pamsshagentauth-code/userauth_pubkey_from_id.c

102 lines
3.7 KiB
C

/*
* Copyright (c) 2008, Jamie Beverly.
* All rights reserved.
*
* 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 notice, this list of
* conditions and the following disclaimer.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY Jamie Beverly ``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 Jamie Beverly OR
* CONTRIBUTORS 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.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of Jamie Beverly.
*/
#include "includes.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include "xmalloc.h"
#include "ssh.h"
#include "ssh2.h"
#include "buffer.h"
#include "log.h"
#include "compat.h"
#include "key.h"
#include "pathnames.h"
#include "misc.h"
#include "secure_filename.h"
#include "identity.h"
#include "pam_user_authorized_keys.h"
/* extern u_char *session_id2;
extern uint8_t session_id_len;
*/
int
userauth_pubkey_from_id(const char *ruser, Identity * id, Buffer * session_id2)
{
Buffer b = { 0 };
char *pkalg = NULL;
u_char *pkblob = NULL, *sig = NULL;
u_int blen = 0, slen = 0;
int authenticated = 0;
pkalg = (char *) key_ssh_name(id->key);
/* first test if this key is even allowed */
if(! pam_user_key_allowed(ruser, id->key))
goto user_auth_clean_exit;
if(pamsshagentauth_key_to_blob(id->key, &pkblob, &blen) == 0)
goto user_auth_clean_exit;
/* construct packet to sign and test */
pamsshagentauth_buffer_init(&b);
pamsshagentauth_buffer_put_string(&b, session_id2->buf + session_id2->offset, session_id2->end - session_id2->offset);
pamsshagentauth_buffer_put_char(&b, SSH2_MSG_USERAUTH_TRUST_REQUEST);
pamsshagentauth_buffer_put_cstring(&b, ruser);
pamsshagentauth_buffer_put_cstring(&b, "pam_ssh_agent_auth");
pamsshagentauth_buffer_put_cstring(&b, "publickey");
pamsshagentauth_buffer_put_char(&b, 1);
pamsshagentauth_buffer_put_cstring(&b, pkalg);
pamsshagentauth_buffer_put_string(&b, pkblob, blen);
if(ssh_agent_sign(id->ac, id->key, &sig, &slen, pamsshagentauth_buffer_ptr(&b), pamsshagentauth_buffer_len(&b)) != 0)
goto user_auth_clean_exit;
/* test for correct signature */
if(pamsshagentauth_key_verify(id->key, sig, slen, pamsshagentauth_buffer_ptr(&b), pamsshagentauth_buffer_len(&b)) == 1)
authenticated = 1;
user_auth_clean_exit:
/* if(&b != NULL) */
pamsshagentauth_buffer_free(&b);
if(sig != NULL)
pamsshagentauth_xfree(sig);
if(pkblob != NULL)
pamsshagentauth_xfree(pkblob);
CRYPTO_cleanup_all_ex_data();
return authenticated;
}