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