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a306f2dd | 1 | /* |
2 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
3 | * | |
4 | * Redistribution and use in source and binary forms, with or without | |
5 | * modification, are permitted provided that the following conditions | |
6 | * are met: | |
7 | * 1. Redistributions of source code must retain the above copyright | |
8 | * notice, this list of conditions and the following disclaimer. | |
9 | * 2. Redistributions in binary form must reproduce the above copyright | |
10 | * notice, this list of conditions and the following disclaimer in the | |
11 | * documentation and/or other materials provided with the distribution. | |
a306f2dd | 12 | * |
13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
23 | */ | |
bcbf86ec | 24 | |
a306f2dd | 25 | #include "includes.h" |
848bf884 | 26 | RCSID("$OpenBSD: auth2.c,v 1.95 2002/08/22 21:33:58 markus Exp $"); |
a306f2dd | 27 | |
42f11eb2 | 28 | #include "ssh2.h" |
a306f2dd | 29 | #include "xmalloc.h" |
a306f2dd | 30 | #include "packet.h" |
42f11eb2 | 31 | #include "log.h" |
a306f2dd | 32 | #include "servconf.h" |
33 | #include "compat.h" | |
a306f2dd | 34 | #include "auth.h" |
a306f2dd | 35 | #include "dispatch.h" |
42f11eb2 | 36 | #include "pathnames.h" |
1853d1ef | 37 | #include "monitor_wrap.h" |
a306f2dd | 38 | |
39 | /* import */ | |
40 | extern ServerOptions options; | |
1e3b8b07 | 41 | extern u_char *session_id2; |
a306f2dd | 42 | extern int session_id2_len; |
43 | ||
1853d1ef | 44 | Authctxt *x_authctxt = NULL; |
94ec8c6b | 45 | |
01c24737 | 46 | /* methods */ |
47 | ||
48 | extern Authmethod method_none; | |
49 | extern Authmethod method_pubkey; | |
50 | extern Authmethod method_passwd; | |
51 | extern Authmethod method_kbdint; | |
52 | extern Authmethod method_hostbased; | |
53 | ||
54 | Authmethod *authmethods[] = { | |
55 | &method_none, | |
56 | &method_pubkey, | |
57 | &method_passwd, | |
58 | &method_kbdint, | |
59 | &method_hostbased, | |
60 | NULL | |
94ec8c6b | 61 | }; |
62 | ||
a306f2dd | 63 | /* protocol */ |
64 | ||
7819b5c3 | 65 | static void input_service_request(int, u_int32_t, void *); |
66 | static void input_userauth_request(int, u_int32_t, void *); | |
a306f2dd | 67 | |
a306f2dd | 68 | /* helper */ |
396c147e | 69 | static Authmethod *authmethod_lookup(const char *); |
ffb215be | 70 | static char *authmethods_get(void); |
1853d1ef | 71 | int user_key_allowed(struct passwd *, Key *); |
72 | int hostbased_key_allowed(struct passwd *, const char *, char *, Key *); | |
a306f2dd | 73 | |
a306f2dd | 74 | /* |
94ec8c6b | 75 | * loop until authctxt->success == TRUE |
a306f2dd | 76 | */ |
77 | ||
1b34c1b3 | 78 | Authctxt * |
d5bb9418 | 79 | do_authentication2(void) |
a306f2dd | 80 | { |
59c97189 | 81 | Authctxt *authctxt = authctxt_new(); |
82 | ||
94ec8c6b | 83 | x_authctxt = authctxt; /*XXX*/ |
84 | ||
aa8003d6 | 85 | /* challenge-response is implemented via keyboard interactive */ |
5ba55ada | 86 | if (options.challenge_response_authentication) |
d464095c | 87 | options.kbd_interactive_authentication = 1; |
10f72868 | 88 | if (options.pam_authentication_via_kbd_int) |
89 | options.kbd_interactive_authentication = 1; | |
fea8a8e8 | 90 | if (use_privsep) |
91 | options.pam_authentication_via_kbd_int = 0; | |
d464095c | 92 | |
6367063f | 93 | dispatch_init(&dispatch_protocol_error); |
a306f2dd | 94 | dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); |
94ec8c6b | 95 | dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); |
1b34c1b3 | 96 | |
97 | return (authctxt); | |
a306f2dd | 98 | } |
99 | ||
396c147e | 100 | static void |
7819b5c3 | 101 | input_service_request(int type, u_int32_t seq, void *ctxt) |
a306f2dd | 102 | { |
94ec8c6b | 103 | Authctxt *authctxt = ctxt; |
1e3b8b07 | 104 | u_int len; |
7fdc56c5 | 105 | int acceptit = 0; |
a306f2dd | 106 | char *service = packet_get_string(&len); |
95500969 | 107 | packet_check_eom(); |
a306f2dd | 108 | |
94ec8c6b | 109 | if (authctxt == NULL) |
110 | fatal("input_service_request: no authctxt"); | |
111 | ||
a306f2dd | 112 | if (strcmp(service, "ssh-userauth") == 0) { |
94ec8c6b | 113 | if (!authctxt->success) { |
7fdc56c5 | 114 | acceptit = 1; |
a306f2dd | 115 | /* now we can handle user-auth requests */ |
116 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); | |
117 | } | |
118 | } | |
119 | /* XXX all other service requests are denied */ | |
120 | ||
7fdc56c5 | 121 | if (acceptit) { |
a306f2dd | 122 | packet_start(SSH2_MSG_SERVICE_ACCEPT); |
123 | packet_put_cstring(service); | |
124 | packet_send(); | |
125 | packet_write_wait(); | |
126 | } else { | |
127 | debug("bad service request %s", service); | |
128 | packet_disconnect("bad service request %s", service); | |
129 | } | |
130 | xfree(service); | |
131 | } | |
132 | ||
396c147e | 133 | static void |
7819b5c3 | 134 | input_userauth_request(int type, u_int32_t seq, void *ctxt) |
a306f2dd | 135 | { |
94ec8c6b | 136 | Authctxt *authctxt = ctxt; |
137 | Authmethod *m = NULL; | |
59c97189 | 138 | char *user, *service, *method, *style = NULL; |
a306f2dd | 139 | int authenticated = 0; |
a306f2dd | 140 | |
94ec8c6b | 141 | if (authctxt == NULL) |
142 | fatal("input_userauth_request: no authctxt"); | |
a306f2dd | 143 | |
94ec8c6b | 144 | user = packet_get_string(NULL); |
145 | service = packet_get_string(NULL); | |
146 | method = packet_get_string(NULL); | |
147 | debug("userauth-request for user %s service %s method %s", user, service, method); | |
8abcdba4 | 148 | debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
94ec8c6b | 149 | |
59c97189 | 150 | if ((style = strchr(user, ':')) != NULL) |
151 | *style++ = 0; | |
152 | ||
2b87da3b | 153 | if (authctxt->attempt++ == 0) { |
63284fbb | 154 | /* setup auth context */ |
f7ed12f1 | 155 | authctxt->pw = PRIVSEP(getpwnamallow(user)); |
156 | if (authctxt->pw && strcmp(service, "ssh-connection")==0) { | |
94ec8c6b | 157 | authctxt->valid = 1; |
158 | debug2("input_userauth_request: setting up authctxt for %s", user); | |
159 | #ifdef USE_PAM | |
ad200abb | 160 | PRIVSEP(start_pam(authctxt->pw->pw_name)); |
94ec8c6b | 161 | #endif |
162 | } else { | |
163 | log("input_userauth_request: illegal user %s", user); | |
04fc7a67 | 164 | #ifdef USE_PAM |
ad200abb | 165 | PRIVSEP(start_pam("NOUSER")); |
04fc7a67 | 166 | #endif |
94ec8c6b | 167 | } |
5f1f36b5 | 168 | setproctitle("%s%s", authctxt->pw ? user : "unknown", |
1853d1ef | 169 | use_privsep ? " [net]" : ""); |
94ec8c6b | 170 | authctxt->user = xstrdup(user); |
171 | authctxt->service = xstrdup(service); | |
2a6a054e | 172 | authctxt->style = style ? xstrdup(style) : NULL; |
1853d1ef | 173 | if (use_privsep) |
174 | mm_inform_authserv(service, style); | |
2a6a054e | 175 | } else if (strcmp(user, authctxt->user) != 0 || |
176 | strcmp(service, authctxt->service) != 0) { | |
177 | packet_disconnect("Change of username or service not allowed: " | |
178 | "(%s,%s) -> (%s,%s)", | |
179 | authctxt->user, authctxt->service, user, service); | |
a306f2dd | 180 | } |
59c97189 | 181 | /* reset state */ |
2f293d43 | 182 | auth2_challenge_stop(authctxt); |
59c97189 | 183 | authctxt->postponed = 0; |
9cd45ea4 | 184 | |
59c97189 | 185 | /* try to authenticate user */ |
94ec8c6b | 186 | m = authmethod_lookup(method); |
187 | if (m != NULL) { | |
188 | debug2("input_userauth_request: try method %s", method); | |
189 | authenticated = m->userauth(authctxt); | |
9cd45ea4 | 190 | } |
d9cd3575 | 191 | userauth_finish(authctxt, authenticated, method); |
192 | ||
193 | xfree(service); | |
194 | xfree(user); | |
195 | xfree(method); | |
196 | } | |
197 | ||
198 | void | |
199 | userauth_finish(Authctxt *authctxt, int authenticated, char *method) | |
200 | { | |
4e81159c | 201 | char *methods; |
202 | ||
59c97189 | 203 | if (!authctxt->valid && authenticated) |
204 | fatal("INTERNAL ERROR: authenticated invalid user %s", | |
205 | authctxt->user); | |
9cd45ea4 | 206 | |
94ec8c6b | 207 | /* Special handling for root */ |
848bf884 | 208 | if (!use_privsep && |
209 | authenticated && authctxt->pw->pw_uid == 0 && | |
15853e93 | 210 | !auth_root_allowed(method)) |
a306f2dd | 211 | authenticated = 0; |
a306f2dd | 212 | |
213 | #ifdef USE_PAM | |
ad200abb | 214 | if (!use_privsep && authenticated && authctxt->user && |
215 | !do_pam_account(authctxt->user, NULL)) | |
9cd45ea4 | 216 | authenticated = 0; |
a306f2dd | 217 | #endif /* USE_PAM */ |
218 | ||
ef51930f | 219 | #ifdef _UNICOS |
220 | if (authenticated && cray_access_denied(authctxt->user)) { | |
221 | authenticated = 0; | |
222 | fatal("Access denied for user %s.",authctxt->user); | |
223 | } | |
224 | #endif /* _UNICOS */ | |
225 | ||
94ec8c6b | 226 | /* Log before sending the reply */ |
59c97189 | 227 | auth_log(authctxt, authenticated, method, " ssh2"); |
228 | ||
4e81159c | 229 | if (authctxt->postponed) |
230 | return; | |
231 | ||
232 | /* XXX todo: check if multiple auth methods are needed */ | |
233 | if (authenticated == 1) { | |
234 | /* turn off userauth */ | |
6367063f | 235 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore); |
4e81159c | 236 | packet_start(SSH2_MSG_USERAUTH_SUCCESS); |
237 | packet_send(); | |
238 | packet_write_wait(); | |
239 | /* now we can break out */ | |
240 | authctxt->success = 1; | |
241 | } else { | |
19e810f6 | 242 | if (authctxt->failures++ > AUTH_FAIL_MAX) { |
4e81159c | 243 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); |
19e810f6 | 244 | } |
ef51930f | 245 | #ifdef _UNICOS |
246 | if (strcmp(method, "password") == 0) | |
247 | cray_login_failure(authctxt->user, IA_UDBERR); | |
248 | #endif /* _UNICOS */ | |
4e81159c | 249 | methods = authmethods_get(); |
250 | packet_start(SSH2_MSG_USERAUTH_FAILURE); | |
251 | packet_put_cstring(methods); | |
252 | packet_put_char(0); /* XXX partial success, unused */ | |
253 | packet_send(); | |
254 | packet_write_wait(); | |
255 | xfree(methods); | |
256 | } | |
94ec8c6b | 257 | } |
258 | ||
94ec8c6b | 259 | /* get current user */ |
a306f2dd | 260 | |
261 | struct passwd* | |
262 | auth_get_user(void) | |
263 | { | |
94ec8c6b | 264 | return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL; |
a306f2dd | 265 | } |
266 | ||
94ec8c6b | 267 | #define DELIM "," |
268 | ||
ffb215be | 269 | static char * |
94ec8c6b | 270 | authmethods_get(void) |
a306f2dd | 271 | { |
3469eac4 | 272 | Buffer b; |
94ec8c6b | 273 | char *list; |
01c24737 | 274 | int i; |
94ec8c6b | 275 | |
3469eac4 | 276 | buffer_init(&b); |
01c24737 | 277 | for (i = 0; authmethods[i] != NULL; i++) { |
278 | if (strcmp(authmethods[i]->name, "none") == 0) | |
94ec8c6b | 279 | continue; |
01c24737 | 280 | if (authmethods[i]->enabled != NULL && |
281 | *(authmethods[i]->enabled) != 0) { | |
3469eac4 | 282 | if (buffer_len(&b) > 0) |
283 | buffer_append(&b, ",", 1); | |
01c24737 | 284 | buffer_append(&b, authmethods[i]->name, |
285 | strlen(authmethods[i]->name)); | |
a306f2dd | 286 | } |
287 | } | |
3469eac4 | 288 | buffer_append(&b, "\0", 1); |
289 | list = xstrdup(buffer_ptr(&b)); | |
290 | buffer_free(&b); | |
94ec8c6b | 291 | return list; |
292 | } | |
293 | ||
396c147e | 294 | static Authmethod * |
94ec8c6b | 295 | authmethod_lookup(const char *name) |
296 | { | |
01c24737 | 297 | int i; |
298 | ||
94ec8c6b | 299 | if (name != NULL) |
01c24737 | 300 | for (i = 0; authmethods[i] != NULL; i++) |
301 | if (authmethods[i]->enabled != NULL && | |
302 | *(authmethods[i]->enabled) != 0 && | |
303 | strcmp(name, authmethods[i]->name) == 0) | |
304 | return authmethods[i]; | |
305 | debug2("Unrecognized authentication method name: %s", | |
306 | name ? name : "NULL"); | |
94ec8c6b | 307 | return NULL; |
a306f2dd | 308 | } |