From 7844f3c784bfc93c9b94ae5a4082f9d01e82e0af Mon Sep 17 00:00:00 2001
From: Matt Caswell <matt@openssl.org>
Date: Wed, 14 Oct 2020 15:13:28 +0100
Subject: [PATCH 083/147] Pass an EVP_PKEY for SSL_SECOP_TMP_DH in the security
 callback

The security operation SSL_SECOP_TMP_DH is defined to take an EVP_PKEY
in the "other" parameter:

 /* Temporary DH key */
 # define SSL_SECOP_TMP_DH                (7 | SSL_SECOP_OTHER_PKEY)

In most places this is what is passed. All these places occur server side.
However there is one client side call of this security operation and it
passes a DH object instead. This is incorrect according to the
definition of SSL_SECOP_TMP_DH, and is inconsistent with all of the other
locations.

Our own default security callback, and the debug callback in the apps,
never look at this value and therefore this issue was never noticed
previously. In theory a client side application could be relying on this
behaviour and could be broken by this change. This is probably fairly
unlikely but can't be ruled out.

Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/13136)
---
 ssl/statem/statem_clnt.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index 64e392c..3bf8aac 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -2145,18 +2145,19 @@ static int tls_process_ske_dhe(SSL *s, PACKET *pkt, EVP_PKEY **pkey)
     }
     bnpub_key = NULL;
 
-    if (!ssl_security(s, SSL_SECOP_TMP_DH, DH_security_bits(dh), 0, dh)) {
-        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PROCESS_SKE_DHE,
-                 SSL_R_DH_KEY_TOO_SMALL);
-        goto err;
-    }
-
     if (EVP_PKEY_assign_DH(peer_tmp, dh) == 0) {
         SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_SKE_DHE,
                  ERR_R_EVP_LIB);
         goto err;
     }
 
+    if (!ssl_security(s, SSL_SECOP_TMP_DH, EVP_PKEY_security_bits(peer_tmp),
+                      0, peer_tmp)) {
+        SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_TLS_PROCESS_SKE_DHE,
+                 SSL_R_DH_KEY_TOO_SMALL);
+        goto err;
+    }
+
     s->s3->peer_tmp = peer_tmp;
 
     /*
-- 
1.8.3.1

