ct_servmgmt.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2011 Daniel Borkmann.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdint.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <limits.h>
  13
  14 #include "die.h"
  15 #include "built_in.h"
  16 #include "locking.h"
  17 #include "xmalloc.h"
  18 #include "curvetun.h"
  19 #include "xutils.h"
  20 #include "curve.h"
  21 #include "ct_servmgmt.h"
  22 #include "crypto_box_curve25519xsalsa20poly1305.h"
  23 #include "crypto_auth_hmacsha512256.h"
  24
  25 #define crypto_box_pub_key_size crypto_box_curve25519xsalsa20poly1305_PUBLICKEYBYTES
  26
  27 /* Config line format: alias;serverip|servername;port;udp|tcp;pubkey\n */
  28
  29 struct server_store {
  30         int udp;
  31         char alias[256];
  32         char host[256];
  33         char port[6]; /* 5 + \0 */
  34         unsigned char publickey[crypto_box_pub_key_size];
  35         struct curve25519_proto proto_inf;
  36         unsigned char auth_token[crypto_auth_hmacsha512256_KEYBYTES];
  37         struct server_store *next;
  38 };
  39
  40 static struct server_store *store = NULL;
  41 static struct server_store *selected = NULL;
  42 static struct rwlock store_lock;
  43
  44 static struct server_store *server_store_alloc(void)
  45 {
  46         return xzmalloc(sizeof(struct server_store));
  47 }
  48
  49 static void server_store_free(struct server_store *ss)
  50 {
  51         if (!ss)
  52                 return;
  53         memset(ss, 0, sizeof(struct server_store));
  54         xfree(ss);
  55 }
  56
  57 enum parse_states {
  58         PARSE_ALIAS,
  59         PARSE_SERVER,
  60         PARSE_PORT,
  61         PARSE_CARRIER,
  62         PARSE_PUBKEY,
  63         PARSE_DONE,
  64 };
  65
  66 static int parse_line(char *line, char *homedir)
  67 {
  68         int ret;
  69         char *str;
  70         enum parse_states s = PARSE_ALIAS;
  71         struct server_store *elem;
  72         unsigned char pkey[crypto_box_pub_key_size];
  73
  74         elem = server_store_alloc();
  75         elem->next = store;
  76
  77         str = strtok(line, ";");
  78         for (; str != NULL;) {
  79                 switch (s) {
  80                 case PARSE_ALIAS:
  81                         strlcpy(elem->alias, str, sizeof(elem->alias));
  82                         s = PARSE_SERVER;
  83                         break;
  84                 case PARSE_SERVER:
  85                         strlcpy(elem->host, str, sizeof(elem->host));
  86                         s = PARSE_PORT;
  87                         break;
  88                 case PARSE_PORT:
  89                         strlcpy(elem->port, str, sizeof(elem->port));
  90                         s = PARSE_CARRIER;
  91                         break;
  92                 case PARSE_CARRIER:
  93                         if (!strncmp("udp", str, strlen("udp")))
  94                                 elem->udp = 1;
  95                         else
  96                                 elem->udp = 0;
  97                         s = PARSE_PUBKEY;
  98                         break;
  99                 case PARSE_PUBKEY:
 100                         if (!curve25519_pubkey_hexparse_32(pkey, sizeof(pkey),
 101                                                            str, strlen(str)))
 102                                 return -EINVAL;
 103                         memcpy(elem->publickey, pkey, sizeof(elem->publickey));
 104                         memcpy(elem->auth_token, pkey, sizeof(elem->auth_token));
 105                         ret = curve25519_proto_init(&elem->proto_inf,
 106                                                     elem->publickey,
 107                                                     sizeof(elem->publickey),
 108                                                     homedir, 1);
 109                         if (ret)
 110                                 return -EIO;
 111                         s = PARSE_DONE;
 112                         break;
 113                 case PARSE_DONE:
 114                         break;
 115                 default:
 116                         return -EIO;
 117                 }
 118
 119                 str = strtok(NULL, ";");
 120         }
 121
 122         store = elem;
 123         return s == PARSE_DONE ? 0 : -EIO;
 124 }
 125
 126 void parse_userfile_and_generate_serv_store_or_die(char *homedir)
 127 {
 128         FILE *fp;
 129         char path[PATH_MAX], buff[1024];
 130         int line = 1, ret;
 131
 132         memset(path, 0, sizeof(path));
 133         slprintf(path, sizeof(path), "%s/%s", homedir, FILE_SERVERS);
 134
 135         rwlock_init(&store_lock);
 136         rwlock_wr_lock(&store_lock);
 137
 138         fp = fopen(path, "r");
 139         if (!fp)
 140                 panic("Cannot open server file!\n");
 141
 142         memset(buff, 0, sizeof(buff));
 143         while (fgets(buff, sizeof(buff), fp) != NULL) {
 144                 buff[sizeof(buff) - 1] = 0;
 145                 /* A comment. Skip this line */
 146                 if (buff[0] == '#' || buff[0] == '\n') {
 147                         memset(buff, 0, sizeof(buff));
 148                         line++;
 149                         continue;
 150                 }
 151
 152                 ret = parse_line(buff, homedir);
 153                 if (ret < 0)
 154                         panic("Cannot parse line %d from clients!\n", line);
 155                 line++;
 156                 memset(buff, 0, sizeof(buff));
 157         }
 158
 159         fclose(fp);
 160
 161         if (store == NULL)
 162                 panic("No registered servers found!\n");
 163
 164         rwlock_unlock(&store_lock);
 165 }
 166
 167 void dump_serv_store(void)
 168 {
 169         int i;
 170         struct server_store *elem;
 171
 172         rwlock_rd_lock(&store_lock);
 173         elem = store;
 174         while (elem) {
 175                 printf("[%s] -> %s:%s via %s -> ", elem->alias,
 176                        elem->host, elem->port,
 177                        elem->udp ? "udp" : "tcp");
 178                 for (i = 0; i < sizeof(elem->publickey); ++i)
 179                         if (i == (sizeof(elem->publickey) - 1))
 180                                 printf("%02x\n", (unsigned char)
 181                                        elem->publickey[i]);
 182                         else
 183                                 printf("%02x:", (unsigned char)
 184                                        elem->publickey[i]);
 185                 elem = elem->next;
 186         }
 187         rwlock_unlock(&store_lock);
 188 }
 189
 190 void destroy_serv_store(void)
 191 {
 192         struct server_store *elem, *nelem = NULL;
 193
 194         rwlock_wr_lock(&store_lock);
 195         selected = NULL;
 196         elem = store;
 197         while (elem) {
 198                 nelem = elem->next;
 199                 elem->next = NULL;
 200                 server_store_free(elem);
 201                 elem = nelem;
 202         }
 203         rwlock_unlock(&store_lock);
 204         rwlock_destroy(&store_lock);
 205 }
 206
 207 void get_serv_store_entry_by_alias(char *alias, size_t len,
 208                                    char **host, char **port, int *udp)
 209 {
 210         struct server_store *elem;
 211
 212         rwlock_rd_lock(&store_lock);
 213         elem = store;
 214         if (!alias) {
 215                 while (elem && elem->next)
 216                         elem = elem->next;
 217                 if (elem) {
 218                         (*host) = elem->host;
 219                         (*port) = elem->port;
 220                         (*udp) = elem->udp;
 221                         selected = elem;
 222                 } else {
 223                         rwlock_unlock(&store_lock);
 224                         goto nothing;
 225                 }
 226         } else {
 227                 while (elem) {
 228                         if (!strncmp(elem->alias, alias,
 229                                      min(len, strlen(elem->alias) + 1)))
 230                                 break;
 231                         elem = elem->next;
 232                 }
 233                 if (elem) {
 234                         (*host) = elem->host;
 235                         (*port) = elem->port;
 236                         (*udp) = elem->udp;
 237                         selected = elem;
 238                 } else {
 239                         rwlock_unlock(&store_lock);
 240                         goto nothing;
 241                 }
 242         }
 243         rwlock_unlock(&store_lock);
 244
 245         return;
 246 nothing:
 247         (*host) = NULL;
 248         (*port) = NULL;
 249         (*udp) = -1;
 250 }
 251
 252 struct curve25519_proto *get_serv_store_entry_proto_inf(void)
 253 {
 254         struct curve25519_proto *ret = NULL;
 255
 256         rwlock_rd_lock(&store_lock);
 257         if (selected)
 258                 ret = &selected->proto_inf;
 259         rwlock_unlock(&store_lock);
 260
 261         return ret;
 262 }
 263
 264 unsigned char *get_serv_store_entry_auth_token(void)
 265 {
 266         unsigned char *ret = NULL;
 267
 268         rwlock_rd_lock(&store_lock);
 269         if (selected)
 270                 ret = selected->auth_token;
 271         rwlock_unlock(&store_lock);
 272
 273         return ret;
 274 }