Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 1 | /* $OpenBSD: auth2.c,v 1.135 2015/01/19 20:07:45 markus Exp $ */ |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 2 | /* |
| 3 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * |
| 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 24 | */ |
| 25 | |
| 26 | #include "includes.h" |
| 27 | |
| 28 | #include <sys/types.h> |
| 29 | #include <sys/stat.h> |
| 30 | #include <sys/uio.h> |
| 31 | |
| 32 | #include <fcntl.h> |
| 33 | #include <pwd.h> |
| 34 | #include <stdarg.h> |
| 35 | #include <string.h> |
| 36 | #include <unistd.h> |
| 37 | |
| 38 | #include "atomicio.h" |
| 39 | #include "xmalloc.h" |
| 40 | #include "ssh2.h" |
| 41 | #include "packet.h" |
| 42 | #include "log.h" |
| 43 | #include "buffer.h" |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 44 | #include "misc.h" |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 45 | #include "servconf.h" |
| 46 | #include "compat.h" |
| 47 | #include "key.h" |
| 48 | #include "hostfile.h" |
| 49 | #include "auth.h" |
| 50 | #include "dispatch.h" |
| 51 | #include "pathnames.h" |
| 52 | #include "buffer.h" |
| 53 | |
| 54 | #ifdef GSSAPI |
| 55 | #include "ssh-gss.h" |
| 56 | #endif |
| 57 | #include "monitor_wrap.h" |
| 58 | |
| 59 | /* import */ |
| 60 | extern ServerOptions options; |
| 61 | extern u_char *session_id2; |
| 62 | extern u_int session_id2_len; |
| 63 | extern Buffer loginmsg; |
| 64 | |
| 65 | /* methods */ |
| 66 | |
| 67 | extern Authmethod method_none; |
| 68 | extern Authmethod method_pubkey; |
| 69 | extern Authmethod method_passwd; |
| 70 | extern Authmethod method_kbdint; |
| 71 | extern Authmethod method_hostbased; |
| 72 | #ifdef GSSAPI |
| 73 | extern Authmethod method_gssapi; |
| 74 | #endif |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 75 | |
| 76 | Authmethod *authmethods[] = { |
| 77 | &method_none, |
| 78 | &method_pubkey, |
| 79 | #ifdef GSSAPI |
| 80 | &method_gssapi, |
| 81 | #endif |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 82 | &method_passwd, |
| 83 | &method_kbdint, |
| 84 | &method_hostbased, |
| 85 | NULL |
| 86 | }; |
| 87 | |
| 88 | /* protocol */ |
| 89 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 90 | static int input_service_request(int, u_int32_t, void *); |
| 91 | static int input_userauth_request(int, u_int32_t, void *); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 92 | |
| 93 | /* helper */ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 94 | static Authmethod *authmethod_lookup(Authctxt *, const char *); |
| 95 | static char *authmethods_get(Authctxt *authctxt); |
| 96 | |
| 97 | #define MATCH_NONE 0 /* method or submethod mismatch */ |
| 98 | #define MATCH_METHOD 1 /* method matches (no submethod specified) */ |
| 99 | #define MATCH_BOTH 2 /* method and submethod match */ |
| 100 | #define MATCH_PARTIAL 3 /* method matches, submethod can't be checked */ |
| 101 | static int list_starts_with(const char *, const char *, const char *); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 102 | |
| 103 | char * |
| 104 | auth2_read_banner(void) |
| 105 | { |
| 106 | struct stat st; |
| 107 | char *banner = NULL; |
| 108 | size_t len, n; |
| 109 | int fd; |
| 110 | |
| 111 | if ((fd = open(options.banner, O_RDONLY)) == -1) |
| 112 | return (NULL); |
| 113 | if (fstat(fd, &st) == -1) { |
| 114 | close(fd); |
| 115 | return (NULL); |
| 116 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 117 | if (st.st_size <= 0 || st.st_size > 1*1024*1024) { |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 118 | close(fd); |
| 119 | return (NULL); |
| 120 | } |
| 121 | |
| 122 | len = (size_t)st.st_size; /* truncate */ |
| 123 | banner = xmalloc(len + 1); |
| 124 | n = atomicio(read, fd, banner, len); |
| 125 | close(fd); |
| 126 | |
| 127 | if (n != len) { |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 128 | free(banner); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 129 | return (NULL); |
| 130 | } |
| 131 | banner[n] = '\0'; |
| 132 | |
| 133 | return (banner); |
| 134 | } |
| 135 | |
| 136 | void |
| 137 | userauth_send_banner(const char *msg) |
| 138 | { |
| 139 | if (datafellows & SSH_BUG_BANNER) |
| 140 | return; |
| 141 | |
| 142 | packet_start(SSH2_MSG_USERAUTH_BANNER); |
| 143 | packet_put_cstring(msg); |
| 144 | packet_put_cstring(""); /* language, unused */ |
| 145 | packet_send(); |
| 146 | debug("%s: sent", __func__); |
| 147 | } |
| 148 | |
| 149 | static void |
| 150 | userauth_banner(void) |
| 151 | { |
| 152 | char *banner = NULL; |
| 153 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 154 | if (options.banner == NULL || (datafellows & SSH_BUG_BANNER) != 0) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 155 | return; |
| 156 | |
| 157 | if ((banner = PRIVSEP(auth2_read_banner())) == NULL) |
| 158 | goto done; |
| 159 | userauth_send_banner(banner); |
| 160 | |
| 161 | done: |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 162 | free(banner); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 163 | } |
| 164 | |
| 165 | /* |
| 166 | * loop until authctxt->success == TRUE |
| 167 | */ |
| 168 | void |
| 169 | do_authentication2(Authctxt *authctxt) |
| 170 | { |
| 171 | dispatch_init(&dispatch_protocol_error); |
| 172 | dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); |
| 173 | dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); |
| 174 | } |
| 175 | |
| 176 | /*ARGSUSED*/ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 177 | static int |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 178 | input_service_request(int type, u_int32_t seq, void *ctxt) |
| 179 | { |
| 180 | Authctxt *authctxt = ctxt; |
| 181 | u_int len; |
| 182 | int acceptit = 0; |
| 183 | char *service = packet_get_cstring(&len); |
| 184 | packet_check_eom(); |
| 185 | |
| 186 | if (authctxt == NULL) |
| 187 | fatal("input_service_request: no authctxt"); |
| 188 | |
| 189 | if (strcmp(service, "ssh-userauth") == 0) { |
| 190 | if (!authctxt->success) { |
| 191 | acceptit = 1; |
| 192 | /* now we can handle user-auth requests */ |
| 193 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); |
| 194 | } |
| 195 | } |
| 196 | /* XXX all other service requests are denied */ |
| 197 | |
| 198 | if (acceptit) { |
| 199 | packet_start(SSH2_MSG_SERVICE_ACCEPT); |
| 200 | packet_put_cstring(service); |
| 201 | packet_send(); |
| 202 | packet_write_wait(); |
| 203 | } else { |
| 204 | debug("bad service request %s", service); |
| 205 | packet_disconnect("bad service request %s", service); |
| 206 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 207 | free(service); |
| 208 | return 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 209 | } |
| 210 | |
| 211 | /*ARGSUSED*/ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 212 | static int |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 213 | input_userauth_request(int type, u_int32_t seq, void *ctxt) |
| 214 | { |
| 215 | Authctxt *authctxt = ctxt; |
| 216 | Authmethod *m = NULL; |
| 217 | char *user, *service, *method, *style = NULL; |
| 218 | int authenticated = 0; |
| 219 | |
| 220 | if (authctxt == NULL) |
| 221 | fatal("input_userauth_request: no authctxt"); |
| 222 | |
| 223 | user = packet_get_cstring(NULL); |
| 224 | service = packet_get_cstring(NULL); |
| 225 | method = packet_get_cstring(NULL); |
| 226 | debug("userauth-request for user %s service %s method %s", user, service, method); |
| 227 | debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
| 228 | |
| 229 | if ((style = strchr(user, ':')) != NULL) |
| 230 | *style++ = 0; |
| 231 | |
| 232 | if (authctxt->attempt++ == 0) { |
| 233 | /* setup auth context */ |
| 234 | authctxt->pw = PRIVSEP(getpwnamallow(user)); |
| 235 | authctxt->user = xstrdup(user); |
| 236 | if (authctxt->pw && strcmp(service, "ssh-connection")==0) { |
| 237 | authctxt->valid = 1; |
| 238 | debug2("input_userauth_request: setting up authctxt for %s", user); |
| 239 | } else { |
| 240 | logit("input_userauth_request: invalid user %s", user); |
| 241 | authctxt->pw = fakepw(); |
| 242 | #ifdef SSH_AUDIT_EVENTS |
| 243 | PRIVSEP(audit_event(SSH_INVALID_USER)); |
| 244 | #endif |
| 245 | } |
| 246 | #ifdef USE_PAM |
| 247 | if (options.use_pam) |
| 248 | PRIVSEP(start_pam(authctxt)); |
| 249 | #endif |
| 250 | setproctitle("%s%s", authctxt->valid ? user : "unknown", |
| 251 | use_privsep ? " [net]" : ""); |
| 252 | authctxt->service = xstrdup(service); |
| 253 | authctxt->style = style ? xstrdup(style) : NULL; |
| 254 | if (use_privsep) |
| 255 | mm_inform_authserv(service, style); |
| 256 | userauth_banner(); |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 257 | if (auth2_setup_methods_lists(authctxt) != 0) |
| 258 | packet_disconnect("no authentication methods enabled"); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 259 | } else if (strcmp(user, authctxt->user) != 0 || |
| 260 | strcmp(service, authctxt->service) != 0) { |
| 261 | packet_disconnect("Change of username or service not allowed: " |
| 262 | "(%s,%s) -> (%s,%s)", |
| 263 | authctxt->user, authctxt->service, user, service); |
| 264 | } |
| 265 | /* reset state */ |
| 266 | auth2_challenge_stop(authctxt); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 267 | |
| 268 | #ifdef GSSAPI |
| 269 | /* XXX move to auth2_gssapi_stop() */ |
| 270 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); |
| 271 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL); |
| 272 | #endif |
| 273 | |
| 274 | authctxt->postponed = 0; |
| 275 | authctxt->server_caused_failure = 0; |
| 276 | |
| 277 | /* try to authenticate user */ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 278 | m = authmethod_lookup(authctxt, method); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 279 | if (m != NULL && authctxt->failures < options.max_authtries) { |
| 280 | debug2("input_userauth_request: try method %s", method); |
| 281 | authenticated = m->userauth(authctxt); |
| 282 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 283 | userauth_finish(authctxt, authenticated, method, NULL); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 284 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 285 | free(service); |
| 286 | free(user); |
| 287 | free(method); |
| 288 | return 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 289 | } |
| 290 | |
| 291 | void |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 292 | userauth_finish(Authctxt *authctxt, int authenticated, const char *method, |
| 293 | const char *submethod) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 294 | { |
| 295 | char *methods; |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 296 | int partial = 0; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 297 | |
| 298 | if (!authctxt->valid && authenticated) |
| 299 | fatal("INTERNAL ERROR: authenticated invalid user %s", |
| 300 | authctxt->user); |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 301 | if (authenticated && authctxt->postponed) |
| 302 | fatal("INTERNAL ERROR: authenticated and postponed"); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 303 | |
| 304 | /* Special handling for root */ |
| 305 | if (authenticated && authctxt->pw->pw_uid == 0 && |
| 306 | !auth_root_allowed(method)) { |
| 307 | authenticated = 0; |
| 308 | #ifdef SSH_AUDIT_EVENTS |
| 309 | PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED)); |
| 310 | #endif |
| 311 | } |
| 312 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 313 | if (authenticated && options.num_auth_methods != 0) { |
| 314 | if (!auth2_update_methods_lists(authctxt, method, submethod)) { |
| 315 | authenticated = 0; |
| 316 | partial = 1; |
| 317 | } |
| 318 | } |
| 319 | |
| 320 | /* Log before sending the reply */ |
| 321 | auth_log(authctxt, authenticated, partial, method, submethod); |
| 322 | |
| 323 | if (authctxt->postponed) |
| 324 | return; |
| 325 | |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 326 | #ifdef USE_PAM |
| 327 | if (options.use_pam && authenticated) { |
| 328 | if (!PRIVSEP(do_pam_account())) { |
| 329 | /* if PAM returned a message, send it to the user */ |
| 330 | if (buffer_len(&loginmsg) > 0) { |
| 331 | buffer_append(&loginmsg, "\0", 1); |
| 332 | userauth_send_banner(buffer_ptr(&loginmsg)); |
| 333 | packet_write_wait(); |
| 334 | } |
| 335 | fatal("Access denied for user %s by PAM account " |
| 336 | "configuration", authctxt->user); |
| 337 | } |
| 338 | } |
| 339 | #endif |
| 340 | |
| 341 | #ifdef _UNICOS |
| 342 | if (authenticated && cray_access_denied(authctxt->user)) { |
| 343 | authenticated = 0; |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 344 | fatal("Access denied for user %s.", authctxt->user); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 345 | } |
| 346 | #endif /* _UNICOS */ |
| 347 | |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 348 | if (authenticated == 1) { |
| 349 | /* turn off userauth */ |
| 350 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore); |
| 351 | packet_start(SSH2_MSG_USERAUTH_SUCCESS); |
| 352 | packet_send(); |
| 353 | packet_write_wait(); |
| 354 | /* now we can break out */ |
| 355 | authctxt->success = 1; |
| 356 | } else { |
| 357 | |
| 358 | /* Allow initial try of "none" auth without failure penalty */ |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 359 | if (!partial && !authctxt->server_caused_failure && |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 360 | (authctxt->attempt > 1 || strcmp(method, "none") != 0)) |
| 361 | authctxt->failures++; |
| 362 | if (authctxt->failures >= options.max_authtries) { |
| 363 | #ifdef SSH_AUDIT_EVENTS |
| 364 | PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES)); |
| 365 | #endif |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 366 | auth_maxtries_exceeded(authctxt); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 367 | } |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 368 | methods = authmethods_get(authctxt); |
| 369 | debug3("%s: failure partial=%d next methods=\"%s\"", __func__, |
| 370 | partial, methods); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 371 | packet_start(SSH2_MSG_USERAUTH_FAILURE); |
| 372 | packet_put_cstring(methods); |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 373 | packet_put_char(partial); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 374 | packet_send(); |
| 375 | packet_write_wait(); |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 376 | free(methods); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 377 | } |
| 378 | } |
| 379 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 380 | /* |
| 381 | * Checks whether method is allowed by at least one AuthenticationMethods |
| 382 | * methods list. Returns 1 if allowed, or no methods lists configured. |
| 383 | * 0 otherwise. |
| 384 | */ |
| 385 | int |
| 386 | auth2_method_allowed(Authctxt *authctxt, const char *method, |
| 387 | const char *submethod) |
| 388 | { |
| 389 | u_int i; |
| 390 | |
| 391 | /* |
| 392 | * NB. authctxt->num_auth_methods might be zero as a result of |
| 393 | * auth2_setup_methods_lists(), so check the configuration. |
| 394 | */ |
| 395 | if (options.num_auth_methods == 0) |
| 396 | return 1; |
| 397 | for (i = 0; i < authctxt->num_auth_methods; i++) { |
| 398 | if (list_starts_with(authctxt->auth_methods[i], method, |
| 399 | submethod) != MATCH_NONE) |
| 400 | return 1; |
| 401 | } |
| 402 | return 0; |
| 403 | } |
| 404 | |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 405 | static char * |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 406 | authmethods_get(Authctxt *authctxt) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 407 | { |
| 408 | Buffer b; |
| 409 | char *list; |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 410 | u_int i; |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 411 | |
| 412 | buffer_init(&b); |
| 413 | for (i = 0; authmethods[i] != NULL; i++) { |
| 414 | if (strcmp(authmethods[i]->name, "none") == 0) |
| 415 | continue; |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 416 | if (authmethods[i]->enabled == NULL || |
| 417 | *(authmethods[i]->enabled) == 0) |
| 418 | continue; |
| 419 | if (!auth2_method_allowed(authctxt, authmethods[i]->name, |
| 420 | NULL)) |
| 421 | continue; |
| 422 | if (buffer_len(&b) > 0) |
| 423 | buffer_append(&b, ",", 1); |
| 424 | buffer_append(&b, authmethods[i]->name, |
| 425 | strlen(authmethods[i]->name)); |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 426 | } |
| 427 | buffer_append(&b, "\0", 1); |
| 428 | list = xstrdup(buffer_ptr(&b)); |
| 429 | buffer_free(&b); |
| 430 | return list; |
| 431 | } |
| 432 | |
| 433 | static Authmethod * |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 434 | authmethod_lookup(Authctxt *authctxt, const char *name) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 435 | { |
| 436 | int i; |
| 437 | |
| 438 | if (name != NULL) |
| 439 | for (i = 0; authmethods[i] != NULL; i++) |
| 440 | if (authmethods[i]->enabled != NULL && |
| 441 | *(authmethods[i]->enabled) != 0 && |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 442 | strcmp(name, authmethods[i]->name) == 0 && |
| 443 | auth2_method_allowed(authctxt, |
| 444 | authmethods[i]->name, NULL)) |
Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 445 | return authmethods[i]; |
| 446 | debug2("Unrecognized authentication method name: %s", |
| 447 | name ? name : "NULL"); |
| 448 | return NULL; |
| 449 | } |
| 450 | |
Adam Langley | d059297 | 2015-03-30 14:49:51 -0700 | [diff] [blame^] | 451 | /* |
| 452 | * Check a comma-separated list of methods for validity. Is need_enable is |
| 453 | * non-zero, then also require that the methods are enabled. |
| 454 | * Returns 0 on success or -1 if the methods list is invalid. |
| 455 | */ |
| 456 | int |
| 457 | auth2_methods_valid(const char *_methods, int need_enable) |
| 458 | { |
| 459 | char *methods, *omethods, *method, *p; |
| 460 | u_int i, found; |
| 461 | int ret = -1; |
| 462 | |
| 463 | if (*_methods == '\0') { |
| 464 | error("empty authentication method list"); |
| 465 | return -1; |
| 466 | } |
| 467 | omethods = methods = xstrdup(_methods); |
| 468 | while ((method = strsep(&methods, ",")) != NULL) { |
| 469 | for (found = i = 0; !found && authmethods[i] != NULL; i++) { |
| 470 | if ((p = strchr(method, ':')) != NULL) |
| 471 | *p = '\0'; |
| 472 | if (strcmp(method, authmethods[i]->name) != 0) |
| 473 | continue; |
| 474 | if (need_enable) { |
| 475 | if (authmethods[i]->enabled == NULL || |
| 476 | *(authmethods[i]->enabled) == 0) { |
| 477 | error("Disabled method \"%s\" in " |
| 478 | "AuthenticationMethods list \"%s\"", |
| 479 | method, _methods); |
| 480 | goto out; |
| 481 | } |
| 482 | } |
| 483 | found = 1; |
| 484 | break; |
| 485 | } |
| 486 | if (!found) { |
| 487 | error("Unknown authentication method \"%s\" in list", |
| 488 | method); |
| 489 | goto out; |
| 490 | } |
| 491 | } |
| 492 | ret = 0; |
| 493 | out: |
| 494 | free(omethods); |
| 495 | return ret; |
| 496 | } |
| 497 | |
| 498 | /* |
| 499 | * Prune the AuthenticationMethods supplied in the configuration, removing |
| 500 | * any methods lists that include disabled methods. Note that this might |
| 501 | * leave authctxt->num_auth_methods == 0, even when multiple required auth |
| 502 | * has been requested. For this reason, all tests for whether multiple is |
| 503 | * enabled should consult options.num_auth_methods directly. |
| 504 | */ |
| 505 | int |
| 506 | auth2_setup_methods_lists(Authctxt *authctxt) |
| 507 | { |
| 508 | u_int i; |
| 509 | |
| 510 | if (options.num_auth_methods == 0) |
| 511 | return 0; |
| 512 | debug3("%s: checking methods", __func__); |
| 513 | authctxt->auth_methods = xcalloc(options.num_auth_methods, |
| 514 | sizeof(*authctxt->auth_methods)); |
| 515 | authctxt->num_auth_methods = 0; |
| 516 | for (i = 0; i < options.num_auth_methods; i++) { |
| 517 | if (auth2_methods_valid(options.auth_methods[i], 1) != 0) { |
| 518 | logit("Authentication methods list \"%s\" contains " |
| 519 | "disabled method, skipping", |
| 520 | options.auth_methods[i]); |
| 521 | continue; |
| 522 | } |
| 523 | debug("authentication methods list %d: %s", |
| 524 | authctxt->num_auth_methods, options.auth_methods[i]); |
| 525 | authctxt->auth_methods[authctxt->num_auth_methods++] = |
| 526 | xstrdup(options.auth_methods[i]); |
| 527 | } |
| 528 | if (authctxt->num_auth_methods == 0) { |
| 529 | error("No AuthenticationMethods left after eliminating " |
| 530 | "disabled methods"); |
| 531 | return -1; |
| 532 | } |
| 533 | return 0; |
| 534 | } |
| 535 | |
| 536 | static int |
| 537 | list_starts_with(const char *methods, const char *method, |
| 538 | const char *submethod) |
| 539 | { |
| 540 | size_t l = strlen(method); |
| 541 | int match; |
| 542 | const char *p; |
| 543 | |
| 544 | if (strncmp(methods, method, l) != 0) |
| 545 | return MATCH_NONE; |
| 546 | p = methods + l; |
| 547 | match = MATCH_METHOD; |
| 548 | if (*p == ':') { |
| 549 | if (!submethod) |
| 550 | return MATCH_PARTIAL; |
| 551 | l = strlen(submethod); |
| 552 | p += 1; |
| 553 | if (strncmp(submethod, p, l)) |
| 554 | return MATCH_NONE; |
| 555 | p += l; |
| 556 | match = MATCH_BOTH; |
| 557 | } |
| 558 | if (*p != ',' && *p != '\0') |
| 559 | return MATCH_NONE; |
| 560 | return match; |
| 561 | } |
| 562 | |
| 563 | /* |
| 564 | * Remove method from the start of a comma-separated list of methods. |
| 565 | * Returns 0 if the list of methods did not start with that method or 1 |
| 566 | * if it did. |
| 567 | */ |
| 568 | static int |
| 569 | remove_method(char **methods, const char *method, const char *submethod) |
| 570 | { |
| 571 | char *omethods = *methods, *p; |
| 572 | size_t l = strlen(method); |
| 573 | int match; |
| 574 | |
| 575 | match = list_starts_with(omethods, method, submethod); |
| 576 | if (match != MATCH_METHOD && match != MATCH_BOTH) |
| 577 | return 0; |
| 578 | p = omethods + l; |
| 579 | if (submethod && match == MATCH_BOTH) |
| 580 | p += 1 + strlen(submethod); /* include colon */ |
| 581 | if (*p == ',') |
| 582 | p++; |
| 583 | *methods = xstrdup(p); |
| 584 | free(omethods); |
| 585 | return 1; |
| 586 | } |
| 587 | |
| 588 | /* |
| 589 | * Called after successful authentication. Will remove the successful method |
| 590 | * from the start of each list in which it occurs. If it was the last method |
| 591 | * in any list, then authentication is deemed successful. |
| 592 | * Returns 1 if the method completed any authentication list or 0 otherwise. |
| 593 | */ |
| 594 | int |
| 595 | auth2_update_methods_lists(Authctxt *authctxt, const char *method, |
| 596 | const char *submethod) |
| 597 | { |
| 598 | u_int i, found = 0; |
| 599 | |
| 600 | debug3("%s: updating methods list after \"%s\"", __func__, method); |
| 601 | for (i = 0; i < authctxt->num_auth_methods; i++) { |
| 602 | if (!remove_method(&(authctxt->auth_methods[i]), method, |
| 603 | submethod)) |
| 604 | continue; |
| 605 | found = 1; |
| 606 | if (*authctxt->auth_methods[i] == '\0') { |
| 607 | debug2("authentication methods list %d complete", i); |
| 608 | return 1; |
| 609 | } |
| 610 | debug3("authentication methods list %d remaining: \"%s\"", |
| 611 | i, authctxt->auth_methods[i]); |
| 612 | } |
| 613 | /* This should not happen, but would be bad if it did */ |
| 614 | if (!found) |
| 615 | fatal("%s: method not in AuthenticationMethods", __func__); |
| 616 | return 0; |
| 617 | } |
| 618 | |
| 619 | |