2 * Copyright (c) 1999-2005, 2007-2008, 2010-2011
3 * Todd C. Miller <Todd.Miller@courtesan.com>
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
17 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
18 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
20 * Sponsored in part by the Defense Advanced Research Projects
21 * Agency (DARPA) and Air Force Research Laboratory, Air Force
22 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
27 #include <sys/types.h>
28 #include <sys/param.h>
37 #endif /* STDC_HEADERS */
40 #endif /* HAVE_STRING_H */
43 #endif /* HAVE_STRING_H */
46 #endif /* HAVE_UNISTD_H */
54 #include "sudo_auth.h"
57 # define extract_name(c, p) krb5_principal_get_comp_string(c, p, 1)
58 # define krb5_free_data_contents(c, d) krb5_data_free(d)
60 # define extract_name(c, p) (krb5_princ_component(c, p, 1)->data)
63 #ifndef HAVE_KRB5_VERIFY_USER
64 static int verify_krb_v5_tgt(krb5_context, krb5_creds *, char *);
66 static struct _sudo_krb5_data {
67 krb5_context sudo_context;
70 } sudo_krb5_data = { NULL, NULL, NULL };
71 typedef struct _sudo_krb5_data *sudo_krb5_datap;
73 #ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_ALLOC
74 static krb5_error_code
75 krb5_get_init_creds_opt_alloc(krb5_context context,
76 krb5_get_init_creds_opt **opts)
78 *opts = emalloc(sizeof(krb5_get_init_creds_opt));
79 krb5_get_init_creds_opt_init(*opts);
84 krb5_get_init_creds_opt_free(krb5_get_init_creds_opt *opts)
91 kerb5_init(struct passwd *pw, char **promptp, sudo_auth *auth)
93 krb5_context sudo_context;
96 krb5_error_code error;
100 auth->data = (void *) &sudo_krb5_data; /* Stash all our data here */
102 #ifdef HAVE_KRB5_INIT_SECURE_CONTEXT
103 error = krb5_init_secure_context(&(sudo_krb5_data.sudo_context));
105 error = krb5_init_context(&(sudo_krb5_data.sudo_context));
109 sudo_context = sudo_krb5_data.sudo_context;
111 if ((error = krb5_parse_name(sudo_context, pw->pw_name,
112 &(sudo_krb5_data.princ)))) {
113 log_error(NO_EXIT|NO_MAIL,
114 _("%s: unable to parse '%s': %s"), auth->name, pw->pw_name,
115 error_message(error));
118 princ = sudo_krb5_data.princ;
121 * Really, we need to tell the caller not to prompt for password.
122 * The API does not currently provide this unless the auth is standalone.
125 if ((error = krb5_unparse_name(sudo_context, princ, &pname))) {
126 log_error(NO_EXIT|NO_MAIL,
127 _("%s: unable to unparse princ ('%s'): %s"), auth->name,
128 pw->pw_name, error_message(error));
132 /* Only rewrite prompt if user didn't specify their own. */
133 /*if (!strcmp(prompt, PASSPROMPT)) { */
134 easprintf(promptp, "Password for %s: ", pname);
139 (void) snprintf(cache_name, sizeof(cache_name), "MEMORY:sudocc_%ld",
141 if ((error = krb5_cc_resolve(sudo_context, cache_name,
142 &(sudo_krb5_data.ccache)))) {
143 log_error(NO_EXIT|NO_MAIL,
144 _("%s: unable to resolve ccache: %s"), auth->name,
145 error_message(error));
148 ccache = sudo_krb5_data.ccache;
153 #ifdef HAVE_KRB5_VERIFY_USER
155 kerb5_verify(struct passwd *pw, char *pass, sudo_auth *auth)
157 krb5_context sudo_context;
158 krb5_principal princ;
160 krb5_error_code error;
162 sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
163 princ = ((sudo_krb5_datap) auth->data)->princ;
164 ccache = ((sudo_krb5_datap) auth->data)->ccache;
166 error = krb5_verify_user(sudo_context, princ, ccache, pass, 1, NULL);
167 return error ? AUTH_FAILURE : AUTH_SUCCESS;
171 kerb5_verify(struct passwd *pw, char *pass, sudo_auth *auth)
173 krb5_context sudo_context;
174 krb5_principal princ;
175 krb5_creds credbuf, *creds = NULL;
177 krb5_error_code error;
178 krb5_get_init_creds_opt *opts = NULL;
180 sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
181 princ = ((sudo_krb5_datap) auth->data)->princ;
182 ccache = ((sudo_krb5_datap) auth->data)->ccache;
184 /* Set default flags based on the local config file. */
185 error = krb5_get_init_creds_opt_alloc(sudo_context, &opts);
187 log_error(NO_EXIT|NO_MAIL,
188 _("%s: unable to allocate options: %s"), auth->name,
189 error_message(error));
193 krb5_get_init_creds_opt_set_default_flags(sudo_context, NULL,
194 krb5_principal_get_realm(sudo_context, princ), opts);
197 /* Note that we always obtain a new TGT to verify the user */
198 if ((error = krb5_get_init_creds_password(sudo_context, &credbuf, princ,
199 pass, krb5_prompter_posix,
200 NULL, 0, NULL, opts))) {
201 /* Don't print error if just a bad password */
202 if (error != KRB5KRB_AP_ERR_BAD_INTEGRITY)
203 log_error(NO_EXIT|NO_MAIL,
204 _("%s: unable to get credentials: %s"), auth->name,
205 error_message(error));
210 /* Verify the TGT to prevent spoof attacks. */
211 if ((error = verify_krb_v5_tgt(sudo_context, creds, auth->name)))
214 /* Store cred in cred cache. */
215 if ((error = krb5_cc_initialize(sudo_context, ccache, princ))) {
216 log_error(NO_EXIT|NO_MAIL,
217 _("%s: unable to initialize ccache: %s"), auth->name,
218 error_message(error));
219 } else if ((error = krb5_cc_store_cred(sudo_context, ccache, creds))) {
220 log_error(NO_EXIT|NO_MAIL,
221 _("%s: unable to store cred in ccache: %s"), auth->name,
222 error_message(error));
227 #ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_FREE_TWO_ARGS
228 krb5_get_init_creds_opt_free(sudo_context, opts);
230 krb5_get_init_creds_opt_free(opts);
234 krb5_free_cred_contents(sudo_context, creds);
235 return error ? AUTH_FAILURE : AUTH_SUCCESS;
240 kerb5_cleanup(struct passwd *pw, sudo_auth *auth)
242 krb5_context sudo_context;
243 krb5_principal princ;
246 sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
247 princ = ((sudo_krb5_datap) auth->data)->princ;
248 ccache = ((sudo_krb5_datap) auth->data)->ccache;
252 krb5_cc_destroy(sudo_context, ccache);
254 krb5_free_principal(sudo_context, princ);
255 krb5_free_context(sudo_context);
261 #ifndef HAVE_KRB5_VERIFY_USER
263 * Verify the Kerberos ticket-granting ticket just retrieved for the
264 * user. If the Kerberos server doesn't respond, assume the user is
265 * trying to fake us out (since we DID just get a TGT from what is
266 * supposedly our KDC).
268 * Returns 0 for successful authentication, non-zero for failure.
271 verify_krb_v5_tgt(krb5_context sudo_context, krb5_creds *cred, char *auth_name)
273 krb5_error_code error;
274 krb5_principal server;
275 krb5_verify_init_creds_opt vopt;
278 * Get the server principal for the local host.
279 * (Use defaults of "host" and canonicalized local name.)
281 if ((error = krb5_sname_to_principal(sudo_context, NULL, NULL,
282 KRB5_NT_SRV_HST, &server))) {
283 log_error(NO_EXIT|NO_MAIL,
284 _("%s: unable to get host principal: %s"), auth_name,
285 error_message(error));
289 /* Initialize verify opts and set secure mode */
290 krb5_verify_init_creds_opt_init(&vopt);
291 krb5_verify_init_creds_opt_set_ap_req_nofail(&vopt, 1);
293 /* verify the Kerberos ticket-granting ticket we just retrieved */
294 error = krb5_verify_init_creds(sudo_context, cred, server, NULL,
296 krb5_free_principal(sudo_context, server);
298 log_error(NO_EXIT|NO_MAIL,
299 _("%s: Cannot verify TGT! Possible attack!: %s"),
300 auth_name, error_message(error));