| Current Path : /usr/src/lib/libpam/modules/pam_krb5/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/lib/libpam/modules/pam_krb5/pam_krb5.c |
/*-
* This pam_krb5 module contains code that is:
* Copyright (c) Derrick J. Brashear, 1996. All rights reserved.
* Copyright (c) Frank Cusack, 1999-2001. All rights reserved.
* Copyright (c) Jacques A. Vidrine, 2000-2001. All rights reserved.
* Copyright (c) Nicolas Williams, 2001. All rights reserved.
* Copyright (c) Perot Systems Corporation, 2001. All rights reserved.
* Copyright (c) Mark R V Murray, 2001. All rights reserved.
* Copyright (c) Networks Associates Technology, Inc., 2002-2005.
* All rights reserved.
*
* Portions of this software were developed for the FreeBSD Project by
* ThinkSec AS and NAI Labs, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
* ("CBOSS"), as part of the DARPA CHATS research program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notices, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* the GNU Public License, in which case the provisions of the GPL are
* required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the GPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/lib/libpam/modules/pam_krb5/pam_krb5.c 207555 2010-05-03 07:39:51Z mm $");
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <krb5.h>
#include <com_err.h>
#define PAM_SM_AUTH
#define PAM_SM_ACCOUNT
#define PAM_SM_PASSWORD
#include <security/pam_appl.h>
#include <security/pam_modules.h>
#include <security/pam_mod_misc.h>
#include <security/openpam.h>
#define COMPAT_HEIMDAL
/* #define COMPAT_MIT */
static int verify_krb_v5_tgt(krb5_context, krb5_ccache, char *, int);
static void cleanup_cache(pam_handle_t *, void *, int);
static const char *compat_princ_component(krb5_context, krb5_principal, int);
static void compat_free_data_contents(krb5_context, krb5_data *);
#define USER_PROMPT "Username: "
#define PASSWORD_PROMPT "Password:"
#define NEW_PASSWORD_PROMPT "New Password:"
#define PAM_OPT_CCACHE "ccache"
#define PAM_OPT_DEBUG "debug"
#define PAM_OPT_FORWARDABLE "forwardable"
#define PAM_OPT_NO_CCACHE "no_ccache"
#define PAM_OPT_NO_USER_CHECK "no_user_check"
#define PAM_OPT_REUSE_CCACHE "reuse_ccache"
/*
* authentication management
*/
PAM_EXTERN int
pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
int argc __unused, const char *argv[] __unused)
{
krb5_error_code krbret;
krb5_context pam_context;
krb5_creds creds;
krb5_principal princ;
krb5_ccache ccache;
krb5_get_init_creds_opt opts;
struct passwd *pwd;
int retval;
const void *ccache_data;
const char *user, *pass;
const void *sourceuser, *service;
char *principal, *princ_name, *ccache_name, luser[32], *srvdup;
retval = pam_get_user(pamh, &user, USER_PROMPT);
if (retval != PAM_SUCCESS)
return (retval);
PAM_LOG("Got user: %s", user);
retval = pam_get_item(pamh, PAM_RUSER, &sourceuser);
if (retval != PAM_SUCCESS)
return (retval);
PAM_LOG("Got ruser: %s", (const char *)sourceuser);
service = NULL;
pam_get_item(pamh, PAM_SERVICE, &service);
if (service == NULL)
service = "unknown";
PAM_LOG("Got service: %s", (const char *)service);
krbret = krb5_init_context(&pam_context);
if (krbret != 0) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
return (PAM_SERVICE_ERR);
}
PAM_LOG("Context initialised");
krb5_get_init_creds_opt_init(&opts);
if (openpam_get_option(pamh, PAM_OPT_FORWARDABLE))
krb5_get_init_creds_opt_set_forwardable(&opts, 1);
PAM_LOG("Credentials initialised");
krbret = krb5_cc_register(pam_context, &krb5_mcc_ops, FALSE);
if (krbret != 0 && krbret != KRB5_CC_TYPE_EXISTS) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
retval = PAM_SERVICE_ERR;
goto cleanup3;
}
PAM_LOG("Done krb5_cc_register()");
/* Get principal name */
if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF))
asprintf(&principal, "%s/%s", (const char *)sourceuser, user);
else
principal = strdup(user);
PAM_LOG("Created principal: %s", principal);
krbret = krb5_parse_name(pam_context, principal, &princ);
free(principal);
if (krbret != 0) {
PAM_LOG("Error krb5_parse_name(): %s",
krb5_get_err_text(pam_context, krbret));
PAM_VERBOSE_ERROR("Kerberos 5 error");
retval = PAM_SERVICE_ERR;
goto cleanup3;
}
PAM_LOG("Done krb5_parse_name()");
/* Now convert the principal name into something human readable */
princ_name = NULL;
krbret = krb5_unparse_name(pam_context, princ, &princ_name);
if (krbret != 0) {
PAM_LOG("Error krb5_unparse_name(): %s",
krb5_get_err_text(pam_context, krbret));
PAM_VERBOSE_ERROR("Kerberos 5 error");
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
PAM_LOG("Got principal: %s", princ_name);
/* Get password */
retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT);
if (retval != PAM_SUCCESS)
goto cleanup2;
PAM_LOG("Got password");
if (openpam_get_option(pamh, PAM_OPT_NO_USER_CHECK))
PAM_LOG("Skipping local user check");
else {
/* Verify the local user exists (AFTER getting the password) */
if (strchr(user, '@')) {
/* get a local account name for this principal */
krbret = krb5_aname_to_localname(pam_context, princ,
sizeof(luser), luser);
if (krbret != 0) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
PAM_LOG("Error krb5_aname_to_localname(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_USER_UNKNOWN;
goto cleanup2;
}
retval = pam_set_item(pamh, PAM_USER, luser);
if (retval != PAM_SUCCESS)
goto cleanup2;
PAM_LOG("PAM_USER Redone");
}
pwd = getpwnam(user);
if (pwd == NULL) {
retval = PAM_USER_UNKNOWN;
goto cleanup2;
}
PAM_LOG("Done getpwnam()");
}
/* Get a TGT */
memset(&creds, 0, sizeof(krb5_creds));
krbret = krb5_get_init_creds_password(pam_context, &creds, princ,
pass, NULL, pamh, 0, NULL, &opts);
if (krbret != 0) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
PAM_LOG("Error krb5_get_init_creds_password(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_AUTH_ERR;
goto cleanup2;
}
PAM_LOG("Got TGT");
/* Generate a temporary cache */
krbret = krb5_cc_gen_new(pam_context, &krb5_mcc_ops, &ccache);
if (krbret != 0) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
PAM_LOG("Error krb5_cc_gen_new(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_SERVICE_ERR;
goto cleanup;
}
krbret = krb5_cc_initialize(pam_context, ccache, princ);
if (krbret != 0) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
PAM_LOG("Error krb5_cc_initialize(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_SERVICE_ERR;
goto cleanup;
}
krbret = krb5_cc_store_cred(pam_context, ccache, &creds);
if (krbret != 0) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
PAM_LOG("Error krb5_cc_store_cred(): %s",
krb5_get_err_text(pam_context, krbret));
krb5_cc_destroy(pam_context, ccache);
retval = PAM_SERVICE_ERR;
goto cleanup;
}
PAM_LOG("Credentials stashed");
/* Verify them */
if ((srvdup = strdup(service)) == NULL) {
retval = PAM_BUF_ERR;
goto cleanup;
}
krbret = verify_krb_v5_tgt(pam_context, ccache, srvdup,
openpam_get_option(pamh, PAM_OPT_DEBUG) ? 1 : 0);
free(srvdup);
if (krbret == -1) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
krb5_cc_destroy(pam_context, ccache);
retval = PAM_AUTH_ERR;
goto cleanup;
}
PAM_LOG("Credentials stash verified");
retval = pam_get_data(pamh, "ccache", &ccache_data);
if (retval == PAM_SUCCESS) {
krb5_cc_destroy(pam_context, ccache);
PAM_VERBOSE_ERROR("Kerberos 5 error");
retval = PAM_AUTH_ERR;
goto cleanup;
}
PAM_LOG("Credentials stash not pre-existing");
asprintf(&ccache_name, "%s:%s", krb5_cc_get_type(pam_context,
ccache), krb5_cc_get_name(pam_context, ccache));
if (ccache_name == NULL) {
PAM_VERBOSE_ERROR("Kerberos 5 error");
retval = PAM_BUF_ERR;
goto cleanup;
}
retval = pam_set_data(pamh, "ccache", ccache_name, cleanup_cache);
if (retval != 0) {
krb5_cc_destroy(pam_context, ccache);
PAM_VERBOSE_ERROR("Kerberos 5 error");
retval = PAM_SERVICE_ERR;
goto cleanup;
}
PAM_LOG("Credentials stash saved");
cleanup:
krb5_free_cred_contents(pam_context, &creds);
PAM_LOG("Done cleanup");
cleanup2:
krb5_free_principal(pam_context, princ);
PAM_LOG("Done cleanup2");
cleanup3:
if (princ_name)
free(princ_name);
krb5_free_context(pam_context);
PAM_LOG("Done cleanup3");
if (retval != PAM_SUCCESS)
PAM_VERBOSE_ERROR("Kerberos 5 refuses you");
return (retval);
}
PAM_EXTERN int
pam_sm_setcred(pam_handle_t *pamh, int flags,
int argc __unused, const char *argv[] __unused)
{
#ifdef _FREEFALL_CONFIG
return (PAM_SUCCESS);
#else
krb5_error_code krbret;
krb5_context pam_context;
krb5_principal princ;
krb5_creds creds;
krb5_ccache ccache_temp, ccache_perm;
krb5_cc_cursor cursor;
struct passwd *pwd = NULL;
int retval;
const char *cache_name, *q;
const void *user;
const void *cache_data;
char *cache_name_buf = NULL, *p;
uid_t euid;
gid_t egid;
if (flags & PAM_DELETE_CRED)
return (PAM_SUCCESS);
if (flags & PAM_REFRESH_CRED)
return (PAM_SUCCESS);
if (flags & PAM_REINITIALIZE_CRED)
return (PAM_SUCCESS);
if (!(flags & PAM_ESTABLISH_CRED))
return (PAM_SERVICE_ERR);
/* If a persistent cache isn't desired, stop now. */
if (openpam_get_option(pamh, PAM_OPT_NO_CCACHE) ||
openpam_get_option(pamh, PAM_OPT_NO_USER_CHECK))
return (PAM_SUCCESS);
PAM_LOG("Establishing credentials");
/* Get username */
retval = pam_get_item(pamh, PAM_USER, &user);
if (retval != PAM_SUCCESS)
return (retval);
PAM_LOG("Got user: %s", (const char *)user);
krbret = krb5_init_context(&pam_context);
if (krbret != 0) {
PAM_LOG("Error krb5_init_context() failed");
return (PAM_SERVICE_ERR);
}
PAM_LOG("Context initialised");
euid = geteuid(); /* Usually 0 */
egid = getegid();
PAM_LOG("Got euid, egid: %d %d", euid, egid);
/* Retrieve the temporary cache */
retval = pam_get_data(pamh, "ccache", &cache_data);
if (retval != PAM_SUCCESS) {
retval = PAM_CRED_UNAVAIL;
goto cleanup3;
}
krbret = krb5_cc_resolve(pam_context, cache_data, &ccache_temp);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)cache_data,
krb5_get_err_text(pam_context, krbret));
retval = PAM_SERVICE_ERR;
goto cleanup3;
}
/* Get the uid. This should exist. */
pwd = getpwnam(user);
if (pwd == NULL) {
retval = PAM_USER_UNKNOWN;
goto cleanup3;
}
PAM_LOG("Done getpwnam()");
/* Avoid following a symlink as root */
if (setegid(pwd->pw_gid)) {
retval = PAM_SERVICE_ERR;
goto cleanup3;
}
if (seteuid(pwd->pw_uid)) {
retval = PAM_SERVICE_ERR;
goto cleanup3;
}
PAM_LOG("Done setegid() & seteuid()");
/* Get the cache name */
cache_name = openpam_get_option(pamh, PAM_OPT_CCACHE);
if (cache_name == NULL) {
asprintf(&cache_name_buf, "FILE:/tmp/krb5cc_%d", pwd->pw_uid);
cache_name = cache_name_buf;
}
p = calloc(PATH_MAX + 16, sizeof(char));
q = cache_name;
if (p == NULL) {
PAM_LOG("Error malloc(): failure");
retval = PAM_BUF_ERR;
goto cleanup3;
}
cache_name = p;
/* convert %u and %p */
while (*q) {
if (*q == '%') {
q++;
if (*q == 'u') {
sprintf(p, "%d", pwd->pw_uid);
p += strlen(p);
}
else if (*q == 'p') {
sprintf(p, "%d", getpid());
p += strlen(p);
}
else {
/* Not a special token */
*p++ = '%';
q--;
}
q++;
}
else {
*p++ = *q++;
}
}
PAM_LOG("Got cache_name: %s", cache_name);
/* Initialize the new ccache */
krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_get_principal(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_SERVICE_ERR;
goto cleanup3;
}
krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_resolve(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
krbret = krb5_cc_initialize(pam_context, ccache_perm, princ);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_initialize(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
PAM_LOG("Cache initialised");
/* Prepare for iteration over creds */
krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_start_seq_get(): %s",
krb5_get_err_text(pam_context, krbret));
krb5_cc_destroy(pam_context, ccache_perm);
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
PAM_LOG("Prepared for iteration");
/* Copy the creds (should be two of them) */
while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp,
&cursor, &creds) == 0)) {
krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_store_cred(): %s",
krb5_get_err_text(pam_context, krbret));
krb5_cc_destroy(pam_context, ccache_perm);
krb5_free_cred_contents(pam_context, &creds);
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
krb5_free_cred_contents(pam_context, &creds);
PAM_LOG("Iteration");
}
krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor);
PAM_LOG("Done iterating");
if (strstr(cache_name, "FILE:") == cache_name) {
if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) {
PAM_LOG("Error chown(): %s", strerror(errno));
krb5_cc_destroy(pam_context, ccache_perm);
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
PAM_LOG("Done chown()");
if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) {
PAM_LOG("Error chmod(): %s", strerror(errno));
krb5_cc_destroy(pam_context, ccache_perm);
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
PAM_LOG("Done chmod()");
}
krb5_cc_close(pam_context, ccache_perm);
PAM_LOG("Cache closed");
retval = pam_setenv(pamh, "KRB5CCNAME", cache_name, 1);
if (retval != PAM_SUCCESS) {
PAM_LOG("Error pam_setenv(): %s", pam_strerror(pamh, retval));
krb5_cc_destroy(pam_context, ccache_perm);
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name);
cleanup2:
krb5_free_principal(pam_context, princ);
PAM_LOG("Done cleanup2");
cleanup3:
krb5_free_context(pam_context);
PAM_LOG("Done cleanup3");
seteuid(euid);
setegid(egid);
PAM_LOG("Done seteuid() & setegid()");
if (cache_name_buf != NULL)
free(cache_name_buf);
return (retval);
#endif
}
/*
* account management
*/
PAM_EXTERN int
pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused,
int argc __unused, const char *argv[] __unused)
{
krb5_error_code krbret;
krb5_context pam_context;
krb5_ccache ccache;
krb5_principal princ;
int retval;
const void *user;
const void *ccache_name;
retval = pam_get_item(pamh, PAM_USER, &user);
if (retval != PAM_SUCCESS)
return (retval);
PAM_LOG("Got user: %s", (const char *)user);
retval = pam_get_data(pamh, "ccache", &ccache_name);
if (retval != PAM_SUCCESS)
return (PAM_SUCCESS);
PAM_LOG("Got credentials");
krbret = krb5_init_context(&pam_context);
if (krbret != 0) {
PAM_LOG("Error krb5_init_context() failed");
return (PAM_PERM_DENIED);
}
PAM_LOG("Context initialised");
krbret = krb5_cc_resolve(pam_context, (const char *)ccache_name, &ccache);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)ccache_name,
krb5_get_err_text(pam_context, krbret));
krb5_free_context(pam_context);
return (PAM_PERM_DENIED);
}
PAM_LOG("Got ccache %s", (const char *)ccache_name);
krbret = krb5_cc_get_principal(pam_context, ccache, &princ);
if (krbret != 0) {
PAM_LOG("Error krb5_cc_get_principal(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_PERM_DENIED;;
goto cleanup;
}
PAM_LOG("Got principal");
if (krb5_kuserok(pam_context, princ, (const char *)user))
retval = PAM_SUCCESS;
else
retval = PAM_PERM_DENIED;
krb5_free_principal(pam_context, princ);
PAM_LOG("Done kuserok()");
cleanup:
krb5_free_context(pam_context);
PAM_LOG("Done cleanup");
return (retval);
}
/*
* password management
*/
PAM_EXTERN int
pam_sm_chauthtok(pam_handle_t *pamh, int flags,
int argc __unused, const char *argv[] __unused)
{
krb5_error_code krbret;
krb5_context pam_context;
krb5_creds creds;
krb5_principal princ;
krb5_get_init_creds_opt opts;
krb5_data result_code_string, result_string;
int result_code, retval;
const char *pass;
const void *user;
char *princ_name, *passdup;
if (!(flags & PAM_UPDATE_AUTHTOK))
return (PAM_AUTHTOK_ERR);
retval = pam_get_item(pamh, PAM_USER, &user);
if (retval != PAM_SUCCESS)
return (retval);
PAM_LOG("Got user: %s", (const char *)user);
krbret = krb5_init_context(&pam_context);
if (krbret != 0) {
PAM_LOG("Error krb5_init_context() failed");
return (PAM_SERVICE_ERR);
}
PAM_LOG("Context initialised");
krb5_get_init_creds_opt_init(&opts);
PAM_LOG("Credentials options initialised");
/* Get principal name */
krbret = krb5_parse_name(pam_context, (const char *)user, &princ);
if (krbret != 0) {
PAM_LOG("Error krb5_parse_name(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_USER_UNKNOWN;
goto cleanup3;
}
/* Now convert the principal name into something human readable */
princ_name = NULL;
krbret = krb5_unparse_name(pam_context, princ, &princ_name);
if (krbret != 0) {
PAM_LOG("Error krb5_unparse_name(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_SERVICE_ERR;
goto cleanup2;
}
PAM_LOG("Got principal: %s", princ_name);
/* Get password */
retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT);
if (retval != PAM_SUCCESS)
goto cleanup2;
PAM_LOG("Got password");
memset(&creds, 0, sizeof(krb5_creds));
krbret = krb5_get_init_creds_password(pam_context, &creds, princ,
pass, NULL, pamh, 0, "kadmin/changepw", &opts);
if (krbret != 0) {
PAM_LOG("Error krb5_get_init_creds_password(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_AUTH_ERR;
goto cleanup2;
}
PAM_LOG("Credentials established");
/* Now get the new password */
for (;;) {
retval = pam_get_authtok(pamh,
PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT);
if (retval != PAM_TRY_AGAIN)
break;
pam_error(pamh, "Mismatch; try again, EOF to quit.");
}
if (retval != PAM_SUCCESS)
goto cleanup;
PAM_LOG("Got new password");
/* Change it */
if ((passdup = strdup(pass)) == NULL) {
retval = PAM_BUF_ERR;
goto cleanup;
}
krbret = krb5_change_password(pam_context, &creds, passdup,
&result_code, &result_code_string, &result_string);
free(passdup);
if (krbret != 0) {
PAM_LOG("Error krb5_change_password(): %s",
krb5_get_err_text(pam_context, krbret));
retval = PAM_AUTHTOK_ERR;
goto cleanup;
}
if (result_code) {
PAM_LOG("Error krb5_change_password(): (result_code)");
retval = PAM_AUTHTOK_ERR;
goto cleanup;
}
PAM_LOG("Password changed");
if (result_string.data)
free(result_string.data);
if (result_code_string.data)
free(result_code_string.data);
cleanup:
krb5_free_cred_contents(pam_context, &creds);
PAM_LOG("Done cleanup");
cleanup2:
krb5_free_principal(pam_context, princ);
PAM_LOG("Done cleanup2");
cleanup3:
if (princ_name)
free(princ_name);
krb5_free_context(pam_context);
PAM_LOG("Done cleanup3");
return (retval);
}
PAM_MODULE_ENTRY("pam_krb5");
/*
* This routine with some modification is from the MIT V5B6 appl/bsd/login.c
* Modified by Sam Hartman <hartmans@mit.edu> to support PAM services
* for Debian.
*
* Verify the Kerberos ticket-granting ticket just retrieved for the
* user. If the Kerberos server doesn't respond, assume the user is
* trying to fake us out (since we DID just get a TGT from what is
* supposedly our KDC). If the host/<host> service is unknown (i.e.,
* the local keytab doesn't have it), and we cannot find another
* service we do have, let her in.
*
* Returns 1 for confirmation, -1 for failure, 0 for uncertainty.
*/
/* ARGSUSED */
static int
verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache,
char *pam_service, int debug)
{
krb5_error_code retval;
krb5_principal princ;
krb5_keyblock *keyblock;
krb5_data packet;
krb5_auth_context auth_context;
char phost[BUFSIZ];
const char *services[3], **service;
packet.data = 0;
/* If possible we want to try and verify the ticket we have
* received against a keytab. We will try multiple service
* principals, including at least the host principal and the PAM
* service principal. The host principal is preferred because access
* to that key is generally sufficient to compromise root, while the
* service key for this PAM service may be less carefully guarded.
* It is important to check the keytab first before the KDC so we do
* not get spoofed by a fake KDC.
*/
services[0] = "host";
services[1] = pam_service;
services[2] = NULL;
keyblock = 0;
retval = -1;
for (service = &services[0]; *service != NULL; service++) {
retval = krb5_sname_to_principal(context, NULL, *service,
KRB5_NT_SRV_HST, &princ);
if (retval != 0) {
if (debug)
syslog(LOG_DEBUG,
"pam_krb5: verify_krb_v5_tgt(): %s: %s",
"krb5_sname_to_principal()",
krb5_get_err_text(context, retval));
return -1;
}
/* Extract the name directly. */
strncpy(phost, compat_princ_component(context, princ, 1),
BUFSIZ);
phost[BUFSIZ - 1] = '\0';
/*
* Do we have service/<host> keys?
* (use default/configured keytab, kvno IGNORE_VNO to get the
* first match, and ignore enctype.)
*/
retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0,
&keyblock);
if (retval != 0)
continue;
break;
}
if (retval != 0) { /* failed to find key */
/* Keytab or service key does not exist */
if (debug)
syslog(LOG_DEBUG,
"pam_krb5: verify_krb_v5_tgt(): %s: %s",
"krb5_kt_read_service_key()",
krb5_get_err_text(context, retval));
retval = 0;
goto cleanup;
}
if (keyblock)
krb5_free_keyblock(context, keyblock);
/* Talk to the kdc and construct the ticket. */
auth_context = NULL;
retval = krb5_mk_req(context, &auth_context, 0, *service, phost,
NULL, ccache, &packet);
if (auth_context) {
krb5_auth_con_free(context, auth_context);
auth_context = NULL; /* setup for rd_req */
}
if (retval) {
if (debug)
syslog(LOG_DEBUG,
"pam_krb5: verify_krb_v5_tgt(): %s: %s",
"krb5_mk_req()",
krb5_get_err_text(context, retval));
retval = -1;
goto cleanup;
}
/* Try to use the ticket. */
retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL,
NULL, NULL);
if (retval) {
if (debug)
syslog(LOG_DEBUG,
"pam_krb5: verify_krb_v5_tgt(): %s: %s",
"krb5_rd_req()",
krb5_get_err_text(context, retval));
retval = -1;
}
else
retval = 1;
cleanup:
if (packet.data)
compat_free_data_contents(context, &packet);
krb5_free_principal(context, princ);
return retval;
}
/* Free the memory for cache_name. Called by pam_end() */
/* ARGSUSED */
static void
cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused)
{
krb5_context pam_context;
krb5_ccache ccache;
krb5_error_code krbret;
if (krb5_init_context(&pam_context))
return;
krbret = krb5_cc_resolve(pam_context, data, &ccache);
if (krbret == 0)
krb5_cc_destroy(pam_context, ccache);
krb5_free_context(pam_context);
free(data);
}
#ifdef COMPAT_HEIMDAL
#ifdef COMPAT_MIT
#error This cannot be MIT and Heimdal compatible!
#endif
#endif
#ifndef COMPAT_HEIMDAL
#ifndef COMPAT_MIT
#error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified!
#endif
#endif
#ifdef COMPAT_HEIMDAL
/* ARGSUSED */
static const char *
compat_princ_component(krb5_context context __unused, krb5_principal princ, int n)
{
return princ->name.name_string.val[n];
}
/* ARGSUSED */
static void
compat_free_data_contents(krb5_context context __unused, krb5_data * data)
{
krb5_xfree(data->data);
}
#endif
#ifdef COMPAT_MIT
static const char *
compat_princ_component(krb5_context context, krb5_principal princ, int n)
{
return krb5_princ_component(context, princ, n)->data;
}
static void
compat_free_data_contents(krb5_context context, krb5_data * data)
{
krb5_free_data_contents(context, data);
}
#endif