- markus@cvs.openbsd.org 2001/04/30 15:50:46

     [compat.c compat.h kex.c]
     allow interop with weaker key generation used by ssh-2.0.x, x < 10

1 files changed, 5 insertions, 3 deletions

diff --git a/kex.c b/kex.c
index 69ba102e1..6b68ba504 100644
--- a/kex.c
+++ b/kex.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: kex.c,v 1.33 2001/04/05 10:42:50 markus Exp $");
+RCSID("$OpenBSD: kex.c,v 1.34 2001/04/30 15:50:46 markus Exp $");
 
 #include <openssl/crypto.h>
 
@@ -375,7 +375,8 @@ derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret)
 
         /* K1 = HASH(K || H || "A" || session_id) */
         EVP_DigestInit(&md, evp_md);
-        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
+        if (!(datafellows & SSH_BUG_DERIVEKEY))
+                EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
         EVP_DigestUpdate(&md, hash, mdsz);
         EVP_DigestUpdate(&md, &c, 1);
         EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
@@ -388,7 +389,8 @@ derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret)
          */
         for (have = mdsz; need > have; have += mdsz) {
                 EVP_DigestInit(&md, evp_md);
-                EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
+                if (!(datafellows & SSH_BUG_DERIVEKEY))
+                        EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
                 EVP_DigestUpdate(&md, hash, mdsz);
                 EVP_DigestUpdate(&md, digest, have);
                 EVP_DigestFinal(&md, digest + have, NULL);