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/*
* Option handling for pam-krb5.
*
* Responsible for initializing the args struct that's passed to nearly all
* internal functions. Retrieves configuration information from krb5.conf and
* parses the PAM configuration.
*
* Copyright 2011, 2012
* The Board of Trustees of the Leland Stanford Junior University
* Copyright 2005, 2006, 2007, 2008, 2009, 2010
* Russ Allbery <rra@stanford.edu>
* Copyright 2005 Andres Salomon <dilinger@debian.org>
* Copyright 1999, 2000 Frank Cusack <fcusack@fcusack.com>
*
* See LICENSE for licensing terms.
*/
#include <config.h>
#include <portable/krb5.h>
#include <portable/system.h>
#include <errno.h>
#include <internal.h>
#include <pam-util/args.h>
#include <pam-util/logging.h>
#include <pam-util/options.h>
#include <pam-util/vector.h>
/* Our option definition. Must be sorted. */
#define K(name) (#name), offsetof(struct pam_config, name)
static const struct option options[] = {
{ K(alt_auth_map), true, STRING (NULL) },
{ K(anon_fast), true, BOOL (false) },
{ K(banner), true, STRING ("Kerberos") },
{ K(ccache), true, STRING (NULL) },
{ K(ccache_dir), true, STRING ("FILE:/tmp") },
{ K(clear_on_fail), true, BOOL (false) },
{ K(debug), true, BOOL (false) },
{ K(defer_pwchange), true, BOOL (false) },
{ K(expose_account), true, BOOL (false) },
{ K(fail_pwchange), true, BOOL (false) },
{ K(fast_ccache), true, STRING (NULL) },
{ K(force_alt_auth), true, BOOL (false) },
{ K(force_first_pass), false, BOOL (false) },
{ K(force_pwchange), true, BOOL (false) },
{ K(forwardable), true, BOOL (false) },
{ K(ignore_k5login), true, BOOL (false) },
{ K(ignore_root), true, BOOL (false) },
{ K(keytab), true, STRING (NULL) },
{ K(minimum_uid), true, NUMBER (0) },
{ K(no_ccache), false, BOOL (false) },
{ K(no_prompt), true, BOOL (false) },
{ K(only_alt_auth), true, BOOL (false) },
{ K(pkinit_anchors), true, STRING (NULL) },
{ K(pkinit_prompt), true, BOOL (false) },
{ K(pkinit_user), true, STRING (NULL) },
{ K(preauth_opt), true, LIST (NULL) },
{ K(prompt_principal), true, BOOL (false) },
{ K(realm), false, STRING (NULL) },
{ K(renew_lifetime), true, TIME (0) },
{ K(retain_after_close), true, BOOL (false) },
{ K(search_k5login), true, BOOL (false) },
{ K(silent), false, BOOL (false) },
{ K(ticket_lifetime), true, TIME (0) },
{ K(trace), false, STRING (NULL) },
{ K(try_first_pass), false, BOOL (false) },
{ K(try_pkinit), true, BOOL (false) },
{ K(use_authtok), false, BOOL (false) },
{ K(use_first_pass), false, BOOL (false) },
{ K(use_pkinit), true, BOOL (false) },
{ K(user_realm), true, STRING (NULL) },
};
static const size_t optlen = sizeof(options) / sizeof(options[0]);
/*
* Allocate a new struct pam_args and initialize its data members, including
* parsing the arguments and getting settings from krb5.conf. Check the
* resulting options for consistency.
*/
struct pam_args *
pamk5_init(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
int i;
struct pam_args *args;
struct pam_config *config = NULL;
args = putil_args_new(pamh, flags);
if (args == NULL)
return NULL;
config = calloc(1, sizeof(struct pam_config));
if (config == NULL)
goto nomem;
args->config = config;
/*
* Do an initial scan to see if the realm is already set in our options.
* If so, make sure that's set before we start loading option values,
* since it affects what comes out of krb5.conf.
*
* We will then ignore args->config->realm, set later by option parsing,
* in favor of using args->realm extracted here. However, the latter must
* exist to avoid throwing unknown option errors.
*/
for (i = 0; i < argc; i++) {
if (strncmp(argv[i], "realm=", 6) != 0)
continue;
if (args->realm != NULL)
free(args->realm);
args->realm = strdup(&argv[i][strlen("realm=")]);
if (args->realm == NULL)
goto nomem;
}
if (!putil_args_defaults(args, options, optlen)) {
free(config);
putil_args_free(args);
return NULL;
}
if (!putil_args_krb5(args, "pam", options, optlen))
goto fail;
if (!putil_args_parse(args, argc, argv, options, optlen))
goto fail;
if (config->debug)
args->debug = true;
if (config->silent)
args->silent = true;
/* An empty banner should be treated the same as not having one. */
if (config->banner != NULL && config->banner[0] == '\0') {
free(config->banner);
config->banner = NULL;
}
/* Sanity-check try_first_pass, use_first_pass, and force_first_pass. */
if (config->force_first_pass && config->try_first_pass) {
putil_err(args, "force_first_pass set, ignoring try_first_pass");
config->try_first_pass = 0;
}
if (config->force_first_pass && config->use_first_pass) {
putil_err(args, "force_first_pass set, ignoring use_first_pass");
config->use_first_pass = 0;
}
if (config->use_first_pass && config->try_first_pass) {
putil_err(args, "use_first_pass set, ignoring try_first_pass");
config->try_first_pass = 0;
}
/*
* Don't set expose_account if we're using search_k5login. The user will
* get a principal formed from the account into which they're logging in,
* which isn't the password they'll use (that's the whole point of
* search_k5login).
*/
if (config->search_k5login)
config->expose_account = 0;
/* UIDs are unsigned on some systems. */
if (config->minimum_uid < 0)
config->minimum_uid = 0;
/*
* Warn if PKINIT options were set and PKINIT isn't supported. The MIT
* method (krb5_get_init_creds_opt_set_pa) can't support use_pkinit.
*/
#ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_SET_PKINIT
# ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_SET_PA
if (config->try_pkinit)
putil_err(args, "try_pkinit requested but PKINIT not available");
# endif
if (config->use_pkinit)
putil_err(args, "use_pkinit requested but PKINIT not available or"
" cannot be enforced");
#endif
/* Warn if the FAST option was set and FAST isn't supported. */
#ifndef HAVE_KRB5_GET_INIT_CREDS_OPT_SET_FAST_CCACHE_NAME
if (config->fast_ccache || config->anon_fast)
putil_err(args, "fast_ccache or anon_fast requested but FAST not"
" supported by Kerberos libraries");
#endif
/* If tracing was requested enable it if possible. */
#ifdef HAVE_KRB5_SET_TRACE_FILENAME
if (config->trace != NULL) {
krb5_error_code retval;
retval = krb5_set_trace_filename(args->ctx, config->trace);
if (retval == 0)
putil_debug(args, "enabled trace logging to %s", config->trace);
else
putil_err_krb5(args, retval, "cannot enable trace logging to %s",
config->trace);
}
#else
if (config->trace != NULL)
putil_err(args, "trace logging requested but not supported");
#endif
return args;
nomem:
putil_crit(args, "cannot allocate memory: %s", strerror(errno));
if (config != NULL)
free(config);
putil_args_free(args);
return NULL;
fail:
pamk5_free(args);
return NULL;
}
/*
* Free the allocated args struct and any memory it points to.
*/
void
pamk5_free(struct pam_args *args)
{
struct pam_config *config;
if (args == NULL)
return;
config = args->config;
if (config != NULL) {
if (config->alt_auth_map != NULL)
free(config->alt_auth_map);
if (config->banner != NULL)
free(config->banner);
if (config->ccache != NULL)
free(config->ccache);
if (config->ccache_dir != NULL)
free(config->ccache_dir);
if (config->fast_ccache != NULL)
free(config->fast_ccache);
if (config->keytab != NULL)
free(config->keytab);
if (config->pkinit_anchors != NULL)
free(config->pkinit_anchors);
if (config->pkinit_user != NULL)
free(config->pkinit_user);
if (config->preauth_opt != NULL)
vector_free(config->preauth_opt);
if (config->realm != NULL)
free(config->realm);
if (config->trace != NULL)
free(config->trace);
if (config->user_realm != NULL)
free(config->user_realm);
free(args->config);
args->config = NULL;
}
putil_args_free(args);
}
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