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-rw-r--r--gss-genr.c276
1 files changed, 272 insertions, 4 deletions
diff --git a/gss-genr.c b/gss-genr.c
index b39281bc1..b7d1b7dbf 100644
--- a/gss-genr.c
+++ b/gss-genr.c
@@ -1,7 +1,7 @@
1/* $OpenBSD: gss-genr.c,v 1.22 2013/11/08 00:39:15 djm Exp $ */ 1/* $OpenBSD: gss-genr.c,v 1.22 2013/11/08 00:39:15 djm Exp $ */
2 2
3/* 3/*
4 * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved. 4 * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
5 * 5 *
6 * Redistribution and use in source and binary forms, with or without 6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions 7 * modification, are permitted provided that the following conditions
@@ -39,12 +39,167 @@
39#include "buffer.h" 39#include "buffer.h"
40#include "log.h" 40#include "log.h"
41#include "ssh2.h" 41#include "ssh2.h"
42#include "cipher.h"
43#include "key.h"
44#include "kex.h"
45#include <openssl/evp.h>
42 46
43#include "ssh-gss.h" 47#include "ssh-gss.h"
44 48
45extern u_char *session_id2; 49extern u_char *session_id2;
46extern u_int session_id2_len; 50extern u_int session_id2_len;
47 51
52typedef struct {
53 char *encoded;
54 gss_OID oid;
55} ssh_gss_kex_mapping;
56
57/*
58 * XXX - It would be nice to find a more elegant way of handling the
59 * XXX passing of the key exchange context to the userauth routines
60 */
61
62Gssctxt *gss_kex_context = NULL;
63
64static ssh_gss_kex_mapping *gss_enc2oid = NULL;
65
66int
67ssh_gssapi_oid_table_ok() {
68 return (gss_enc2oid != NULL);
69}
70
71/*
72 * Return a list of the gss-group1-sha1 mechanisms supported by this program
73 *
74 * We test mechanisms to ensure that we can use them, to avoid starting
75 * a key exchange with a bad mechanism
76 */
77
78char *
79ssh_gssapi_client_mechanisms(const char *host, const char *client) {
80 gss_OID_set gss_supported;
81 OM_uint32 min_status;
82
83 if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
84 return NULL;
85
86 return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
87 host, client));
88}
89
90char *
91ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
92 const char *host, const char *client) {
93 Buffer buf;
94 size_t i;
95 int oidpos, enclen;
96 char *mechs, *encoded;
97 u_char digest[EVP_MAX_MD_SIZE];
98 char deroid[2];
99 const EVP_MD *evp_md = EVP_md5();
100 EVP_MD_CTX md;
101
102 if (gss_enc2oid != NULL) {
103 for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
104 free(gss_enc2oid[i].encoded);
105 free(gss_enc2oid);
106 }
107
108 gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
109 (gss_supported->count + 1));
110
111 buffer_init(&buf);
112
113 oidpos = 0;
114 for (i = 0; i < gss_supported->count; i++) {
115 if (gss_supported->elements[i].length < 128 &&
116 (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
117
118 deroid[0] = SSH_GSS_OIDTYPE;
119 deroid[1] = gss_supported->elements[i].length;
120
121 EVP_DigestInit(&md, evp_md);
122 EVP_DigestUpdate(&md, deroid, 2);
123 EVP_DigestUpdate(&md,
124 gss_supported->elements[i].elements,
125 gss_supported->elements[i].length);
126 EVP_DigestFinal(&md, digest, NULL);
127
128 encoded = xmalloc(EVP_MD_size(evp_md) * 2);
129 enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
130 encoded, EVP_MD_size(evp_md) * 2);
131
132 if (oidpos != 0)
133 buffer_put_char(&buf, ',');
134
135 buffer_append(&buf, KEX_GSS_GEX_SHA1_ID,
136 sizeof(KEX_GSS_GEX_SHA1_ID) - 1);
137 buffer_append(&buf, encoded, enclen);
138 buffer_put_char(&buf, ',');
139 buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID,
140 sizeof(KEX_GSS_GRP1_SHA1_ID) - 1);
141 buffer_append(&buf, encoded, enclen);
142 buffer_put_char(&buf, ',');
143 buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID,
144 sizeof(KEX_GSS_GRP14_SHA1_ID) - 1);
145 buffer_append(&buf, encoded, enclen);
146
147 gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
148 gss_enc2oid[oidpos].encoded = encoded;
149 oidpos++;
150 }
151 }
152 gss_enc2oid[oidpos].oid = NULL;
153 gss_enc2oid[oidpos].encoded = NULL;
154
155 buffer_put_char(&buf, '\0');
156
157 mechs = xmalloc(buffer_len(&buf));
158 buffer_get(&buf, mechs, buffer_len(&buf));
159 buffer_free(&buf);
160
161 if (strlen(mechs) == 0) {
162 free(mechs);
163 mechs = NULL;
164 }
165
166 return (mechs);
167}
168
169gss_OID
170ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
171 int i = 0;
172
173 switch (kex_type) {
174 case KEX_GSS_GRP1_SHA1:
175 if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
176 return GSS_C_NO_OID;
177 name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
178 break;
179 case KEX_GSS_GRP14_SHA1:
180 if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
181 return GSS_C_NO_OID;
182 name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
183 break;
184 case KEX_GSS_GEX_SHA1:
185 if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
186 return GSS_C_NO_OID;
187 name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
188 break;
189 default:
190 return GSS_C_NO_OID;
191 }
192
193 while (gss_enc2oid[i].encoded != NULL &&
194 strcmp(name, gss_enc2oid[i].encoded) != 0)
195 i++;
196
197 if (gss_enc2oid[i].oid != NULL && ctx != NULL)
198 ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
199
200 return gss_enc2oid[i].oid;
201}
202
48/* Check that the OID in a data stream matches that in the context */ 203/* Check that the OID in a data stream matches that in the context */
49int 204int
50ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len) 205ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
@@ -197,7 +352,7 @@ ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
197 } 352 }
198 353
199 ctx->major = gss_init_sec_context(&ctx->minor, 354 ctx->major = gss_init_sec_context(&ctx->minor,
200 GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid, 355 ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
201 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag, 356 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
202 0, NULL, recv_tok, NULL, send_tok, flags, NULL); 357 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
203 358
@@ -227,8 +382,42 @@ ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
227} 382}
228 383
229OM_uint32 384OM_uint32
385ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
386{
387 gss_buffer_desc gssbuf;
388 gss_name_t gssname;
389 OM_uint32 status;
390 gss_OID_set oidset;
391
392 gssbuf.value = (void *) name;
393 gssbuf.length = strlen(gssbuf.value);
394
395 gss_create_empty_oid_set(&status, &oidset);
396 gss_add_oid_set_member(&status, ctx->oid, &oidset);
397
398 ctx->major = gss_import_name(&ctx->minor, &gssbuf,
399 GSS_C_NT_USER_NAME, &gssname);
400
401 if (!ctx->major)
402 ctx->major = gss_acquire_cred(&ctx->minor,
403 gssname, 0, oidset, GSS_C_INITIATE,
404 &ctx->client_creds, NULL, NULL);
405
406 gss_release_name(&status, &gssname);
407 gss_release_oid_set(&status, &oidset);
408
409 if (ctx->major)
410 ssh_gssapi_error(ctx);
411
412 return(ctx->major);
413}
414
415OM_uint32
230ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash) 416ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
231{ 417{
418 if (ctx == NULL)
419 return -1;
420
232 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context, 421 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
233 GSS_C_QOP_DEFAULT, buffer, hash))) 422 GSS_C_QOP_DEFAULT, buffer, hash)))
234 ssh_gssapi_error(ctx); 423 ssh_gssapi_error(ctx);
@@ -236,6 +425,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
236 return (ctx->major); 425 return (ctx->major);
237} 426}
238 427
428/* Priviledged when used by server */
429OM_uint32
430ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
431{
432 if (ctx == NULL)
433 return -1;
434
435 ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
436 gssbuf, gssmic, NULL);
437
438 return (ctx->major);
439}
440
239void 441void
240ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service, 442ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
241 const char *context) 443 const char *context)
@@ -249,11 +451,16 @@ ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
249} 451}
250 452
251int 453int
252ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host) 454ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
455 const char *client)
253{ 456{
254 gss_buffer_desc token = GSS_C_EMPTY_BUFFER; 457 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
255 OM_uint32 major, minor; 458 OM_uint32 major, minor;
256 gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"}; 459 gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
460 Gssctxt *intctx = NULL;
461
462 if (ctx == NULL)
463 ctx = &intctx;
257 464
258 /* RFC 4462 says we MUST NOT do SPNEGO */ 465 /* RFC 4462 says we MUST NOT do SPNEGO */
259 if (oid->length == spnego_oid.length && 466 if (oid->length == spnego_oid.length &&
@@ -263,6 +470,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
263 ssh_gssapi_build_ctx(ctx); 470 ssh_gssapi_build_ctx(ctx);
264 ssh_gssapi_set_oid(*ctx, oid); 471 ssh_gssapi_set_oid(*ctx, oid);
265 major = ssh_gssapi_import_name(*ctx, host); 472 major = ssh_gssapi_import_name(*ctx, host);
473
474 if (!GSS_ERROR(major) && client)
475 major = ssh_gssapi_client_identity(*ctx, client);
476
266 if (!GSS_ERROR(major)) { 477 if (!GSS_ERROR(major)) {
267 major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token, 478 major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
268 NULL); 479 NULL);
@@ -272,10 +483,67 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
272 GSS_C_NO_BUFFER); 483 GSS_C_NO_BUFFER);
273 } 484 }
274 485
275 if (GSS_ERROR(major)) 486 if (GSS_ERROR(major) || intctx != NULL)
276 ssh_gssapi_delete_ctx(ctx); 487 ssh_gssapi_delete_ctx(ctx);
277 488
278 return (!GSS_ERROR(major)); 489 return (!GSS_ERROR(major));
279} 490}
280 491
492int
493ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
494 static gss_name_t saved_name = GSS_C_NO_NAME;
495 static OM_uint32 saved_lifetime = 0;
496 static gss_OID saved_mech = GSS_C_NO_OID;
497 static gss_name_t name;
498 static OM_uint32 last_call = 0;
499 OM_uint32 lifetime, now, major, minor;
500 int equal;
501 gss_cred_usage_t usage = GSS_C_INITIATE;
502
503 now = time(NULL);
504
505 if (ctxt) {
506 debug("Rekey has happened - updating saved versions");
507
508 if (saved_name != GSS_C_NO_NAME)
509 gss_release_name(&minor, &saved_name);
510
511 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
512 &saved_name, &saved_lifetime, NULL, NULL);
513
514 if (!GSS_ERROR(major)) {
515 saved_mech = ctxt->oid;
516 saved_lifetime+= now;
517 } else {
518 /* Handle the error */
519 }
520 return 0;
521 }
522
523 if (now - last_call < 10)
524 return 0;
525
526 last_call = now;
527
528 if (saved_mech == GSS_C_NO_OID)
529 return 0;
530
531 major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
532 &name, &lifetime, NULL, NULL);
533 if (major == GSS_S_CREDENTIALS_EXPIRED)
534 return 0;
535 else if (GSS_ERROR(major))
536 return 0;
537
538 major = gss_compare_name(&minor, saved_name, name, &equal);
539 gss_release_name(&minor, &name);
540 if (GSS_ERROR(major))
541 return 0;
542
543 if (equal && (saved_lifetime < lifetime + now - 10))
544 return 1;
545
546 return 0;
547}
548
281#endif /* GSSAPI */ 549#endif /* GSSAPI */