1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
#include "k5-int.h"
#include "int-proto.h"
static krb5_error_code
krb5_cc_copy_creds_except(krb5_context context, krb5_ccache incc, krb5_ccache outcc, krb5_principal princ)
{
krb5_error_code code;
krb5_flags flags;
krb5_cc_cursor cur;
krb5_creds creds;
flags = 0; /* turns off OPENCLOSE mode */
if ((code = krb5_cc_set_flags(context, incc, flags)))
return(code);
if ((code = krb5_cc_set_flags(context, outcc, flags)))
return(code);
if ((code = krb5_cc_start_seq_get(context, incc, &cur)))
goto cleanup;
while (!(code = krb5_cc_next_cred(context, incc, &cur, &creds))) {
if (krb5_principal_compare(context, princ, creds.server))
continue;
code = krb5_cc_store_cred(context, outcc, &creds);
krb5_free_cred_contents(context, &creds);
if (code)
goto cleanup;
}
if (code != KRB5_CC_END)
goto cleanup;
code = 0;
cleanup:
flags = KRB5_TC_OPENCLOSE;
if (code)
krb5_cc_set_flags(context, incc, flags);
else
code = krb5_cc_set_flags(context, incc, flags);
if (code)
krb5_cc_set_flags(context, outcc, flags);
else
code = krb5_cc_set_flags(context, outcc, flags);
return(code);
}
krb5_error_code KRB5_CALLCONV
krb5_verify_init_creds(krb5_context context,
krb5_creds *creds,
krb5_principal server_arg,
krb5_keytab keytab_arg,
krb5_ccache *ccache_arg,
krb5_verify_init_creds_opt *options)
{
krb5_error_code ret;
krb5_principal server;
krb5_keytab keytab;
krb5_ccache ccache;
krb5_keytab_entry kte;
krb5_creds in_creds, *out_creds;
krb5_auth_context authcon;
krb5_data ap_req;
/* KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN */
server = NULL;
keytab = NULL;
ccache = NULL;
out_creds = NULL;
authcon = NULL;
ap_req.data = NULL;
if (server_arg) {
server = server_arg;
} else {
if ((ret = krb5_sname_to_principal(context, NULL, NULL,
KRB5_NT_SRV_HST, &server)))
goto cleanup;
}
/* first, check if the server is in the keytab. If not, there's
no reason to continue. rd_req does all this, but there's
no way to know that a given error is caused by a missing
keytab or key, and not by some other problem. */
if (keytab_arg) {
keytab = keytab_arg;
} else {
if ((ret = krb5_kt_default(context, &keytab)))
goto cleanup;
}
if ((ret = krb5_kt_get_entry(context, keytab, server, 0, 0, &kte))) {
/* this means there is no keying material. This is ok, as long as
it is not prohibited by the configuration */
int nofail;
if (options &&
(options->flags & KRB5_VERIFY_INIT_CREDS_OPT_AP_REQ_NOFAIL)) {
if (options->ap_req_nofail)
goto cleanup;
} else if (krb5_libdefault_boolean(context,
&creds->client->realm,
"verify_ap_req_nofail",
&nofail)
== 0) {
if (nofail)
goto cleanup;
}
ret = 0;
goto cleanup;
}
krb5_kt_free_entry(context, &kte);
/* If the creds are for the server principal, we're set, just do
a mk_req. Otherwise, do a get_credentials first. */
if (krb5_principal_compare(context, server, creds->server)) {
/* make an ap_req */
if ((ret = krb5_mk_req_extended(context, &authcon, 0, NULL, creds,
&ap_req)))
goto cleanup;
} else {
/* this is unclean, but it's the easiest way without ripping the
library into very small pieces. store the client's initial cred
in a memory ccache, then call the library. Later, we'll copy
everything except the initial cred into the ccache we return to
the user. A clean implementation would involve library
internals with a coherent idea of "in" and "out". */
/* insert the initial cred into the ccache */
if ((ret = krb5_cc_resolve(context, "MEMORY:rd_req", &ccache)))
goto cleanup;
if ((ret = krb5_cc_initialize(context, ccache, creds->client)))
goto cleanup;
if ((ret = krb5_cc_store_cred(context, ccache, creds)))
goto cleanup;
/* set up for get_creds */
memset(&in_creds, 0, sizeof(in_creds));
in_creds.client = creds->client;
in_creds.server = server;
if ((ret = krb5_timeofday(context, &in_creds.times.endtime)))
goto cleanup;
in_creds.times.endtime += 5*60;
if ((ret = krb5_get_credentials(context, 0, ccache, &in_creds,
&out_creds)))
goto cleanup;
/* make an ap_req */
if ((ret = krb5_mk_req_extended(context, &authcon, 0, NULL, out_creds,
&ap_req)))
goto cleanup;
}
/* wipe the auth context for mk_req */
if (authcon) {
krb5_auth_con_free(context, authcon);
authcon = NULL;
}
/* verify the ap_req */
if ((ret = krb5_rd_req(context, &authcon, &ap_req, server, keytab,
NULL, NULL)))
goto cleanup;
/* if we get this far, then the verification succeeded. We can
still fail if the library stuff here fails, but that's it */
if (ccache_arg && ccache) {
if (*ccache_arg == NULL) {
krb5_ccache retcc;
retcc = NULL;
if ((ret = krb5_cc_resolve(context, "MEMORY:rd_req2", &retcc)) ||
(ret = krb5_cc_initialize(context, retcc, creds->client)) ||
(ret = krb5_cc_copy_creds_except(context, ccache, retcc,
creds->server))) {
if (retcc)
krb5_cc_destroy(context, retcc);
} else {
*ccache_arg = retcc;
}
} else {
ret = krb5_cc_copy_creds_except(context, ccache, *ccache_arg,
server);
}
}
/* if any of the above paths returned an errors, then ret is set
accordingly. either that, or it's zero, which is fine, too */
cleanup:
if (!server_arg && server)
krb5_free_principal(context, server);
if (!keytab_arg && keytab)
krb5_kt_close(context, keytab);
if (ccache)
krb5_cc_destroy(context, ccache);
if (out_creds)
krb5_free_creds(context, out_creds);
if (authcon)
krb5_auth_con_free(context, authcon);
if (ap_req.data)
krb5_xfree(ap_req.data);
return(ret);
}
|