/*
- * SSH-2 key creation method.
- * (Currently assumes 2 lots of any hash are sufficient to generate
- * keys/IVs for any cipher/MAC. SSH2_MKKEY_ITERS documents this assumption.)
+ * SSH-2 key derivation (RFC 4253 section 7.2).
*/
-#define SSH2_MKKEY_ITERS (2)
-static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, char chr,
- unsigned char *keyspace)
+static unsigned char *ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
+ char chr, int keylen)
{
const struct ssh_hash *h = ssh->kex->hash;
- void *s;
+ int keylen_padded;
+ unsigned char *key;
+ void *s, *s2;
+
+ if (keylen == 0)
+ return NULL;
+
+ /* Round up to the next multiple of hash length. */
+ keylen_padded = ((keylen + h->hlen - 1) / h->hlen) * h->hlen;
+
+ key = snewn(keylen_padded, unsigned char);
+
/* First hlen bytes. */
s = h->init();
if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
h->bytes(s, H, h->hlen);
h->bytes(s, &chr, 1);
h->bytes(s, ssh->v2_session_id, ssh->v2_session_id_len);
- h->final(s, keyspace);
- /* Next hlen bytes. */
- s = h->init();
- if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
- hash_mpint(h, s, K);
- h->bytes(s, H, h->hlen);
- h->bytes(s, keyspace, h->hlen);
- h->final(s, keyspace + h->hlen);
+ h->final(s, key);
+
+ /* Subsequent blocks of hlen bytes. */
+ if (keylen_padded > h->hlen) {
+ int offset;
+
+ s = h->init();
+ if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
+ hash_mpint(h, s, K);
+ h->bytes(s, H, h->hlen);
+
+ for (offset = h->hlen; offset < keylen_padded; offset += h->hlen) {
+ h->bytes(s, key + offset - h->hlen, h->hlen);
+ s2 = h->copy(s);
+ h->final(s2, key + offset);
+ }
+
+ h->free(s);
+ }
+
+ /* Now clear any extra bytes of key material beyond the length
+ * we're officially returning, because the caller won't know to
+ * smemclr those. */
+ if (keylen_padded > keylen)
+ smemclr(key + keylen, keylen_padded - keylen);
+
+ return key;
}
/*
return &list[i];
}
assert(!"No space in KEXINIT list");
+ return NULL;
}
/*
}
set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */
ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
+ if (!s->hostkeydata) {
+ bombout(("unable to parse key exchange reply packet"));
+ crStopV;
+ }
s->hkey = ssh->hostkey->newkey(ssh->hostkey,
s->hostkeydata, s->hostkeylen);
s->f = ssh2_pkt_getmp(pktin);
crStopV;
}
ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
+ if (!s->sigdata) {
+ bombout(("unable to parse key exchange reply packet"));
+ crStopV;
+ }
{
const char *err = dh_validate_f(ssh->kex_ctx, s->f);
}
ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
+ if (!s->hostkeydata) {
+ bombout(("unable to parse ECDH reply packet"));
+ crStopV;
+ }
hash_string(ssh->kex->hash, ssh->exhash, s->hostkeydata, s->hostkeylen);
s->hkey = ssh->hostkey->newkey(ssh->hostkey,
s->hostkeydata, s->hostkeylen);
char *keydata;
int keylen;
ssh_pkt_getstring(pktin, &keydata, &keylen);
+ if (!keydata) {
+ bombout(("unable to parse ECDH reply packet"));
+ crStopV;
+ }
hash_string(ssh->kex->hash, ssh->exhash, keydata, keylen);
s->K = ssh_ecdhkex_getkey(s->eckey, keydata, keylen);
if (!s->K) {
}
ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
+ if (!s->sigdata) {
+ bombout(("unable to parse key exchange reply packet"));
+ crStopV;
+ }
ssh_ecdhkex_freekey(s->eckey);
} else {
}
ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen);
+ if (!s->hostkeydata) {
+ bombout(("unable to parse RSA public key packet"));
+ crStopV;
+ }
hash_string(ssh->kex->hash, ssh->exhash,
s->hostkeydata, s->hostkeylen);
s->hkey = ssh->hostkey->newkey(ssh->hostkey,
{
char *keydata;
ssh_pkt_getstring(pktin, &keydata, &s->rsakeylen);
+ if (!keydata) {
+ bombout(("unable to parse RSA public key packet"));
+ crStopV;
+ }
s->rsakeydata = snewn(s->rsakeylen, char);
memcpy(s->rsakeydata, keydata, s->rsakeylen);
}
}
ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen);
+ if (!s->sigdata) {
+ bombout(("unable to parse signature packet"));
+ crStopV;
+ }
sfree(s->rsakeydata);
}
* hash from the _first_ key exchange.
*/
{
- unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
- assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh2_mkkey(ssh,s->K,s->exchange_hash,'C',keyspace);
- assert((ssh->cscipher->keylen+7) / 8 <=
- ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
- ssh2_mkkey(ssh,s->K,s->exchange_hash,'A',keyspace);
- assert(ssh->cscipher->blksize <=
- ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
- ssh2_mkkey(ssh,s->K,s->exchange_hash,'E',keyspace);
- assert(ssh->csmac->len <=
- ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
- smemclr(keyspace, sizeof(keyspace));
+ unsigned char *key;
+
+ key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'C',
+ (ssh->cscipher->keylen+7) / 8);
+ ssh->cscipher->setkey(ssh->cs_cipher_ctx, key);
+ smemclr(key, (ssh->cscipher->keylen+7) / 8);
+ sfree(key);
+
+ key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'A',
+ ssh->cscipher->blksize);
+ ssh->cscipher->setiv(ssh->cs_cipher_ctx, key);
+ smemclr(key, ssh->cscipher->blksize);
+ sfree(key);
+
+ key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'E',
+ ssh->csmac->keylen);
+ ssh->csmac->setkey(ssh->cs_mac_ctx, key);
+ smemclr(key, ssh->csmac->keylen);
+ sfree(key);
}
logeventf(ssh, "Initialised %.200s client->server encryption",
* hash from the _first_ key exchange.
*/
{
- unsigned char keyspace[SSH2_KEX_MAX_HASH_LEN * SSH2_MKKEY_ITERS];
- assert(sizeof(keyspace) >= ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh2_mkkey(ssh,s->K,s->exchange_hash,'D',keyspace);
- assert((ssh->sccipher->keylen+7) / 8 <=
- ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
- ssh2_mkkey(ssh,s->K,s->exchange_hash,'B',keyspace);
- assert(ssh->sccipher->blksize <=
- ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
- ssh2_mkkey(ssh,s->K,s->exchange_hash,'F',keyspace);
- assert(ssh->scmac->len <=
- ssh->kex->hash->hlen * SSH2_MKKEY_ITERS);
- ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
- smemclr(keyspace, sizeof(keyspace));
+ unsigned char *key;
+
+ key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'D',
+ (ssh->sccipher->keylen + 7) / 8);
+ ssh->sccipher->setkey(ssh->sc_cipher_ctx, key);
+ smemclr(key, (ssh->sccipher->keylen + 7) / 8);
+ sfree(key);
+
+ key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'B',
+ ssh->sccipher->blksize);
+ ssh->sccipher->setiv(ssh->sc_cipher_ctx, key);
+ smemclr(key, ssh->sccipher->blksize);
+ sfree(key);
+
+ key = ssh2_mkkey(ssh, s->K, s->exchange_hash, 'F',
+ ssh->scmac->keylen);
+ ssh->scmac->setkey(ssh->sc_mac_ctx, key);
+ smemclr(key, ssh->scmac->keylen);
+ sfree(key);
}
logeventf(ssh, "Initialised %.200s server->client encryption",
ssh->sccipher->text_name);
{
if (ssh->version == 2 &&
!conf_get_int(ssh->conf, CONF_ssh_no_shell) &&
- count234(ssh->channels) == 0 &&
+ (ssh->channels && count234(ssh->channels) == 0) &&
!(ssh->connshare && share_ndownstreams(ssh->connshare) > 0)) {
/*
* We used to send SSH_MSG_DISCONNECT here, because I'd
s->can_keyb_inter = conf_get_int(ssh->conf, CONF_try_ki_auth) &&
in_commasep_string("keyboard-interactive", methods, methlen);
#ifndef NO_GSSAPI
- if (!ssh->gsslibs)
- ssh->gsslibs = ssh_gss_setup(ssh->conf);
- s->can_gssapi = conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
- in_commasep_string("gssapi-with-mic", methods, methlen) &&
- ssh->gsslibs->nlibraries > 0;
+ if (conf_get_int(ssh->conf, CONF_try_gssapi_auth) &&
+ in_commasep_string("gssapi-with-mic", methods, methlen)) {
+ /* Try loading the GSS libraries and see if we
+ * have any. */
+ if (!ssh->gsslibs)
+ ssh->gsslibs = ssh_gss_setup(ssh->conf);
+ s->can_gssapi = (ssh->gsslibs->nlibraries > 0);
+ } else {
+ /* No point in even bothering to try to load the
+ * GSS libraries, if the user configuration and
+ * server aren't both prepared to attempt GSSAPI
+ * auth in the first place. */
+ s->can_gssapi = FALSE;
+ }
#endif
}
* Try to send data on all channels if we can.
*/
for (i = 0; NULL != (c = index234(ssh->channels, i)); i++)
- ssh2_try_send_and_unthrottle(ssh, c);
+ if (c->type != CHAN_SHARING)
+ ssh2_try_send_and_unthrottle(ssh, c);
}
}