CVE-2026-31748 Linux内核me_daq固件缓冲区溢出漏洞

/* * Conceptual PoC for CVE-2026-31748 * demonstrating the missing bounds check. */ #include <stdio.h> #include <stdlib.h> #include <string.h> // Mock structure for firmware typedef struct { size_t size; char *data; } firmware; // Vulnerable function logic (simplified reproduction) int vulnerable_firmware_load(firmware *fw) { // Check if firmware is at least 16 bytes if (fw->size < 16) { printf("Error: Firmware too small for header.\n"); return -1; } // Read file_length from first 4 bytes (blind trust) unsigned int file_length = *(unsigned int *)(fw->data); printf("File Length from header: %u\n", file_length); // VULNERABILITY: Missing check for (fw->size >= 16 + file_length) // If file_length is huge (e.g., 0xFFFFFFFF), the loop below overruns the buffer if (fw->size < 16 + file_length) { printf("[Potential Exploit] Buffer Overrun detected!\n"); // In the real kernel, this leads to OOB read/write } printf("Simulating data copy...\n"); // This would crash or read OOB in real scenario return 0; } int main() { // Construct a malicious firmware: 20 bytes total, but claims 1000 bytes of data unsigned int fake_length = 1000; char malicious_data[20]; memset(malicious_data, 0, 20); memcpy(malicious_data, &fake_length, 4); // Set length in header firmware fw; fw.size = 20; // Actual size is 20 (> 16, passes initial check) fw.data = malicious_data; printf("Triggering vulnerable function...\n"); vulnerable_firmware_load(&fw); return 0; }