CVE-2024-49888

{"id": "CVE-2024-49888", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2024-10-21T18:15:11.443", "references": [{"url": "https://git.kernel.org/stable/c/4902a6a0dc593c82055fc8c9ada371bafe26c9cc", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7dd34d7b7dcf9309fc6224caf4dd5b35bedddcb7", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d22e45a369afc7c28f11acfa5b5e8e478227ca5d", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-190"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix a sdiv overflow issue\n\nZac Ecob reported a problem where a bpf program may cause kernel crash due\nto the following error:\n Oops: divide error: 0000 [#1] PREEMPT SMP KASAN PTI\n\nThe failure is due to the below signed divide:\n LLONG_MIN/-1 where LLONG_MIN equals to -9,223,372,036,854,775,808.\nLLONG_MIN/-1 is supposed to give a positive number 9,223,372,036,854,775,808,\nbut it is impossible since for 64-bit system, the maximum positive\nnumber is 9,223,372,036,854,775,807. On x86_64, LLONG_MIN/-1 will\ncause a kernel exception. On arm64, the result for LLONG_MIN/-1 is\nLLONG_MIN.\n\nFurther investigation found all the following sdiv/smod cases may trigger\nan exception when bpf program is running on x86_64 platform:\n - LLONG_MIN/-1 for 64bit operation\n - INT_MIN/-1 for 32bit operation\n - LLONG_MIN%-1 for 64bit operation\n - INT_MIN%-1 for 32bit operation\nwhere -1 can be an immediate or in a register.\n\nOn arm64, there are no exceptions:\n - LLONG_MIN/-1 = LLONG_MIN\n - INT_MIN/-1 = INT_MIN\n - LLONG_MIN%-1 = 0\n - INT_MIN%-1 = 0\nwhere -1 can be an immediate or in a register.\n\nInsn patching is needed to handle the above cases and the patched codes\nproduced results aligned with above arm64 result. The below are pseudo\ncodes to handle sdiv/smod exceptions including both divisor -1 and divisor 0\nand the divisor is stored in a register.\n\nsdiv:\n tmp = rX\n tmp += 1 /* [-1, 0] -> [0, 1]\n if tmp >(unsigned) 1 goto L2\n if tmp == 0 goto L1\n rY = 0\n L1:\n rY = -rY;\n goto L3\n L2:\n rY /= rX\n L3:\n\nsmod:\n tmp = rX\n tmp += 1 /* [-1, 0] -> [0, 1]\n if tmp >(unsigned) 1 goto L1\n if tmp == 1 (is64 ? goto L2 : goto L3)\n rY = 0;\n goto L2\n L1:\n rY %= rX\n L2:\n goto L4 // only when !is64\n L3:\n wY = wY // only when !is64\n L4:\n\n [1] https://lore.kernel.org/bpf/tPJLTEh7S_DxFEqAI2Ji5MBSoZVg7_G-Py2iaZpAaWtM961fFTWtsnlzwvTbzBzaUzwQAoNATXKUlt0LZOFgnDcIyKCswAnAGdUF3LBrhGQ=@protonmail.com/"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: soluciona un problema de desbordamiento de sdiv Zac Ecob inform\u00f3 de un problema en el que un programa bpf puede provocar un fallo del kernel debido al siguiente error: Oops: error de divisi\u00f3n: 0000 [#1] PREEMPT SMP KASAN PTI El fallo se debe a la siguiente divisi\u00f3n con signo: LLONG_MIN/-1 donde LLONG_MIN equivale a -9.223.372.036.854.775.808. Se supone que LLONG_MIN/-1 da un n\u00famero positivo 9.223.372.036.854.775.808, pero es imposible ya que para sistemas de 64 bits, el n\u00famero positivo m\u00e1ximo es 9.223.372.036.854.775.807. En x86_64, LLONG_MIN/-1 provocar\u00e1 una excepci\u00f3n del kernel. En arm64, el resultado para LLONG_MIN/-1 es LLONG_MIN. Una investigaci\u00f3n m\u00e1s profunda encontr\u00f3 que todos los siguientes casos de sdiv/smod pueden activar una excepci\u00f3n cuando el programa bpf se ejecuta en la plataforma x86_64: - LLONG_MIN/-1 para operaci\u00f3n de 64 bits - INT_MIN/-1 para operaci\u00f3n de 32 bits - LLONG_MIN%-1 para operaci\u00f3n de 64 bits - INT_MIN%-1 para operaci\u00f3n de 32 bits donde -1 puede ser inmediato o en un registro. En arm64, no hay excepciones: - LLONG_MIN/-1 = LLONG_MIN - INT_MIN/-1 = INT_MIN - LLONG_MIN%-1 = 0 - INT_MIN%-1 = 0 donde -1 puede ser inmediato o en un registro. Se necesita aplicar un parche a Insn para manejar los casos anteriores y los c\u00f3digos parcheados produjeron resultados alineados con el resultado de arm64 anterior. Los siguientes son pseudoc\u00f3digos para manejar excepciones sdiv/smod incluyendo tanto el divisor -1 como el divisor 0 y el divisor se almacena en un registro. sdiv: tmp = rX tmp += 1 /* [-1, 0] -> [0, 1] if tmp >(unsigned) 1 goto L2 if tmp == 0 goto L1 rY = 0 L1: rY = -rY; goto L3 L2: rY /= rX L3: smod: tmp = rX tmp += 1 /* [-1, 0] -> [0, 1] if tmp >(unsigned) 1 goto L1 if tmp == 1 (is64 ? goto L2 : goto L3) rY = 0; goto L2 L1: rY %= rX L2: goto L4 // solo cuando !is64 L3: wY = wY // solo cuando !is64 L4: [1] https://lore.kernel.org/bpf/tPJLTEh7S_DxFEqAI2Ji5MBSoZVg7_G-Py2iaZpAaWtM961fFTWtsnlzwvTbzBzaUzwQAoNATXKUlt0LZOFgnDcIyKCswAnAGdUF3LBrhGQ=@protonmail.com/"}], "lastModified": "2024-11-13T14:54:25.787", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "652638C5-5F25-4DF3-AD42-DD3252A97152", "versionEndExcluding": "6.10.14"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "54D9C704-D679-41A7-9C40-10A6B1E7FFE9", "versionEndExcluding": "6.11.3", "versionStartIncluding": "6.11"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}