CVE-2024-50275

{"id": "CVE-2024-50275", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.0, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.0}]}, "published": "2024-11-19T02:16:29.760", "references": [{"url": "https://git.kernel.org/stable/c/51d11ea0250d6ee461987403bbfd4b2abb5613a7", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/51d3d80a6dc314982a9a0aeb0961085922a1aa15", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/751ecf6afd6568adc98f2a6052315552c0483d18", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/de529504b3274d57caf8f66800b714b0d3ee235a", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/fa9ce027b3ce37a2bb173bf2553b5caa438fd8c9", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Modified", "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\narm64/sve: Discard stale CPU state when handling SVE traps\n\nThe logic for handling SVE traps manipulates saved FPSIMD/SVE state\nincorrectly, and a race with preemption can result in a task having\nTIF_SVE set and TIF_FOREIGN_FPSTATE clear even though the live CPU state\nis stale (e.g. with SVE traps enabled). This has been observed to result\nin warnings from do_sve_acc() where SVE traps are not expected while\nTIF_SVE is set:\n\n| if (test_and_set_thread_flag(TIF_SVE))\n| WARN_ON(1); /* SVE access shouldn't have trapped */\n\nWarnings of this form have been reported intermittently, e.g.\n\n https://lore.kernel.org/linux-arm-kernel/CA+G9fYtEGe_DhY2Ms7+L7NKsLYUomGsgqpdBj+QwDLeSg=JhGg@mail.gmail.com/\n https://lore.kernel.org/linux-arm-kernel/000000000000511e9a060ce5a45c@google.com/\n\nThe race can occur when the SVE trap handler is preempted before and\nafter manipulating the saved FPSIMD/SVE state, starting and ending on\nthe same CPU, e.g.\n\n| void do_sve_acc(unsigned long esr, struct pt_regs *regs)\n| {\n| // Trap on CPU 0 with TIF_SVE clear, SVE traps enabled\n| // task->fpsimd_cpu is 0.\n| // per_cpu_ptr(&fpsimd_last_state, 0) is task.\n|\n| ...\n|\n| // Preempted; migrated from CPU 0 to CPU 1.\n| // TIF_FOREIGN_FPSTATE is set.\n|\n| get_cpu_fpsimd_context();\n|\n| if (test_and_set_thread_flag(TIF_SVE))\n| WARN_ON(1); /* SVE access shouldn't have trapped */\n|\n| sve_init_regs() {\n| if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {\n| ...\n| } else {\n| fpsimd_to_sve(current);\n| current->thread.fp_type = FP_STATE_SVE;\n| }\n| }\n|\n| put_cpu_fpsimd_context();\n|\n| // Preempted; migrated from CPU 1 to CPU 0.\n| // task->fpsimd_cpu is still 0\n| // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then:\n| // - Stale HW state is reused (with SVE traps enabled)\n| // - TIF_FOREIGN_FPSTATE is cleared\n| // - A return to userspace skips HW state restore\n| }\n\nFix the case where the state is not live and TIF_FOREIGN_FPSTATE is set\nby calling fpsimd_flush_task_state() to detach from the saved CPU\nstate. This ensures that a subsequent context switch will not reuse the\nstale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the\nnew state to be reloaded from memory prior to a return to userspace."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: arm64/sve: descartar estado de CPU obsoleto al manejar trampas SVE La l\u00f3gica para manejar trampas SVE manipula incorrectamente el estado FPSIMD/SVE guardado, y una ejecuci\u00f3n con preempci\u00f3n puede resultar en una tarea que tenga TIF_SVE establecido y TIF_FOREIGN_FPSTATE borrado incluso aunque el estado de CPU en vivo est\u00e9 obsoleto (por ejemplo, con trampas SVE habilitadas). Se ha observado que esto da como resultado advertencias de do_sve_acc() donde no se esperan trampas SVE mientras TIF_SVE est\u00e1 establecido: | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* El acceso a SVE no deber\u00eda haber generado una trampa */ Se han informado advertencias de este formato de forma intermitente, por ejemplo, https://lore.kernel.org/linux-arm-kernel/CA+G9fYtEGe_DhY2Ms7+L7NKsLYUomGsgqpdBj+QwDLeSg=JhGg@mail.gmail.com/ https://lore.kernel.org/linux-arm-kernel/000000000000511e9a060ce5a45c@google.com/ La ejecuci\u00f3n puede ocurrir cuando el controlador de trampa SVE se interrumpe antes y despu\u00e9s de manipular el estado FPSIMD/SVE guardado, comenzando y terminando en la misma CPU, por ejemplo, | void do_sve_acc(unsigned long esr, struct pt_regs *regs) | { | // Trampa en CPU 0 con TIF_SVE limpio, trampas SVE habilitadas | // task->fpsimd_cpu es 0. | // per_cpu_ptr(&fpsimd_last_state, 0) es la tarea. | | ... | | // Preempleado; migrado de la CPU 0 a la CPU 1. | // TIF_FOREIGN_FPSTATE est\u00e1 establecido. | | get_cpu_fpsimd_context(); | | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* El acceso a SVE no deber\u00eda haber quedado atrapado */ | | sve_init_regs() { | if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { | ... | } else { | fpsimd_to_sve(current); | current->thread.fp_type = FP_STATE_SVE; | } | } | | put_cpu_fpsimd_context(); | | // Preempleado; migrado de CPU 1 a CPU 0. | // task->fpsimd_cpu sigue siendo 0 | // Si per_cpu_ptr(&fpsimd_last_state, 0) sigue siendo tarea entonces: | // - Se reutiliza el estado de HW obsoleto (con trampas SVE habilitadas) | // - Se borra TIF_FOREIGN_FPSTATE | // - Un retorno al espacio de usuario omite la restauraci\u00f3n del estado de HW | } Corrija el caso donde el estado no est\u00e1 activo y TIF_FOREIGN_FPSTATE se establece llamando a fpsimd_flush_task_state() para separarse del estado de CPU guardado. Esto garantiza que un cambio de contexto posterior no reutilizar\u00e1 el estado de CPU obsoleto y, en su lugar, establecer\u00e1 TIF_FOREIGN_FPSTATE, lo que obligar\u00e1 a que el nuevo estado se vuelva a cargar desde la memoria antes de un retorno al espacio de usuario."}], "lastModified": "2024-12-14T21:15:34.270", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4713F9C0-902B-42E7-8BC3-EA25AE3D4238", "versionEndExcluding": "6.6.61", "versionStartIncluding": "5.13"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0BD000F7-3DAD-4DD3-8906-98EA1EC67E95", "versionEndExcluding": "6.11.8", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "7F361E1D-580F-4A2D-A509-7615F73167A1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "925478D0-3E3D-4E6F-ACD5-09F28D5DF82C"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3C95E234-D335-4B6C-96BF-E2CEBD8654ED"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E0F717D8-3014-4F84-8086-0124B2111379"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc5:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "24DBE6C7-2AAE-4818-AED2-E131F153D2FA"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc6:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "24B88717-53F5-42AA-9B72-14C707639E3F"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}