Annotation of src/usr.bin/ssh/gss-serv.c, Revision 1.17
1.17 ! djm 1: /* $OpenBSD: gss-serv.c,v 1.16 2006/03/25 22:22:43 djm 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: #include "includes.h"
28:
29: #ifdef GSSAPI
30:
31: #include "bufaux.h"
32: #include "auth.h"
33: #include "log.h"
34: #include "channels.h"
35: #include "session.h"
36: #include "servconf.h"
37: #include "xmalloc.h"
1.17 ! djm 38: #include "misc.h"
1.1 markus 39:
40: #include "ssh-gss.h"
41:
42: static ssh_gssapi_client gssapi_client =
43: { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
44: GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL}};
45:
46: ssh_gssapi_mech gssapi_null_mech =
47: { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
48:
49: #ifdef KRB5
50: extern ssh_gssapi_mech gssapi_kerberos_mech;
51: #endif
52:
53: ssh_gssapi_mech* supported_mechs[]= {
54: #ifdef KRB5
55: &gssapi_kerberos_mech,
56: #endif
57: &gssapi_null_mech,
58: };
59:
1.11 stevesk 60: /* Unprivileged */
1.1 markus 61: void
62: ssh_gssapi_supported_oids(gss_OID_set *oidset)
63: {
64: int i = 0;
65: OM_uint32 min_status;
66: int present;
67: gss_OID_set supported;
68:
69: gss_create_empty_oid_set(&min_status, oidset);
70: gss_indicate_mechs(&min_status, &supported);
71:
72: while (supported_mechs[i]->name != NULL) {
73: if (GSS_ERROR(gss_test_oid_set_member(&min_status,
74: &supported_mechs[i]->oid, supported, &present)))
75: present = 0;
76: if (present)
77: gss_add_oid_set_member(&min_status,
78: &supported_mechs[i]->oid, oidset);
79: i++;
80: }
1.15 djm 81:
82: gss_release_oid_set(&min_status, &supported);
1.1 markus 83: }
84:
85:
86: /* Wrapper around accept_sec_context
87: * Requires that the context contains:
88: * oid
89: * credentials (from ssh_gssapi_acquire_cred)
90: */
1.11 stevesk 91: /* Privileged */
1.1 markus 92: OM_uint32
93: ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *recv_tok,
94: gss_buffer_desc *send_tok, OM_uint32 *flags)
95: {
96: OM_uint32 status;
97: gss_OID mech;
98:
99: ctx->major = gss_accept_sec_context(&ctx->minor,
100: &ctx->context, ctx->creds, recv_tok,
101: GSS_C_NO_CHANNEL_BINDINGS, &ctx->client, &mech,
102: send_tok, flags, NULL, &ctx->client_creds);
103:
104: if (GSS_ERROR(ctx->major))
105: ssh_gssapi_error(ctx);
106:
107: if (ctx->client_creds)
108: debug("Received some client credentials");
109: else
110: debug("Got no client credentials");
111:
112: status = ctx->major;
113:
114: /* Now, if we're complete and we have the right flags, then
115: * we flag the user as also having been authenticated
116: */
117:
118: if (((flags == NULL) || ((*flags & GSS_C_MUTUAL_FLAG) &&
119: (*flags & GSS_C_INTEG_FLAG))) && (ctx->major == GSS_S_COMPLETE)) {
120: if (ssh_gssapi_getclient(ctx, &gssapi_client))
121: fatal("Couldn't convert client name");
122: }
123:
124: return (status);
125: }
126:
127: /*
128: * This parses an exported name, extracting the mechanism specific portion
129: * to use for ACL checking. It verifies that the name belongs the mechanism
130: * originally selected.
131: */
132: static OM_uint32
133: ssh_gssapi_parse_ename(Gssctxt *ctx, gss_buffer_t ename, gss_buffer_t name)
134: {
1.6 djm 135: u_char *tok;
1.1 markus 136: OM_uint32 offset;
137: OM_uint32 oidl;
1.3 markus 138:
1.13 stevesk 139: tok = ename->value;
1.3 markus 140:
141: /*
142: * Check that ename is long enough for all of the fixed length
1.1 markus 143: * header, and that the initial ID bytes are correct
144: */
145:
1.13 stevesk 146: if (ename->length < 6 || memcmp(tok, "\x04\x01", 2) != 0)
1.1 markus 147: return GSS_S_FAILURE;
148:
149: /*
150: * Extract the OID, and check it. Here GSSAPI breaks with tradition
151: * and does use the OID type and length bytes. To confuse things
152: * there are two lengths - the first including these, and the
153: * second without.
154: */
155:
1.17 ! djm 156: oidl = get_u16(tok+2); /* length including next two bytes */
1.1 markus 157: oidl = oidl-2; /* turn it into the _real_ length of the variable OID */
158:
159: /*
160: * Check the BER encoding for correct type and length, that the
161: * string is long enough and that the OID matches that in our context
162: */
163: if (tok[4] != 0x06 || tok[5] != oidl ||
1.3 markus 164: ename->length < oidl+6 ||
1.13 stevesk 165: !ssh_gssapi_check_oid(ctx, tok+6, oidl))
1.1 markus 166: return GSS_S_FAILURE;
167:
168: offset = oidl+6;
1.3 markus 169:
1.1 markus 170: if (ename->length < offset+4)
171: return GSS_S_FAILURE;
1.3 markus 172:
1.17 ! djm 173: name->length = get_u32(tok+offset);
1.1 markus 174: offset += 4;
1.3 markus 175:
1.1 markus 176: if (ename->length < offset+name->length)
1.3 markus 177: return GSS_S_FAILURE;
178:
1.2 markus 179: name->value = xmalloc(name->length+1);
1.14 stevesk 180: memcpy(name->value, tok+offset, name->length);
1.2 markus 181: ((char *)name->value)[name->length] = 0;
182:
1.1 markus 183: return GSS_S_COMPLETE;
1.3 markus 184: }
1.1 markus 185:
186: /* Extract the client details from a given context. This can only reliably
187: * be called once for a context */
188:
1.11 stevesk 189: /* Privileged (called from accept_secure_ctx) */
1.1 markus 190: OM_uint32
191: ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
192: {
193: int i = 0;
194:
195: gss_buffer_desc ename;
1.3 markus 196:
1.1 markus 197: client->mech = NULL;
198:
199: while (supported_mechs[i]->name != NULL) {
200: if (supported_mechs[i]->oid.length == ctx->oid->length &&
201: (memcmp(supported_mechs[i]->oid.elements,
202: ctx->oid->elements, ctx->oid->length) == 0))
203: client->mech = supported_mechs[i];
204: i++;
205: }
206:
1.3 markus 207: if (client->mech == NULL)
1.1 markus 208: return GSS_S_FAILURE;
1.3 markus 209:
210: if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
1.1 markus 211: &client->displayname, NULL))) {
1.3 markus 212: ssh_gssapi_error(ctx);
213: return (ctx->major);
1.1 markus 214: }
1.3 markus 215:
216: if ((ctx->major = gss_export_name(&ctx->minor, ctx->client,
1.1 markus 217: &ename))) {
218: ssh_gssapi_error(ctx);
219: return (ctx->major);
220: }
1.3 markus 221:
1.1 markus 222: if ((ctx->major = ssh_gssapi_parse_ename(ctx,&ename,
223: &client->exportedname))) {
224: return (ctx->major);
225: }
226:
227: /* We can't copy this structure, so we just move the pointer to it */
228: client->creds = ctx->client_creds;
229: ctx->client_creds = GSS_C_NO_CREDENTIAL;
230: return (ctx->major);
231: }
232:
1.4 markus 233: /* As user - called on fatal/exit */
1.1 markus 234: void
1.4 markus 235: ssh_gssapi_cleanup_creds(void)
1.1 markus 236: {
237: if (gssapi_client.store.filename != NULL) {
238: /* Unlink probably isn't sufficient */
1.14 stevesk 239: debug("removing gssapi cred file\"%s\"",
240: gssapi_client.store.filename);
1.1 markus 241: unlink(gssapi_client.store.filename);
242: }
243: }
244:
245: /* As user */
246: void
247: ssh_gssapi_storecreds(void)
248: {
249: if (gssapi_client.mech && gssapi_client.mech->storecreds) {
250: (*gssapi_client.mech->storecreds)(&gssapi_client);
251: } else
252: debug("ssh_gssapi_storecreds: Not a GSSAPI mechanism");
253: }
254:
255: /* This allows GSSAPI methods to do things to the childs environment based
256: * on the passed authentication process and credentials.
257: */
258: /* As user */
259: void
260: ssh_gssapi_do_child(char ***envp, u_int *envsizep)
261: {
262:
263: if (gssapi_client.store.envvar != NULL &&
264: gssapi_client.store.envval != NULL) {
265: debug("Setting %s to %s", gssapi_client.store.envvar,
1.13 stevesk 266: gssapi_client.store.envval);
1.1 markus 267: child_set_env(envp, envsizep, gssapi_client.store.envvar,
1.7 djm 268: gssapi_client.store.envval);
1.1 markus 269: }
270: }
271:
1.9 djm 272: /* Privileged */
1.1 markus 273: int
274: ssh_gssapi_userok(char *user)
275: {
1.8 djm 276: OM_uint32 lmin;
277:
1.1 markus 278: if (gssapi_client.exportedname.length == 0 ||
279: gssapi_client.exportedname.value == NULL) {
280: debug("No suitable client data");
281: return 0;
282: }
283: if (gssapi_client.mech && gssapi_client.mech->userok)
1.8 djm 284: if ((*gssapi_client.mech->userok)(&gssapi_client, user))
285: return 1;
286: else {
287: /* Destroy delegated credentials if userok fails */
288: gss_release_buffer(&lmin, &gssapi_client.displayname);
289: gss_release_buffer(&lmin, &gssapi_client.exportedname);
290: gss_release_cred(&lmin, &gssapi_client.creds);
291: memset(&gssapi_client, 0, sizeof(ssh_gssapi_client));
292: return 0;
293: }
1.1 markus 294: else
295: debug("ssh_gssapi_userok: Unknown GSSAPI mechanism");
296: return (0);
1.5 markus 297: }
298:
1.11 stevesk 299: /* Privileged */
1.5 markus 300: OM_uint32
301: ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
302: {
303: ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
304: gssbuf, gssmic, NULL);
305:
306: return (ctx->major);
1.1 markus 307: }
308:
309: #endif
![[BACK]](/icons/back.gif){kind=icon}
Return to gss-serv.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh