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 */
27 # if defined(HAVE_GSSAPI_H) && !defined(HAVE_GSSAPI_GSSAPI_H)
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 static void decode_subr(const char *m, uint32_t code, int type)
43 uint32_t maj, min, context;
44 gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
48 maj = gss_display_status(&min, code, type, GSS_C_NO_OID,
51 if (maj != GSS_S_COMPLETE) {
52 report(stderr, GT_("GSSAPI error in gss_display_status called from <%s>\n"), m);
55 report(stderr, GT_("GSSAPI error %s: %s\n"), m,
56 msg.value ? (char *)msg.value : GT_("(null)"));
58 (void)gss_release_buffer(&min, &msg);
62 static void decode_status(const char *m, uint32_t major, uint32_t minor)
64 decode_subr(m, major, GSS_C_GSS_CODE);
65 decode_subr(m, minor, GSS_C_MECH_CODE);
68 #define GSSAUTH_P_NONE 1
69 #define GSSAUTH_P_INTEGRITY 2
70 #define GSSAUTH_P_PRIVACY 4
72 int do_gssauth(int sock, const char *command, const char *service,
73 const char *hostname, const char *username)
75 gss_buffer_desc request_buf, send_token;
76 gss_buffer_t sec_token;
77 gss_name_t target_name;
82 OM_uint32 maj_stat, min_stat;
83 char buf1[8192], buf2[8192], server_conf_flags;
84 unsigned long buf_size;
87 /* first things first: get an imap ticket for host */
88 snprintf(buf1, sizeof(buf1), "%s@%s", service, hostname);
89 request_buf.value = buf1;
90 request_buf.length = strlen(buf1) + 1;
91 maj_stat = gss_import_name(&min_stat, &request_buf, GSS_C_NT_HOSTBASED_SERVICE,
93 if (maj_stat != GSS_S_COMPLETE) {
94 decode_status("gss_import_name", maj_stat, min_stat);
95 report(stderr, GT_("Couldn't get service name for [%s]\n"), buf1);
98 else if (outlevel >= O_DEBUG) {
99 gss_display_name(&min_stat, target_name, &request_buf, &mech_name);
100 report(stderr, GT_("Using service name [%s]\n"),
101 (char *)request_buf.value);
102 gss_release_buffer(&min_stat, &request_buf);
105 gen_send(sock, "%s GSSAPI", command);
107 /* upon receipt of the GSSAPI authentication request, server returns
108 * null data ready response. */
109 result = gen_recv(sock, buf1, sizeof buf1);
113 /* now start the security context initialisation loop... */
114 sec_token = GSS_C_NO_BUFFER;
115 context = GSS_C_NO_CONTEXT;
116 if (outlevel >= O_VERBOSE)
117 report(stdout, GT_("Sending credentials\n"));
119 send_token.length = 0;
120 send_token.value = NULL;
121 maj_stat = gss_init_sec_context(&min_stat,
126 GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG,
128 GSS_C_NO_CHANNEL_BINDINGS,
134 if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
135 decode_status("gss_init_sec_context", maj_stat, min_stat);
136 gss_release_name(&min_stat, &target_name);
137 report(stderr, GT_("Error exchanging credentials\n"));
139 /* wake up server and await NO response */
140 SockWrite(sock, "\r\n", 2);
141 result = gen_recv(sock, buf1, sizeof buf1);
146 to64frombits(buf1, send_token.value, send_token.length);
147 gss_release_buffer(&min_stat, &send_token);
149 suppress_tags = TRUE;
150 gen_send(sock, "%s", buf1);
151 suppress_tags = FALSE;
153 if (maj_stat == GSS_S_CONTINUE_NEEDED) {
154 result = gen_recv(sock, buf1, sizeof buf1);
156 gss_release_name(&min_stat, &target_name);
159 request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
160 if ((int)request_buf.length == -1) /* in case of bad data */
161 request_buf.length = 0;
162 request_buf.value = buf2;
163 sec_token = &request_buf;
166 (maj_stat == GSS_S_CONTINUE_NEEDED);
167 gss_release_name(&min_stat, &target_name);
169 /* get security flags and buffer size */
170 result = gen_recv(sock, buf1, sizeof buf1);
174 request_buf.length = from64tobits(buf2, buf1 + 2, sizeof(buf2));
175 if ((int)request_buf.length == -1) /* in case of bad data */
176 request_buf.length = 0;
177 request_buf.value = buf2;
179 maj_stat = gss_unwrap(&min_stat, context,
180 &request_buf, &send_token, &cflags, &quality);
181 if (maj_stat != GSS_S_COMPLETE) {
182 decode_status("gss_unwrap", maj_stat, min_stat);
183 report(stderr, GT_("Couldn't unwrap security level data\n"));
184 gss_release_buffer(&min_stat, &send_token);
187 if (outlevel >= O_DEBUG)
188 report(stdout, GT_("Credential exchange complete\n"));
189 /* first octet is security levels supported. We want none, for now */
190 server_conf_flags = ((char *)send_token.value)[0];
191 if ( !(((char *)send_token.value)[0] & GSSAUTH_P_NONE) ) {
192 report(stderr, GT_("Server requires integrity and/or privacy\n"));
193 gss_release_buffer(&min_stat, &send_token);
196 ((char *)send_token.value)[0] = 0;
197 buf_size = ntohl(*((long *)send_token.value));
198 /* we don't care about buffer size if we don't wrap data */
199 gss_release_buffer(&min_stat, &send_token);
200 if (outlevel >= O_DEBUG) {
201 report(stdout, GT_("Unwrapped security level flags: %s%s%s\n"),
202 server_conf_flags & GSSAUTH_P_NONE ? "N" : "-",
203 server_conf_flags & GSSAUTH_P_INTEGRITY ? "I" : "-",
204 server_conf_flags & GSSAUTH_P_PRIVACY ? "C" : "-");
205 report(stdout, GT_("Maximum GSS token size is %ld\n"),buf_size);
208 /* now respond in kind (hack!!!) */
209 buf_size = htonl(buf_size); /* do as they do... only matters if we do enc */
210 memcpy(buf1, &buf_size, 4);
211 buf1[0] = GSSAUTH_P_NONE;
212 strlcpy(buf1+4, username, sizeof(buf1) - 4); /* server decides if princ is user */
213 request_buf.length = 4 + strlen(username) + 1;
214 request_buf.value = buf1;
215 maj_stat = gss_wrap(&min_stat, context, 0, GSS_C_QOP_DEFAULT, &request_buf,
216 &cflags, &send_token);
217 if (maj_stat != GSS_S_COMPLETE) {
218 report(stderr, GT_("Error creating security level request\n"));
221 to64frombits(buf1, send_token.value, send_token.length);
223 suppress_tags = TRUE;
224 result = gen_transact(sock, "%s", buf1);
225 suppress_tags = FALSE;
227 /* flush security context */
228 if (outlevel >= O_DEBUG)
229 report(stdout, GT_("Releasing GSS credentials\n"));
230 maj_stat = gss_delete_sec_context(&min_stat, &context, &send_token);
231 if (maj_stat != GSS_S_COMPLETE) {
232 decode_status("gss_delete_sec_context", maj_stat, min_stat);
233 report(stderr, GT_("Error releasing credentials\n"));
236 /* send_token may contain a notification to the server to flush
237 * credentials. RFC 1731 doesn't specify what to do, and since this
238 * support is only for authentication, we'll assume the server
239 * knows enough to flush its own credentials */
240 gss_release_buffer(&min_stat, &send_token);
249 /* gssapi.c ends here */