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Commit 1a59667e authored by Niels Möller's avatar Niels Möller
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Bug fixes. Handling of NEWKEYS messages. 

Rev: src/keyexchange.c:1.10
parent 523e27c4
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src/keyexchange.c
View file @ 1a59667e
......@@ -23,13 +23,17 @@
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "keyexchange.h"
#include "abstract_io.h"
#include "alist.h"
#include "connection.h"
#include "disconnect.h"
#include "format.h"
#include "keyexchange.h"
#include "parse.h"
#include "publickey_crypto.h"
#include "ssh.h"
#include "werror.h"
#include "xalloc.h"
#define NLISTS 10
......@@ -80,7 +84,7 @@ struct kexinit *parse_kexinit(struct lsh_string *packet)
}
res->kex_algorithms = lists[0];
res->server_host_key_algorithms = lists[1];
res->server_hostkey_algorithms = lists[1];
for (i=0; i<KEX_PARAMETERS; i++)
res->parameters[i] = lists[2 + i];
......@@ -110,7 +114,7 @@ struct lsh_string *format_kex(struct kexinit *kex)
SSH_MSG_KEXINIT,
16, kex->cookie,
kex->kex_algorithms,
kex->server_host_key_algorithms,
kex->server_hostkey_algorithms,
kex->parameters[KEX_ENCRYPTION_CLIENT_TO_SERVER],
kex->parameters[KEX_ENCRYPTION_SERVER_TO_CLIENT],
kex->parameters[KEX_MAC_CLIENT_TO_SERVER],
......@@ -128,7 +132,7 @@ int initiate_keyexchange(struct ssh_connection *connection,
struct lsh_string *first_packet)
{
int res;
lsh_string *s;
struct lsh_string *s;
kex->first_kex_packet_follows = !!first_packet;
connection->kexinits[connection->type] = kex;
......@@ -158,27 +162,25 @@ int select_algorithm(int *server_list, int *client_list)
/* Unknown algorithm */
continue;
for(j = 0; server_list[j] > 0; j++)
if (client_list[i] = server_list[j])
if (client_list[i] == server_list[j])
return client_list[i];
}
return 0;
}
int send_disconnect(struct ssh_conection, char *msg)
int disconnect_kex_failed(struct ssh_connection *connection, char *msg)
{
return A_WRITE(connection->write,
ssh_format("%c%i%z%z",
SSH_MSG_DISCONNECT,
SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
msg, ""));
format_disconnect(SSH_DISCONNECT_KEY_EXCHANGE_FAILED,
msg));
}
static int do_handle_kexinit(struct packet_hander *c,
static int do_handle_kexinit(struct packet_handler *c,
struct ssh_connection *connection,
struct lsh_string *packet)
{
struct handle_kexinit *closure = (struct handle_kexinit_packet *) c;
struct handle_kexinit *closure = (struct handle_kexinit *) c;
struct kexinit *msg = parse_kexinit(packet);
int kex_algorithm;
......@@ -187,8 +189,6 @@ static int do_handle_kexinit(struct packet_hander *c,
int parameters[KEX_PARAMETERS];
void **algorithms;
struct packet_handler newkeys;
int i;
if (!msg)
......@@ -204,10 +204,10 @@ static int do_handle_kexinit(struct packet_hander *c,
{
int res;
struct lsh_string *packet;
struct kexinit *sent = GENERATE_KEXINIT(closure->init);
struct kexinit *sent = MAKE_KEXINIT(closure->init);
connection->kexinits[connection->type] = sent;
packet = format_kex(sent);
connection->kexinits[connection->type] = lsh_string_dup(packet);
connection->literal_kexinits[connection->type] = lsh_string_dup(packet);
res = A_WRITE(connection->write, packet);
if (res != WRITE_OK)
......@@ -217,10 +217,10 @@ static int do_handle_kexinit(struct packet_hander *c,
/* Select key exchange algorithms */
if (connection->kexinits[0]->kex_algorithms[0]
== connection->kexinits[1]->kex_algorithms[1])
== connection->kexinits[1]->kex_algorithms[0])
{
/* Use this algorithm */
kex_algorithm = connection->sent_kexinit->kex_algorithms[0];
kex_algorithm = connection->kexinits[0]->kex_algorithms[0];
}
else
{
......@@ -232,55 +232,68 @@ static int do_handle_kexinit(struct packet_hander *c,
/* FIXME: Ignores that some keyechange algorithms require
* certain features of the host key algorithms. */
kex_algorithm = select_algorithm(connection->kexinits[0]->kex_algorithm,
connection->kexinits[1]->kex_algorithm);
kex_algorithm = select_algorithm(connection->kexinits[0]->kex_algorithms,
connection->kexinits[1]->kex_algorithms);
if (!kex_algorithm)
{
send_disconnect(connection, "No common key exchange method.\r\n");
disconnect_kex_failed(connection, "No common key exchange method.\r\n");
/* FIXME: We want the disconnect message to be sent
* before the socket is closed. How? */
return WRITE_CLOSED;
}
hostkey_algorithm
= select_algorithm(connection->kexinits[0]->server_hostkey_algorithms,
connection->kexinits[1]->server_hostkey_algorithms);
for(i = 0; i<KEX_PARAMETERS; i++)
{
parameters[i]
= select_algorithm(connection->kexinits[0]->parameters[i],
}
hostkey_algorithm
= select_algorithm(connection->kexinits[0]->server_hostkey_algorithms,
connection->kexinits[1]->server_hostkey_algorithms);
for(i = 0; i<KEX_PARAMETERS; i++)
{
parameters[i]
= select_algorithm(connection->kexinits[0]->parameters[i],
connection->kexinits[1]->parameters[i]);
if (!parameters[i])
{
send_disconnect(connection, "");
return WRITE_CLOSED;
}
if (!parameters[i])
{
disconnect_kex_failed(connection, "");
return WRITE_CLOSED;
}
}
algorithms = xalloc(KEX_PARAMETERS*sizeof(void *));
for (i = 0; i<KEX_PARAMETERS; i++)
algorithms[i] = ALIST_GET(closure->algorithms, parameters[i]);
return KEYEXCHANGE_INIT( (struct keyexchange_algorithm *)
ALIST_GET(closure->algorithms, kex_algorithm),
connection,
hostkey_algorithm,
ALIST_GET(closure->algorithms, hostkey_algorithm),
algorithms);
}
algorithms = xalloc(KEX_PARAMETERS*sizeof(void *));
struct packet_handler *make_kexinit_handler(struct make_kexinit *init,
struct alist *algorithms)
{
struct handle_kexinit *self = xalloc(sizeof(struct handle_kexinit));
for (i = 0; i<KEX_PARAMETERS; i++)
algorithms[i] = ALIST_GET(closure->algorithms, parameters[i]);
newkeys = make_newkeys_handler(ALIST_GET(closure->algorithms,
hostkey_algorithm),
algorithms);
self->super.handler = do_handle_kexinit;
self->init = init;
self->algorithms = algorithms;
return KEYEXCHANGE_INIT(ALIST_GET(algorithms, kex_algorithm), connection);
}
return &self->super;
}
/* FIXME: THis function can't handle IV:s at all */
struct lsh_string *kex_make_key(struct hash_instance *secret,
UINT32 key_length,
int type,
strut lsh_string *session_id)
struct lsh_string *session_id)
{
/* Indexed by the KEX_* values */
static const char *tags = "CDEF";
static /* const */ char *tags = "CDEF";
struct lsh_string *key;
struct hash_instance *hash;
......@@ -292,14 +305,14 @@ struct lsh_string *kex_make_key(struct hash_instance *secret,
return key;
hash = HASH_COPY(secret);
digest = alloca(hash->digest_size);
digest = alloca(hash->hash_size);
HASH_UPDATE(hash, tags + type, 1);
HASH_UPDATE(hash, 1, tags + type);
HASH_UPDATE(hash, session_id->length, session_id->data);
HASH_DIGEST(hash, digest);
if (key_length < hash->digest_size)
fatal("Not implemmented\n");
if (key_length < hash->hash_size)
fatal("Not implemented\n");
memcpy(key->data, digest, key_length);
lsh_free(hash);
......@@ -307,62 +320,115 @@ struct lsh_string *kex_make_key(struct hash_instance *secret,
}
struct crypto_instance *kex_make_encrypt(struct hash_instance *secret,
struct crypto_algorithm *algorithm,
void **algorithms,
int type,
struct ssh_connection *connection)
{
struct lsh_string *key = kex_make_key(secret, algorithm->key_size,
struct crypto_algorithm *algorithm = algorithms[type];
struct lsh_string *key;
struct crypto_instance *crypto;
if (!algorithm)
return NULL;
key = kex_make_key(secret, algorithm->key_size,
type, connection->session_id);
/* FIXME: No IV. Note that for DES, instantiating the crypto can
* fail, if the key happens to be weak. */
struct crypto_instance *crypt
= MAKE_ENCRYPT(algorithm, key->data);
crypto = MAKE_ENCRYPT(algorithm, key->data);
lsh_string_free(key);
return crypt;
return crypto;
}
struct crypto_instance *kex_make_decrypt(struct hash_instance *secret,
struct crypto_algorithm *algorithm,
void **algorithms,
int type,
struct ssh_connection *connection)
{
struct lsh_string *key = kex_make_key(secret, algorithm->key_size,
type, connection->session_id);
struct crypto_algorithm *algorithm = algorithms[type];
struct lsh_string *key;
struct crypto_instance *crypto;
if (!algorithm)
return NULL;
key = kex_make_key(secret, algorithm->key_size,
type, connection->session_id);
/* FIXME: No IV. Note that for DES, instantiating the crypto can
* fail, if the key happens to be weak. */
struct crypto_instance *crypt
= MAKE_DECRYPT(algorithm, key->data);
crypto = MAKE_DECRYPT(algorithm, key->data);
lsh_string_free(key);
return crypt;
return crypto;
}
struct mac_instance *kex_make_mac(struct hash_instance *secret,
struct mac_algorithm *algorithm,
void **algorithms,
int type,
struct ssh_connection *connection)
{
struct lsh_string *key = kex_make_key(secret, algorithm->key_size,
type, connection->session_id);
struct mac_algorithm *algorithm = algorithms[type];
struct mac_instance *mac;
struct lsh_string *key;
if (!algorithm)
return NULL;
struct mac_instance *mac
= MAKE_MAC(algorithm, key->data);
key = kex_make_key(secret, algorithm->key_size,
type, connection->session_id);
mac = MAKE_MAC(algorithm, key->data);
lsh_string_free(key);
return mac;
}
struct handle_newkeys
{
struct packet_handler super;
struct crypto_instance *crypto;
struct mac_instance *mac;
};
static int do_handle_newkeys(struct packet_handler *c,
struct ssh_connection *connection,
struct lsh_string *packet)
{
struct handle_newkeys *closure = (struct handle_newkeys *) c;
struct simple_buffer buffer;
UINT8 msg_number;
simple_buffer_init(&buffer, packet->length, packet->data);
if (parse_uint8(&buffer, &msg_number)
&& (msg_number == SSH_MSG_NEWKEYS)
&& (parse_eod(&buffer)))
{
connection->rec_crypto = closure->crypto;
connection->rec_mac = closure->mac;
connection->dispatch[SSH_MSG_NEWKEYS] = NULL;
lsh_free(closure);
return WRITE_OK;
}
else
return WRITE_CLOSED;
}
struct packet_handler *
make_newkeys_handler(struct signature_algorithm *hostkey_algorithm,
void *parameters)
make_newkeys_handler(struct crypto_instance *crypto,
struct mac_instance *mac)
{
struct handle_newkeys *self = xalloc(sizeof(struct handle_newkeys));
self->super.handler = do_handle_newkeys;
self->crypto = crypto;
self->mac = mac;
return &self->super;
}
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