Annotation of src/usr.bin/ssh/gss-genr.c, Revision 1.13
1.13 ! deraadt 1: /* $OpenBSD: gss-genr.c,v 1.12 2006/07/26 02:35:17 stevesk Exp $ */
1.1 markus 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: #ifdef GSSAPI
1.12 stevesk 28:
29: #include <sys/param.h>
1.11 stevesk 30:
31: #include <string.h>
1.13 ! deraadt 32: #include <stdarg.h>
1.1 markus 33:
34: #include "xmalloc.h"
1.13 ! deraadt 35: #include "buffer.h"
1.1 markus 36: #include "log.h"
1.2 markus 37: #include "ssh2.h"
1.1 markus 38:
39: #include "ssh-gss.h"
40:
1.2 markus 41: extern u_char *session_id2;
42: extern u_int session_id2_len;
1.1 markus 43:
44: /* Check that the OID in a data stream matches that in the context */
45: int
46: ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
47: {
48: return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
49: ctx->oid->length == len &&
50: memcmp(ctx->oid->elements, data, len) == 0);
51: }
52:
53: /* Set the contexts OID from a data stream */
54: void
55: ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
56: {
57: if (ctx->oid != GSS_C_NO_OID) {
58: xfree(ctx->oid->elements);
59: xfree(ctx->oid);
60: }
61: ctx->oid = xmalloc(sizeof(gss_OID_desc));
62: ctx->oid->length = len;
63: ctx->oid->elements = xmalloc(len);
64: memcpy(ctx->oid->elements, data, len);
65: }
66:
67: /* Set the contexts OID */
68: void
69: ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
70: {
71: ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
72: }
73:
74: /* All this effort to report an error ... */
75: void
76: ssh_gssapi_error(Gssctxt *ctxt)
77: {
1.7 djm 78: char *s;
79:
80: s = ssh_gssapi_last_error(ctxt, NULL, NULL);
81: debug("%s", s);
82: xfree(s);
1.1 markus 83: }
84:
85: char *
1.4 djm 86: ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
87: OM_uint32 *minor_status)
1.1 markus 88: {
89: OM_uint32 lmin;
90: gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
91: OM_uint32 ctx;
92: Buffer b;
93: char *ret;
94:
95: buffer_init(&b);
96:
97: if (major_status != NULL)
98: *major_status = ctxt->major;
99: if (minor_status != NULL)
100: *minor_status = ctxt->minor;
101:
102: ctx = 0;
103: /* The GSSAPI error */
104: do {
105: gss_display_status(&lmin, ctxt->major,
106: GSS_C_GSS_CODE, GSS_C_NULL_OID, &ctx, &msg);
107:
108: buffer_append(&b, msg.value, msg.length);
109: buffer_put_char(&b, '\n');
110:
111: gss_release_buffer(&lmin, &msg);
112: } while (ctx != 0);
113:
114: /* The mechanism specific error */
115: do {
116: gss_display_status(&lmin, ctxt->minor,
117: GSS_C_MECH_CODE, GSS_C_NULL_OID, &ctx, &msg);
118:
119: buffer_append(&b, msg.value, msg.length);
120: buffer_put_char(&b, '\n');
121:
122: gss_release_buffer(&lmin, &msg);
123: } while (ctx != 0);
124:
125: buffer_put_char(&b, '\0');
126: ret = xmalloc(buffer_len(&b));
127: buffer_get(&b, ret, buffer_len(&b));
128: buffer_free(&b);
129: return (ret);
130: }
131:
132: /*
133: * Initialise our GSSAPI context. We use this opaque structure to contain all
134: * of the data which both the client and server need to persist across
135: * {accept,init}_sec_context calls, so that when we do it from the userauth
136: * stuff life is a little easier
137: */
138: void
139: ssh_gssapi_build_ctx(Gssctxt **ctx)
140: {
1.8 djm 141: *ctx = xcalloc(1, sizeof (Gssctxt));
1.1 markus 142: (*ctx)->context = GSS_C_NO_CONTEXT;
143: (*ctx)->name = GSS_C_NO_NAME;
144: (*ctx)->oid = GSS_C_NO_OID;
145: (*ctx)->creds = GSS_C_NO_CREDENTIAL;
146: (*ctx)->client = GSS_C_NO_NAME;
147: (*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
148: }
149:
150: /* Delete our context, providing it has been built correctly */
151: void
152: ssh_gssapi_delete_ctx(Gssctxt **ctx)
153: {
154: OM_uint32 ms;
155:
156: if ((*ctx) == NULL)
157: return;
158: if ((*ctx)->context != GSS_C_NO_CONTEXT)
159: gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
160: if ((*ctx)->name != GSS_C_NO_NAME)
161: gss_release_name(&ms, &(*ctx)->name);
162: if ((*ctx)->oid != GSS_C_NO_OID) {
163: xfree((*ctx)->oid->elements);
164: xfree((*ctx)->oid);
165: (*ctx)->oid = GSS_C_NO_OID;
166: }
167: if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
168: gss_release_cred(&ms, &(*ctx)->creds);
169: if ((*ctx)->client != GSS_C_NO_NAME)
170: gss_release_name(&ms, &(*ctx)->client);
171: if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
172: gss_release_cred(&ms, &(*ctx)->client_creds);
173:
174: xfree(*ctx);
175: *ctx = NULL;
176: }
177:
178: /*
179: * Wrapper to init_sec_context
180: * Requires that the context contains:
181: * oid
182: * server name (from ssh_gssapi_import_name)
183: */
184: OM_uint32
185: ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
186: gss_buffer_desc* send_tok, OM_uint32 *flags)
187: {
188: int deleg_flag = 0;
189:
190: if (deleg_creds) {
191: deleg_flag = GSS_C_DELEG_FLAG;
192: debug("Delegating credentials");
193: }
194:
195: ctx->major = gss_init_sec_context(&ctx->minor,
196: GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
197: GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
198: 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
199:
200: if (GSS_ERROR(ctx->major))
201: ssh_gssapi_error(ctx);
202:
203: return (ctx->major);
204: }
205:
206: /* Create a service name for the given host */
207: OM_uint32
208: ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
209: {
210: gss_buffer_desc gssbuf;
1.10 djm 211: char *val;
1.1 markus 212:
1.10 djm 213: xasprintf(&val, "host@%s", host);
214: gssbuf.value = val;
215: gssbuf.length = strlen(gssbuf.value);
1.1 markus 216:
217: if ((ctx->major = gss_import_name(&ctx->minor,
218: &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
219: ssh_gssapi_error(ctx);
220:
221: xfree(gssbuf.value);
222: return (ctx->major);
223: }
224:
225: /* Acquire credentials for a server running on the current host.
226: * Requires that the context structure contains a valid OID
227: */
228:
229: /* Returns a GSSAPI error code */
230: OM_uint32
231: ssh_gssapi_acquire_cred(Gssctxt *ctx)
232: {
233: OM_uint32 status;
234: char lname[MAXHOSTNAMELEN];
235: gss_OID_set oidset;
236:
237: gss_create_empty_oid_set(&status, &oidset);
238: gss_add_oid_set_member(&status, ctx->oid, &oidset);
239:
1.7 djm 240: if (gethostname(lname, MAXHOSTNAMELEN)) {
241: gss_release_oid_set(&status, &oidset);
1.1 markus 242: return (-1);
1.7 djm 243: }
1.1 markus 244:
1.7 djm 245: if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname))) {
246: gss_release_oid_set(&status, &oidset);
1.1 markus 247: return (ctx->major);
1.7 djm 248: }
1.1 markus 249:
250: if ((ctx->major = gss_acquire_cred(&ctx->minor,
251: ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
252: ssh_gssapi_error(ctx);
253:
254: gss_release_oid_set(&status, &oidset);
255: return (ctx->major);
1.2 markus 256: }
257:
258: OM_uint32
259: ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
260: {
261: if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
262: GSS_C_QOP_DEFAULT, buffer, hash)))
263: ssh_gssapi_error(ctx);
1.3 djm 264:
1.2 markus 265: return (ctx->major);
266: }
267:
268: void
1.3 djm 269: ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service,
270: const char *context)
271: {
1.2 markus 272: buffer_init(b);
273: buffer_put_string(b, session_id2, session_id2_len);
274: buffer_put_char(b, SSH2_MSG_USERAUTH_REQUEST);
275: buffer_put_cstring(b, user);
276: buffer_put_cstring(b, service);
277: buffer_put_cstring(b, context);
1.1 markus 278: }
279:
280: OM_uint32
1.6 stevesk 281: ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
282: {
1.1 markus 283: if (*ctx)
284: ssh_gssapi_delete_ctx(ctx);
285: ssh_gssapi_build_ctx(ctx);
286: ssh_gssapi_set_oid(*ctx, oid);
287: return (ssh_gssapi_acquire_cred(*ctx));
288: }
289:
290: #endif /* GSSAPI */
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