diff options
author | Colin Watson <cjwatson@debian.org> | 2009-12-29 20:42:47 +0000 |
---|---|---|
committer | Colin Watson <cjwatson@debian.org> | 2009-12-29 20:42:47 +0000 |
commit | 9ad7b718d42e43f3a285fcbc8f91193931fce324 (patch) | |
tree | 95afe9b315fb73da54752d5bb71c682485b2d370 /kexgsss.c | |
parent | 5d05471f6657646d1d6500c7c43134462c407ee6 (diff) |
import openssh-4.0p1-gssapikex.patch
Diffstat (limited to 'kexgsss.c')
-rw-r--r-- | kexgsss.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/kexgsss.c b/kexgsss.c new file mode 100644 index 000000000..80c133ac9 --- /dev/null +++ b/kexgsss.c | |||
@@ -0,0 +1,204 @@ | |||
1 | /* | ||
2 | * Copyright (c) 2001-2004 Simon Wilkinson. 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. | ||
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 | */ | ||
24 | |||
25 | #include "includes.h" | ||
26 | |||
27 | #ifdef GSSAPI | ||
28 | |||
29 | #include <openssl/crypto.h> | ||
30 | #include <openssl/bn.h> | ||
31 | |||
32 | #include "xmalloc.h" | ||
33 | #include "buffer.h" | ||
34 | #include "bufaux.h" | ||
35 | #include "kex.h" | ||
36 | #include "log.h" | ||
37 | #include "packet.h" | ||
38 | #include "dh.h" | ||
39 | #include "ssh2.h" | ||
40 | #include "ssh-gss.h" | ||
41 | #include "monitor_wrap.h" | ||
42 | |||
43 | void | ||
44 | kexgss_server(Kex *kex) | ||
45 | { | ||
46 | OM_uint32 maj_status, min_status; | ||
47 | |||
48 | /* | ||
49 | * Some GSSAPI implementations use the input value of ret_flags (an | ||
50 | * output variable) as a means of triggering mechanism specific | ||
51 | * features. Initializing it to zero avoids inadvertently | ||
52 | * activating this non-standard behaviour. | ||
53 | */ | ||
54 | |||
55 | OM_uint32 ret_flags = 0; | ||
56 | gss_buffer_desc gssbuf, send_tok, recv_tok, msg_tok; | ||
57 | Gssctxt *ctxt = NULL; | ||
58 | unsigned int klen, kout; | ||
59 | unsigned char *kbuf, *hash; | ||
60 | DH *dh; | ||
61 | BIGNUM *shared_secret = NULL; | ||
62 | BIGNUM *dh_client_pub = NULL; | ||
63 | int type =0; | ||
64 | u_int slen; | ||
65 | gss_OID oid; | ||
66 | |||
67 | /* Initialise GSSAPI */ | ||
68 | |||
69 | debug2("%s: Identifying %s", __func__, kex->name); | ||
70 | oid = ssh_gssapi_id_kex(NULL, kex->name); | ||
71 | if (oid == NULL) | ||
72 | fatal("Unknown gssapi mechanism"); | ||
73 | |||
74 | debug2("%s: Acquiring credentials", __func__); | ||
75 | |||
76 | if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid)))) | ||
77 | fatal("Unable to acquire credentials for the server"); | ||
78 | |||
79 | do { | ||
80 | debug("Wait SSH2_MSG_GSSAPI_INIT"); | ||
81 | type = packet_read(); | ||
82 | switch(type) { | ||
83 | case SSH2_MSG_KEXGSS_INIT: | ||
84 | if (dh_client_pub != NULL) | ||
85 | fatal("Received KEXGSS_INIT after initialising"); | ||
86 | recv_tok.value = packet_get_string(&slen); | ||
87 | recv_tok.length = slen; | ||
88 | |||
89 | dh_client_pub = BN_new(); | ||
90 | |||
91 | if (dh_client_pub == NULL) | ||
92 | fatal("dh_client_pub == NULL"); | ||
93 | packet_get_bignum2(dh_client_pub); | ||
94 | |||
95 | /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */ | ||
96 | break; | ||
97 | case SSH2_MSG_KEXGSS_CONTINUE: | ||
98 | recv_tok.value = packet_get_string(&slen); | ||
99 | recv_tok.length = slen; | ||
100 | break; | ||
101 | default: | ||
102 | packet_disconnect( | ||
103 | "Protocol error: didn't expect packet type %d", | ||
104 | type); | ||
105 | } | ||
106 | |||
107 | maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok, | ||
108 | &send_tok, &ret_flags)); | ||
109 | |||
110 | gss_release_buffer(&min_status, &recv_tok); | ||
111 | |||
112 | if (maj_status != GSS_S_COMPLETE && send_tok.length == 0) | ||
113 | fatal("Zero length token output when incomplete"); | ||
114 | |||
115 | if (dh_client_pub == NULL) | ||
116 | fatal("No client public key"); | ||
117 | |||
118 | if (maj_status & GSS_S_CONTINUE_NEEDED) { | ||
119 | debug("Sending GSSAPI_CONTINUE"); | ||
120 | packet_start(SSH2_MSG_KEXGSS_CONTINUE); | ||
121 | packet_put_string(send_tok.value, send_tok.length); | ||
122 | packet_send(); | ||
123 | gss_release_buffer(&min_status, &send_tok); | ||
124 | } | ||
125 | } while (maj_status & GSS_S_CONTINUE_NEEDED); | ||
126 | |||
127 | if (GSS_ERROR(maj_status)) { | ||
128 | if (send_tok.length>0) { | ||
129 | packet_start(SSH2_MSG_KEXGSS_CONTINUE); | ||
130 | packet_put_string(send_tok.value, send_tok.length); | ||
131 | packet_send(); | ||
132 | } | ||
133 | fatal("accept_ctx died"); | ||
134 | } | ||
135 | |||
136 | if (!(ret_flags & GSS_C_MUTUAL_FLAG)) | ||
137 | fatal("Mutual Authentication flag wasn't set"); | ||
138 | |||
139 | if (!(ret_flags & GSS_C_INTEG_FLAG)) | ||
140 | fatal("Integrity flag wasn't set"); | ||
141 | |||
142 | dh = dh_new_group1(); | ||
143 | dh_gen_key(dh, kex->we_need * 8); | ||
144 | |||
145 | if (!dh_pub_is_valid(dh, dh_client_pub)) | ||
146 | packet_disconnect("bad client public DH value"); | ||
147 | |||
148 | klen = DH_size(dh); | ||
149 | kbuf = xmalloc(klen); | ||
150 | kout = DH_compute_key(kbuf, dh_client_pub, dh); | ||
151 | |||
152 | shared_secret = BN_new(); | ||
153 | BN_bin2bn(kbuf, kout, shared_secret); | ||
154 | memset(kbuf, 0, klen); | ||
155 | xfree(kbuf); | ||
156 | |||
157 | /* The GSSAPI hash is identical to the Diffie Helman one */ | ||
158 | hash = kex_dh_hash( | ||
159 | kex->client_version_string, kex->server_version_string, | ||
160 | buffer_ptr(&kex->peer), buffer_len(&kex->peer), | ||
161 | buffer_ptr(&kex->my), buffer_len(&kex->my), | ||
162 | NULL, 0, /* Change this if we start sending host keys */ | ||
163 | dh_client_pub, dh->pub_key, shared_secret | ||
164 | ); | ||
165 | BN_free(dh_client_pub); | ||
166 | |||
167 | if (kex->session_id == NULL) { | ||
168 | kex->session_id_len = 20; | ||
169 | kex->session_id = xmalloc(kex->session_id_len); | ||
170 | memcpy(kex->session_id, hash, kex->session_id_len); | ||
171 | } | ||
172 | |||
173 | gssbuf.value = hash; | ||
174 | gssbuf.length = 20; /* Hashlen appears to always be 20 */ | ||
175 | |||
176 | if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt,&gssbuf,&msg_tok)))) | ||
177 | fatal("Couldn't get MIC"); | ||
178 | |||
179 | packet_start(SSH2_MSG_KEXGSS_COMPLETE); | ||
180 | packet_put_bignum2(dh->pub_key); | ||
181 | packet_put_string((char *)msg_tok.value,msg_tok.length); | ||
182 | |||
183 | if (send_tok.length!=0) { | ||
184 | packet_put_char(1); /* true */ | ||
185 | packet_put_string((char *)send_tok.value, send_tok.length); | ||
186 | } else { | ||
187 | packet_put_char(0); /* false */ | ||
188 | } | ||
189 | packet_send(); | ||
190 | |||
191 | gss_release_buffer(&min_status, &send_tok); | ||
192 | |||
193 | if (gss_kex_context == NULL) | ||
194 | gss_kex_context = ctxt; | ||
195 | else | ||
196 | ssh_gssapi_delete_ctx(&ctxt); | ||
197 | |||
198 | DH_free(dh); | ||
199 | |||
200 | kex_derive_keys(kex, hash, shared_secret); | ||
201 | BN_clear_free(shared_secret); | ||
202 | kex_finish(kex); | ||
203 | } | ||
204 | #endif /* GSSAPI */ | ||