| 1 | /* |
| 2 | * Support rsync daemon authentication. |
| 3 | * |
| 4 | * Copyright (C) 1998-2000 Andrew Tridgell |
| 5 | * Copyright (C) 2002-2009 Wayne Davison |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 3 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License along |
| 18 | * with this program; if not, visit the http://fsf.org website. |
| 19 | */ |
| 20 | |
| 21 | #include "rsync.h" |
| 22 | #include "itypes.h" |
| 23 | |
| 24 | extern int read_only; |
| 25 | extern char *password_file; |
| 26 | |
| 27 | /*************************************************************************** |
| 28 | encode a buffer using base64 - simple and slow algorithm. null terminates |
| 29 | the result. |
| 30 | ***************************************************************************/ |
| 31 | void base64_encode(const char *buf, int len, char *out, int pad) |
| 32 | { |
| 33 | char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
| 34 | int bit_offset, byte_offset, idx, i; |
| 35 | const uchar *d = (const uchar *)buf; |
| 36 | int bytes = (len*8 + 5)/6; |
| 37 | |
| 38 | for (i = 0; i < bytes; i++) { |
| 39 | byte_offset = (i*6)/8; |
| 40 | bit_offset = (i*6)%8; |
| 41 | if (bit_offset < 3) { |
| 42 | idx = (d[byte_offset] >> (2-bit_offset)) & 0x3F; |
| 43 | } else { |
| 44 | idx = (d[byte_offset] << (bit_offset-2)) & 0x3F; |
| 45 | if (byte_offset+1 < len) { |
| 46 | idx |= (d[byte_offset+1] >> (8-(bit_offset-2))); |
| 47 | } |
| 48 | } |
| 49 | out[i] = b64[idx]; |
| 50 | } |
| 51 | |
| 52 | while (pad && (i % 4)) |
| 53 | out[i++] = '='; |
| 54 | |
| 55 | out[i] = '\0'; |
| 56 | } |
| 57 | |
| 58 | /* Generate a challenge buffer and return it base64-encoded. */ |
| 59 | static void gen_challenge(const char *addr, char *challenge) |
| 60 | { |
| 61 | char input[32]; |
| 62 | char digest[MAX_DIGEST_LEN]; |
| 63 | struct timeval tv; |
| 64 | int len; |
| 65 | |
| 66 | memset(input, 0, sizeof input); |
| 67 | |
| 68 | strlcpy(input, addr, 17); |
| 69 | sys_gettimeofday(&tv); |
| 70 | SIVAL(input, 16, tv.tv_sec); |
| 71 | SIVAL(input, 20, tv.tv_usec); |
| 72 | SIVAL(input, 24, getpid()); |
| 73 | |
| 74 | sum_init(0); |
| 75 | sum_update(input, sizeof input); |
| 76 | len = sum_end(digest); |
| 77 | |
| 78 | base64_encode(digest, len, challenge, 0); |
| 79 | } |
| 80 | |
| 81 | /* Generate an MD4 hash created from the combination of the password |
| 82 | * and the challenge string and return it base64-encoded. */ |
| 83 | static void generate_hash(const char *in, const char *challenge, char *out) |
| 84 | { |
| 85 | char buf[MAX_DIGEST_LEN]; |
| 86 | int len; |
| 87 | |
| 88 | sum_init(0); |
| 89 | sum_update(in, strlen(in)); |
| 90 | sum_update(challenge, strlen(challenge)); |
| 91 | len = sum_end(buf); |
| 92 | |
| 93 | base64_encode(buf, len, out, 0); |
| 94 | } |
| 95 | |
| 96 | /* Return the secret for a user from the secret file, null terminated. |
| 97 | * Maximum length is len (not counting the null). */ |
| 98 | static const char *check_secret(int module, const char *user, const char *group, |
| 99 | const char *challenge, const char *pass) |
| 100 | { |
| 101 | char line[1024]; |
| 102 | char pass2[MAX_DIGEST_LEN*2]; |
| 103 | const char *fname = lp_secrets_file(module); |
| 104 | STRUCT_STAT st; |
| 105 | int fd, ok = 1; |
| 106 | int user_len = strlen(user); |
| 107 | int group_len = group ? strlen(group) : 0; |
| 108 | char *err; |
| 109 | |
| 110 | if (!fname || !*fname || (fd = open(fname, O_RDONLY)) < 0) |
| 111 | return "no secrets file"; |
| 112 | |
| 113 | if (do_fstat(fd, &st) == -1) { |
| 114 | rsyserr(FLOG, errno, "fstat(%s)", fname); |
| 115 | ok = 0; |
| 116 | } else if (lp_strict_modes(module)) { |
| 117 | if ((st.st_mode & 06) != 0) { |
| 118 | rprintf(FLOG, "secrets file must not be other-accessible (see strict modes option)\n"); |
| 119 | ok = 0; |
| 120 | } else if (MY_UID() == 0 && st.st_uid != 0) { |
| 121 | rprintf(FLOG, "secrets file must be owned by root when running as root (see strict modes)\n"); |
| 122 | ok = 0; |
| 123 | } |
| 124 | } |
| 125 | if (!ok) { |
| 126 | close(fd); |
| 127 | return "ignoring secrets file"; |
| 128 | } |
| 129 | |
| 130 | if (*user == '#') { |
| 131 | /* Reject attempt to match a comment. */ |
| 132 | close(fd); |
| 133 | return "invalid username"; |
| 134 | } |
| 135 | |
| 136 | /* Try to find a line that starts with the user (or @group) name and a ':'. */ |
| 137 | err = "secret not found"; |
| 138 | while ((user || group) && read_line_old(fd, line, sizeof line, 1)) { |
| 139 | const char **ptr, *s; |
| 140 | int len; |
| 141 | if (*line == '@') { |
| 142 | ptr = &group; |
| 143 | len = group_len; |
| 144 | s = line+1; |
| 145 | } else { |
| 146 | ptr = &user; |
| 147 | len = user_len; |
| 148 | s = line; |
| 149 | } |
| 150 | if (!*ptr || strncmp(s, *ptr, len) != 0 || s[len] != ':') |
| 151 | continue; |
| 152 | generate_hash(s+len+1, challenge, pass2); |
| 153 | if (strcmp(pass, pass2) == 0) { |
| 154 | err = NULL; |
| 155 | break; |
| 156 | } |
| 157 | err = "password mismatch"; |
| 158 | *ptr = NULL; /* Don't look for name again. */ |
| 159 | } |
| 160 | |
| 161 | close(fd); |
| 162 | |
| 163 | memset(line, 0, sizeof line); |
| 164 | memset(pass2, 0, sizeof pass2); |
| 165 | |
| 166 | return err; |
| 167 | } |
| 168 | |
| 169 | static const char *getpassf(const char *filename) |
| 170 | { |
| 171 | STRUCT_STAT st; |
| 172 | char buffer[512], *p; |
| 173 | int fd, n, ok = 1; |
| 174 | const char *envpw = getenv("RSYNC_PASSWORD"); |
| 175 | |
| 176 | if (!filename) |
| 177 | return NULL; |
| 178 | |
| 179 | if ((fd = open(filename,O_RDONLY)) < 0) { |
| 180 | rsyserr(FWARNING, errno, "could not open password file \"%s\"", |
| 181 | filename); |
| 182 | if (envpw) |
| 183 | rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n"); |
| 184 | return NULL; |
| 185 | } |
| 186 | |
| 187 | if (do_stat(filename, &st) == -1) { |
| 188 | rsyserr(FWARNING, errno, "stat(%s)", filename); |
| 189 | ok = 0; |
| 190 | } else if ((st.st_mode & 06) != 0) { |
| 191 | rprintf(FWARNING, "password file must not be other-accessible\n"); |
| 192 | ok = 0; |
| 193 | } else if (MY_UID() == 0 && st.st_uid != 0) { |
| 194 | rprintf(FWARNING, "password file must be owned by root when running as root\n"); |
| 195 | ok = 0; |
| 196 | } |
| 197 | if (!ok) { |
| 198 | close(fd); |
| 199 | rprintf(FWARNING, "continuing without password file\n"); |
| 200 | if (envpw) |
| 201 | rprintf(FINFO, "falling back to RSYNC_PASSWORD environment variable.\n"); |
| 202 | return NULL; |
| 203 | } |
| 204 | |
| 205 | n = read(fd, buffer, sizeof buffer - 1); |
| 206 | close(fd); |
| 207 | if (n > 0) { |
| 208 | buffer[n] = '\0'; |
| 209 | if ((p = strtok(buffer, "\n\r")) != NULL) |
| 210 | return strdup(p); |
| 211 | } |
| 212 | |
| 213 | return NULL; |
| 214 | } |
| 215 | |
| 216 | /* Possibly negotiate authentication with the client. Use "leader" to |
| 217 | * start off the auth if necessary. |
| 218 | * |
| 219 | * Return NULL if authentication failed. Return "" if anonymous access. |
| 220 | * Otherwise return username. |
| 221 | */ |
| 222 | char *auth_server(int f_in, int f_out, int module, const char *host, |
| 223 | const char *addr, const char *leader) |
| 224 | { |
| 225 | char *users = lp_auth_users(module); |
| 226 | char challenge[MAX_DIGEST_LEN*2]; |
| 227 | char line[BIGPATHBUFLEN]; |
| 228 | char **auth_uid_groups = NULL; |
| 229 | int auth_uid_groups_cnt = -1; |
| 230 | const char *err = NULL; |
| 231 | int group_match = -1; |
| 232 | char *tok, *pass; |
| 233 | char opt_ch = '\0'; |
| 234 | |
| 235 | /* if no auth list then allow anyone in! */ |
| 236 | if (!users || !*users) |
| 237 | return ""; |
| 238 | |
| 239 | gen_challenge(addr, challenge); |
| 240 | |
| 241 | io_printf(f_out, "%s%s\n", leader, challenge); |
| 242 | |
| 243 | if (!read_line_old(f_in, line, sizeof line, 0) |
| 244 | || (pass = strchr(line, ' ')) == NULL) { |
| 245 | rprintf(FLOG, "auth failed on module %s from %s (%s): " |
| 246 | "invalid challenge response\n", |
| 247 | lp_name(module), host, addr); |
| 248 | return NULL; |
| 249 | } |
| 250 | *pass++ = '\0'; |
| 251 | |
| 252 | if (!(users = strdup(users))) |
| 253 | out_of_memory("auth_server"); |
| 254 | |
| 255 | for (tok = strtok(users, " ,\t"); tok; tok = strtok(NULL, " ,\t")) { |
| 256 | char *opts; |
| 257 | /* See if the user appended :deny, :ro, or :rw. */ |
| 258 | if ((opts = strchr(tok, ':')) != NULL) { |
| 259 | *opts++ = '\0'; |
| 260 | opt_ch = isUpper(opts) ? toLower(opts) : *opts; |
| 261 | if (opt_ch == 'r') { /* handle ro and rw */ |
| 262 | opt_ch = isUpper(opts+1) ? toLower(opts+1) : opts[1]; |
| 263 | if (opt_ch == 'o') |
| 264 | opt_ch = 'r'; |
| 265 | else if (opt_ch != 'w') |
| 266 | opt_ch = '\0'; |
| 267 | } else if (opt_ch != 'd') /* if it's not deny, ignore it */ |
| 268 | opt_ch = '\0'; |
| 269 | } else |
| 270 | opt_ch = '\0'; |
| 271 | if (*tok != '@') { |
| 272 | /* Match the username */ |
| 273 | if (wildmatch(tok, line)) |
| 274 | break; |
| 275 | } else { |
| 276 | #ifdef HAVE_GETGROUPLIST |
| 277 | int j; |
| 278 | /* See if authorizing user is a real user, and if so, see |
| 279 | * if it is in a group that matches tok+1 wildmat. */ |
| 280 | if (auth_uid_groups_cnt < 0) { |
| 281 | gid_t gid_list[64]; |
| 282 | uid_t auth_uid; |
| 283 | auth_uid_groups_cnt = sizeof gid_list / sizeof (gid_t); |
| 284 | if (!user_to_uid(line, &auth_uid, False) |
| 285 | || getallgroups(auth_uid, gid_list, &auth_uid_groups_cnt) != NULL) |
| 286 | auth_uid_groups_cnt = 0; |
| 287 | else { |
| 288 | if ((auth_uid_groups = new_array(char *, auth_uid_groups_cnt)) == NULL) |
| 289 | out_of_memory("auth_server"); |
| 290 | for (j = 0; j < auth_uid_groups_cnt; j++) |
| 291 | auth_uid_groups[j] = gid_to_group(gid_list[j]); |
| 292 | } |
| 293 | } |
| 294 | for (j = 0; j < auth_uid_groups_cnt; j++) { |
| 295 | if (auth_uid_groups[j] && wildmatch(tok+1, auth_uid_groups[j])) { |
| 296 | group_match = j; |
| 297 | break; |
| 298 | } |
| 299 | } |
| 300 | if (group_match >= 0) |
| 301 | break; |
| 302 | #else |
| 303 | rprintf(FLOG, "your computer doesn't support getgrouplist(), so no @group authorization is possible.\n"); |
| 304 | #endif |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | free(users); |
| 309 | |
| 310 | if (!tok) |
| 311 | err = "no matching rule"; |
| 312 | else if (opt_ch == 'd') |
| 313 | err = "denied by rule"; |
| 314 | else { |
| 315 | char *group = group_match >= 0 ? auth_uid_groups[group_match] : NULL; |
| 316 | err = check_secret(module, line, group, challenge, pass); |
| 317 | } |
| 318 | |
| 319 | memset(challenge, 0, sizeof challenge); |
| 320 | memset(pass, 0, strlen(pass)); |
| 321 | |
| 322 | if (auth_uid_groups) { |
| 323 | int j; |
| 324 | for (j = 0; j < auth_uid_groups_cnt; j++) { |
| 325 | if (auth_uid_groups[j]) |
| 326 | free(auth_uid_groups[j]); |
| 327 | } |
| 328 | free(auth_uid_groups); |
| 329 | } |
| 330 | |
| 331 | if (err) { |
| 332 | rprintf(FLOG, "auth failed on module %s from %s (%s) for %s: %s\n", |
| 333 | lp_name(module), host, addr, line, err); |
| 334 | return NULL; |
| 335 | } |
| 336 | |
| 337 | if (opt_ch == 'r') |
| 338 | read_only = 1; |
| 339 | else if (opt_ch == 'w') |
| 340 | read_only = 0; |
| 341 | |
| 342 | return strdup(line); |
| 343 | } |
| 344 | |
| 345 | void auth_client(int fd, const char *user, const char *challenge) |
| 346 | { |
| 347 | const char *pass; |
| 348 | char pass2[MAX_DIGEST_LEN*2]; |
| 349 | |
| 350 | if (!user || !*user) |
| 351 | user = "nobody"; |
| 352 | |
| 353 | if (!(pass = getpassf(password_file)) |
| 354 | && !(pass = getenv("RSYNC_PASSWORD"))) { |
| 355 | /* XXX: cyeoh says that getpass is deprecated, because |
| 356 | * it may return a truncated password on some systems, |
| 357 | * and it is not in the LSB. |
| 358 | * |
| 359 | * Andrew Klein says that getpassphrase() is present |
| 360 | * on Solaris and reads up to 256 characters. |
| 361 | * |
| 362 | * OpenBSD has a readpassphrase() that might be more suitable. |
| 363 | */ |
| 364 | pass = getpass("Password: "); |
| 365 | } |
| 366 | |
| 367 | if (!pass) |
| 368 | pass = ""; |
| 369 | |
| 370 | generate_hash(pass, challenge, pass2); |
| 371 | io_printf(fd, "%s %s\n", user, pass2); |
| 372 | } |