Annotation of src/usr.bin/ssh/auth2.c, Revision 1.110
1.110 ! djm 1: /* $OpenBSD$ */
1.1 markus 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: */
1.14 deraadt 25:
1.1 markus 26: #include "includes.h"
27:
1.32 markus 28: #include "ssh2.h"
1.1 markus 29: #include "xmalloc.h"
30: #include "packet.h"
1.32 markus 31: #include "log.h"
1.1 markus 32: #include "servconf.h"
33: #include "compat.h"
34: #include "auth.h"
35: #include "dispatch.h"
1.29 markus 36: #include "pathnames.h"
1.88 provos 37: #include "monitor_wrap.h"
1.1 markus 38:
1.100 markus 39: #ifdef GSSAPI
40: #include "ssh-gss.h"
41: #endif
42:
1.1 markus 43: /* import */
44: extern ServerOptions options;
1.23 markus 45: extern u_char *session_id2;
1.99 markus 46: extern u_int session_id2_len;
1.1 markus 47:
1.93 markus 48: /* methods */
49:
50: extern Authmethod method_none;
51: extern Authmethod method_pubkey;
52: extern Authmethod method_passwd;
53: extern Authmethod method_kbdint;
54: extern Authmethod method_hostbased;
1.100 markus 55: #ifdef GSSAPI
56: extern Authmethod method_gssapi;
57: #endif
1.93 markus 58:
59: Authmethod *authmethods[] = {
60: &method_none,
61: &method_pubkey,
1.100 markus 62: #ifdef GSSAPI
63: &method_gssapi,
64: #endif
1.93 markus 65: &method_passwd,
66: &method_kbdint,
67: &method_hostbased,
68: NULL
1.18 markus 69: };
70:
1.1 markus 71: /* protocol */
72:
1.80 markus 73: static void input_service_request(int, u_int32_t, void *);
74: static void input_userauth_request(int, u_int32_t, void *);
1.1 markus 75:
76: /* helper */
1.66 itojun 77: static Authmethod *authmethod_lookup(const char *);
1.67 stevesk 78: static char *authmethods_get(void);
1.88 provos 79: int user_key_allowed(struct passwd *, Key *);
1.1 markus 80:
81: /*
1.18 markus 82: * loop until authctxt->success == TRUE
1.1 markus 83: */
84:
1.103 markus 85: void
86: do_authentication2(Authctxt *authctxt)
1.1 markus 87: {
1.71 markus 88: /* challenge-response is implemented via keyboard interactive */
1.57 markus 89: if (options.challenge_response_authentication)
1.34 markus 90: options.kbd_interactive_authentication = 1;
91:
1.81 markus 92: dispatch_init(&dispatch_protocol_error);
1.1 markus 93: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 94: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.1 markus 95: }
96:
1.109 deraadt 97: /*ARGSUSED*/
1.66 itojun 98: static void
1.80 markus 99: input_service_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 100: {
1.18 markus 101: Authctxt *authctxt = ctxt;
1.23 markus 102: u_int len;
1.94 deraadt 103: int acceptit = 0;
1.1 markus 104: char *service = packet_get_string(&len);
1.79 markus 105: packet_check_eom();
1.1 markus 106:
1.18 markus 107: if (authctxt == NULL)
108: fatal("input_service_request: no authctxt");
109:
1.1 markus 110: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 111: if (!authctxt->success) {
1.94 deraadt 112: acceptit = 1;
1.1 markus 113: /* now we can handle user-auth requests */
114: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
115: }
116: }
117: /* XXX all other service requests are denied */
118:
1.94 deraadt 119: if (acceptit) {
1.1 markus 120: packet_start(SSH2_MSG_SERVICE_ACCEPT);
121: packet_put_cstring(service);
122: packet_send();
123: packet_write_wait();
124: } else {
125: debug("bad service request %s", service);
126: packet_disconnect("bad service request %s", service);
127: }
128: xfree(service);
129: }
130:
1.109 deraadt 131: /*ARGSUSED*/
1.66 itojun 132: static void
1.80 markus 133: input_userauth_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 134: {
1.18 markus 135: Authctxt *authctxt = ctxt;
136: Authmethod *m = NULL;
1.28 markus 137: char *user, *service, *method, *style = NULL;
1.1 markus 138: int authenticated = 0;
139:
1.18 markus 140: if (authctxt == NULL)
141: fatal("input_userauth_request: no authctxt");
1.1 markus 142:
1.18 markus 143: user = packet_get_string(NULL);
144: service = packet_get_string(NULL);
145: method = packet_get_string(NULL);
1.1 markus 146: debug("userauth-request for user %s service %s method %s", user, service, method);
1.24 markus 147: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
1.1 markus 148:
1.28 markus 149: if ((style = strchr(user, ':')) != NULL)
150: *style++ = 0;
151:
1.36 stevesk 152: if (authctxt->attempt++ == 0) {
1.18 markus 153: /* setup auth context */
1.89 markus 154: authctxt->pw = PRIVSEP(getpwnamallow(user));
155: if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
1.18 markus 156: authctxt->valid = 1;
157: debug2("input_userauth_request: setting up authctxt for %s", user);
158: } else {
1.107 markus 159: logit("input_userauth_request: invalid user %s", user);
1.102 markus 160: authctxt->pw = fakepw();
1.18 markus 161: }
1.106 djm 162: setproctitle("%s%s", authctxt->valid ? user : "unknown",
1.88 provos 163: use_privsep ? " [net]" : "");
1.18 markus 164: authctxt->user = xstrdup(user);
165: authctxt->service = xstrdup(service);
1.62 markus 166: authctxt->style = style ? xstrdup(style) : NULL;
1.88 provos 167: if (use_privsep)
168: mm_inform_authserv(service, style);
1.62 markus 169: } else if (strcmp(user, authctxt->user) != 0 ||
170: strcmp(service, authctxt->service) != 0) {
171: packet_disconnect("Change of username or service not allowed: "
172: "(%s,%s) -> (%s,%s)",
173: authctxt->user, authctxt->service, user, service);
1.1 markus 174: }
1.28 markus 175: /* reset state */
1.75 markus 176: auth2_challenge_stop(authctxt);
1.100 markus 177:
178: #ifdef GSSAPI
179: dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
180: dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
181: #endif
182:
1.28 markus 183: authctxt->postponed = 0;
1.18 markus 184:
1.28 markus 185: /* try to authenticate user */
1.18 markus 186: m = authmethod_lookup(method);
187: if (m != NULL) {
188: debug2("input_userauth_request: try method %s", method);
189: authenticated = m->userauth(authctxt);
190: }
1.49 markus 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: {
1.60 markus 201: char *methods;
202:
1.28 markus 203: if (!authctxt->valid && authenticated)
204: fatal("INTERNAL ERROR: authenticated invalid user %s",
205: authctxt->user);
1.18 markus 206:
207: /* Special handling for root */
1.96 markus 208: if (authenticated && authctxt->pw->pw_uid == 0 &&
1.41 markus 209: !auth_root_allowed(method))
1.3 markus 210: authenticated = 0;
211:
1.18 markus 212: /* Log before sending the reply */
1.28 markus 213: auth_log(authctxt, authenticated, method, " ssh2");
214:
1.60 markus 215: if (authctxt->postponed)
216: return;
217:
218: /* XXX todo: check if multiple auth methods are needed */
219: if (authenticated == 1) {
220: /* turn off userauth */
1.81 markus 221: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
1.60 markus 222: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
223: packet_send();
224: packet_write_wait();
225: /* now we can break out */
226: authctxt->success = 1;
227: } else {
1.105 dtucker 228: if (authctxt->failures++ > options.max_authtries)
1.60 markus 229: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
230: methods = authmethods_get();
231: packet_start(SSH2_MSG_USERAUTH_FAILURE);
232: packet_put_cstring(methods);
233: packet_put_char(0); /* XXX partial success, unused */
234: packet_send();
235: packet_write_wait();
236: xfree(methods);
237: }
1.1 markus 238: }
239:
1.18 markus 240: #define DELIM ","
241:
1.67 stevesk 242: static char *
1.18 markus 243: authmethods_get(void)
1.1 markus 244: {
1.82 markus 245: Buffer b;
1.18 markus 246: char *list;
1.93 markus 247: int i;
1.1 markus 248:
1.82 markus 249: buffer_init(&b);
1.93 markus 250: for (i = 0; authmethods[i] != NULL; i++) {
251: if (strcmp(authmethods[i]->name, "none") == 0)
1.18 markus 252: continue;
1.93 markus 253: if (authmethods[i]->enabled != NULL &&
254: *(authmethods[i]->enabled) != 0) {
1.82 markus 255: if (buffer_len(&b) > 0)
256: buffer_append(&b, ",", 1);
1.93 markus 257: buffer_append(&b, authmethods[i]->name,
258: strlen(authmethods[i]->name));
1.1 markus 259: }
260: }
1.82 markus 261: buffer_append(&b, "\0", 1);
262: list = xstrdup(buffer_ptr(&b));
263: buffer_free(&b);
1.18 markus 264: return list;
265: }
266:
1.66 itojun 267: static Authmethod *
1.18 markus 268: authmethod_lookup(const char *name)
269: {
1.93 markus 270: int i;
271:
1.18 markus 272: if (name != NULL)
1.93 markus 273: for (i = 0; authmethods[i] != NULL; i++)
274: if (authmethods[i]->enabled != NULL &&
275: *(authmethods[i]->enabled) != 0 &&
276: strcmp(name, authmethods[i]->name) == 0)
277: return authmethods[i];
278: debug2("Unrecognized authentication method name: %s",
279: name ? name : "NULL");
1.18 markus 280: return NULL;
1.1 markus 281: }
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