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/*
* Dropbear SSH
*
* Copyright (c) 2002,2003 Matt Johnston
* Copyright (c) 2004 by Mihnea Stoenescu
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE. */
#include "includes.h"
#include "buffer.h"
#include "dbutil.h"
#include "session.h"
#include "ssh.h"
#include "runopts.h"
#include "auth.h"
#include "agentfwd.h"
#ifdef ENABLE_CLI_PUBKEY_AUTH
static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign);
/* Called when we receive a SSH_MSG_USERAUTH_FAILURE for a pubkey request.
* We use it to remove the key we tried from the list */
void cli_pubkeyfail() {
m_list_elem *iter;
for (iter = cli_opts.privkeys->first; iter; iter = iter->next) {
sign_key *iter_key = (sign_key*)iter->item;
if (iter_key == cli_ses.lastprivkey)
{
/* found the failing key */
list_remove(iter);
sign_key_free(iter_key);
cli_ses.lastprivkey = NULL;
return;
}
}
}
void recv_msg_userauth_pk_ok() {
m_list_elem *iter;
buffer* keybuf = NULL;
char* algotype = NULL;
unsigned int algolen;
enum signkey_type keytype;
unsigned int remotelen;
TRACE(("enter recv_msg_userauth_pk_ok"))
algotype = (char *)buf_getstring(ses.payload, &algolen);
keytype = signkey_type_from_name(algotype, algolen);
TRACE(("recv_msg_userauth_pk_ok: type %d", keytype))
m_free(algotype);
keybuf = buf_new(MAX_PUBKEY_SIZE);
remotelen = buf_getint(ses.payload);
/* Iterate through our keys, find which one it was that matched, and
* send a real request with that key */
for (iter = cli_opts.privkeys->first; iter; iter = iter->next) {
sign_key *key = (sign_key*)iter->item;
if (key->type != keytype) {
/* Types differed */
TRACE(("types differed"))
continue;
}
/* Now we compare the contents of the key */
keybuf->pos = keybuf->len = 0;
buf_put_pub_key(keybuf, key, keytype);
buf_setpos(keybuf, 0);
buf_incrpos(keybuf, 4); /* first int is the length of the remainder (ie
remotelen) which has already been taken from
the remote buffer */
if (keybuf->len-4 != remotelen) {
TRACE(("lengths differed: localh %d remote %d", keybuf->len, remotelen))
/* Lengths differed */
continue;
}
if (memcmp(buf_getptr(keybuf, remotelen),
buf_getptr(ses.payload, remotelen), remotelen) != 0) {
/* Data didn't match this key */
TRACE(("data differed"))
continue;
}
/* Success */
break;
}
buf_free(keybuf);
if (iter != NULL) {
TRACE(("matching key"))
/* XXX TODO: if it's an encrypted key, here we ask for their
* password */
send_msg_userauth_pubkey((sign_key*)iter->item, keytype, 1);
} else {
TRACE(("That was whacky. We got told that a key was valid, but it didn't match our list. Sounds like dodgy code on Dropbear's part"))
}
TRACE(("leave recv_msg_userauth_pk_ok"))
}
void cli_buf_put_sign(buffer* buf, sign_key *key, int type,
buffer *data_buf) {
#ifdef ENABLE_CLI_AGENTFWD
if (key->source == SIGNKEY_SOURCE_AGENT) {
/* Format the agent signature ourselves, as buf_put_sign would. */
buffer *sigblob;
sigblob = buf_new(MAX_PUBKEY_SIZE);
agent_buf_sign(sigblob, key, data_buf);
buf_putbufstring(buf, sigblob);
buf_free(sigblob);
} else
#endif /* ENABLE_CLI_AGENTFWD */
{
buf_put_sign(buf, key, type, data_buf);
}
}
/* TODO: make it take an agent reference to use as well */
static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign) {
const char *algoname = NULL;
unsigned int algolen;
buffer* sigbuf = NULL;
TRACE(("enter send_msg_userauth_pubkey"))
CHECKCLEARTOWRITE();
buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_REQUEST);
buf_putstring(ses.writepayload, (const unsigned char *)cli_opts.username,
strlen(cli_opts.username));
buf_putstring(ses.writepayload, (const unsigned char *)SSH_SERVICE_CONNECTION,
SSH_SERVICE_CONNECTION_LEN);
buf_putstring(ses.writepayload, (const unsigned char *)AUTH_METHOD_PUBKEY,
AUTH_METHOD_PUBKEY_LEN);
buf_putbyte(ses.writepayload, realsign);
algoname = signkey_name_from_type(type, &algolen);
buf_putstring(ses.writepayload, (const unsigned char *)algoname, algolen);
buf_put_pub_key(ses.writepayload, key, type);
if (realsign) {
TRACE(("realsign"))
/* We put the signature as well - this contains string(session id), then
* the contents of the write payload to this point */
sigbuf = buf_new(4 + ses.session_id->len + ses.writepayload->len);
buf_putbufstring(sigbuf, ses.session_id);
buf_putbytes(sigbuf, ses.writepayload->data, ses.writepayload->len);
cli_buf_put_sign(ses.writepayload, key, type, sigbuf);
buf_free(sigbuf); /* Nothing confidential in the buffer */
}
encrypt_packet();
TRACE(("leave send_msg_userauth_pubkey"))
}
/* Returns 1 if a key was tried */
int cli_auth_pubkey() {
TRACE(("enter cli_auth_pubkey"))
#ifdef ENABLE_CLI_AGENTFWD
if (!cli_opts.agent_keys_loaded) {
/* get the list of available keys from the agent */
cli_load_agent_keys(cli_opts.privkeys);
cli_opts.agent_keys_loaded = 1;
}
#endif
if (cli_opts.privkeys->first) {
sign_key * key = (sign_key*)cli_opts.privkeys->first->item;
/* Send a trial request */
send_msg_userauth_pubkey(key, key->type, 0);
cli_ses.lastprivkey = key;
TRACE(("leave cli_auth_pubkey-success"))
return 1;
} else {
/* no more keys left */
TRACE(("leave cli_auth_pubkey-failure"))
return 0;
}
}
void cli_auth_pubkey_cleanup() {
#ifdef ENABLE_CLI_AGENTFWD
m_close(cli_opts.agent_fd);
cli_opts.agent_fd = -1;
#endif
while (cli_opts.privkeys->first) {
sign_key * key = list_remove(cli_opts.privkeys->first);
sign_key_free(key);
}
}
#endif /* Pubkey auth */
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