fkie_cve-2024-49861
Vulnerability from fkie_nvd
Published
2024-10-21 13:15
Modified
2024-12-14 21:15
Severity ?
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix helper writes to read-only maps Lonial found an issue that despite user- and BPF-side frozen BPF map (like in case of .rodata), it was still possible to write into it from a BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT} as arguments. In check_func_arg() when the argument is as mentioned, the meta->raw_mode is never set. Later, check_helper_mem_access(), under the case of PTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for the subsequent call to check_map_access_type() and given the BPF map is read-only it succeeds. The helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINIT when results are written into them as opposed to read out of them. The latter indicates that it's okay to pass a pointer to uninitialized memory as the memory is written to anyway. However, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEM just with additional alignment requirement. So it is better to just get rid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse the fixed size memory types. For this, add MEM_ALIGNED to additionally ensure alignment given these helpers write directly into the args via *<ptr> = val. The .arg*_size has been initialized reflecting the actual sizeof(*<ptr>). MEM_ALIGNED can only be used in combination with MEM_FIXED_SIZE annotated argument types, since in !MEM_FIXED_SIZE cases the verifier does not know the buffer size a priori and therefore cannot blindly write *<ptr> = val.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1e75d25133158b525e0456876e9bcfd6b2993fd5Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2ed98ee02d1e08afee88f54baec39ea78dc8a23cPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/32556ce93bc45c730829083cb60f95a2728ea48bPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/988e55abcf7fdb8fc9a76a7cf3f4e939a4d4fb3a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a2c8dc7e21803257e762b0bf067fd13e9c995da0Patch
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: "1C50745E-F1ED-43B5-A0AA-2ECE7194E14C",
                     versionEndExcluding: "6.6.54",
                     versionStartIncluding: "5.2",
                     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\nbpf: Fix helper writes to read-only maps\n\nLonial found an issue that despite user- and BPF-side frozen BPF map\n(like in case of .rodata), it was still possible to write into it from\na BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT}\nas arguments.\n\nIn check_func_arg() when the argument is as mentioned, the meta->raw_mode\nis never set. Later, check_helper_mem_access(), under the case of\nPTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for the\nsubsequent call to check_map_access_type() and given the BPF map is\nread-only it succeeds.\n\nThe helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINIT\nwhen results are written into them as opposed to read out of them. The\nlatter indicates that it's okay to pass a pointer to uninitialized memory\nas the memory is written to anyway.\n\nHowever, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEM\njust with additional alignment requirement. So it is better to just get\nrid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse the\nfixed size memory types. For this, add MEM_ALIGNED to additionally ensure\nalignment given these helpers write directly into the args via *<ptr> = val.\nThe .arg*_size has been initialized reflecting the actual sizeof(*<ptr>).\n\nMEM_ALIGNED can only be used in combination with MEM_FIXED_SIZE annotated\nargument types, since in !MEM_FIXED_SIZE cases the verifier does not know\nthe buffer size a priori and therefore cannot blindly write *<ptr> = val.",
      },
      {
         lang: "es",
         value: "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: Arregla las escrituras del ayudante en mapas de solo lectura Lonial encontró un problema que a pesar del mapa BPF congelado del lado del usuario y del BPF (como en el caso de .rodata), aún era posible escribir en él desde el lado del programa BPF a través de ayudantes específicos que tienen ARG_PTR_TO_{LONG,INT} como argumentos. En check_func_arg() cuando el argumento es como se menciona, el meta-&gt;raw_mode nunca se establece. Más tarde, check_helper_mem_access(), bajo el caso de PTR_TO_MAP_VALUE como tipo base de registro, asume BPF_READ para la llamada posterior a check_map_access_type() y dado que el mapa BPF es de solo lectura, tiene éxito. Los ayudantes realmente necesitan ser anotados como ARG_PTR_TO_{LONG,INT} | MEM_UNINIT cuando los resultados se escriben en ellos en lugar de leerse de ellos. Este último indica que está bien pasar un puntero a la memoria no inicializada, ya que la memoria se escribe de todos modos. Sin embargo, ARG_PTR_TO_{LONG,INT} es un caso especial de ARG_PTR_TO_FIXED_SIZE_MEM solo que con un requisito de alineación adicional. Por lo tanto, es mejor deshacerse de los casos especiales ARG_PTR_TO_{LONG,INT} por completo y reutilizar los tipos de memoria de tamaño fijo. Para esto, agregue MEM_ALIGNED para garantizar adicionalmente la alineación dado que estos ayudantes escriben directamente en los argumentos a través de * = val. El .arg*_size se ha inicializado reflejando el tamaño real de (*). MEM_ALIGNED solo se puede usar en combinación con los tipos de argumentos anotados MEM_FIXED_SIZE, ya que en los casos !MEM_FIXED_SIZE el verificador no conoce el tamaño del búfer a priori y, por lo tanto, no puede escribir ciegamente * = val.",
      },
   ],
   id: "CVE-2024-49861",
   lastModified: "2024-12-14T21:15:26.447",
   metrics: {
      cvssMetricV31: [
         {
            cvssData: {
               attackComplexity: "LOW",
               attackVector: "LOCAL",
               availabilityImpact: "HIGH",
               baseScore: 7.1,
               baseSeverity: "HIGH",
               confidentialityImpact: "NONE",
               integrityImpact: "HIGH",
               privilegesRequired: "LOW",
               scope: "UNCHANGED",
               userInteraction: "NONE",
               vectorString: "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
               version: "3.1",
            },
            exploitabilityScore: 1.8,
            impactScore: 5.2,
            source: "nvd@nist.gov",
            type: "Primary",
         },
      ],
   },
   published: "2024-10-21T13:15:06.800",
   references: [
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/1e75d25133158b525e0456876e9bcfd6b2993fd5",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/2ed98ee02d1e08afee88f54baec39ea78dc8a23c",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/32556ce93bc45c730829083cb60f95a2728ea48b",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         url: "https://git.kernel.org/stable/c/988e55abcf7fdb8fc9a76a7cf3f4e939a4d4fb3a",
      },
      {
         source: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
         tags: [
            "Patch",
         ],
         url: "https://git.kernel.org/stable/c/a2c8dc7e21803257e762b0bf067fd13e9c995da0",
      },
   ],
   sourceIdentifier: "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
   vulnStatus: "Modified",
   weaknesses: [
      {
         description: [
            {
               lang: "en",
               value: "NVD-CWE-noinfo",
            },
         ],
         source: "nvd@nist.gov",
         type: "Primary",
      },
   ],
}


Log in or create an account to share your comment.

Security Advisory comment format.

This schema specifies the format of a comment related to a security advisory.

UUIDv4 of the comment
UUIDv4 of the Vulnerability-Lookup instance
When the comment was created originally
When the comment was last updated
Title of the comment
Description of the comment
The identifier of the vulnerability (CVE ID, GHSA-ID, PYSEC ID, etc.).



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.