CVE-2026-31716 Linux内核ntfs3越界写入漏洞

// Simulation of the vulnerable logic in fs/ntfs3/log.c // This demonstrates the integer underflow issue. #include <stdio.h> #include <stdint.h> #include <string.h> struct FILE_RECORD { uint32_t total; uint32_t used; char data[4096]; }; void simulate_vulnerable_handler(struct FILE_RECORD *rec, uint32_t attr_offset) { // Vulnerable logic: rec->used is not validated against attr_offset // This mimics the 'DeleteAttribute' or 'CreateAttribute' logic uint32_t copy_len = rec->used - attr_offset; printf("Calculated copy length: %u\n", copy_len); // If rec->used is small (e.g., 10) and attr_offset is large (e.g., 100) // copy_len underflows to a very large value (e.g., 4294967206) // causing a massive copy into a small buffer. char buffer[100]; // memmove(buffer, rec->data + attr_offset, copy_len); // This would crash } int main() { struct FILE_RECORD corrupted_rec; corrupted_rec.total = 4096; corrupted_rec.used = 10; // Malicious small value uint32_t attr_offset = 100; // Validated attribute offset printf("Simulating CVE-2026-31716 PoC...\n"); simulate_vulnerable_handler(&corrupted_rec, attr_offset); return 0; }