2 * gssapi.c -- GSSAPI authentication (see RFC 1508)
4 * For license terms, see the file COPYING in this directory.
11 #if defined(STDC_HEADERS)
14 #include "fetchmail.h"
20 #include <sys/types.h>
21 #include <netinet/in.h> /* for htonl/ntohl */
30 # ifdef HAVE_GSSAPI_GSSAPI_H
31 # include <gssapi/gssapi.h>
33 # ifdef HAVE_GSSAPI_GSSAPI_GENERIC_H
34 # include <gssapi/gssapi_generic.h>
36 # ifndef HAVE_GSS_C_NT_HOSTBASED_SERVICE
37 # define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
41 #define GSSAUTH_P_NONE 1
42 #define GSSAUTH_P_INTEGRITY 2
43 #define GSSAUTH_P_PRIVACY 4
45 int do_gssauth(int sock, char *command, char *service, char *hostname, char *username)
47 gss_buffer_desc request_buf, send_token;
48 gss_buffer_t sec_token;
49 gss_name_t target_name;
54 OM_uint32 maj_stat, min_stat;
55 char buf1[8192], buf2[8192], server_conf_flags;
56 unsigned long buf_size;
59 /* first things first: get an imap ticket for host */
60 snprintf(buf1, sizeof(buf1), "%s@%s", service, hostname);
61 request_buf.value = buf1;
62 request_buf.length = strlen(buf1) + 1;
63 maj_stat = gss_import_name(&min_stat, &request_buf, GSS_C_NT_HOSTBASED_SERVICE,
65 if (maj_stat != GSS_S_COMPLETE) {
66 report(stderr, GT_("Couldn't get service name for [%s]\n"), buf1);
69 else if (outlevel >= O_DEBUG) {
70 maj_stat = gss_display_name(&min_stat, target_name, &request_buf,
72 report(stderr, GT_("Using service name [%s]\n"),request_buf.value);
73 maj_stat = gss_release_buffer(&min_stat, &request_buf);
76 gen_send(sock, "%s GSSAPI", command);
78 /* upon receipt of the GSSAPI authentication request, server returns
79 * null data ready response. */
80 if (result = gen_recv(sock, buf1, sizeof buf1)) {
84 /* now start the security context initialisation loop... */
85 sec_token = GSS_C_NO_BUFFER;
86 context = GSS_C_NO_CONTEXT;
87 if (outlevel >= O_VERBOSE)
88 report(stdout, GT_("Sending credentials\n"));
90 send_token.length = 0;
91 send_token.value = NULL;
92 maj_stat = gss_init_sec_context(&min_stat,
97 GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG,
99 GSS_C_NO_CHANNEL_BINDINGS,
105 if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
106 report(stderr, GT_("Error exchanging credentials\n"));
107 gss_release_name(&min_stat, &target_name);
108 /* wake up server and await NO response */
109 SockWrite(sock, "\r\n", 2);
110 if (result = gen_recv(sock, buf1, sizeof buf1))
114 to64frombits(buf1, send_token.value, send_token.length);
115 gss_release_buffer(&min_stat, &send_token);
117 suppress_tags = TRUE;
118 gen_send(sock, buf1, strlen(buf1));
119 suppress_tags = FALSE;
121 if (maj_stat == GSS_S_CONTINUE_NEEDED) {
122 if (result = gen_recv(sock, buf1, sizeof buf1)) {
123 gss_release_name(&min_stat, &target_name);
126 request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
127 if (request_buf.length == -1) /* in case of bad data */
128 request_buf.length = 0;
129 request_buf.value = buf2;
130 sec_token = &request_buf;
133 (maj_stat == GSS_S_CONTINUE_NEEDED);
134 gss_release_name(&min_stat, &target_name);
136 /* get security flags and buffer size */
137 if (result = gen_recv(sock, buf1, sizeof buf1))
140 request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
141 if (request_buf.length == -1) /* in case of bad data */
142 request_buf.length = 0;
143 request_buf.value = buf2;
145 maj_stat = gss_unwrap(&min_stat, context,
146 &request_buf, &send_token, &cflags, &quality);
147 if (maj_stat != GSS_S_COMPLETE) {
148 report(stderr, GT_("Couldn't unwrap security level data\n"));
149 gss_release_buffer(&min_stat, &send_token);
152 if (outlevel >= O_DEBUG)
153 report(stdout, GT_("Credential exchange complete\n"));
154 /* first octet is security levels supported. We want none, for now */
155 server_conf_flags = ((char *)send_token.value)[0];
156 if ( !(((char *)send_token.value)[0] & GSSAUTH_P_NONE) ) {
157 report(stderr, GT_("Server requires integrity and/or privacy\n"));
158 gss_release_buffer(&min_stat, &send_token);
161 ((char *)send_token.value)[0] = 0;
162 buf_size = ntohl(*((long *)send_token.value));
163 /* we don't care about buffer size if we don't wrap data */
164 gss_release_buffer(&min_stat, &send_token);
165 if (outlevel >= O_DEBUG) {
166 report(stdout, GT_("Unwrapped security level flags: %s%s%s\n"),
167 server_conf_flags & GSSAUTH_P_NONE ? "N" : "-",
168 server_conf_flags & GSSAUTH_P_INTEGRITY ? "I" : "-",
169 server_conf_flags & GSSAUTH_P_PRIVACY ? "C" : "-");
170 report(stdout, GT_("Maximum GSS token size is %ld\n"),buf_size);
173 /* now respond in kind (hack!!!) */
174 buf_size = htonl(buf_size); /* do as they do... only matters if we do enc */
175 memcpy(buf1, &buf_size, 4);
176 buf1[0] = GSSAUTH_P_NONE;
177 strcpy(buf1+4, username); /* server decides if princ is user */
178 request_buf.length = 4 + strlen(username) + 1;
179 request_buf.value = buf1;
180 maj_stat = gss_wrap(&min_stat, context, 0, GSS_C_QOP_DEFAULT, &request_buf,
181 &cflags, &send_token);
182 if (maj_stat != GSS_S_COMPLETE) {
183 report(stderr, GT_("Error creating security level request\n"));
186 to64frombits(buf1, send_token.value, send_token.length);
188 suppress_tags = TRUE;
189 result = gen_transact(sock, buf1, strlen(buf1));
190 suppress_tags = FALSE;
192 /* flush security context */
193 if (outlevel >= O_DEBUG)
194 report(stdout, GT_("Releasing GSS credentials\n"));
195 maj_stat = gss_delete_sec_context(&min_stat, &context, &send_token);
196 if (maj_stat != GSS_S_COMPLETE) {
197 report(stderr, GT_("Error releasing credentials\n"));
200 /* send_token may contain a notification to the server to flush
201 * credentials. RFC 1731 doesn't specify what to do, and since this
202 * support is only for authentication, we'll assume the server
203 * knows enough to flush its own credentials */
204 gss_release_buffer(&min_stat, &send_token);
213 /* gssapi.c ends here */