From 74fc48398ee58bae79d348e2d4d977d12db465b1 Mon Sep 17 00:00:00 2001
From: Markus Friedl <markus@cvs.openbsd.org>
Date: Mon, 30 Apr 2001 15:50:47 +0000
Subject: allow interop with weaker key generation used by ssh-2.0.x, x < 10

---
 usr.bin/ssh/compat.c | 10 ++++++++--
 usr.bin/ssh/compat.h |  3 ++-
 usr.bin/ssh/kex.c    |  8 +++++---
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/usr.bin/ssh/compat.c b/usr.bin/ssh/compat.c
index b9a518d2f90..44d65c80a30 100644
--- a/usr.bin/ssh/compat.c
+++ b/usr.bin/ssh/compat.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: compat.c,v 1.48 2001/04/29 19:16:52 markus Exp $");
+RCSID("$OpenBSD: compat.c,v 1.49 2001/04/30 15:50:46 markus Exp $");
 
 #include <regex.h>
 
@@ -86,11 +86,17 @@ compat_datafellows(const char *version)
 					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
 					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE },
-		{ "^2\\.0\\.",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
+		{ "^2\\.0\\.1[0-2]",	SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
 					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE },
+		{ "^2\\.0\\.",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
+					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
+					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
+					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
+					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
+					SSH_BUG_DERIVEKEY },
 		{ "^2\\.[23]\\.0",	SSH_BUG_HMAC|SSH_BUG_RSASIGMD5 },
 		{ "^2\\.3\\.",		SSH_BUG_RSASIGMD5 },
 		{ "^2\\.[2-9]\\.",	0 },
diff --git a/usr.bin/ssh/compat.h b/usr.bin/ssh/compat.h
index fa509c247f4..0ccc1ed375f 100644
--- a/usr.bin/ssh/compat.h
+++ b/usr.bin/ssh/compat.h
@@ -21,7 +21,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-/* RCSID("$OpenBSD: compat.h,v 1.24 2001/04/29 19:16:52 markus Exp $"); */
+/* RCSID("$OpenBSD: compat.h,v 1.25 2001/04/30 15:50:46 markus Exp $"); */
 
 #ifndef COMPAT_H
 #define COMPAT_H
@@ -49,6 +49,7 @@
 #define SSH_BUG_NOREKEY		0x00008000
 #define SSH_BUG_HBSERVICE	0x00010000
 #define SSH_BUG_OPENFAILURE	0x00020000
+#define SSH_BUG_DERIVEKEY	0x00040000
 
 void    enable_compat13(void);
 void    enable_compat20(void);
diff --git a/usr.bin/ssh/kex.c b/usr.bin/ssh/kex.c
index 69ba102e169..6b68ba5046d 100644
--- a/usr.bin/ssh/kex.c
+++ b/usr.bin/ssh/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);
-- 
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