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
|
/*
* gssapi.c -- GSSAPI authentication (see RFC 1508)
*
* For license terms, see the file COPYING in this directory.
*/
#include "config.h"
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#if defined(STDC_HEADERS)
#include <stdlib.h>
#endif
#include "fetchmail.h"
#include "socket.h"
#include "i18n.h"
#include "md5.h"
#include <sys/types.h>
#include <netinet/in.h> /* for htonl/ntohl */
#ifdef GSSAPI
# ifdef HAVE_GSS_H
# include <gss.h>
# else
# ifdef HAVE_GSSAPI_H
# include <gssapi.h>
# endif
# ifdef HAVE_GSSAPI_GSSAPI_H
# include <gssapi/gssapi.h>
# endif
# ifdef HAVE_GSSAPI_GSSAPI_GENERIC_H
# include <gssapi/gssapi_generic.h>
# endif
# ifndef HAVE_GSS_C_NT_HOSTBASED_SERVICE
# define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
# endif
# endif
#define GSSAUTH_P_NONE 1
#define GSSAUTH_P_INTEGRITY 2
#define GSSAUTH_P_PRIVACY 4
int do_gssauth(int sock, char *command, char *service, char *hostname, char *username)
{
gss_buffer_desc request_buf, send_token;
gss_buffer_t sec_token;
gss_name_t target_name;
gss_ctx_id_t context;
gss_OID mech_name;
gss_qop_t quality;
int cflags;
OM_uint32 maj_stat, min_stat;
char buf1[8192], buf2[8192], server_conf_flags;
unsigned long buf_size;
int result;
/* first things first: get an imap ticket for host */
sprintf(buf1, "%s@%s", service, hostname);
request_buf.value = buf1;
request_buf.length = strlen(buf1) + 1;
maj_stat = gss_import_name(&min_stat, &request_buf, GSS_C_NT_HOSTBASED_SERVICE,
&target_name);
if (maj_stat != GSS_S_COMPLETE) {
report(stderr, GT_("Couldn't get service name for [%s]\n"), buf1);
return PS_AUTHFAIL;
}
else if (outlevel >= O_DEBUG) {
maj_stat = gss_display_name(&min_stat, target_name, &request_buf,
&mech_name);
report(stderr, GT_("Using service name [%s]\n"),request_buf.value);
maj_stat = gss_release_buffer(&min_stat, &request_buf);
}
gen_send(sock, "%s GSSAPI", command);
/* upon receipt of the GSSAPI authentication request, server returns
* null data ready response. */
if (result = gen_recv(sock, buf1, sizeof buf1)) {
return result;
}
/* now start the security context initialisation loop... */
sec_token = GSS_C_NO_BUFFER;
context = GSS_C_NO_CONTEXT;
if (outlevel >= O_VERBOSE)
report(stdout, GT_("Sending credentials\n"));
do {
send_token.length = 0;
send_token.value = NULL;
maj_stat = gss_init_sec_context(&min_stat,
GSS_C_NO_CREDENTIAL,
&context,
target_name,
GSS_C_NO_OID,
GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG,
0,
GSS_C_NO_CHANNEL_BINDINGS,
sec_token,
NULL,
&send_token,
NULL,
NULL);
if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
report(stderr, GT_("Error exchanging credentials\n"));
gss_release_name(&min_stat, &target_name);
/* wake up server and await NO response */
SockWrite(sock, "\r\n", 2);
if (result = gen_recv(sock, buf1, sizeof buf1))
return result;
return PS_AUTHFAIL;
}
to64frombits(buf1, send_token.value, send_token.length);
gss_release_buffer(&min_stat, &send_token);
suppress_tags = TRUE;
gen_send(sock, buf1, strlen(buf1));
suppress_tags = FALSE;
if (maj_stat == GSS_S_CONTINUE_NEEDED) {
if (result = gen_recv(sock, buf1, sizeof buf1)) {
gss_release_name(&min_stat, &target_name);
return result;
}
request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
if (request_buf.length == -1) /* in case of bad data */
request_buf.length = 0;
request_buf.value = buf2;
sec_token = &request_buf;
}
} while
(maj_stat == GSS_S_CONTINUE_NEEDED);
gss_release_name(&min_stat, &target_name);
/* get security flags and buffer size */
if (result = gen_recv(sock, buf1, sizeof buf1))
return result;
request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
if (request_buf.length == -1) /* in case of bad data */
request_buf.length = 0;
request_buf.value = buf2;
maj_stat = gss_unwrap(&min_stat, context,
&request_buf, &send_token, &cflags, &quality);
if (maj_stat != GSS_S_COMPLETE) {
report(stderr, GT_("Couldn't unwrap security level data\n"));
gss_release_buffer(&min_stat, &send_token);
return PS_AUTHFAIL;
}
if (outlevel >= O_DEBUG)
report(stdout, GT_("Credential exchange complete\n"));
/* first octet is security levels supported. We want none, for now */
server_conf_flags = ((char *)send_token.value)[0];
if ( !(((char *)send_token.value)[0] & GSSAUTH_P_NONE) ) {
report(stderr, GT_("Server requires integrity and/or privacy\n"));
gss_release_buffer(&min_stat, &send_token);
return PS_AUTHFAIL;
}
((char *)send_token.value)[0] = 0;
buf_size = ntohl(*((long *)send_token.value));
/* we don't care about buffer size if we don't wrap data */
gss_release_buffer(&min_stat, &send_token);
if (outlevel >= O_DEBUG) {
report(stdout, GT_("Unwrapped security level flags: %s%s%s\n"),
server_conf_flags & GSSAUTH_P_NONE ? "N" : "-",
server_conf_flags & GSSAUTH_P_INTEGRITY ? "I" : "-",
server_conf_flags & GSSAUTH_P_PRIVACY ? "C" : "-");
report(stdout, GT_("Maximum GSS token size is %ld\n"),buf_size);
}
/* now respond in kind (hack!!!) */
buf_size = htonl(buf_size); /* do as they do... only matters if we do enc */
memcpy(buf1, &buf_size, 4);
buf1[0] = GSSAUTH_P_NONE;
strcpy(buf1+4, username); /* server decides if princ is user */
request_buf.length = 4 + strlen(username) + 1;
request_buf.value = buf1;
maj_stat = gss_wrap(&min_stat, context, 0, GSS_C_QOP_DEFAULT, &request_buf,
&cflags, &send_token);
if (maj_stat != GSS_S_COMPLETE) {
report(stderr, GT_("Error creating security level request\n"));
return PS_AUTHFAIL;
}
to64frombits(buf1, send_token.value, send_token.length);
suppress_tags = TRUE;
result = gen_transact(sock, buf1, strlen(buf1));
suppress_tags = FALSE;
/* flush security context */
if (outlevel >= O_DEBUG)
report(stdout, GT_("Releasing GSS credentials\n"));
maj_stat = gss_delete_sec_context(&min_stat, &context, &send_token);
if (maj_stat != GSS_S_COMPLETE) {
report(stderr, GT_("Error releasing credentials\n"));
return PS_AUTHFAIL;
}
/* send_token may contain a notification to the server to flush
* credentials. RFC 1731 doesn't specify what to do, and since this
* support is only for authentication, we'll assume the server
* knows enough to flush its own credentials */
gss_release_buffer(&min_stat, &send_token);
if (result)
return(result);
else
return(PS_SUCCESS);
}
#endif /* GSSAPI */
/* gssapi.c ends here */
|
