/** Create and return a new connection
*
* libkrb5(s) can talk to the KDC over TCP. Were assuming something sane is implemented
* by libkrb5 and that it does connection caching associated with contexts, so it's
* worth using a connection pool to preserve connections when workers die.
*
* @param instance rlm_krb5 instance instance.
* @return A new context or NULL on error.
*/
void *mod_conn_create(void *instance)
{
rlm_krb5_t *inst = instance;
rlm_krb5_handle_t *conn;
krb5_error_code ret;
MEM(conn = talloc_zero(instance, rlm_krb5_handle_t));
ret = krb5_init_context(&conn->context);
if (ret) {
ERROR("rlm_krb5 (%s): Context initialisation failed: %s", inst->xlat_name,
rlm_krb5_error(NULL, ret));
return NULL;
}
talloc_set_destructor(conn, _free_handle);
ret = inst->keytabname ?
krb5_kt_resolve(conn->context, inst->keytabname, &conn->keytab) :
krb5_kt_default(conn->context, &conn->keytab);
if (ret) {
ERROR("Resolving keytab failed: %s", rlm_krb5_error(conn->context, ret));
goto cleanup;
}
#ifdef HEIMDAL_KRB5
ret = krb5_cc_new_unique(conn->context, "MEMORY", NULL, &conn->ccache);
if (ret) {
ERROR("rlm_krb5 (%s): Credential cache creation failed: %s", inst->xlat_name,
rlm_krb5_error(conn->context, ret));
return NULL;
}
krb5_verify_opt_init(&conn->options);
krb5_verify_opt_set_ccache(&conn->options, conn->ccache);
krb5_verify_opt_set_keytab(&conn->options, conn->keytab);
krb5_verify_opt_set_secure(&conn->options, true);
if (inst->service) {
krb5_verify_opt_set_service(&conn->options, inst->service);
}
#else
krb5_verify_init_creds_opt_set_ap_req_nofail(inst->vic_options, true);
#endif
return conn;
cleanup:
talloc_free(conn);
return NULL;
}
char * /* R: allocated response string */
auth_krb5 (
/* PARAMETERS */
const char *user, /* I: plaintext authenticator */
const char *password, /* I: plaintext password */
const char *service, /* I: service authenticating to */
const char *realm /* I: user's realm */
/* END PARAMETERS */
)
{
/* VARIABLES */
krb5_context context;
krb5_ccache ccache = NULL;
krb5_keytab kt = NULL;
krb5_principal auth_user;
krb5_verify_opt opt;
char * result;
char tfname[2048];
char principalbuf[2048];
/* END VARIABLES */
if (!user || !password) {
syslog(LOG_ERR, "auth_krb5: NULL password or username?");
return strdup("NO saslauthd internal NULL password or username");
}
if (krb5_init_context(&context)) {
syslog(LOG_ERR, "auth_krb5: krb5_init_context");
return strdup("NO saslauthd internal krb5_init_context error");
}
if (form_principal_name(user, service, realm, principalbuf, sizeof (principalbuf))) {
syslog(LOG_ERR, "auth_krb5: form_principal_name");
return strdup("NO saslauthd principal name error");
}
if (krb5_parse_name (context, principalbuf, &auth_user)) {
krb5_free_context(context);
syslog(LOG_ERR, "auth_krb5: krb5_parse_name");
return strdup("NO saslauthd internal krb5_parse_name error");
}
if (krbtf_name(tfname, sizeof (tfname)) != 0) {
syslog(LOG_ERR, "auth_krb5: could not generate ccache name");
return strdup("NO saslauthd internal error");
}
if (krb5_cc_resolve(context, tfname, &ccache)) {
krb5_free_principal(context, auth_user);
krb5_free_context(context);
syslog(LOG_ERR, "auth_krb5: krb5_cc_resolve");
return strdup("NO saslauthd internal error");
}
if (keytabname) {
if (krb5_kt_resolve(context, keytabname, &kt)) {
krb5_free_principal(context, auth_user);
krb5_cc_destroy(context, ccache);
krb5_free_context(context);
syslog(LOG_ERR, "auth_krb5: krb5_kt_resolve");
return strdup("NO saslauthd internal error");
}
}
krb5_verify_opt_init(&opt);
krb5_verify_opt_set_secure(&opt, 1);
krb5_verify_opt_set_ccache(&opt, ccache);
if (kt)
krb5_verify_opt_set_keytab(&opt, kt);
krb5_verify_opt_set_service(&opt, verify_principal);
if (krb5_verify_user_opt(context, auth_user, password, &opt)) {
result = strdup("NO krb5_verify_user_opt failed");
} else {
result = strdup("OK");
}
krb5_free_principal(context, auth_user);
krb5_cc_destroy(context, ccache);
if (kt)
krb5_kt_close(context, kt);
krb5_free_context(context);
return result;
}
/*
* validate user/pass (Heimdal)
*/
static int krb5_auth(void *instance, REQUEST *request)
{
rlm_krb5_t *inst = instance;
krb5_error_code ret;
krb5_ccache id;
krb5_principal userP;
krb5_context context = *(inst->context); /* copy data */
const char *user, *pass;
char service[SERVICE_NAME_LEN] = "host";
char *server_name = NULL;
char *princ_name;
krb5_verify_opt krb_verify_options;
krb5_keytab keytab;
if (inst->service_princ != NULL) {
server_name = strchr(inst->service_princ, '/');
if (server_name != NULL) {
*server_name = '\0';
}
strlcpy(service, inst->service_princ, sizeof(service));
if (server_name != NULL) {
*server_name = '/';
server_name++;
}
}
/*
* We can only authenticate user requests which HAVE
* a User-Name attribute.
*/
if (!request->username) {
radlog(L_AUTH, "rlm_krb5: Attribute \"User-Name\" is required for authentication.");
return RLM_MODULE_INVALID;
}
/*
* We can only authenticate user requests which HAVE
* a User-Password attribute.
*/
if (!request->password) {
radlog(L_AUTH, "rlm_krb5: Attribute \"User-Password\" is required for authentication.");
return RLM_MODULE_INVALID;
}
/*
* Ensure that we're being passed a plain-text password,
* and not anything else.
*/
if (request->password->attribute != PW_USER_PASSWORD) {
radlog(L_AUTH, "rlm_krb5: Attribute \"User-Password\" is required for authentication. Cannot use \"%s\".", request->password->name);
return RLM_MODULE_INVALID;
}
user = request->username->vp_strvalue;
pass = request->password->vp_strvalue;
ret = krb5_parse_name(context, user, &userP);
if (ret) {
radlog(L_AUTH, "rlm_krb5: [%s] krb5_parse_name failed: %s",
user, error_message(ret));
return RLM_MODULE_REJECT;
}
/*
* Heimdal krb5 verification.
*/
/*
* The following bit allows us to also log user/instance@REALM if someone
* logs in using an instance.
*/
ret = krb5_unparse_name(context, userP, &princ_name);
if (ret != 0) {
radlog(L_AUTH, "rlm_krb5: Unparsable name");
} else {
radlog(L_AUTH, "rlm_krb5: Parsed name is: %s", princ_name);
free(princ_name);
}
krb5_cc_default(context, &id);
/*
* Set up krb5_verify_user options.
*/
krb5_verify_opt_init(&krb_verify_options);
krb5_verify_opt_set_ccache(&krb_verify_options, id);
/*
* Resolve keytab name. This allows us to use something other than
* the default system keytab
*/
if (inst->keytab != NULL) {
ret = krb5_kt_resolve(context, inst->keytab, &keytab);
if (ret) {
radlog(L_AUTH, "rlm_krb5: unable to resolve keytab %s: %s",
inst->keytab, error_message(ret));
krb5_kt_close(context, keytab);
return RLM_MODULE_REJECT;
}
krb5_verify_opt_set_keytab(&krb_verify_options, keytab);
}
/*
* Verify aquired credentials against the keytab.
*/
krb5_verify_opt_set_secure(&krb_verify_options, 1);
/*
* Allow us to use an arbitrary service name.
*/
krb5_verify_opt_set_service(&krb_verify_options, service);
/*
* Verify the user, using the above set options.
*/
ret = krb5_verify_user_opt(context, userP, pass, &krb_verify_options);
/*
* We are done with the keytab, close it.
*/
krb5_kt_close(context, keytab);
if (ret == 0)
return RLM_MODULE_OK;
radlog(L_AUTH, "rlm_krb5: failed verify_user: %s (%s@%s)",
error_message(ret),
*userP->name.name_string.val,
userP->realm);
return RLM_MODULE_REJECT;
}
/*
* Validate user/pass (Heimdal)
*/
static rlm_rcode_t krb5_auth(void *instance, REQUEST *request)
{
rlm_krb5_t *inst = instance;
rlm_rcode_t rcode;
krb5_error_code ret;
krb5_principal client;
krb5_ccache ccache;
krb5_keytab keytab;
krb5_verify_opt options;
krb5_context *context = NULL;
/*
* See above in MIT krb5_auth
*/
ret = krb5_copy_context(*(inst->context), context);
if (ret) {
radlog(L_ERR, "rlm_krb5 (%s): Error cloning krb5 context: %s",
inst->xlat_name, error_message(ret));
return RLM_MODULE_FAIL;
}
/*
* Setup krb5_verify_user options
*
* Not entirely sure this is necessary, but as we use context
* to get the cache handle, we probably do have to do this with
* the cloned context.
*/
krb5_cc_default(*context, &ccache);
krb5_verify_opt_init(&options);
krb5_verify_opt_set_ccache(&options, ccache);
memset(&keytab, 0, sizeof(keytab));
ret = inst->keytabname ?
krb5_kt_resolve(*context, inst->keytabname, &keytab) :
krb5_kt_default(*context, &keytab);
if (ret) {
radlog(L_ERR, "rlm_krb5 (%s): Resolving keytab failed: %s",
inst->xlat_name, error_message(ret));
goto cleanup;
}
krb5_verify_opt_set_keytab(&options, keytab);
krb5_verify_opt_set_secure(&options, TRUE);
if (inst->service) {
krb5_verify_opt_set_service(&options, inst->service);
}
rcode = krb5_parse_user(inst, request, &client);
if (rcode != RLM_MODULE_OK) goto cleanup;
/*
* Verify the user, using the options we set in instantiate
*/
ret = krb5_verify_user_opt(*context, client,
request->password->vp_strvalue,
&options);
if (ret) {
switch (ret) {
case KRB5_LIBOS_BADPWDMATCH:
case KRB5KRB_AP_ERR_BAD_INTEGRITY:
RDEBUG("Provided password was incorrect: %s",
error_message(ret));
rcode = RLM_MODULE_REJECT;
break;
case KRB5KDC_ERR_KEY_EXP:
case KRB5KDC_ERR_CLIENT_REVOKED:
case KRB5KDC_ERR_SERVICE_REVOKED:
RDEBUG("Account has been locked out: %s",
error_message(ret));
rcode = RLM_MODULE_USERLOCK;
break;
case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
RDEBUG("User not found: %s", error_message(ret));
rcode = RLM_MODULE_NOTFOUND;
default:
radlog(L_ERR, "rlm_krb5 (%s): Verifying user failed: "
"%s", inst->xlat_name, error_message(ret));
rcode = RLM_MODULE_FAIL;
break;
}
goto cleanup;
}
cleanup:
krb5_free_context(*context);
krb5_kt_close(*context, keytab);
return rcode;
}
