2 * Copyright (c) 1999-2005, 2007-2008, 2010-2012
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 #ifdef SUDO_KRB5_INSTANCE
74 static const char *sudo_krb5_instance = SUDO_KRB5_INSTANCE;
76 static const char *sudo_krb5_instance = NULL;
79 #ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_ALLOC
80 static krb5_error_code
81 krb5_get_init_creds_opt_alloc(krb5_context context,
82 krb5_get_init_creds_opt **opts)
84 *opts = emalloc(sizeof(krb5_get_init_creds_opt));
85 krb5_get_init_creds_opt_init(*opts);
90 krb5_get_init_creds_opt_free(krb5_get_init_creds_opt *opts)
97 sudo_krb5_setup(struct passwd *pw, char **promptp, sudo_auth *auth)
99 static char *krb5_prompt;
100 debug_decl(sudo_krb5_init, SUDO_DEBUG_AUTH)
102 if (krb5_prompt == NULL) {
103 krb5_context sudo_context;
104 krb5_principal princ;
106 krb5_error_code error;
108 sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
109 princ = ((sudo_krb5_datap) auth->data)->princ;
112 * Really, we need to tell the caller not to prompt for password. The
113 * API does not currently provide this unless the auth is standalone.
115 if ((error = krb5_unparse_name(sudo_context, princ, &pname))) {
117 _("%s: unable to unparse princ ('%s'): %s"), auth->name,
118 pw->pw_name, error_message(error));
119 debug_return_int(AUTH_FAILURE);
122 /* Only rewrite prompt if user didn't specify their own. */
123 /*if (!strcmp(prompt, PASSPROMPT)) { */
124 easprintf(&krb5_prompt, "Password for %s: ", pname);
128 *promptp = krb5_prompt;
130 debug_return_int(AUTH_SUCCESS);
134 sudo_krb5_init(struct passwd *pw, sudo_auth *auth)
136 krb5_context sudo_context;
137 krb5_error_code error;
138 char cache_name[64], *pname = pw->pw_name;
139 debug_decl(sudo_krb5_init, SUDO_DEBUG_AUTH)
141 auth->data = (void *) &sudo_krb5_data; /* Stash all our data here */
143 if (sudo_krb5_instance != NULL) {
144 easprintf(&pname, "%s%s%s", pw->pw_name,
145 sudo_krb5_instance[0] != '/' ? "/" : "", sudo_krb5_instance);
148 #ifdef HAVE_KRB5_INIT_SECURE_CONTEXT
149 error = krb5_init_secure_context(&(sudo_krb5_data.sudo_context));
151 error = krb5_init_context(&(sudo_krb5_data.sudo_context));
155 sudo_context = sudo_krb5_data.sudo_context;
157 error = krb5_parse_name(sudo_context, pname, &(sudo_krb5_data.princ));
160 _("%s: unable to parse '%s': %s"), auth->name, pname,
161 error_message(error));
165 (void) snprintf(cache_name, sizeof(cache_name), "MEMORY:sudocc_%ld",
167 if ((error = krb5_cc_resolve(sudo_context, cache_name,
168 &(sudo_krb5_data.ccache)))) {
170 _("%s: unable to resolve ccache: %s"), auth->name,
171 error_message(error));
176 if (sudo_krb5_instance != NULL)
178 debug_return_int(error ? AUTH_FAILURE : AUTH_SUCCESS);
181 #ifdef HAVE_KRB5_VERIFY_USER
183 sudo_krb5_verify(struct passwd *pw, char *pass, sudo_auth *auth)
185 krb5_context sudo_context;
186 krb5_principal princ;
188 krb5_error_code error;
189 debug_decl(sudo_krb5_verify, SUDO_DEBUG_AUTH)
191 sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
192 princ = ((sudo_krb5_datap) auth->data)->princ;
193 ccache = ((sudo_krb5_datap) auth->data)->ccache;
195 error = krb5_verify_user(sudo_context, princ, ccache, pass, 1, NULL);
196 debug_return_int(error ? AUTH_FAILURE : AUTH_SUCCESS);
200 sudo_krb5_verify(struct passwd *pw, char *pass, sudo_auth *auth)
202 krb5_context sudo_context;
203 krb5_principal princ;
204 krb5_creds credbuf, *creds = NULL;
206 krb5_error_code error;
207 krb5_get_init_creds_opt *opts = NULL;
208 debug_decl(sudo_krb5_verify, SUDO_DEBUG_AUTH)
210 sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
211 princ = ((sudo_krb5_datap) auth->data)->princ;
212 ccache = ((sudo_krb5_datap) auth->data)->ccache;
214 /* Set default flags based on the local config file. */
215 error = krb5_get_init_creds_opt_alloc(sudo_context, &opts);
218 _("%s: unable to allocate options: %s"), auth->name,
219 error_message(error));
223 krb5_get_init_creds_opt_set_default_flags(sudo_context, NULL,
224 krb5_principal_get_realm(sudo_context, princ), opts);
227 /* Note that we always obtain a new TGT to verify the user */
228 if ((error = krb5_get_init_creds_password(sudo_context, &credbuf, princ,
229 pass, krb5_prompter_posix,
230 NULL, 0, NULL, opts))) {
231 /* Don't print error if just a bad password */
232 if (error != KRB5KRB_AP_ERR_BAD_INTEGRITY)
234 _("%s: unable to get credentials: %s"), auth->name,
235 error_message(error));
240 /* Verify the TGT to prevent spoof attacks. */
241 if ((error = verify_krb_v5_tgt(sudo_context, creds, auth->name)))
244 /* Store cred in cred cache. */
245 if ((error = krb5_cc_initialize(sudo_context, ccache, princ))) {
247 _("%s: unable to initialize ccache: %s"), auth->name,
248 error_message(error));
249 } else if ((error = krb5_cc_store_cred(sudo_context, ccache, creds))) {
251 _("%s: unable to store cred in ccache: %s"), auth->name,
252 error_message(error));
257 #ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_FREE_TWO_ARGS
258 krb5_get_init_creds_opt_free(sudo_context, opts);
260 krb5_get_init_creds_opt_free(opts);
264 krb5_free_cred_contents(sudo_context, creds);
265 debug_return_int(error ? AUTH_FAILURE : AUTH_SUCCESS);
270 sudo_krb5_cleanup(struct passwd *pw, sudo_auth *auth)
272 krb5_context sudo_context;
273 krb5_principal princ;
275 debug_decl(sudo_krb5_cleanup, SUDO_DEBUG_AUTH)
277 sudo_context = ((sudo_krb5_datap) auth->data)->sudo_context;
278 princ = ((sudo_krb5_datap) auth->data)->princ;
279 ccache = ((sudo_krb5_datap) auth->data)->ccache;
283 krb5_cc_destroy(sudo_context, ccache);
285 krb5_free_principal(sudo_context, princ);
286 krb5_free_context(sudo_context);
289 debug_return_int(AUTH_SUCCESS);
292 #ifndef HAVE_KRB5_VERIFY_USER
294 * Verify the Kerberos ticket-granting ticket just retrieved for the
295 * user. If the Kerberos server doesn't respond, assume the user is
296 * trying to fake us out (since we DID just get a TGT from what is
297 * supposedly our KDC).
299 * Returns 0 for successful authentication, non-zero for failure.
302 verify_krb_v5_tgt(krb5_context sudo_context, krb5_creds *cred, char *auth_name)
304 krb5_error_code error;
305 krb5_principal server;
306 krb5_verify_init_creds_opt vopt;
307 debug_decl(verify_krb_v5_tgt, SUDO_DEBUG_AUTH)
310 * Get the server principal for the local host.
311 * (Use defaults of "host" and canonicalized local name.)
313 if ((error = krb5_sname_to_principal(sudo_context, NULL, NULL,
314 KRB5_NT_SRV_HST, &server))) {
316 _("%s: unable to get host principal: %s"), auth_name,
317 error_message(error));
318 debug_return_int(-1);
321 /* Initialize verify opts and set secure mode */
322 krb5_verify_init_creds_opt_init(&vopt);
323 krb5_verify_init_creds_opt_set_ap_req_nofail(&vopt, 1);
325 /* verify the Kerberos ticket-granting ticket we just retrieved */
326 error = krb5_verify_init_creds(sudo_context, cred, server, NULL,
328 krb5_free_principal(sudo_context, server);
331 _("%s: Cannot verify TGT! Possible attack!: %s"),
332 auth_name, error_message(error));
333 debug_return_int(error);