abstracting out port validation because shared between udp and tcp.
This commit is contained in:
Zakir Durumeric
parent
37630d7325
commit
b70a2835b9
@ -26,7 +26,13 @@
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#include "packet.h"
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probe_module_t module_tcp_synscan;
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uint32_t num_ports = 1;
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static uint32_t num_ports;
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int synscan_global_initialize(struct state_conf *state)
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{
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num_ports = state->source_port_last - state->source_port_first + 1;
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return EXIT_SUCCESS;
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}
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int synscan_init_perthread(void* buf, macaddr_t *src,
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macaddr_t *gw, port_h_t dst_port)
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@ -39,7 +45,6 @@ int synscan_init_perthread(void* buf, macaddr_t *src,
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make_ip_header(ip_header, IPPROTO_TCP, len);
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struct tcphdr *tcp_header = (struct tcphdr*)(&ip_header[1]);
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make_tcp_header(tcp_header, dst_port);
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num_ports = zconf.source_port_last - zconf.source_port_first + 1;
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return EXIT_SUCCESS;
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}
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@ -49,15 +54,13 @@ int synscan_make_packet(void *buf, ipaddr_n_t src_ip, ipaddr_n_t dst_ip,
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struct ethhdr *eth_header = (struct ethhdr *)buf;
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struct iphdr *ip_header = (struct iphdr*)(ð_header[1]);
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struct tcphdr *tcp_header = (struct tcphdr*)(&ip_header[1]);
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uint16_t src_port = zconf.source_port_first
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+ ((validation[1] + probe_num) % num_ports);
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uint32_t tcp_seq = validation[0];
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ip_header->saddr = src_ip;
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ip_header->daddr = dst_ip;
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tcp_header->source = htons(src_port);
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tcp_header->source = htons(get_src_port(num_ports,
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probe_num, validation));
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tcp_header->seq = tcp_seq;
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tcp_header->check = 0;
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tcp_header->check = tcp_checksum(sizeof(struct tcphdr),
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@ -121,19 +124,7 @@ response_type_t* synscan_classify_packet(const u_char *packet, uint32_t len)
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return &(module_tcp_synscan.responses[0]);
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}
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}
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// Returns 0 if dst_port is outside the expected valid range, non-zero otherwise
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static inline int check_dst_port(uint16_t port, uint32_t *validation)
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{
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if (port > zconf.source_port_last
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|| port < zconf.source_port_first) {
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return EXIT_FAILURE;
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}
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int32_t to_validate = port - zconf.source_port_first;
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int32_t min = validation[1] % num_ports;
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int32_t max = (validation[1] + zconf.packet_streams - 1) % num_ports;
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return (((max - min) % num_ports) >= ((to_validate - min) % num_ports));
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}
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int synscan_validate_packet(const struct iphdr *ip_hdr, uint32_t len,
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__attribute__((unused))uint32_t *src_ip, uint32_t *validation)
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@ -156,7 +147,7 @@ int synscan_validate_packet(const struct iphdr *ip_hdr, uint32_t len,
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}
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// validate destination port
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if (!check_dst_port(ntohs(dport), validation)) {
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if (!check_dst_port(ntohs(dport), num_ports, validation)) {
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return 0;
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}
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@ -185,6 +176,7 @@ probe_module_t module_tcp_synscan = {
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.pcap_filter = "tcp && tcp[13] & 4 != 0 || tcp[13] == 18",
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.pcap_snaplen = 96,
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.port_args = 1,
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.global_initialize = &synscan_global_initialize,
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.thread_initialize = &synscan_init_perthread,
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.make_packet = &synscan_make_packet,
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.print_packet = &synscan_print_packet,
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@ -34,25 +34,26 @@ int udp_send_msg_len = 0;
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const char *udp_send_msg_default = "GET / HTTP/1.1\r\nHost: www\r\n\r\n";
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static int num_ports = 1;
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static int num_ports;
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probe_module_t module_udp;
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int udp_global_initialize(struct state_conf * zconf) {
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int udp_global_initialize(struct state_conf *conf) {
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char *args, *c;
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int i;
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unsigned int n;
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FILE *inp;
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num_ports = conf->source_port_last - conf->source_port_first + 1;
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udp_send_msg = strdup(udp_send_msg_default);
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udp_send_msg_len = strlen(udp_send_msg);
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if (! (zconf->probe_args && strlen(zconf->probe_args) > 0))
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if (!(conf->probe_args && strlen(conf->probe_args) > 0))
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return(0);
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args = strdup(zconf->probe_args);
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args = strdup(conf->probe_args);
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if (! args) exit(1);
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c = strchr(args, ':');
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@ -154,23 +155,23 @@ int udp_init_perthread(void* buf, macaddr_t *src,
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memcpy(payload, udp_send_msg, udp_send_msg_len);
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num_ports = zconf.source_port_last - zconf.source_port_first + 1;
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return EXIT_SUCCESS;
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}
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int udp_make_packet(void *buf, ipaddr_n_t src_ip, ipaddr_n_t dst_ip,
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uint32_t *validation, int probe_num)
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{
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struct ethhdr *eth_header = (struct ethhdr *)buf;
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struct iphdr *ip_header = (struct iphdr*)(ð_header[1]);
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struct udphdr *udp_header = (struct udphdr*)(&ip_header[1]);
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uint16_t src_port = zconf.source_port_first
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+ ((validation[1] + probe_num) % num_ports);
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ip_header->saddr = src_ip;
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ip_header->daddr = dst_ip;
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udp_header->source = src_port;
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udp_header->source = get_src_port(num_ports, probe_num,
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validation);
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ip_header->check = 0;
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ip_header->check = ip_checksum((unsigned short *) ip_header);
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@ -218,7 +219,6 @@ void udp_print_packet(FILE *fp, void* packet)
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fprintf(fp, "------------------------------------------------------\n");
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}
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response_type_t* udp_classify_packet(const u_char *packet, uint32_t len)
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{
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(void)len;
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@ -232,20 +232,6 @@ response_type_t* udp_classify_packet(const u_char *packet, uint32_t len)
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}
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}
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// Returns 0 if dst_port is outside the expected valid range, non-zero otherwise
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static inline int check_dst_port(uint16_t port, uint32_t *validation)
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{
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if (port > zconf.source_port_last
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|| port < zconf.source_port_first) {
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return EXIT_FAILURE;
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}
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int32_t to_validate = port - zconf.source_port_first;
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int32_t min = validation[1] % num_ports;
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int32_t max = (validation[1] + zconf.packet_streams - 1) % num_ports;
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return (((max - min) % num_ports) >= ((to_validate - min) % num_ports));
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}
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int udp_validate_packet(const struct iphdr *ip_hdr, uint32_t len,
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__attribute__((unused))uint32_t *src_ip, uint32_t *validation)
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{
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@ -290,7 +276,7 @@ int udp_validate_packet(const struct iphdr *ip_hdr, uint32_t len,
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if (dport != zconf.target_port) {
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return 0;
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}
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if (!check_dst_port(sport, validation)) {
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if (!check_dst_port(sport, num_ports, validation)) {
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return 0;
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}
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return 1;
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@ -79,4 +79,25 @@ static __attribute__((unused)) uint16_t tcp_checksum(unsigned short len_tcp,
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return (unsigned short) (~sum);
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}
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// Returns 0 if dst_port is outside the expected valid range, non-zero otherwise
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static __attribute__((unused)) inline int check_dst_port(uint16_t port,
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int num_ports, uint32_t *validation)
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{
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if (port > zconf.source_port_last
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|| port < zconf.source_port_first) {
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return -1;
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}
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int32_t to_validate = port - zconf.source_port_first;
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int32_t min = validation[1] % num_ports;
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int32_t max = (validation[1] + zconf.packet_streams - 1) % num_ports;
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return (((max - min) % num_ports) >= ((to_validate - min) % num_ports));
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}
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static __attribute__((unused)) inline uint16_t get_src_port(int num_ports,
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int probe_num, uint32_t *validation)
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{
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return zconf.source_port_first + ((validation[1] + probe_num) % num_ports);
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}
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#endif
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