crc32 compensation attack fix from CORE-SDI. "it's not crypto..." -- deraadt@

1 files changed, 23 insertions, 1 deletions

diff --git a/usr.bin/ssh/packet.c b/usr.bin/ssh/packet.c
index cdc11db7c63..a37a09055e1 100644
--- a/usr.bin/ssh/packet.c
+++ b/usr.bin/ssh/packet.c
@@ -15,7 +15,7 @@ with the other side.  This same code is used both on client and server side.
 */
 
 #include "includes.h"
-RCSID("$Id: packet.c,v 1.8 1999/10/03 19:22:38 deraadt Exp $");
+RCSID("$Id: packet.c,v 1.9 1999/10/05 01:23:54 dugsong Exp $");
 
 #include "xmalloc.h"
 #include "buffer.h"
@@ -27,6 +27,7 @@ RCSID("$Id: packet.c,v 1.8 1999/10/03 19:22:38 deraadt Exp $");
 #include "getput.h"
 
 #include "compress.h"
+#include "deattack.h"
 
 /* This variable contains the file descriptors used for communicating with
    the other side.  connection_in is used for reading; connection_out
@@ -204,7 +205,28 @@ void
 packet_decrypt(CipherContext *cc, void *dest, void *src, 
 	       unsigned int bytes)
 {
+  int i;
+  
   assert((bytes % 8) == 0);
+  
+  /*
+    Cryptographic attack detector for ssh - Modifications for packet.c 
+    (C)1998 CORE-SDI, Buenos Aires Argentina
+    Ariel Futoransky(futo@core-sdi.com)
+  */
+  switch (cc->type)
+    {
+    case SSH_CIPHER_NONE:
+      i = DEATTACK_OK;
+      break;
+    default:
+      i = detect_attack(src, bytes, NULL);
+      break;
+    }
+  
+  if (i == DEATTACK_DETECTED)
+    packet_disconnect("crc32 compensation attack: network attack detected");
+  
   cipher_decrypt(cc, dest, src, bytes);
 }