| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: check.c,v 1.1 1997/07/21 13:47:53 mdw Exp $ |
| 4 | * |
| 5 | * Check validity of requests |
| 6 | * |
| 7 | * (c) 1997 EBI |
| 8 | */ |
| 9 | |
| 10 | /*----- Licencing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of `become' |
| 13 | * |
| 14 | * `Become' is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 2 of the License, or |
| 17 | * (at your option) any later version. |
| 18 | * |
| 19 | * `Become' is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with `become'; if not, write to the Free Software |
| 26 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 27 | */ |
| 28 | |
| 29 | /*----- Revision history --------------------------------------------------* |
| 30 | * |
| 31 | * $Log: check.c,v $ |
| 32 | * Revision 1.1 1997/07/21 13:47:53 mdw |
| 33 | * Initial revision |
| 34 | * |
| 35 | */ |
| 36 | |
| 37 | /*----- Header files ------------------------------------------------------*/ |
| 38 | |
| 39 | /* --- ANSI headers --- */ |
| 40 | |
| 41 | #include <ctype.h> |
| 42 | #include <errno.h> |
| 43 | #include <stdio.h> |
| 44 | #include <stdlib.h> |
| 45 | #include <string.h> |
| 46 | #include <time.h> |
| 47 | |
| 48 | /* --- Unix headers --- */ |
| 49 | |
| 50 | #include <sys/time.h> |
| 51 | #include <sys/types.h> |
| 52 | #include <sys/socket.h> |
| 53 | |
| 54 | #include <netinet/in.h> |
| 55 | |
| 56 | #include <arpa/inet.h> |
| 57 | |
| 58 | #include <netdb.h> |
| 59 | #include <unistd.h> |
| 60 | |
| 61 | /* --- Local headers --- */ |
| 62 | |
| 63 | #include "become.h" |
| 64 | #include "config.h" |
| 65 | #include "crypt.h" |
| 66 | #include "idea.h" |
| 67 | #include "lexer.h" |
| 68 | #include "name.h" |
| 69 | #include "rule.h" |
| 70 | #include "parser.h" |
| 71 | #include "tx.h" |
| 72 | #include "utils.h" |
| 73 | |
| 74 | /*----- Main code ---------------------------------------------------------*/ |
| 75 | |
| 76 | /* --- @check__client@ --- * |
| 77 | * |
| 78 | * Arguments: @request *rq@ = pointer to request buffer |
| 79 | * @const char *serv@ = pointer to the server |
| 80 | * @int port@ = port number to use |
| 81 | * |
| 82 | * Returns: Nonzero if OK, zero if forbidden |
| 83 | * |
| 84 | * Use: Contacts a server to decide whether the request is OK. |
| 85 | */ |
| 86 | |
| 87 | static int check__client(request *rq, const char *serv, int port) |
| 88 | { |
| 89 | int fd; |
| 90 | struct sockaddr_in ssin; |
| 91 | unsigned char crq[crq_size]; |
| 92 | unsigned char k[IDEA_KEYSIZE]; |
| 93 | unsigned char sk[IDEA_KEYSIZE]; |
| 94 | time_t t; |
| 95 | pid_t pid; |
| 96 | |
| 97 | /* --- Create my socket --- */ |
| 98 | |
| 99 | if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) |
| 100 | die("couldn't create socket: %s", strerror(errno)); |
| 101 | |
| 102 | /* --- Bind myself to some address --- */ |
| 103 | |
| 104 | { |
| 105 | struct sockaddr_in sin; |
| 106 | |
| 107 | sin.sin_family = AF_INET; |
| 108 | sin.sin_port = 0; |
| 109 | sin.sin_addr.s_addr = htonl(INADDR_ANY); |
| 110 | |
| 111 | if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0) |
| 112 | die("couldn't bind socket to address: %s", strerror(errno)); |
| 113 | } |
| 114 | |
| 115 | /* --- Find the server's address --- */ |
| 116 | |
| 117 | { |
| 118 | struct hostent *he; |
| 119 | |
| 120 | /* --- Resolve the server's name --- */ |
| 121 | |
| 122 | if ((he = gethostbyname(serv)) == 0) |
| 123 | die("couldn't find server host `%s'", serv); |
| 124 | |
| 125 | /* --- Build the address block --- */ |
| 126 | |
| 127 | ssin.sin_family = AF_INET; |
| 128 | ssin.sin_port = htons(port); |
| 129 | memcpy(&ssin.sin_addr, he->h_addr, sizeof(struct in_addr)); |
| 130 | } |
| 131 | |
| 132 | /* --- Read in the encryption key --- */ |
| 133 | |
| 134 | { |
| 135 | FILE *fp; |
| 136 | |
| 137 | if ((fp = fopen(file_KEY, "r")) == 0) { |
| 138 | die("couldn't open key file `%s': %s", file_KEY, |
| 139 | strerror(errno)); |
| 140 | } |
| 141 | tx_getBits(k, 128, fp); |
| 142 | } |
| 143 | |
| 144 | /* --- Now build a request packet --- */ |
| 145 | |
| 146 | t = time(0); |
| 147 | pid = getpid(); |
| 148 | crypt_packRequest(rq, crq, t, pid, k, sk); |
| 149 | |
| 150 | /* --- Send the packet to the server --- */ |
| 151 | |
| 152 | if (sendto(fd, (char *)crq, sizeof(crq), 0, |
| 153 | (struct sockaddr *)&ssin, sizeof(ssin)) < 0) { |
| 154 | burn(k); |
| 155 | die("couldn't send request to server: %s", strerror(errno)); |
| 156 | } |
| 157 | burn(k); |
| 158 | |
| 159 | /* --- Now wait for a reply --- */ |
| 160 | |
| 161 | { |
| 162 | fd_set fds; |
| 163 | struct timeval when, now, tv; |
| 164 | |
| 165 | gettimeofday(&when, 0); |
| 166 | when.tv_sec += 10; |
| 167 | |
| 168 | for (;;) { |
| 169 | int i; |
| 170 | |
| 171 | /* --- Sort out when to return --- */ |
| 172 | |
| 173 | gettimeofday(&now, 0); |
| 174 | if (now.tv_usec > when.tv_usec) { |
| 175 | now.tv_usec -= 1000000; |
| 176 | now.tv_sec += 1; |
| 177 | } |
| 178 | tv.tv_sec = when.tv_sec - now.tv_sec; |
| 179 | tv.tv_usec = when.tv_usec - now.tv_usec; |
| 180 | |
| 181 | /* --- Sort out file descriptors to watch --- */ |
| 182 | |
| 183 | FD_ZERO(&fds); |
| 184 | FD_SET(fd, &fds); |
| 185 | |
| 186 | /* --- Wait for them --- */ |
| 187 | |
| 188 | i = select(FD_SETSIZE, &fds, 0, 0, &tv); |
| 189 | if (i == 0) |
| 190 | die("no answer from server"); |
| 191 | if (i < 0) |
| 192 | die("error waiting for reply: %s", strerror(errno)); |
| 193 | |
| 194 | /* --- A reply should be waiting now --- */ |
| 195 | |
| 196 | { |
| 197 | struct sockaddr_in sin; |
| 198 | int slen = sizeof(sin); |
| 199 | unsigned char buff[256]; |
| 200 | int answer; |
| 201 | |
| 202 | /* --- Read the reply data --- */ |
| 203 | |
| 204 | if (recvfrom(fd, (char *)buff, sizeof(buff), 0, |
| 205 | (struct sockaddr *)&sin, &slen) < 0) |
| 206 | die("error reading server's reply: %s", strerror(errno)); |
| 207 | |
| 208 | /* --- Verify the sender --- */ |
| 209 | |
| 210 | if (sin.sin_addr.s_addr != ssin.sin_addr.s_addr || |
| 211 | sin.sin_port != ssin.sin_port) |
| 212 | continue; |
| 213 | |
| 214 | /* --- Unpack and verify the response --- */ |
| 215 | |
| 216 | answer = crypt_unpackReply(buff, sk, t, pid); |
| 217 | if (answer < 0) |
| 218 | continue; |
| 219 | return (answer); |
| 220 | } |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | die("internal error: can't get here in check_client"); |
| 225 | return (0); |
| 226 | } |
| 227 | |
| 228 | /* --- @check@ --- * |
| 229 | * |
| 230 | * Arguments: @request *rq@ = pointer to request buffer |
| 231 | * |
| 232 | * Returns: Nonzero if OK, zero if forbidden |
| 233 | * |
| 234 | * Use: Checks to see if the request is acceptable. |
| 235 | */ |
| 236 | |
| 237 | int check(request *rq) |
| 238 | { |
| 239 | FILE *fp; |
| 240 | |
| 241 | /* --- Check if we need to talk to a server --- */ |
| 242 | |
| 243 | if ((fp = fopen(file_SERVER, "r")) != 0) { |
| 244 | char buff[64]; |
| 245 | int port; |
| 246 | int ch; |
| 247 | |
| 248 | if (fscanf(fp, " %63[^: \t] ", buff) < 1) |
| 249 | die("error in `%s'", file_SERVER); |
| 250 | ch = getc(fp); |
| 251 | if (ch == ':') { |
| 252 | char b[64]; |
| 253 | struct servent *se; |
| 254 | |
| 255 | fscanf(fp, "%s", b); |
| 256 | if ((se = getservbyname(b, 0)) != 0) |
| 257 | port = ntohs(se->s_port); |
| 258 | else if ((port = atoi(b)) == 0) |
| 259 | die("error in `%s'", file_SERVER); |
| 260 | } else { |
| 261 | struct servent *se; |
| 262 | |
| 263 | if ((se = getservbyname(quis(), "udp")) == 0) |
| 264 | die("no idea which port to use"); |
| 265 | port = ntohs(se->s_port); |
| 266 | } |
| 267 | fclose(fp); |
| 268 | return (check__client(rq, buff, port)); |
| 269 | } |
| 270 | |
| 271 | /* --- Read the configuration in and go --- */ |
| 272 | |
| 273 | if ((fp = fopen(file_RULES, "r")) == 0) { |
| 274 | die("couldn't read configuration file `%s': %s", |
| 275 | file_RULES, strerror(errno)); |
| 276 | } |
| 277 | |
| 278 | name_init(); |
| 279 | rule_init(); |
| 280 | lexer_scan(fp); |
| 281 | yyparse(); |
| 282 | |
| 283 | return (rule_check(rq)); |
| 284 | } |
| 285 | |
| 286 | /*----- That's all, folks -------------------------------------------------*/ |