CVE-2026-23343 Linux内核XDP内存损坏漏洞

// PoC simulation of the integer underflow logic in XDP tailroom calculation // This demonstrates how a driver reporting DMA size instead of truesize leads to vulnerability. #include <stdio.h> #include <stdint.h> #include <limits.h> void trigger_vulnerability() { // Vulnerable scenario: Driver reports 3KB DMA size instead of 4KB Truesize unsigned int frag_size = 3072; // 3KB DMA size unsigned int page_offset = 200; // Non-zero offset unsigned int data_len = 3072; // Data occupies full DMA space // Vulnerable calculation: tailroom = frag_size - data_len - page_offset // Expected: 3072 - 3072 - 200 = -200 (Error) unsigned int tailroom = frag_size - data_len - page_offset; // Check logic: if tailroom is valid, proceed to grow tail (corrupt memory) if (tailroom > 0) { printf("[+] Exploit Triggered! Calculated tailroom: %u\n", tailroom); printf("[+] Bypassed bounds check. Writing to memory...\n"); // In kernel: this would call __skb_put() causing skb_over_panic } else { printf("[-] Check passed. No vulnerability triggered.\n"); } } int main() { trigger_vulnerability(); return 0; }