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 <netinet/in.h> /* for htonl/ntohl */
26 # ifdef HAVE_GSSAPI_GSSAPI_H
27 # include <gssapi/gssapi.h>
29 # ifdef HAVE_GSSAPI_GSSAPI_GENERIC_H
30 # include <gssapi/gssapi_generic.h>
32 # ifndef HAVE_GSS_C_NT_HOSTBASED_SERVICE
33 # define GSS_C_NT_HOSTBASED_SERVICE gss_nt_service_name
36 #define GSSAUTH_P_NONE 1
37 #define GSSAUTH_P_INTEGRITY 2
38 #define GSSAUTH_P_PRIVACY 4
40 int do_gssauth(int sock, char *command, char *hostname, char *username)
42 gss_buffer_desc request_buf, send_token;
43 gss_buffer_t sec_token;
44 gss_name_t target_name;
49 OM_uint32 maj_stat, min_stat;
50 char buf1[8192], buf2[8192], server_conf_flags;
51 unsigned long buf_size;
54 /* first things first: get an imap ticket for host */
55 sprintf(buf1, "imap@%s", hostname);
56 request_buf.value = buf1;
57 request_buf.length = strlen(buf1) + 1;
58 maj_stat = gss_import_name(&min_stat, &request_buf, GSS_C_NT_HOSTBASED_SERVICE,
60 if (maj_stat != GSS_S_COMPLETE) {
61 report(stderr, _("Couldn't get service name for [%s]\n"), buf1);
64 else if (outlevel >= O_DEBUG) {
65 maj_stat = gss_display_name(&min_stat, target_name, &request_buf,
67 report(stderr, _("Using service name [%s]\n"),request_buf.value);
68 maj_stat = gss_release_buffer(&min_stat, &request_buf);
71 gen_send(sock, "%s GSSAPI", command);
73 /* upon receipt of the GSSAPI authentication request, server returns
74 * null data ready response. */
75 if (result = gen_recv(sock, buf1, sizeof buf1)) {
79 /* now start the security context initialisation loop... */
80 sec_token = GSS_C_NO_BUFFER;
81 context = GSS_C_NO_CONTEXT;
82 if (outlevel >= O_VERBOSE)
83 report(stdout, _("Sending credentials\n"));
85 send_token.length = 0;
86 send_token.value = NULL;
87 maj_stat = gss_init_sec_context(&min_stat,
92 GSS_C_MUTUAL_FLAG | GSS_C_SEQUENCE_FLAG,
94 GSS_C_NO_CHANNEL_BINDINGS,
100 if (maj_stat!=GSS_S_COMPLETE && maj_stat!=GSS_S_CONTINUE_NEEDED) {
101 report(stderr, _("Error exchanging credentials\n"));
102 gss_release_name(&min_stat, &target_name);
103 /* wake up server and await NO response */
104 SockWrite(sock, "\r\n", 2);
105 if (result = gen_recv(sock, buf1, sizeof buf1))
109 to64frombits(buf1, send_token.value, send_token.length);
110 gss_release_buffer(&min_stat, &send_token);
112 suppress_tags = TRUE;
113 gen_send(sock, buf1, strlen(buf1));
114 suppress_tags = FALSE;
116 if (maj_stat == GSS_S_CONTINUE_NEEDED) {
117 if (result = gen_recv(sock, buf1, sizeof buf1)) {
118 gss_release_name(&min_stat, &target_name);
121 request_buf.length = from64tobits(buf2, buf1 + 2);
122 request_buf.value = buf2;
123 sec_token = &request_buf;
126 (maj_stat == GSS_S_CONTINUE_NEEDED);
127 gss_release_name(&min_stat, &target_name);
129 /* get security flags and buffer size */
130 if (result = gen_recv(sock, buf1, sizeof buf1))
133 request_buf.length = from64tobits(buf2, buf1 + 2);
134 request_buf.value = buf2;
136 maj_stat = gss_unwrap(&min_stat, context,
137 &request_buf, &send_token, &cflags, &quality);
138 if (maj_stat != GSS_S_COMPLETE) {
139 report(stderr, _("Couldn't unwrap security level data\n"));
140 gss_release_buffer(&min_stat, &send_token);
143 if (outlevel >= O_DEBUG)
144 report(stdout, _("Credential exchange complete\n"));
145 /* first octet is security levels supported. We want none, for now */
146 server_conf_flags = ((char *)send_token.value)[0];
147 if ( !(((char *)send_token.value)[0] & GSSAUTH_P_NONE) ) {
148 report(stderr, _("Server requires integrity and/or privacy\n"));
149 gss_release_buffer(&min_stat, &send_token);
152 ((char *)send_token.value)[0] = 0;
153 buf_size = ntohl(*((long *)send_token.value));
154 /* we don't care about buffer size if we don't wrap data */
155 gss_release_buffer(&min_stat, &send_token);
156 if (outlevel >= O_DEBUG) {
157 report(stdout, _("Unwrapped security level flags: %s%s%s\n"),
158 server_conf_flags & GSSAUTH_P_NONE ? "N" : "-",
159 server_conf_flags & GSSAUTH_P_INTEGRITY ? "I" : "-",
160 server_conf_flags & GSSAUTH_P_PRIVACY ? "C" : "-");
161 report(stdout, _("Maximum GSS token size is %ld\n"),buf_size);
164 /* now respond in kind (hack!!!) */
165 buf_size = htonl(buf_size); /* do as they do... only matters if we do enc */
166 memcpy(buf1, &buf_size, 4);
167 buf1[0] = GSSAUTH_P_NONE;
168 strcpy(buf1+4, username); /* server decides if princ is user */
169 request_buf.length = 4 + strlen(username) + 1;
170 request_buf.value = buf1;
171 maj_stat = gss_wrap(&min_stat, context, 0, GSS_C_QOP_DEFAULT, &request_buf,
172 &cflags, &send_token);
173 if (maj_stat != GSS_S_COMPLETE) {
174 report(stderr, _("Error creating security level request\n"));
177 to64frombits(buf1, send_token.value, send_token.length);
179 suppress_tags = TRUE;
180 result = gen_transact(sock, buf1, strlen(buf1));
181 suppress_tags = FALSE;
183 /* flush security context */
184 if (outlevel >= O_DEBUG)
185 report(stdout, _("Releasing GSS credentials\n"));
186 maj_stat = gss_delete_sec_context(&min_stat, &context, &send_token);
187 if (maj_stat != GSS_S_COMPLETE) {
188 report(stderr, _("Error releasing credentials\n"));
191 /* send_token may contain a notification to the server to flush
192 * credentials. RFC 1731 doesn't specify what to do, and since this
193 * support is only for authentication, we'll assume the server
194 * knows enough to flush its own credentials */
195 gss_release_buffer(&min_stat, &send_token);
204 /* gssapi.c ends here */