Annotation of src/usr.bin/ssh/auth2.c, Revision 1.116
1.116 ! dtucker 1: /* $OpenBSD: auth2.c,v 1.115 2007/04/14 22:01:58 stevesk Exp $ */
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:
1.111 stevesk 26:
27: #include <sys/types.h>
28:
29: #include <pwd.h>
1.112 stevesk 30: #include <string.h>
1.113 deraadt 31: #include <stdarg.h>
1.1 markus 32:
1.113 deraadt 33: #include "xmalloc.h"
1.32 markus 34: #include "ssh2.h"
1.1 markus 35: #include "packet.h"
1.32 markus 36: #include "log.h"
1.113 deraadt 37: #include "buffer.h"
1.1 markus 38: #include "servconf.h"
39: #include "compat.h"
1.113 deraadt 40: #include "key.h"
41: #include "hostfile.h"
1.1 markus 42: #include "auth.h"
43: #include "dispatch.h"
1.29 markus 44: #include "pathnames.h"
1.100 markus 45: #ifdef GSSAPI
46: #include "ssh-gss.h"
47: #endif
1.113 deraadt 48: #include "monitor_wrap.h"
1.100 markus 49:
1.1 markus 50: /* import */
51: extern ServerOptions options;
1.23 markus 52: extern u_char *session_id2;
1.99 markus 53: extern u_int session_id2_len;
1.1 markus 54:
1.93 markus 55: /* methods */
56:
57: extern Authmethod method_none;
58: extern Authmethod method_pubkey;
59: extern Authmethod method_passwd;
60: extern Authmethod method_kbdint;
61: extern Authmethod method_hostbased;
1.100 markus 62: #ifdef GSSAPI
63: extern Authmethod method_gssapi;
64: #endif
1.93 markus 65:
66: Authmethod *authmethods[] = {
67: &method_none,
68: &method_pubkey,
1.100 markus 69: #ifdef GSSAPI
70: &method_gssapi,
71: #endif
1.93 markus 72: &method_passwd,
73: &method_kbdint,
74: &method_hostbased,
75: NULL
1.18 markus 76: };
77:
1.1 markus 78: /* protocol */
79:
1.80 markus 80: static void input_service_request(int, u_int32_t, void *);
81: static void input_userauth_request(int, u_int32_t, void *);
1.1 markus 82:
83: /* helper */
1.66 itojun 84: static Authmethod *authmethod_lookup(const char *);
1.67 stevesk 85: static char *authmethods_get(void);
1.1 markus 86:
87: /*
1.18 markus 88: * loop until authctxt->success == TRUE
1.1 markus 89: */
90:
1.103 markus 91: void
92: do_authentication2(Authctxt *authctxt)
1.1 markus 93: {
1.81 markus 94: dispatch_init(&dispatch_protocol_error);
1.1 markus 95: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 96: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.1 markus 97: }
98:
1.109 deraadt 99: /*ARGSUSED*/
1.66 itojun 100: static void
1.80 markus 101: input_service_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 102: {
1.18 markus 103: Authctxt *authctxt = ctxt;
1.23 markus 104: u_int len;
1.94 deraadt 105: int acceptit = 0;
1.1 markus 106: char *service = packet_get_string(&len);
1.79 markus 107: packet_check_eom();
1.1 markus 108:
1.18 markus 109: if (authctxt == NULL)
110: fatal("input_service_request: no authctxt");
111:
1.1 markus 112: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 113: if (!authctxt->success) {
1.94 deraadt 114: acceptit = 1;
1.1 markus 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:
1.94 deraadt 121: if (acceptit) {
1.1 markus 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:
1.109 deraadt 133: /*ARGSUSED*/
1.66 itojun 134: static void
1.80 markus 135: input_userauth_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 136: {
1.18 markus 137: Authctxt *authctxt = ctxt;
138: Authmethod *m = NULL;
1.28 markus 139: char *user, *service, *method, *style = NULL;
1.1 markus 140: int authenticated = 0;
141:
1.18 markus 142: if (authctxt == NULL)
143: fatal("input_userauth_request: no authctxt");
1.1 markus 144:
1.18 markus 145: user = packet_get_string(NULL);
146: service = packet_get_string(NULL);
147: method = packet_get_string(NULL);
1.1 markus 148: debug("userauth-request for user %s service %s method %s", user, service, method);
1.24 markus 149: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
1.1 markus 150:
1.28 markus 151: if ((style = strchr(user, ':')) != NULL)
152: *style++ = 0;
153:
1.36 stevesk 154: if (authctxt->attempt++ == 0) {
1.18 markus 155: /* setup auth context */
1.89 markus 156: authctxt->pw = PRIVSEP(getpwnamallow(user));
157: if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
1.18 markus 158: authctxt->valid = 1;
159: debug2("input_userauth_request: setting up authctxt for %s", user);
160: } else {
1.107 markus 161: logit("input_userauth_request: invalid user %s", user);
1.102 markus 162: authctxt->pw = fakepw();
1.18 markus 163: }
1.106 djm 164: setproctitle("%s%s", authctxt->valid ? user : "unknown",
1.88 provos 165: use_privsep ? " [net]" : "");
1.18 markus 166: authctxt->user = xstrdup(user);
167: authctxt->service = xstrdup(service);
1.62 markus 168: authctxt->style = style ? xstrdup(style) : NULL;
1.88 provos 169: if (use_privsep)
170: mm_inform_authserv(service, style);
1.62 markus 171: } else if (strcmp(user, authctxt->user) != 0 ||
172: strcmp(service, authctxt->service) != 0) {
173: packet_disconnect("Change of username or service not allowed: "
174: "(%s,%s) -> (%s,%s)",
175: authctxt->user, authctxt->service, user, service);
1.1 markus 176: }
1.28 markus 177: /* reset state */
1.75 markus 178: auth2_challenge_stop(authctxt);
1.100 markus 179:
180: #ifdef GSSAPI
181: dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
182: dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
183: #endif
184:
1.28 markus 185: authctxt->postponed = 0;
1.18 markus 186:
1.28 markus 187: /* try to authenticate user */
1.18 markus 188: m = authmethod_lookup(method);
189: if (m != NULL) {
190: debug2("input_userauth_request: try method %s", method);
191: authenticated = m->userauth(authctxt);
192: }
1.49 markus 193: userauth_finish(authctxt, authenticated, method);
194:
195: xfree(service);
196: xfree(user);
197: xfree(method);
198: }
199:
200: void
201: userauth_finish(Authctxt *authctxt, int authenticated, char *method)
202: {
1.60 markus 203: char *methods;
204:
1.28 markus 205: if (!authctxt->valid && authenticated)
206: fatal("INTERNAL ERROR: authenticated invalid user %s",
207: authctxt->user);
1.18 markus 208:
209: /* Special handling for root */
1.96 markus 210: if (authenticated && authctxt->pw->pw_uid == 0 &&
1.41 markus 211: !auth_root_allowed(method))
1.3 markus 212: authenticated = 0;
213:
1.18 markus 214: /* Log before sending the reply */
1.28 markus 215: auth_log(authctxt, authenticated, method, " ssh2");
216:
1.60 markus 217: if (authctxt->postponed)
218: return;
219:
220: /* XXX todo: check if multiple auth methods are needed */
221: if (authenticated == 1) {
222: /* turn off userauth */
1.81 markus 223: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
1.60 markus 224: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
225: packet_send();
226: packet_write_wait();
227: /* now we can break out */
228: authctxt->success = 1;
229: } else {
1.105 dtucker 230: if (authctxt->failures++ > options.max_authtries)
1.60 markus 231: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
232: methods = authmethods_get();
233: packet_start(SSH2_MSG_USERAUTH_FAILURE);
234: packet_put_cstring(methods);
235: packet_put_char(0); /* XXX partial success, unused */
236: packet_send();
237: packet_write_wait();
238: xfree(methods);
239: }
1.1 markus 240: }
1.18 markus 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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