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Diffstat (limited to 'auth2-gss.c')
-rw-r--r-- | auth2-gss.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/auth2-gss.c b/auth2-gss.c new file mode 100644 index 000000000..c7651112d --- /dev/null +++ b/auth2-gss.c | |||
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1 | /* $OpenBSD: auth2-gss.c,v 1.1 2003/08/22 10:56:08 markus Exp $ */ | ||
2 | |||
3 | /* | ||
4 | * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. | ||
5 | * | ||
6 | * Redistribution and use in source and binary forms, with or without | ||
7 | * modification, are permitted provided that the following conditions | ||
8 | * are met: | ||
9 | * 1. Redistributions of source code must retain the above copyright | ||
10 | * notice, this list of conditions and the following disclaimer. | ||
11 | * 2. Redistributions in binary form must reproduce the above copyright | ||
12 | * notice, this list of conditions and the following disclaimer in the | ||
13 | * documentation and/or other materials provided with the distribution. | ||
14 | * | ||
15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS'' AND ANY EXPRESS OR | ||
16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | ||
17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | ||
18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | ||
19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | ||
20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | ||
21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | ||
22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | ||
23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | ||
24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
25 | */ | ||
26 | |||
27 | #include "includes.h" | ||
28 | |||
29 | #ifdef GSSAPI | ||
30 | |||
31 | #include "auth.h" | ||
32 | #include "ssh2.h" | ||
33 | #include "xmalloc.h" | ||
34 | #include "log.h" | ||
35 | #include "dispatch.h" | ||
36 | #include "servconf.h" | ||
37 | #include "compat.h" | ||
38 | #include "packet.h" | ||
39 | #include "monitor_wrap.h" | ||
40 | |||
41 | #include "ssh-gss.h" | ||
42 | |||
43 | extern ServerOptions options; | ||
44 | |||
45 | static void input_gssapi_token(int type, u_int32_t plen, void *ctxt); | ||
46 | static void input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt); | ||
47 | static void input_gssapi_errtok(int, u_int32_t, void *); | ||
48 | |||
49 | /* | ||
50 | * We only support those mechanisms that we know about (ie ones that we know | ||
51 | * how to check local user kuserok and the like | ||
52 | */ | ||
53 | static int | ||
54 | userauth_gssapi(Authctxt *authctxt) | ||
55 | { | ||
56 | gss_OID_desc oid = {0, NULL}; | ||
57 | Gssctxt *ctxt = NULL; | ||
58 | int mechs; | ||
59 | gss_OID_set supported; | ||
60 | int present; | ||
61 | OM_uint32 ms; | ||
62 | u_int len; | ||
63 | char *doid = NULL; | ||
64 | |||
65 | if (!authctxt->valid || authctxt->user == NULL) | ||
66 | return (0); | ||
67 | |||
68 | mechs = packet_get_int(); | ||
69 | if (mechs == 0) { | ||
70 | debug("Mechanism negotiation is not supported"); | ||
71 | return (0); | ||
72 | } | ||
73 | |||
74 | ssh_gssapi_supported_oids(&supported); | ||
75 | do { | ||
76 | mechs--; | ||
77 | |||
78 | if (doid) | ||
79 | xfree(doid); | ||
80 | |||
81 | doid = packet_get_string(&len); | ||
82 | |||
83 | if (doid[0] != SSH_GSS_OIDTYPE || doid[1] != len-2) { | ||
84 | logit("Mechanism OID received using the old encoding form"); | ||
85 | oid.elements = doid; | ||
86 | oid.length = len; | ||
87 | } else { | ||
88 | oid.elements = doid + 2; | ||
89 | oid.length = len - 2; | ||
90 | } | ||
91 | gss_test_oid_set_member(&ms, &oid, supported, &present); | ||
92 | } while (mechs > 0 && !present); | ||
93 | |||
94 | gss_release_oid_set(&ms, &supported); | ||
95 | |||
96 | if (!present) { | ||
97 | xfree(doid); | ||
98 | return (0); | ||
99 | } | ||
100 | |||
101 | if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, &oid)))) | ||
102 | return (0); | ||
103 | |||
104 | authctxt->methoddata=(void *)ctxt; | ||
105 | |||
106 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE); | ||
107 | |||
108 | /* Return OID in same format as we received it*/ | ||
109 | packet_put_string(doid, len); | ||
110 | |||
111 | packet_send(); | ||
112 | xfree(doid); | ||
113 | |||
114 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); | ||
115 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); | ||
116 | authctxt->postponed = 1; | ||
117 | |||
118 | return (0); | ||
119 | } | ||
120 | |||
121 | static void | ||
122 | input_gssapi_token(int type, u_int32_t plen, void *ctxt) | ||
123 | { | ||
124 | Authctxt *authctxt = ctxt; | ||
125 | Gssctxt *gssctxt; | ||
126 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | ||
127 | gss_buffer_desc recv_tok; | ||
128 | OM_uint32 maj_status, min_status; | ||
129 | u_int len; | ||
130 | |||
131 | if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) | ||
132 | fatal("No authentication or GSSAPI context"); | ||
133 | |||
134 | gssctxt = authctxt->methoddata; | ||
135 | recv_tok.value = packet_get_string(&len); | ||
136 | recv_tok.length = len; /* u_int vs. size_t */ | ||
137 | |||
138 | packet_check_eom(); | ||
139 | |||
140 | maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, | ||
141 | &send_tok, NULL)); | ||
142 | |||
143 | xfree(recv_tok.value); | ||
144 | |||
145 | if (GSS_ERROR(maj_status)) { | ||
146 | if (send_tok.length != 0) { | ||
147 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); | ||
148 | packet_put_string(send_tok.value, send_tok.length); | ||
149 | packet_send(); | ||
150 | } | ||
151 | authctxt->postponed = 0; | ||
152 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); | ||
153 | userauth_finish(authctxt, 0, "gssapi"); | ||
154 | } else { | ||
155 | if (send_tok.length != 0) { | ||
156 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); | ||
157 | packet_put_string(send_tok.value, send_tok.length); | ||
158 | packet_send(); | ||
159 | } | ||
160 | if (maj_status == GSS_S_COMPLETE) { | ||
161 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); | ||
162 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, | ||
163 | &input_gssapi_exchange_complete); | ||
164 | } | ||
165 | } | ||
166 | |||
167 | gss_release_buffer(&min_status, &send_tok); | ||
168 | } | ||
169 | |||
170 | static void | ||
171 | input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) | ||
172 | { | ||
173 | Authctxt *authctxt = ctxt; | ||
174 | Gssctxt *gssctxt; | ||
175 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | ||
176 | gss_buffer_desc recv_tok; | ||
177 | OM_uint32 maj_status; | ||
178 | |||
179 | if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) | ||
180 | fatal("No authentication or GSSAPI context"); | ||
181 | |||
182 | gssctxt = authctxt->methoddata; | ||
183 | recv_tok.value = packet_get_string(&recv_tok.length); | ||
184 | |||
185 | packet_check_eom(); | ||
186 | |||
187 | /* Push the error token into GSSAPI to see what it says */ | ||
188 | maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok, | ||
189 | &send_tok, NULL)); | ||
190 | |||
191 | xfree(recv_tok.value); | ||
192 | |||
193 | /* We can't return anything to the client, even if we wanted to */ | ||
194 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); | ||
195 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL); | ||
196 | |||
197 | /* The client will have already moved on to the next auth */ | ||
198 | |||
199 | gss_release_buffer(&maj_status, &send_tok); | ||
200 | } | ||
201 | |||
202 | /* | ||
203 | * This is called when the client thinks we've completed authentication. | ||
204 | * It should only be enabled in the dispatch handler by the function above, | ||
205 | * which only enables it once the GSSAPI exchange is complete. | ||
206 | */ | ||
207 | |||
208 | static void | ||
209 | input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt) | ||
210 | { | ||
211 | Authctxt *authctxt = ctxt; | ||
212 | Gssctxt *gssctxt; | ||
213 | int authenticated; | ||
214 | |||
215 | if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep)) | ||
216 | fatal("No authentication or GSSAPI context"); | ||
217 | |||
218 | gssctxt = authctxt->methoddata; | ||
219 | |||
220 | /* | ||
221 | * We don't need to check the status, because the stored credentials | ||
222 | * which userok uses are only populated once the context init step | ||
223 | * has returned complete. | ||
224 | */ | ||
225 | |||
226 | packet_check_eom(); | ||
227 | |||
228 | authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user)); | ||
229 | |||
230 | authctxt->postponed = 0; | ||
231 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); | ||
232 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL); | ||
233 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL); | ||
234 | userauth_finish(authctxt, authenticated, "gssapi"); | ||
235 | } | ||
236 | |||
237 | Authmethod method_gssapi = { | ||
238 | "gssapi", | ||
239 | userauth_gssapi, | ||
240 | &options.gss_authentication | ||
241 | }; | ||
242 | |||
243 | #endif /* GSSAPI */ | ||