From: Matt Caswell <matt@openssl.org>
Date: Mon, 23 Apr 2018 16:14:47 +0000 (+0100)
Subject: In a reneg use the same client_version we used last time
X-Git-Tag: OpenSSL_1_1_0i~155
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ba2fd95037b9550e3efb4547034951151cc0e273;p=openssl

In a reneg use the same client_version we used last time

In 1.0.2 and below we always send the same client_version in a reneg
ClientHello that we sent the first time around, regardless of what
version eventually gets negotiated. According to a comment in
statem_clnt.c this is a workaround for some buggy servers that choked if
we changed the version used in the RSA encrypted premaster secret.

In 1.1.0+ this behaviour no longer occurs. This restores the original
behaviour.

Fixes #1651

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6060)
---

diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index d86bd7e8e2..85c754968c 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -347,6 +347,9 @@
 
 /* we have used 0000003f - 26 bits left to go */
 
+# define SSL_IS_FIRST_HANDSHAKE(S) ((s)->s3->tmp.finish_md_len == 0 \
+                                    || (s)->s3->tmp.peer_finish_md_len == 0)
+
 /* Check if an SSL structure is using DTLS */
 # define SSL_IS_DTLS(s)  (s->method->ssl3_enc->enc_flags & SSL_ENC_FLAG_DTLS)
 /* See if we need explicit IV */
diff --git a/ssl/statem/statem_lib.c b/ssl/statem/statem_lib.c
index 36d410bdf7..c4d4f26f7e 100644
--- a/ssl/statem/statem_lib.c
+++ b/ssl/statem/statem_lib.c
@@ -1073,6 +1073,13 @@ int ssl_set_client_hello_version(SSL *s)
 {
     int ver_min, ver_max, ret;
 
+    /*
+     * In a renegotiation we always send the same client_version that we sent
+     * last time, regardless of which version we eventually negotiated.
+     */
+    if (!SSL_IS_FIRST_HANDSHAKE(s))
+        return 0;
+
     ret = ssl_get_client_min_max_version(s, &ver_min, &ver_max);
 
     if (ret != 0)