CVE-2026-23250: Linux内核XFS文件系统xchk_scrub_create_subord返回值检查漏洞

/* CVE-2026-23250 PoC - XFS scrub function NULL pointer issue * This is a conceptual PoC demonstrating the vulnerability trigger * Requires: Local access, ability to mount XFS filesystem */ #include <stdio.h> #include <stdlib.h> #include <string.h> /* Simulated vulnerable function behavior */ void* xchk_scrub_create_subord_vuln(int memory_available) { void *ptr = NULL; /* Simulate memory allocation failure scenario */ if (!memory_available) { /* VULNERABLE: Returns mangled ENOMEM instead of NULL */ return (void*)-ENOMEM; /* Should return NULL */ } ptr = malloc(1024); return ptr; } /* Vulnerable caller that doesn't check properly */ int caller_vuln(int memory_available) { void *subord = xchk_scrub_create_subord_vuln(memory_available); /* VULNERABLE: Only checks for NULL, not for error values */ if (subord == NULL) { return -ENOMEM; } /* This code path is reached with mangled return value */ /* leading to potential NULL pointer dereference */ memset(subord, 0, 1024); /* Undefined behavior */ return 0; } /* Fixed version */ void* xchk_scrub_create_subord_fixed(int memory_available) { void *ptr = NULL; if (!memory_available) { /* FIXED: Properly return NULL on ENOMEM */ return NULL; } ptr = malloc(1024); return ptr; } int main() { printf("CVE-2026-23250 PoC - XFS xchk_scrub_create_subord\n"); printf("Trigger condition: Memory pressure during XFS scrub operation\n"); printf("Impact: System crash / Denial of Service\n"); return 0; }