130 lines
3.5 KiB
C
130 lines
3.5 KiB
C
/*
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* Blacklist Copyright 2013 Regents of the University of Michigan
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy
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* of the License at http://www.apache.org/licenses/LICENSE-2.0
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*/
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#include "blacklist.h"
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#include <errno.h>
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#include <stdio.h>
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#include <assert.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include "constraint.h"
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#include "logger.h"
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#define ADDR_DISALLOWED 0
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#define ADDR_ALLOWED 1
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static constraint_t *constraint = NULL;
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// check whether a single IP address is allowed to be scanned.
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// 1 => is allowed
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// 0 => is not allowed
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int blacklist_is_allowed(uint32_t s_addr) {
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return constraint_lookup_ip(constraint, ntohl(s_addr)) == ADDR_ALLOWED;
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}
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// blacklist a CIDR network allocation
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// e.g. blacklist_add("128.255.134.0", 24)
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void blacklist_prefix(char *ip, int prefix_len)
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{
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assert(constraint);
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constraint_set(constraint, ntohl(inet_addr(ip)), prefix_len, ADDR_DISALLOWED);
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}
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// whitelist a CIDR network allocation
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void whitelist_prefix(char *ip, int prefix_len)
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{
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assert(constraint);
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constraint_set(constraint, ntohl(inet_addr(ip)), prefix_len, ADDR_ALLOWED);
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}
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static int init(char *file, const char *name, int value)
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{
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FILE *fp;
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char line[1000];
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fp = fopen(file, "r");
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if (fp == NULL) {
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log_fatal(name, "Unable to open %s file: %s: %s", name, file, strerror(errno));
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}
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while (fgets(line, sizeof(line), fp) != NULL) {
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char *comment = strchr(line, '#');
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if (comment) {
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*comment = '\0';
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}
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char ip[33];
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if ((sscanf(line, "%32s", ip)) == EOF) {
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continue;
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}
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int prefix_len = 32;
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char *slash = strchr(ip, '/');
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if (slash) { // split apart network and prefix length
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*slash = '\0';
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char *end;
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char *len = slash+1;
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errno = 0;
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prefix_len = strtol(len, &end, 10);
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if (end == len || errno != 0 || prefix_len < 0 || prefix_len > 32) {
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log_fatal(name, "Unable to parse %s file: %s ('%s' is not a valid prefix length)", name, file, len);
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}
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}
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struct in_addr addr;
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if (inet_aton(ip, &addr) == 0) {
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log_fatal(name, "Unable to parse %s file: %s ('%s' is not a valid IP address)", name, file, ip);
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}
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constraint_set(constraint, ntohl(addr.s_addr), prefix_len, value);
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log_trace(name, "%sing %s/%i",
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name, ip, prefix_len);
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}
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fclose(fp);
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return 0;
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}
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uint64_t blacklist_count_allowed()
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{
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assert(constraint);
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return constraint_count_ips(constraint, ADDR_ALLOWED);
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}
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uint64_t blacklist_count_not_allowed()
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{
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assert(constraint);
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return constraint_count_ips(constraint, ADDR_DISALLOWED);
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}
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// Initialize address constraints from whitelist and blacklist files.
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// Either can be set to NULL to omit.
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int blacklist_init_from_files(char *whitelist_filename, char *blacklist_filename)
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{
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assert(!constraint);
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if (whitelist_filename) {
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// using a whitelist, so default to allowing nothing
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constraint = constraint_init(ADDR_DISALLOWED);
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log_trace("whitelist", "blacklisting 0.0.0.0/0");
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init(whitelist_filename, "whitelist", ADDR_ALLOWED);
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} else {
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// no whitelist, so default to allowing everything
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constraint = constraint_init(ADDR_ALLOWED);
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}
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if (blacklist_filename) {
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init(blacklist_filename, "blacklist", ADDR_DISALLOWED);
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}
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constraint_optimize(constraint);
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uint64_t allowed = blacklist_count_allowed();
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log_debug("blacklist", "%lu addresses allowed to be scanned (%0.0f%% of address space)",
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allowed, allowed*100./(1L << 32));
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return 0;
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}
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