X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/514702987c9252fcb0ab98882a6603b3bd0505ce..0183b2423868df18b2297c9052854e5a7db79425:/ssh.c

diff --git a/ssh.c b/ssh.c
index 115e902f..677ff870 100644
--- a/ssh.c
+++ b/ssh.c
@@ -371,19 +371,28 @@ const static struct ssh_kex *kex_algs[] = {
 
 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
 
-static void nullmac_key(unsigned char *key)
+static void *nullmac_make_context(void)
+{
+    return NULL;
+}
+static void nullmac_free_context(void *handle)
+{
+}
+static void nullmac_key(void *handle, unsigned char *key)
 {
 }
-static void nullmac_generate(unsigned char *blk, int len,
+static void nullmac_generate(void *handle, unsigned char *blk, int len,
 			     unsigned long seq)
 {
 }
-static int nullmac_verify(unsigned char *blk, int len, unsigned long seq)
+static int nullmac_verify(void *handle, unsigned char *blk, int len,
+			  unsigned long seq)
 {
     return 1;
 }
 const static struct ssh_mac ssh_mac_none = {
-    nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
+    nullmac_make_context, nullmac_free_context, nullmac_key,
+    nullmac_generate, nullmac_verify, "none", 0
 };
 const static struct ssh_mac *macs[] = {
     &ssh_sha1, &ssh_md5, &ssh_mac_none
@@ -550,8 +559,12 @@ struct ssh_tag {
     int X11_fwd_enabled;
     int remote_bugs;
     const struct ssh_cipher *cipher;
+    void *v1_cipher_ctx;
+    void *crcda_ctx;
     const struct ssh2_cipher *cscipher, *sccipher;
+    void *cs_cipher_ctx, *sc_cipher_ctx;
     const struct ssh_mac *csmac, *scmac;
+    void *cs_mac_ctx, *sc_mac_ctx;
     const struct ssh_compress *cscomp, *sccomp;
     const struct ssh_kex *kex;
     const struct ssh_signkey *hostkey;
@@ -797,13 +810,14 @@ static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
 	st->to_read -= st->chunk;
     }
 
-    if (ssh->cipher && detect_attack(ssh->pktin.data, st->biglen, NULL)) {
+    if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
+				     st->biglen, NULL)) {
         bombout(("Network attack (CRC compensation) detected!"));
         crReturn(0);
     }
 
     if (ssh->cipher)
-	ssh->cipher->decrypt(ssh->pktin.data, st->biglen);
+	ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
 
     st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
     st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
@@ -917,7 +931,8 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
     }
 
     if (ssh->sccipher)
-	ssh->sccipher->decrypt(ssh->pktin.data, st->cipherblk);
+	ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
+			       ssh->pktin.data, st->cipherblk);
 
     /*
      * Now get the length and padding figures.
@@ -968,14 +983,15 @@ static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
     }
     /* Decrypt everything _except_ the MAC. */
     if (ssh->sccipher)
-	ssh->sccipher->decrypt(ssh->pktin.data + st->cipherblk,
+	ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
+			       ssh->pktin.data + st->cipherblk,
 			       st->packetlen - st->cipherblk);
 
     /*
      * Check the MAC.
      */
     if (ssh->scmac
-	&& !ssh->scmac->verify(ssh->pktin.data, st->len + 4,
+	&& !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
 			       st->incoming_sequence)) {
 	bombout(("Incorrect MAC received on packet"));
 	crReturn(0);
@@ -1172,7 +1188,7 @@ static int s_wrpkt_prepare(Ssh ssh)
     PUT_32BIT(ssh->pktout.data, len);
 
     if (ssh->cipher)
-	ssh->cipher->encrypt(ssh->pktout.data + 4, biglen);
+	ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
 
     return biglen + 4;
 }
@@ -1464,12 +1480,14 @@ static int ssh2_pkt_construct(Ssh ssh)
 	ssh->pktout.data[ssh->pktout.length + i] = random_byte();
     PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
     if (ssh->csmac)
-	ssh->csmac->generate(ssh->pktout.data, ssh->pktout.length + padding,
+	ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
+			     ssh->pktout.length + padding,
 			     ssh->v2_outgoing_sequence);
     ssh->v2_outgoing_sequence++;       /* whether or not we MACed */
 
     if (ssh->cscipher)
-	ssh->cscipher->encrypt(ssh->pktout.data, ssh->pktout.length + padding);
+	ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
+			       ssh->pktout.data, ssh->pktout.length + padding);
 
     /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
     return ssh->pktout.length + padding + maclen;
@@ -2353,7 +2371,16 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
 		   s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
 		   &ssh_3des);
-    ssh->cipher->sesskey(ssh->session_key);
+    ssh->v1_cipher_ctx = ssh->cipher->make_context();
+    ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
+    {
+	char buf[256];
+	sprintf(buf, "Initialised %.200s encryption", ssh->cipher->text_name);
+	logevent(buf);
+    }
+
+    ssh->crcda_ctx = crcda_make_context();
+    logevent("Installing CRC compensation attack detector");
 
     crWaitUntil(ispkt);
 
@@ -4016,10 +4043,26 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
     /*
      * Create and initialise session keys.
      */
+    if (ssh->cs_cipher_ctx)
+	ssh->cscipher->free_context(ssh->cs_cipher_ctx);
     ssh->cscipher = s->cscipher_tobe;
+    ssh->cs_cipher_ctx = ssh->cscipher->make_context();
+
+    if (ssh->sc_cipher_ctx)
+	ssh->sccipher->free_context(ssh->sc_cipher_ctx);
     ssh->sccipher = s->sccipher_tobe;
+    ssh->sc_cipher_ctx = ssh->sccipher->make_context();
+
+    if (ssh->cs_mac_ctx)
+	ssh->csmac->free_context(ssh->cs_mac_ctx);
     ssh->csmac = s->csmac_tobe;
+    ssh->cs_mac_ctx = ssh->csmac->make_context();
+
+    if (ssh->sc_mac_ctx)
+	ssh->scmac->free_context(ssh->sc_mac_ctx);
     ssh->scmac = s->scmac_tobe;
+    ssh->sc_mac_ctx = ssh->scmac->make_context();
+
     ssh->cscomp = s->cscomp_tobe;
     ssh->sccomp = s->sccomp_tobe;
     ssh->cscomp->compress_init();
@@ -4034,19 +4077,29 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
 	    memcpy(ssh->v2_session_id, s->exchange_hash,
 		   sizeof(s->exchange_hash));
 	ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
-	ssh->cscipher->setcskey(keyspace);
+	ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
 	ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
-	ssh->sccipher->setsckey(keyspace);
+	ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
 	ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
-	ssh->cscipher->setcsiv(keyspace);
+	ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
 	ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
-	ssh->sccipher->setsciv(keyspace);
+	ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
 	ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
-	ssh->csmac->setcskey(keyspace);
+	ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
 	ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
-	ssh->scmac->setsckey(keyspace);
+	ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
+    }
+    {
+	char buf[256];
+	sprintf(buf, "Initialised %.200s client->server encryption",
+		ssh->cscipher->text_name);
+	logevent(buf);
+	sprintf(buf, "Initialised %.200s server->client encryption",
+		ssh->sccipher->text_name);
+	logevent(buf);
     }
 
+
     /*
      * If this is the first key exchange phase, we must pass the
      * SSH2_MSG_NEWKEYS packet to the next layer, not because it
@@ -5752,10 +5805,16 @@ static char *ssh_init(void *frontend_handle, void **backend_handle,
     ssh = smalloc(sizeof(*ssh));
     ssh->s = NULL;
     ssh->cipher = NULL;
+    ssh->v1_cipher_ctx = NULL;
+    ssh->crcda_ctx = NULL;
     ssh->cscipher = NULL;
+    ssh->cs_cipher_ctx = NULL;
     ssh->sccipher = NULL;
+    ssh->sc_cipher_ctx = NULL;
     ssh->csmac = NULL;
+    ssh->sc_mac_ctx = NULL;
     ssh->scmac = NULL;
+    ssh->sc_mac_ctx = NULL;
     ssh->cscomp = NULL;
     ssh->sccomp = NULL;
     ssh->kex = NULL;