CVE-2026-45254 FreeBSD cap_net服务权限提升漏洞

/* * PoC for CVE-2026-45254: FreeBSD cap_net Logic Flaw * This code demonstrates the concept where omitting a key in the new limit * results in "allow any" instead of rejection. */ #include <stdio.h> #include <stdlib.h> #include <string.h> // Hypothetical structure for cap_net limits struct cap_limit { char key[64]; int action; // 0: deny, 1: allow }; // Simulated vulnerable function to update limits void update_limits_vulnerable(struct cap_limit *old_limits, int old_count, struct cap_limit *new_limits, int new_count) { printf("[VULNERABLE] Updating limits...\n"); // In the vulnerable scenario, the system assumes missing keys are implicitly allowed for (int i = 0; i < old_count; i++) { int found = 0; for (int j = 0; j < new_count; j++) { if (strcmp(old_limits[i].key, new_limits[j].key) == 0) { found = 1; break; } } if (!found) { printf("Key '%s' omitted in new limits. Treating as ALLOW ANY (VULNERABILITY)!\n", old_limits[i].key); } } } int main() { // Initial strict limits: restrict HTTP and DNS struct cap_limit old_limits[2]; strcpy(old_limits[0].key, "net.http"); old_limits[0].action = 0; // Deny strcpy(old_limits[1].key, "net.dns"); old_limits[1].action = 0; // Deny // New limits: Only explicitly restrict HTTP, omitting DNS struct cap_limit new_limits[1]; strcpy(new_limits[0].key, "net.http"); new_limits[0].action = 0; // Deny // Trigger the vulnerable logic update_limits_vulnerable(old_limits, 2, new_limits, 1); return 0; }