kerberos.c

samba-3.0.22.tar.gz 编译smb服务器的源码

/* 
   Unix SMB/CIFS implementation.
   kerberos utility library
   Copyright (C) Andrew Tridgell 2001
   Copyright (C) Remus Koos 2001
   Copyright (C) Nalin Dahyabhai <[e-mail]> 2004.
   Copyright (C) Jeremy Allison 2004.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

#ifdef HAVE_KRB5

#define LIBADS_CCACHE_NAME "MEMORY:libads"

/*
  we use a prompter to avoid a crash bug in the kerberos libs when 
  dealing with empty passwords
  this prompter is just a string copy ...
*/
static krb5_error_code 
kerb_prompter(krb5_context ctx, void *data,
	       const char *name,
	       const char *banner,
	       int num_prompts,
	       krb5_prompt prompts[])
{
	if (num_prompts == 0) return 0;

	memset(prompts[0].reply->data, '\0', prompts[0].reply->length);
	if (prompts[0].reply->length > 0) {
		if (data) {
			strncpy(prompts[0].reply->data, data, prompts[0].reply->length-1);
			prompts[0].reply->length = strlen(prompts[0].reply->data);
		} else {
			prompts[0].reply->length = 0;
		}
	}
	return 0;
}

/*
  simulate a kinit, putting the tgt in the given cache location. If cache_name == NULL
  place in default cache location.
  [e-mail]
*/
int kerberos_kinit_password(const char *principal,
				const char *password,
				int time_offset,
				time_t *expire_time,
				const char *cache_name)
{
	krb5_context ctx = NULL;
	krb5_error_code code = 0;
	krb5_ccache cc = NULL;
	krb5_principal me;
	krb5_creds my_creds;

	initialize_krb5_error_table();
	if ((code = krb5_init_context(&ctx)))
		return code;

	if (time_offset != 0) {
		krb5_set_real_time(ctx, time(NULL) + time_offset, 0);
	}
	
	if ((code = krb5_cc_resolve(ctx, cache_name ?
			cache_name : krb5_cc_default_name(ctx), &cc))) {
		krb5_free_context(ctx);
		return code;
	}
	
	if ((code = krb5_parse_name(ctx, principal, &me))) {
		krb5_free_context(ctx);	
		return code;
	}
	
	if ((code = krb5_get_init_creds_password(ctx, &my_creds, me, CONST_DISCARD(char *,password), 
						 kerb_prompter, 
						 NULL, 0, NULL, NULL))) {
		krb5_free_principal(ctx, me);
		krb5_free_context(ctx);		
		return code;
	}
	
	if ((code = krb5_cc_initialize(ctx, cc, me))) {
		krb5_free_cred_contents(ctx, &my_creds);
		krb5_free_principal(ctx, me);
		krb5_free_context(ctx);		
		return code;
	}
	
	if ((code = krb5_cc_store_cred(ctx, cc, &my_creds))) {
		krb5_cc_close(ctx, cc);
		krb5_free_cred_contents(ctx, &my_creds);
		krb5_free_principal(ctx, me);
		krb5_free_context(ctx);		
		return code;
	}
	
	if (expire_time)
		*expire_time = (time_t) my_creds.times.endtime;

	krb5_cc_close(ctx, cc);
	krb5_free_cred_contents(ctx, &my_creds);
	krb5_free_principal(ctx, me);
	krb5_free_context(ctx);		
	
	return 0;
}



/* run kinit to setup our ccache */
int ads_kinit_password(ADS_STRUCT *ads)
{
	char *s;
	int ret;
	const char *account_name;
	fstring acct_name;

	if ( IS_DC ) {
		/* this will end up getting a ticket for [e-mail] */
		account_name = lp_workgroup();
	} else {
		/* always use the sAMAccountName for security = domain */
		/* global_myname()$@REA.LM */
		if ( lp_security() == SEC_DOMAIN ) {
			fstr_sprintf( acct_name, "%s$", global_myname() );
			account_name = acct_name;
		}
		else 
			/* This looks like host/global_myname()@REA.LM */
			account_name = ads->auth.user_name;
	}

	if (asprintf(&s, "%s@%s", account_name, ads->auth.realm) == -1) {
		return KRB5_CC_NOMEM;
	}

	if (!ads->auth.password) {
		return KRB5_LIBOS_CANTREADPWD;
	}
	
	ret = kerberos_kinit_password(s, ads->auth.password, ads->auth.time_offset,
			&ads->auth.expire, NULL);

	if (ret) {
		DEBUG(0,("kerberos_kinit_password %s failed: %s\n", 
			 s, error_message(ret)));
	}
	free(s);
	return ret;
}

int ads_kdestroy(const char *cc_name)
{
	krb5_error_code code;
	krb5_context ctx = NULL;
	krb5_ccache cc = NULL;

	initialize_krb5_error_table();
	if ((code = krb5_init_context (&ctx))) {
		DEBUG(3, ("ads_kdestroy: kdb5_init_context failed: %s\n", 
			error_message(code)));
		return code;
	}
  
	if (!cc_name) {
		if ((code = krb5_cc_default(ctx, &cc))) {
			krb5_free_context(ctx);
			return code;
		}
	} else {
		if ((code = krb5_cc_resolve(ctx, cc_name, &cc))) {
			DEBUG(3, ("ads_kdestroy: krb5_cc_resolve failed: %s\n",
				  error_message(code)));
			krb5_free_context(ctx);
			return code;
		}
	}

	if ((code = krb5_cc_destroy (ctx, cc))) {
		DEBUG(3, ("ads_kdestroy: krb5_cc_destroy failed: %s\n", 
			error_message(code)));
	}

	krb5_free_context (ctx);
	return code;
}

/************************************************************************
 Routine to fetch the salting principal for a service.  Active
 Directory may use a non-obvious principal name to generate the salt
 when it determines the key to use for encrypting tickets for a service,
 and hopefully we detected that when we joined the domain.
 ************************************************************************/

static char *kerberos_secrets_fetch_salting_principal(const char *service, int enctype)
{
	char *key = NULL;
	char *ret = NULL;

	asprintf(&key, "%s/%s/enctype=%d", SECRETS_SALTING_PRINCIPAL, service, enctype);
	if (!key) {
		return NULL;
	}
	ret = (char *)secrets_fetch(key, NULL);
	SAFE_FREE(key);
	return ret;
}

/************************************************************************
 Routine to get the salting principal for this service.  Active
 Directory may use a non-obvious principal name to generate the salt
 when it determines the key to use for encrypting tickets for a service,
 and hopefully we detected that when we joined the domain.
 Caller must free if return is not null.
 ************************************************************************/

krb5_principal kerberos_fetch_salt_princ_for_host_princ(krb5_context context,
							krb5_principal host_princ,
							int enctype)
{
	char *unparsed_name = NULL, *salt_princ_s = NULL;
	krb5_principal ret_princ = NULL;

	if (krb5_unparse_name(context, host_princ, &unparsed_name) != 0) {
		return (krb5_principal)NULL;
	}

	if ((salt_princ_s = kerberos_secrets_fetch_salting_principal(unparsed_name, enctype)) == NULL) {
		krb5_free_unparsed_name(context, unparsed_name);
		return (krb5_principal)NULL;
	}

	if (krb5_parse_name(context, salt_princ_s, &ret_princ) != 0) {
		krb5_free_unparsed_name(context, unparsed_name);
		SAFE_FREE(salt_princ_s);
		return (krb5_principal)NULL;
	}
	krb5_free_unparsed_name(context, unparsed_name);
	SAFE_FREE(salt_princ_s);
	return ret_princ;
}

/************************************************************************
 Routine to set the salting principal for this service.  Active
 Directory may use a non-obvious principal name to generate the salt
 when it determines the key to use for encrypting tickets for a service,
 and hopefully we detected that when we joined the domain.
 Setting principal to NULL deletes this entry.
 ************************************************************************/

BOOL kerberos_secrets_store_salting_principal(const char *service,
					      int enctype,
					      const char *principal)
{
	char *key = NULL;
	BOOL ret = False;
	krb5_context context = NULL;
	krb5_principal princ = NULL;
	char *princ_s = NULL;
	char *unparsed_name = NULL;

	krb5_init_context(&context);
	if (!context) {
		return False;
	}
	if (strchr_m(service, '@')) {
		asprintf(&princ_s, "%s", service);
	} else {
		asprintf(&princ_s, "%s@%s", service, lp_realm());
	}

	if (krb5_parse_name(context, princ_s, &princ) != 0) {
		goto out;
		
	}
	if (krb5_unparse_name(context, princ, &unparsed_name) != 0) {
		goto out;
	}

	asprintf(&key, "%s/%s/enctype=%d", SECRETS_SALTING_PRINCIPAL, unparsed_name, enctype);
	if (!key)  {
		goto out;
	}

	if ((principal != NULL) && (strlen(principal) > 0)) {
		ret = secrets_store(key, principal, strlen(principal) + 1);
	} else {
		ret = secrets_delete(key);
	}

 out:

	SAFE_FREE(key);
	SAFE_FREE(princ_s);

	if (unparsed_name) {
		krb5_free_unparsed_name(context, unparsed_name);
	}
	if (context) {
		krb5_free_context(context);
	}

	return ret;
}

/************************************************************************
 Routine to get initial credentials as a service ticket for the local machine.
 Returns a buffer initialized with krb5_mk_req_extended.
 ************************************************************************/

static krb5_error_code get_service_ticket(krb5_context ctx,
					krb5_ccache ccache,
					const char *service_principal,
					int enctype,
					krb5_data *p_outbuf)
{
	krb5_creds creds, *new_creds = NULL;
	char *service_s = NULL;
	char *machine_account = NULL, *password = NULL;
	krb5_data in_data;
	krb5_auth_context auth_context = NULL;
	krb5_error_code err = 0;

	ZERO_STRUCT(creds);

	asprintf(&machine_account, "%s$@%s", global_myname(), lp_realm());
	if (machine_account == NULL) {
		goto out;
	}
	password = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
	if (password == NULL) {
		goto out;
	}
	if ((err = kerberos_kinit_password(machine_account, password, 0, NULL, LIBADS_CCACHE_NAME)) != 0) {
		DEBUG(0,("get_service_ticket: kerberos_kinit_password %s@%s failed: %s\n", 
			machine_account,
			lp_realm(),
			error_message(err)));
		goto out;
	}

	/* Ok - the above call has gotten a TGT. Now we need to get a service
	   ticket to ourselves. */

	/* Set up the enctype and client and server principal fields for krb5_get_credentials. */
	kerberos_set_creds_enctype(&creds, enctype);

	if ((err = krb5_cc_get_principal(ctx, ccache, &creds.client))) {
		DEBUG(3, ("get_service_ticket: krb5_cc_get_principal failed: %s\n", 
			error_message(err)));
		goto out;
	}

	if (strchr_m(service_principal, '@')) {
		asprintf(&service_s, "%s", service_principal);
	} else {
		asprintf(&service_s, "%s@%s", service_principal, lp_realm());
	}

	if ((err = krb5_parse_name(ctx, service_s, &creds.server))) {
		DEBUG(0,("get_service_ticket: krb5_parse_name %s failed: %s\n", 
			service_s, error_message(err)));
		goto out;
	}

	if ((err = krb5_get_credentials(ctx, 0, ccache, &creds, &new_creds))) {
		DEBUG(5,("get_service_ticket: krb5_get_credentials for %s enctype %d failed: %s\n", 
			service_s, enctype, error_message(err)));
		goto out;
	}

	memset(&in_data, '\0', sizeof(in_data));
	if ((err = krb5_mk_req_extended(ctx, &auth_context, 0, &in_data,
			new_creds, p_outbuf)) != 0) {