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CVE-2021-47585 (GCVE-0-2021-47585)

Vulnerability from cvelistv5 – Published: 2024-06-19 14:53 – Updated: 2026-05-11 13:57
VLAI
Title
btrfs: fix memory leak in __add_inode_ref()
Summary
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix memory leak in __add_inode_ref() Line 1169 (#3) allocates a memory chunk for victim_name by kmalloc(), but when the function returns in line 1184 (#4) victim_name allocated by line 1169 (#3) is not freed, which will lead to a memory leak. There is a similar snippet of code in this function as allocating a memory chunk for victim_name in line 1104 (#1) as well as releasing the memory in line 1116 (#2). We should kfree() victim_name when the return value of backref_in_log() is less than zero and before the function returns in line 1184 (#4). 1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans, 1058 struct btrfs_root *root, 1059 struct btrfs_path *path, 1060 struct btrfs_root *log_root, 1061 struct btrfs_inode *dir, 1062 struct btrfs_inode *inode, 1063 u64 inode_objectid, u64 parent_objectid, 1064 u64 ref_index, char *name, int namelen, 1065 int *search_done) 1066 { 1104 victim_name = kmalloc(victim_name_len, GFP_NOFS); // #1: kmalloc (victim_name-1) 1105 if (!victim_name) 1106 return -ENOMEM; 1112 ret = backref_in_log(log_root, &search_key, 1113 parent_objectid, victim_name, 1114 victim_name_len); 1115 if (ret < 0) { 1116 kfree(victim_name); // #2: kfree (victim_name-1) 1117 return ret; 1118 } else if (!ret) { 1169 victim_name = kmalloc(victim_name_len, GFP_NOFS); // #3: kmalloc (victim_name-2) 1170 if (!victim_name) 1171 return -ENOMEM; 1180 ret = backref_in_log(log_root, &search_key, 1181 parent_objectid, victim_name, 1182 victim_name_len); 1183 if (ret < 0) { 1184 return ret; // #4: missing kfree (victim_name-2) 1185 } else if (!ret) { 1241 return 0; 1242 }
Severity
No CVSS data available.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-06-24 18:08 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: d3316c8233bb05e0dd855d30aac347bb8ad76ee4 , < 005d9292b5b2e71a009f911bd85d755009b37242 (git)
Affected: d3316c8233bb05e0dd855d30aac347bb8ad76ee4 , < 493ff661d434d6bdf02e3a21adae04d7a0b4265d (git)
Affected: d3316c8233bb05e0dd855d30aac347bb8ad76ee4 , < f35838a6930296fc1988764cfa54cb3f705c0665 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.5
Unaffected: 0 , < 5.5 (semver)
Unaffected: 5.10.88 , ≤ 5.10.* (semver)
Unaffected: 5.15.11 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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                "negate": false,
                "operator": "OR"
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          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix memory leak in __add_inode_ref()\n\nLine 1169 (#3) allocates a memory chunk for victim_name by kmalloc(),\nbut  when the function returns in line 1184 (#4) victim_name allocated\nby line 1169 (#3) is not freed, which will lead to a memory leak.\nThere is a similar snippet of code in this function as allocating a memory\nchunk for victim_name in line 1104 (#1) as well as releasing the memory\nin line 1116 (#2).\n\nWe should kfree() victim_name when the return value of backref_in_log()\nis less than zero and before the function returns in line 1184 (#4).\n\n1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans,\n1058 \t\t\t\t  struct btrfs_root *root,\n1059 \t\t\t\t  struct btrfs_path *path,\n1060 \t\t\t\t  struct btrfs_root *log_root,\n1061 \t\t\t\t  struct btrfs_inode *dir,\n1062 \t\t\t\t  struct btrfs_inode *inode,\n1063 \t\t\t\t  u64 inode_objectid, u64 parent_objectid,\n1064 \t\t\t\t  u64 ref_index, char *name, int namelen,\n1065 \t\t\t\t  int *search_done)\n1066 {\n\n1104 \tvictim_name = kmalloc(victim_name_len, GFP_NOFS);\n\t// #1: kmalloc (victim_name-1)\n1105 \tif (!victim_name)\n1106 \t\treturn -ENOMEM;\n\n1112\tret = backref_in_log(log_root, \u0026search_key,\n1113\t\t\tparent_objectid, victim_name,\n1114\t\t\tvictim_name_len);\n1115\tif (ret \u003c 0) {\n1116\t\tkfree(victim_name); // #2: kfree (victim_name-1)\n1117\t\treturn ret;\n1118\t} else if (!ret) {\n\n1169 \tvictim_name = kmalloc(victim_name_len, GFP_NOFS);\n\t// #3: kmalloc (victim_name-2)\n1170 \tif (!victim_name)\n1171 \t\treturn -ENOMEM;\n\n1180 \tret = backref_in_log(log_root, \u0026search_key,\n1181 \t\t\tparent_objectid, victim_name,\n1182 \t\t\tvictim_name_len);\n1183 \tif (ret \u003c 0) {\n1184 \t\treturn ret; // #4: missing kfree (victim_name-2)\n1185 \t} else if (!ret) {\n\n1241 \treturn 0;\n1242 }"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: btrfs: corrige la p\u00e9rdida de memoria en __add_inode_ref() La l\u00ednea 1169 (#3) asigna un fragmento de memoria para victim_name mediante kmalloc(), pero cuando la funci\u00f3n regresa en la l\u00ednea 1184 (#4) victim_name asignado por la l\u00ednea 1169 (#3) no se libera, lo que provocar\u00e1 una p\u00e9rdida de memoria. Hay un fragmento de c\u00f3digo similar en esta funci\u00f3n para asignar un fragmento de memoria para victim_name en la l\u00ednea 1104 (n.\u00ba 1), as\u00ed como para liberar la memoria en la l\u00ednea 1116 (n.\u00ba 2). Deber\u00edamos kfree() victim_name cuando el valor de retorno de backref_in_log() sea menor que cero y antes de que la funci\u00f3n regrese en la l\u00ednea 1184 (#4). 1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans, 1058 struct btrfs_root *root, 1059 struct btrfs_path *path, 1060 struct btrfs_root *log_root, 1061 struct btrfs_inode *dir, 1062 struct btrfs_inode *inode, 63 u64 inode_objectid, u64 parent_objectid, 1064 u64 ref_index, char *nombre, int nombrelen, 1065 int *search_done) 1066 { 1104 nombre_v\u00edctima = kmalloc(nombre_v\u00edctima_len, GFP_NOFS); // #1: kmalloc (nombre_v\u00edctima-1) 1105 if (!nombre_v\u00edctima) 1106 return -ENOMEM; 1112 ret = backref_in_log(log_root, \u0026amp;search_key, 1113 parent_objectid, victim_name, 1114 victim_name_len); 1115 if (ret \u0026lt; 0) { 1116 kfree(nombre_v\u00edctima); // #2: kfree (nombre_v\u00edctima-1) 1117 return ret; 1118 } else if (!ret) { 1169 nombre_v\u00edctima = kmalloc(nombre_v\u00edctima_len, GFP_NOFS); // #3: kmalloc (nombre_v\u00edctima-2) 1170 if (!nombre_v\u00edctima) 1171 return -ENOMEM; 1180 ret = backref_in_log(log_root, \u0026amp;search_key, 1181 parent_objectid, victim_name, 1182 victim_name_len); 1183 si (ret \u0026lt; 0) { 1184 retorno ret; // #4: falta kfree (nombre_v\u00edctima-2) 1185 } else if (!ret) { 1241 return 0; 1242 }"
          }
        ],
        "id": "CVE-2021-47585",
        "lastModified": "2026-06-17T04:17:49.000",
        "metrics": {
          "cvssMetricV31": [
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              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 5.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 3.6,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2021-47585",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-06-24T18:08:01.516987Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2024-06-19T15:15:53.057",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
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                "lang": "en",
                "value": "CWE-401"
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    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2025-11-21T14:39:58+00:00",
      "cve": "CVE-2021-47585",
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      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_affected": "42",
      "product_status:known_not_affected": "156",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: btrfs: fix memory leak in __add_inode_ref()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47585.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-11T02:36:50Z",
      "cve": "CVE-2021-47585",
      "id": "CVE-2021-47585",
      "initial_release_date": "2024-06-21T03:52:30Z",
      "product_status:known_affected": "330",
      "product_status:known_not_affected": "254",
      "product_status:recommended": "391",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-47585",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-47585.json",
      "version": "52"
    },
    "vulnrichment": {
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            "providerMetadata": {
              "dateUpdated": "2024-08-04T05:39:59.778Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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                "url": "https://git.kernel.org/stable/c/005d9292b5b2e71a009f911bd85d755009b37242"
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                "url": "https://git.kernel.org/stable/c/493ff661d434d6bdf02e3a21adae04d7a0b4265d"
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                "url": "https://git.kernel.org/stable/c/f35838a6930296fc1988764cfa54cb3f705c0665"
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            ],
            "title": "CVE Program Container"
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          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-47585",
                    "options": [
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                        "Exploitation": "none"
                      },
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                      },
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                      }
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                    "role": "CISA Coordinator",
                    "timestamp": "2024-06-24T18:08:01.516987Z",
                    "version": "2.0.3"
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              "dateUpdated": "2024-06-24T18:08:06.072Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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            },
            "title": "CISA ADP Vulnrichment"
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        "cna": {
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              "product": "Linux",
              "programFiles": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
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              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix memory leak in __add_inode_ref()\n\nLine 1169 (#3) allocates a memory chunk for victim_name by kmalloc(),\nbut  when the function returns in line 1184 (#4) victim_name allocated\nby line 1169 (#3) is not freed, which will lead to a memory leak.\nThere is a similar snippet of code in this function as allocating a memory\nchunk for victim_name in line 1104 (#1) as well as releasing the memory\nin line 1116 (#2).\n\nWe should kfree() victim_name when the return value of backref_in_log()\nis less than zero and before the function returns in line 1184 (#4).\n\n1057 static inline int __add_inode_ref(struct btrfs_trans_handle *trans,\n1058 \t\t\t\t  struct btrfs_root *root,\n1059 \t\t\t\t  struct btrfs_path *path,\n1060 \t\t\t\t  struct btrfs_root *log_root,\n1061 \t\t\t\t  struct btrfs_inode *dir,\n1062 \t\t\t\t  struct btrfs_inode *inode,\n1063 \t\t\t\t  u64 inode_objectid, u64 parent_objectid,\n1064 \t\t\t\t  u64 ref_index, char *name, int namelen,\n1065 \t\t\t\t  int *search_done)\n1066 {\n\n1104 \tvictim_name = kmalloc(victim_name_len, GFP_NOFS);\n\t// #1: kmalloc (victim_name-1)\n1105 \tif (!victim_name)\n1106 \t\treturn -ENOMEM;\n\n1112\tret = backref_in_log(log_root, \u0026search_key,\n1113\t\t\tparent_objectid, victim_name,\n1114\t\t\tvictim_name_len);\n1115\tif (ret \u003c 0) {\n1116\t\tkfree(victim_name); // #2: kfree (victim_name-1)\n1117\t\treturn ret;\n1118\t} else if (!ret) {\n\n1169 \tvictim_name = kmalloc(victim_name_len, GFP_NOFS);\n\t// #3: kmalloc (victim_name-2)\n1170 \tif (!victim_name)\n1171 \t\treturn -ENOMEM;\n\n1180 \tret = backref_in_log(log_root, \u0026search_key,\n1181 \t\t\tparent_objectid, victim_name,\n1182 \t\t\tvictim_name_len);\n1183 \tif (ret \u003c 0) {\n1184 \t\treturn ret; // #4: missing kfree (victim_name-2)\n1185 \t} else if (!ret) {\n\n1241 \treturn 0;\n1242 }"
            }
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          "providerMetadata": {
            "dateUpdated": "2024-12-19T07:45:15.543Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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              "url": "https://git.kernel.org/stable/c/f35838a6930296fc1988764cfa54cb3f705c0665"
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          "title": "btrfs: fix memory leak in __add_inode_ref()",
          "x_generator": {
            "engine": "bippy-5f407fcff5a0"
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      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2021-47585",
        "datePublished": "2024-06-19T14:53:50.780Z",
        "dateReserved": "2024-05-24T15:11:00.731Z",
        "dateUpdated": "2024-12-19T07:45:15.543Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



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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

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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.