xref: /freebsd/crypto/heimdal/lib/krb5/build_auth.c (revision a79b71281cd63ad7a6cc43a6d5673a2510b51630)
1 /*
2  * Copyright (c) 1997, 1998 Kungliga Tekniska H�gskolan
3  * (Royal Institute of Technology, Stockholm, Sweden).
4  * 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  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * 3. Neither the name of the Institute nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <krb5_locl.h>
35 
36 RCSID("$Id: build_auth.c,v 1.32 1999/12/02 17:05:08 joda Exp $");
37 
38 krb5_error_code
39 krb5_build_authenticator (krb5_context context,
40 			  krb5_auth_context auth_context,
41 			  krb5_enctype enctype,
42 			  krb5_creds *cred,
43 			  Checksum *cksum,
44 			  Authenticator **auth_result,
45 			  krb5_data *result)
46 {
47   Authenticator *auth;
48   u_char *buf = NULL;
49   size_t buf_size;
50   size_t len;
51   krb5_error_code ret;
52   krb5_crypto crypto;
53 
54   auth = malloc(sizeof(*auth));
55   if (auth == NULL)
56       return ENOMEM;
57 
58   memset (auth, 0, sizeof(*auth));
59   auth->authenticator_vno = 5;
60   copy_Realm(&cred->client->realm, &auth->crealm);
61   copy_PrincipalName(&cred->client->name, &auth->cname);
62 
63   {
64       int32_t sec, usec;
65 
66       krb5_us_timeofday (context, &sec, &usec);
67       auth->ctime = sec;
68       auth->cusec = usec;
69   }
70   ret = krb5_auth_con_getlocalsubkey(context, auth_context, &auth->subkey);
71   if(ret)
72       goto fail;
73 
74   if(auth->subkey == NULL) {
75       krb5_generate_subkey (context, &cred->session, &auth->subkey);
76       ret = krb5_auth_con_setlocalsubkey(context, auth_context, auth->subkey);
77       if(ret)
78 	  goto fail;
79   }
80 
81   if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
82     krb5_generate_seq_number (context,
83 			      &cred->session,
84 			      &auth_context->local_seqnumber);
85     ALLOC(auth->seq_number, 1);
86     *auth->seq_number = auth_context->local_seqnumber;
87   } else
88     auth->seq_number = NULL;
89   auth->authorization_data = NULL;
90   auth->cksum = cksum;
91 
92   /* XXX - Copy more to auth_context? */
93 
94   if (auth_context) {
95     auth_context->authenticator->ctime = auth->ctime;
96     auth_context->authenticator->cusec = auth->cusec;
97   }
98 
99   buf_size = 1024;
100   buf = malloc (buf_size);
101   if (buf == NULL) {
102       ret = ENOMEM;
103       goto fail;
104   }
105 
106   do {
107       ret = krb5_encode_Authenticator (context,
108 				       buf + buf_size - 1,
109 				       buf_size,
110 				       auth, &len);
111       if (ret) {
112 	  if (ret == ASN1_OVERFLOW) {
113 	      u_char *tmp;
114 
115 	      buf_size *= 2;
116 	      tmp = realloc (buf, buf_size);
117 	      if (tmp == NULL) {
118 		  ret = ENOMEM;
119 		  goto fail;
120 	      }
121 	      buf = tmp;
122 	  } else {
123 	      goto fail;
124 	  }
125       }
126   } while(ret == ASN1_OVERFLOW);
127 
128   ret = krb5_crypto_init(context, &cred->session, enctype, &crypto);
129   ret = krb5_encrypt (context,
130 		      crypto,
131 		      KRB5_KU_AP_REQ_AUTH,
132 		      buf + buf_size - len,
133 		      len,
134 		      result);
135   krb5_crypto_destroy(context, crypto);
136 
137   if (ret)
138       goto fail;
139 
140   free (buf);
141 
142   if (auth_result)
143     *auth_result = auth;
144   else {
145     /* Don't free the `cksum', it's allocated by the caller */
146     auth->cksum = NULL;
147     free_Authenticator (auth);
148     free (auth);
149   }
150   return ret;
151 fail:
152   free_Authenticator (auth);
153   free (auth);
154   free (buf);
155   return ret;
156 }
157