- markus@cvs.openbsd.org 2001/04/03 23:32:12

     [kex.c kex.h packet.c sshconnect2.c sshd.c]
     undo parts of recent my changes: main part of keyexchange does not
     need dispatch-callbacks, since application data is delayed until
     the keyexchange completes (if i understand the drafts correctly).
     add some infrastructure for re-keying.

1 files changed, 52 insertions, 56 deletions

diff --git a/packet.c b/packet.c
index 1a634cff4..a4a0b0595 100644
--- a/packet.c
+++ b/packet.c
@@ -37,7 +37,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: packet.c,v 1.56 2001/03/03 21:41:07 millert Exp $");
+RCSID("$OpenBSD: packet.c,v 1.57 2001/04/03 23:32:12 markus Exp $");
 
 #include "xmalloc.h"
 #include "buffer.h"
@@ -121,21 +121,9 @@ static int interactive_mode = 0;
 int use_ssh2_packet_format = 0;
 
 /* Session key information for Encryption and MAC */
-Kex     *kex = NULL;
+Newkeys *newkeys[MODE_MAX];
 
 void
-packet_set_kex(Kex *k)
-{
-        if( k->mac[MODE_IN ].key == NULL ||
-            k->enc[MODE_IN ].key == NULL ||
-            k->enc[MODE_IN ].iv  == NULL ||
-            k->mac[MODE_OUT].key == NULL ||
-            k->enc[MODE_OUT].key == NULL ||
-            k->enc[MODE_OUT].iv  == NULL)
-                fatal("bad KEX");
-        kex = k;
-}
-void
 clear_enc_keys(Enc *enc, int len)
 {
         memset(enc->iv,  0, len);
@@ -150,6 +138,7 @@ packet_set_ssh2_format(void)
 {
         DBG(debug("use_ssh2_packet_format"));
         use_ssh2_packet_format = 1;
+        newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
 }
 
 /*
@@ -522,6 +511,41 @@ packet_send1(void)
          */
 }
 
+void
+set_newkeys(int mode)
+{
+        Enc *enc;
+        Mac *mac;
+        Comp *comp;
+        CipherContext *cc;
+
+        debug("newkeys: mode %d", mode);
+
+        cc = (mode == MODE_OUT) ? &send_context : &receive_context;
+        if (newkeys[mode] != NULL) {
+                debug("newkeys: rekeying");
+                memset(cc, 0, sizeof(*cc));
+                // free old keys, reset compression cipher-contexts;
+        }
+        newkeys[mode] = kex_get_newkeys(mode);
+        if (newkeys[mode] == NULL)
+                fatal("newkeys: no keys for mode %d", mode);
+        enc  = &newkeys[mode]->enc;
+        mac  = &newkeys[mode]->mac;
+        comp = &newkeys[mode]->comp;
+        if (mac->md != NULL)
+                mac->enabled = 1;
+        DBG(debug("cipher_init_context: %d", mode));
+        cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,
+            enc->iv, enc->cipher->block_size);
+        clear_enc_keys(enc, enc->cipher->key_len);
+        if (comp->type != 0 && comp->enabled == 0) {
+                comp->enabled = 1;
+                if (! packet_compression)
+                        packet_start_compression(6);
+        }
+}
+
 /*
  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
  */
@@ -540,10 +564,10 @@ packet_send2(void)
         Comp *comp = NULL;
         int block_size;
 
-        if (kex != NULL) {
-                enc  = &kex->enc[MODE_OUT];
-                mac  = &kex->mac[MODE_OUT];
-                comp = &kex->comp[MODE_OUT];
+        if (newkeys[MODE_OUT] != NULL) {
+                enc  = &newkeys[MODE_OUT]->enc;
+                mac  = &newkeys[MODE_OUT]->mac;
+                comp = &newkeys[MODE_OUT]->comp;
         }
         block_size = enc ? enc->cipher->block_size : 8;
 
@@ -622,22 +646,8 @@ packet_send2(void)
                 log("outgoing seqnr wraps around");
         buffer_clear(&outgoing_packet);
 
-        if (type == SSH2_MSG_NEWKEYS) {
-                if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
-                        fatal("packet_send2: no KEX");
-                if (mac->md != NULL)
-                        mac->enabled = 1;
-                DBG(debug("cipher_init send_context"));
-                cipher_init(&send_context, enc->cipher,
-                    enc->key, enc->cipher->key_len,
-                    enc->iv, enc->cipher->block_size);
-                clear_enc_keys(enc, kex->we_need);
-                if (comp->type != 0 && comp->enabled == 0) {
-                        comp->enabled = 1;
-                        if (! packet_compression)
-                                packet_start_compression(6);
-                }
-        }
+        if (type == SSH2_MSG_NEWKEYS)
+                set_newkeys(MODE_OUT);
 }
 
 void
@@ -833,10 +843,10 @@ packet_read_poll2(int *payload_len_ptr)
         Mac *mac   = NULL;
         Comp *comp = NULL;
 
-        if (kex != NULL) {
-                enc  = &kex->enc[MODE_IN];
-                mac  = &kex->mac[MODE_IN];
-                comp = &kex->comp[MODE_IN];
+        if (newkeys[MODE_IN] != NULL) {
+                enc  = &newkeys[MODE_IN]->enc;
+                mac  = &newkeys[MODE_IN]->mac;
+                comp = &newkeys[MODE_IN]->comp;
         }
         maclen = mac && mac->enabled ? mac->mac_len : 0;
         block_size = enc ? enc->cipher->block_size : 8;
@@ -930,22 +940,8 @@ packet_read_poll2(int *payload_len_ptr)
         /* extract packet type */
         type = (u_char)buf[0];
 
-        if (type == SSH2_MSG_NEWKEYS) {
-                if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
-                        fatal("packet_read_poll2: no KEX");
-                if (mac->md != NULL)
-                        mac->enabled = 1;
-                DBG(debug("cipher_init receive_context"));
-                cipher_init(&receive_context, enc->cipher,
-                    enc->key, enc->cipher->key_len,
-                    enc->iv, enc->cipher->block_size);
-                clear_enc_keys(enc, kex->we_need);
-                if (comp->type != 0 && comp->enabled == 0) {
-                        comp->enabled = 1;
-                        if (! packet_compression)
-                                packet_start_compression(6);
-                }
-        }
+        if (type == SSH2_MSG_NEWKEYS)
+                set_newkeys(MODE_IN);
 
 #ifdef PACKET_DEBUG
         fprintf(stderr, "read/plain[%d]:\r\n", type);
@@ -1339,8 +1335,8 @@ packet_inject_ignore(int sumlen)
 
         have = buffer_len(&outgoing_packet);
         debug2("packet_inject_ignore: current %d", have);
-        if (kex != NULL)
-        enc  = &kex->enc[MODE_OUT];
+        if (newkeys[MODE_OUT] != NULL)
+                enc  = &newkeys[MODE_OUT]->enc;
         blocksize = enc ? enc->cipher->block_size : 8;
         padlen = blocksize - (have % blocksize);
         if (padlen < 4)