for 0-length data payloads so\nthe driver could detect abusive clients sending 0-length asynchronous\ntransactions to a server by enforcing limits on async_free_size.\n\nUnfortunately, on the \"free\" side, the accounting of async_free_space\ndid not add the sizeof(void *) back. The result was that up to 8-bytes of\nasync_free_space were leaked on every async transaction of 8-bytes or\nless.  These small transactions are uncommon, so this accounting issue\nhas gone undetected for several years.\n\nThe fix is to use \"buffer_size\" (the allocated buffer size) instead of\n\"size\" (the logical buffer size) when updating the async_free_space\nduring the free operation. These are the same except for this\ncorner case of asynchronous transactions with payloads \u003c 8 bytes."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2024-12-19T07:32:07.436Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495"
        },
        {
          "url": "https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593"
        },
        {
          "url": "https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5da"
        },
        {
          "url": "https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4"
        },
        {
          "url": "https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ff"
        },
        {
          "url": "https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901"
        }
      ],
      "title": "binder: fix async_free_space accounting for empty parcels",
      "x_generator": {
        "engine": "bippy-5f407fcff5a0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-46935",
    "datePublished": "2024-02-27T09:44:02.071Z",
    "dateReserved": "2024-02-25T13:45:52.720Z",
    "dateUpdated": "2024-12-19T07:32:07.436Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-46935\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-02-27T10:15:07.957\",\"lastModified\":\"2024-11-21T06:34:58.220\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbinder: fix async_free_space accounting for empty parcels\\n\\nIn 4.13, commit 74310e06be4d (\\\"android: binder: Move buffer out of area shared with user space\\\")\\nfixed a kernel structure visibility issue. As part of that patch,\\nsizeof(void *) was used as the buffer size for 0-length data payloads so\\nthe driver could detect abusive clients sending 0-length asynchronous\\ntransactions to a server by enforcing limits on async_free_size.\\n\\nUnfortunately, on the \\\"free\\\" side, the accounting of async_free_space\\ndid not add the sizeof(void *) back. The result was that up to 8-bytes of\\nasync_free_space were leaked on every async transaction of 8-bytes or\\nless.  These small transactions are uncommon, so this accounting issue\\nhas gone undetected for several years.\\n\\nThe fix is to use \\\"buffer_size\\\" (the allocated buffer size) instead of\\n\\\"size\\\" (the logical buffer size) when updating the async_free_space\\nduring the free operation. These are the same except for this\\ncorner case of asynchronous transactions with payloads \u003c 8 bytes.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: binder: corrige la contabilidad async_free_space para paquetes vac\u00edos En 4.13, el commit 74310e06be4d (\\\"android: binder: mover el b\u00fafer fuera del \u00e1rea compartida con el espacio del usuario\\\") solucion\u00f3 un problema de visibilidad de la estructura del kernel. Como parte de ese parche, se us\u00f3 sizeof(void *) como tama\u00f1o de b\u00fafer para cargas de datos de longitud 0, de modo que el controlador pudiera detectar clientes abusivos que enviaran transacciones asincr\u00f3nicas de longitud 0 a un servidor imponiendo l\u00edmites en async_free_size. Desafortunadamente, en el lado \\\"libre\\\", la contabilidad de async_free_space no volvi\u00f3 a agregar el tama\u00f1o de (void *). El resultado fue que se filtraron hasta 8 bytes de async_free_space en cada transacci\u00f3n as\u00edncrona de 8 bytes o menos. Estas peque\u00f1as transacciones son poco comunes, por lo que este problema contable ha pasado desapercibido durante varios a\u00f1os. La soluci\u00f3n es utilizar \\\"buffer_size\\\" (el tama\u00f1o del b\u00fafer asignado) en lugar de \\\"size\\\" (el tama\u00f1o del b\u00fafer l\u00f3gico) al actualizar async_free_space durante la operaci\u00f3n libre. Son iguales excepto por este caso de esquina de transacciones asincr\u00f3nicas con payloads \u0026lt;8 bytes.\"}],\"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:N/A:N\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-668\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.14.0\",\"versionEndExcluding\":\"4.14.261\",\"matchCriteriaId\":\"D04E4F21-CE5F-4E9D-A182-492968E35204\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.15.0\",\"versionEndExcluding\":\"4.19.224\",\"matchCriteriaId\":\"B34A1353-506A-4AB9-87EC-CD50F09DFB8A\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.20.0\",\"versionEndExcluding\":\"5.4.170\",\"matchCriteriaId\":\"56D16FBB-453E-4316-A027-E517828203D7\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.5.0\",\"versionEndExcluding\":\"5.10.90\",\"matchCriteriaId\":\"C87FB3FD-3E74-4588-A1A4-B9BA8AE0C06B\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11.0\",\"versionEndExcluding\":\"5.15.13\",\"matchCriteriaId\":\"083E0940-932B-447B-A6B2-677DAE27FD04\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5da\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ff\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5da\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ff\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.