CVE-2024-49861

{"id": "CVE-2024-49861", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.1, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 5.2, "exploitabilityScore": 1.8}]}, "published": "2024-10-21T13:15:06.800", "references": [{"url": "https://git.kernel.org/stable/c/1e75d25133158b525e0456876e9bcfd6b2993fd5", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/2ed98ee02d1e08afee88f54baec39ea78dc8a23c", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/32556ce93bc45c730829083cb60f95a2728ea48b", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/a2c8dc7e21803257e762b0bf067fd13e9c995da0", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "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 encontr\u00f3 un problema que a pesar del mapa BPF congelado del lado del usuario y del BPF (como en el caso de .rodata), a\u00fan era posible escribir en \u00e9l desde el lado del programa BPF a trav\u00e9s de ayudantes espec\u00edficos 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. M\u00e1s 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 \u00e9xito. 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 \u00faltimo indica que est\u00e1 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 alineaci\u00f3n 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 tama\u00f1o fijo. Para esto, agregue MEM_ALIGNED para garantizar adicionalmente la alineaci\u00f3n dado que estos ayudantes escriben directamente en los argumentos a trav\u00e9s de * = val. El .arg*_size se ha inicializado reflejando el tama\u00f1o real de (*). MEM_ALIGNED solo se puede usar en combinaci\u00f3n con los tipos de argumentos anotados MEM_FIXED_SIZE, ya que en los casos !MEM_FIXED_SIZE el verificador no conoce el tama\u00f1o del b\u00fafer a priori y, por lo tanto, no puede escribir ciegamente * = val."}], "lastModified": "2024-10-23T16:48:47.573", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1C50745E-F1ED-43B5-A0AA-2ECE7194E14C", "versionEndExcluding": "6.6.54", "versionStartIncluding": "5.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CE94BB8D-B0AB-4563-9ED7-A12122B56EBE", "versionEndExcluding": "6.10.13", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "AB755D26-97F4-43B6-8604-CD076811E181", "versionEndExcluding": "6.11.2", "versionStartIncluding": "6.11"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}