diff options
Diffstat (limited to 'gss-genr.c')
-rw-r--r-- | gss-genr.c | 276 |
1 files changed, 272 insertions, 4 deletions
diff --git a/gss-genr.c b/gss-genr.c index e9190575d..c51fa727d 100644 --- a/gss-genr.c +++ b/gss-genr.c | |||
@@ -1,7 +1,7 @@ | |||
1 | /* $OpenBSD: gss-genr.c,v 1.19 2007/06/12 11:56:15 dtucker Exp $ */ | 1 | /* $OpenBSD: gss-genr.c,v 1.19 2007/06/12 11:56:15 dtucker 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 | ||
45 | extern u_char *session_id2; | 49 | extern u_char *session_id2; |
46 | extern u_int session_id2_len; | 50 | extern u_int session_id2_len; |
47 | 51 | ||
52 | typedef 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 | |||
62 | Gssctxt *gss_kex_context = NULL; | ||
63 | |||
64 | static ssh_gss_kex_mapping *gss_enc2oid = NULL; | ||
65 | |||
66 | int | ||
67 | ssh_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 | |||
78 | char * | ||
79 | ssh_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 | |||
90 | char * | ||
91 | ssh_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 | xfree(gss_enc2oid[i].encoded); | ||
105 | xfree(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 | xfree(mechs); | ||
163 | mechs = NULL; | ||
164 | } | ||
165 | |||
166 | return (mechs); | ||
167 | } | ||
168 | |||
169 | gss_OID | ||
170 | ssh_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 */ |
49 | int | 204 | int |
50 | ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len) | 205 | ssh_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 | ||
229 | OM_uint32 | 384 | OM_uint32 |
385 | ssh_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 | |||
415 | OM_uint32 | ||
230 | ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash) | 416 | ssh_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 */ | ||
429 | OM_uint32 | ||
430 | ssh_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 | |||
239 | void | 441 | void |
240 | ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service, | 442 | ssh_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 | ||
251 | int | 453 | int |
252 | ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host) | 454 | ssh_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 | ||
492 | int | ||
493 | ssh_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 */ |