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cm-12.0

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cli-authpubkey.c

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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"

#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() {

struct SignKeyList *keyitem;

struct SignKeyList **previtem;

TRACE(("enter cli_pubkeyfail"))

previtem = &cli_opts.privkeys;

/* Find the key we failed with, and remove it */

for (keyitem = cli_opts.privkeys; keyitem != NULL; keyitem = keyitem->next) {

if (keyitem == cli_ses.lastprivkey) {

*previtem = keyitem->next;

}

previtem = &keyitem;

}

sign_key_free(cli_ses.lastprivkey->key); /* It won't be used again */

m_free(cli_ses.lastprivkey);

TRACE(("leave cli_pubkeyfail"))

}

void recv_msg_userauth_pk_ok() {

struct SignKeyList *keyitem = NULL;

buffer* keybuf = NULL;

char* algotype = NULL;

unsigned int algolen;

int keytype;

unsigned int remotelen;

TRACE(("enter recv_msg_userauth_pk_ok"))

algotype = 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 (keyitem = cli_opts.privkeys; keyitem != NULL; keyitem = keyitem->next) {

if (keyitem->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, keyitem->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 (keyitem != NULL) {

TRACE(("matching key"))

/* XXX TODO: if it's an encrypted key, here we ask for their

* password */

send_msg_userauth_pubkey(keyitem->key, 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"))

}

/* 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;

int algolen;

buffer* sigbuf = NULL;

TRACE(("enter send_msg_userauth_pubkey"))

CHECKCLEARTOWRITE();

buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_REQUEST);

buf_putstring(ses.writepayload, cli_opts.username,

strlen(cli_opts.username));

buf_putstring(ses.writepayload, SSH_SERVICE_CONNECTION,

SSH_SERVICE_CONNECTION_LEN);

buf_putstring(ses.writepayload, AUTH_METHOD_PUBKEY,

AUTH_METHOD_PUBKEY_LEN);

buf_putbyte(ses.writepayload, realsign);

algoname = signkey_name_from_type(type, &algolen);

buf_putstring(ses.writepayload, 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 + SHA1_HASH_SIZE + ses.writepayload->len);

buf_putstring(sigbuf, ses.session_id, SHA1_HASH_SIZE);

buf_putbytes(sigbuf, ses.writepayload->data, ses.writepayload->len);

buf_put_sign(ses.writepayload, key, type, sigbuf->data, sigbuf->len);

buf_free(sigbuf); /* Nothing confidential in the buffer */

}

encrypt_packet();

TRACE(("leave send_msg_userauth_pubkey"))

}

int cli_auth_pubkey() {

TRACE(("enter cli_auth_pubkey"))

if (cli_opts.privkeys != NULL) {

/* Send a trial request */

send_msg_userauth_pubkey(cli_opts.privkeys->key,

cli_opts.privkeys->type, 0);

cli_ses.lastprivkey = cli_opts.privkeys;

TRACE(("leave cli_auth_pubkey-success"))

return 1;

} else {

TRACE(("leave cli_auth_pubkey-failure"))

return 0;

}

}

#endif /* Pubkey auth */