* 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.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by Markus Friedl.
- * 4. The name of the author may not be used to endorse or promote products
- * derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
*/
#include "includes.h"
-RCSID("$Id$");
-
-#include "ssh.h"
-#include "ssh2.h"
-#include "xmalloc.h"
-#include "buffer.h"
-#include "bufaux.h"
-#include "cipher.h"
-#include "compat.h"
-
-#include <openssl/bn.h>
-#include <openssl/dh.h>
+RCSID("$OpenBSD: kex.c,v 1.19 2001/02/04 15:32:23 stevesk Exp $");
#include <openssl/crypto.h>
#include <openssl/bio.h>
#include <openssl/dh.h>
#include <openssl/pem.h>
+#include "ssh2.h"
+#include "xmalloc.h"
+#include "buffer.h"
+#include "bufaux.h"
+#include "packet.h"
+#include "compat.h"
+#include "cipher.h"
#include "kex.h"
+#include "key.h"
+#include "log.h"
+
+#define KEX_COOKIE_LEN 16
Buffer *
kex_init(char *myproposal[PROPOSAL_MAX])
{
- char c = 0;
- unsigned char cookie[16];
+ int first_kex_packet_follows = 0;
+ u_char cookie[KEX_COOKIE_LEN];
u_int32_t rand = 0;
int i;
Buffer *ki = xmalloc(sizeof(*ki));
- for (i = 0; i < 16; i++) {
+ for (i = 0; i < KEX_COOKIE_LEN; i++) {
if (i % 4 == 0)
rand = arc4random();
cookie[i] = rand & 0xff;
buffer_append(ki, (char *)cookie, sizeof cookie);
for (i = 0; i < PROPOSAL_MAX; i++)
buffer_put_cstring(ki, myproposal[i]);
- buffer_append(ki, &c, 1); /* boolean first_kex_packet_follows */
- buffer_put_int(ki, 0); /* uint32 0 (reserved for future extension) */
+ buffer_put_char(ki, first_kex_packet_follows);
+ buffer_put_int(ki, 0); /* uint32 reserved */
return ki;
}
+/* send kexinit, parse and save reply */
+void
+kex_exchange_kexinit(
+ Buffer *my_kexinit, Buffer *peer_kexint,
+ char *peer_proposal[PROPOSAL_MAX])
+{
+ int i;
+ char *ptr;
+ int plen;
+
+ debug("send KEXINIT");
+ packet_start(SSH2_MSG_KEXINIT);
+ packet_put_raw(buffer_ptr(my_kexinit), buffer_len(my_kexinit));
+ packet_send();
+ packet_write_wait();
+ debug("done");
+
+ /*
+ * read and save raw KEXINIT payload in buffer. this is used during
+ * computation of the session_id and the session keys.
+ */
+ debug("wait KEXINIT");
+ packet_read_expect(&plen, SSH2_MSG_KEXINIT);
+ ptr = packet_get_raw(&plen);
+ buffer_append(peer_kexint, ptr, plen);
+
+ /* parse packet and save algorithm proposal */
+ /* skip cookie */
+ for (i = 0; i < KEX_COOKIE_LEN; i++)
+ packet_get_char();
+ /* extract kex init proposal strings */
+ for (i = 0; i < PROPOSAL_MAX; i++) {
+ peer_proposal[i] = packet_get_string(NULL);
+ debug("got kexinit: %s", peer_proposal[i]);
+ }
+ /* first kex follow / reserved */
+ i = packet_get_char();
+ debug("first kex follow: %d ", i);
+ i = packet_get_int();
+ debug("reserved: %d ", i);
+ packet_done();
+ debug("done");
+}
+
/* diffie-hellman-group1-sha1 */
int
int n = BN_num_bits(dh_pub);
int bits_set = 0;
- /* we only accept g==2 */
- if (!BN_is_word(dh->g, 2)) {
- log("invalid DH base != 2");
- return 0;
- }
if (dh_pub->neg) {
log("invalid public DH value: negativ");
return 0;
return 0;
}
-DH *
-dh_new_group1()
+void
+dh_gen_key(DH *dh)
{
- static char *group1 =
- "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
- "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
- "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
- "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
- "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381"
- "FFFFFFFF" "FFFFFFFF";
- DH *dh;
- int ret, tries = 0;
- dh = DH_new();
- if(dh == NULL)
- fatal("DH_new");
- ret = BN_hex2bn(&dh->p, group1);
- if(ret<0)
- fatal("BN_hex2bn");
- dh->g = BN_new();
- if(dh->g == NULL)
- fatal("DH_new g");
- BN_set_word(dh->g, 2);
+ int tries = 0;
+
do {
if (DH_generate_key(dh) == 0)
fatal("DH_generate_key");
if (tries++ > 10)
fatal("dh_new_group1: too many bad keys: giving up");
} while (!dh_pub_is_valid(dh, dh->pub_key));
- return dh;
}
-void
-bignum_print(BIGNUM *b)
+DH *
+dh_new_group_asc(const char *gen, const char *modulus)
+{
+ DH *dh;
+ int ret;
+
+ dh = DH_new();
+ if (dh == NULL)
+ fatal("DH_new");
+
+ if ((ret = BN_hex2bn(&dh->p, modulus)) < 0)
+ fatal("BN_hex2bn p");
+ if ((ret = BN_hex2bn(&dh->g, gen)) < 0)
+ fatal("BN_hex2bn g");
+
+ return (dh);
+}
+
+/*
+ * This just returns the group, we still need to generate the exchange
+ * value.
+ */
+
+DH *
+dh_new_group(BIGNUM *gen, BIGNUM *modulus)
{
- BN_print_fp(stderr,b);
+ DH *dh;
+
+ dh = DH_new();
+ if (dh == NULL)
+ fatal("DH_new");
+ dh->p = modulus;
+ dh->g = gen;
+
+ return (dh);
+}
+
+DH *
+dh_new_group1(void)
+{
+ static char *gen = "2", *group1 =
+ "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
+ "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
+ "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
+ "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
+ "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381"
+ "FFFFFFFF" "FFFFFFFF";
+
+ return (dh_new_group_asc(gen, group1));
}
void
-dump_digest(unsigned char *digest, int len)
+dump_digest(u_char *digest, int len)
{
int i;
for (i = 0; i< len; i++){
fprintf(stderr, "\n");
}
-unsigned char *
+u_char *
kex_hash(
char *client_version_string,
char *server_version_string,
BIGNUM *shared_secret)
{
Buffer b;
- static unsigned char digest[EVP_MAX_MD_SIZE];
+ static u_char digest[EVP_MAX_MD_SIZE];
+ EVP_MD *evp_md = EVP_sha1();
+ EVP_MD_CTX md;
+
+ buffer_init(&b);
+ buffer_put_string(&b, client_version_string, strlen(client_version_string));
+ buffer_put_string(&b, server_version_string, strlen(server_version_string));
+
+ /* kexinit messages: fake header: len+SSH2_MSG_KEXINIT */
+ buffer_put_int(&b, ckexinitlen+1);
+ buffer_put_char(&b, SSH2_MSG_KEXINIT);
+ buffer_append(&b, ckexinit, ckexinitlen);
+ buffer_put_int(&b, skexinitlen+1);
+ buffer_put_char(&b, SSH2_MSG_KEXINIT);
+ buffer_append(&b, skexinit, skexinitlen);
+
+ buffer_put_string(&b, serverhostkeyblob, sbloblen);
+ buffer_put_bignum2(&b, client_dh_pub);
+ buffer_put_bignum2(&b, server_dh_pub);
+ buffer_put_bignum2(&b, shared_secret);
+
+#ifdef DEBUG_KEX
+ buffer_dump(&b);
+#endif
+
+ EVP_DigestInit(&md, evp_md);
+ EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
+ EVP_DigestFinal(&md, digest, NULL);
+
+ buffer_free(&b);
+
+#ifdef DEBUG_KEX
+ dump_digest(digest, evp_md->md_size);
+#endif
+ return digest;
+}
+
+u_char *
+kex_hash_gex(
+ char *client_version_string,
+ char *server_version_string,
+ char *ckexinit, int ckexinitlen,
+ char *skexinit, int skexinitlen,
+ char *serverhostkeyblob, int sbloblen,
+ int minbits, BIGNUM *prime, BIGNUM *gen,
+ BIGNUM *client_dh_pub,
+ BIGNUM *server_dh_pub,
+ BIGNUM *shared_secret)
+{
+ Buffer b;
+ static u_char digest[EVP_MAX_MD_SIZE];
EVP_MD *evp_md = EVP_sha1();
EVP_MD_CTX md;
buffer_append(&b, skexinit, skexinitlen);
buffer_put_string(&b, serverhostkeyblob, sbloblen);
+ buffer_put_int(&b, minbits);
+ buffer_put_bignum2(&b, prime);
+ buffer_put_bignum2(&b, gen);
buffer_put_bignum2(&b, client_dh_pub);
buffer_put_bignum2(&b, server_dh_pub);
buffer_put_bignum2(&b, shared_secret);
-
+
#ifdef DEBUG_KEX
buffer_dump(&b);
#endif
return digest;
}
-unsigned char *
-derive_key(int id, int need, char unsigned *hash, BIGNUM *shared_secret)
+u_char *
+derive_key(int id, int need, u_char *hash, BIGNUM *shared_secret)
{
Buffer b;
EVP_MD *evp_md = EVP_sha1();
char c = id;
int have;
int mdsz = evp_md->md_size;
- unsigned char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz);
+ u_char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz);
buffer_init(&b);
buffer_put_bignum2(&b, shared_secret);
get_match(char *client, char *server)
{
char *sproposals[MAX_PROP];
- char *p;
+ char *c, *s, *p, *ret, *cp, *sp;
int i, j, nproposals;
- for ((p = strtok(server, SEP)), i=0; p; (p = strtok(NULL, SEP)), i++) {
+ c = cp = xstrdup(client);
+ s = sp = xstrdup(server);
+
+ for ((p = strsep(&sp, SEP)), i=0; p && *p != '\0';
+ (p = strsep(&sp, SEP)), i++) {
if (i < MAX_PROP)
sproposals[i] = p;
else
}
nproposals = i;
- for ((p = strtok(client, SEP)), i=0; p; (p = strtok(NULL, SEP)), i++) {
- for (j = 0; j < nproposals; j++)
- if (strcmp(p, sproposals[j]) == 0)
- return xstrdup(p);
+ for ((p = strsep(&cp, SEP)), i=0; p && *p != '\0';
+ (p = strsep(&cp, SEP)), i++) {
+ for (j = 0; j < nproposals; j++) {
+ if (strcmp(p, sproposals[j]) == 0) {
+ ret = xstrdup(p);
+ xfree(c);
+ xfree(s);
+ return ret;
+ }
+ }
}
+ xfree(c);
+ xfree(s);
return NULL;
}
void
char *name = get_match(client, server);
if (name == NULL)
fatal("no matching cipher found: client %s server %s", client, server);
- enc->type = cipher_number(name);
-
- switch (enc->type) {
- case SSH_CIPHER_3DES_CBC:
- enc->key_len = 24;
- enc->iv_len = 8;
- enc->block_size = 8;
- break;
- case SSH_CIPHER_BLOWFISH_CBC:
- case SSH_CIPHER_CAST128_CBC:
- enc->key_len = 16;
- enc->iv_len = 8;
- enc->block_size = 8;
- break;
- case SSH_CIPHER_ARCFOUR:
- enc->key_len = 16;
- enc->iv_len = 0;
- enc->block_size = 8;
- break;
- default:
- fatal("unsupported cipher %s", name);
- }
+ enc->cipher = cipher_by_name(name);
+ if (enc->cipher == NULL)
+ fatal("matching cipher is not supported: %s", name);
enc->name = name;
enc->enabled = 0;
enc->iv = NULL;
}
mac->name = name;
mac->mac_len = mac->md->md_size;
- mac->key_len = datafellows ? 16 : mac->mac_len;
+ mac->key_len = (datafellows & SSH_BUG_HMAC) ? 16 : mac->mac_len;
mac->key = NULL;
mac->enabled = 0;
}
k->name = get_match(client, server);
if (k->name == NULL)
fatal("no kex alg");
- if (strcmp(k->name, KEX_DH1) != 0)
+ if (strcmp(k->name, KEX_DH1) == 0) {
+ k->kex_type = DH_GRP1_SHA1;
+ } else if (strcmp(k->name, KEX_DHGEX) == 0) {
+ k->kex_type = DH_GEX_SHA1;
+ } else
fatal("bad kex alg %s", k->name);
}
void
choose_hostkeyalg(Kex *k, char *client, char *server)
{
- k->hostkeyalg = get_match(client, server);
- if (k->hostkeyalg == NULL)
+ char *hostkeyalg = get_match(client, server);
+ if (hostkeyalg == NULL)
fatal("no hostkey alg");
- if (strcmp(k->hostkeyalg, KEX_DSS) != 0)
- fatal("bad hostkey alg %s", k->hostkeyalg);
+ k->hostkey_type = key_type_from_name(hostkeyalg);
+ if (k->hostkey_type == KEY_UNSPEC)
+ fatal("bad hostkey alg '%s'", hostkeyalg);
+ xfree(hostkeyalg);
}
Kex *
kex_choose_conf(char *cprop[PROPOSAL_MAX], char *sprop[PROPOSAL_MAX], int server)
{
- int i;
int mode;
int ctos; /* direction: if true client-to-server */
int need;
choose_kex(k, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
choose_hostkeyalg(k, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
- for (i = 0; i < PROPOSAL_MAX; i++) {
- xfree(cprop[i]);
- xfree(sprop[i]);
- }
need = 0;
for (mode = 0; mode < MODE_MAX; mode++) {
- if (need < k->enc[mode].key_len)
- need = k->enc[mode].key_len;
- if (need < k->enc[mode].iv_len)
- need = k->enc[mode].iv_len;
+ if (need < k->enc[mode].cipher->key_len)
+ need = k->enc[mode].cipher->key_len;
+ if (need < k->enc[mode].cipher->block_size)
+ need = k->enc[mode].cipher->block_size;
if (need < k->mac[mode].key_len)
need = k->mac[mode].key_len;
}
- /* need runden? */
-#define WE_NEED 32
- k->we_need = WE_NEED;
+ /* XXX need runden? */
k->we_need = need;
return k;
}
int
-kex_derive_keys(Kex *k, unsigned char *hash, BIGNUM *shared_secret)
+kex_derive_keys(Kex *k, u_char *hash, BIGNUM *shared_secret)
{
int i;
int mode;
int ctos;
- unsigned char *keys[NKEYS];
+ u_char *keys[NKEYS];
for (i = 0; i < NKEYS; i++)
keys[i] = derive_key('A'+i, k->we_need, hash, shared_secret);
andersk / openssh.git / blobdiff