From 855a54a9a50b165c314262e5e626a18e4e5ce2ad Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Thu, 12 May 2011 17:35:03 +0000
Subject: [PATCH] Provisional support for TLS v1.2 client authentication:
 client side only.

Parse certificate request message and set digests appropriately.

Generate new TLS v1.2 format certificate verify message.

Keep handshake caches around for longer as they are needed for client auth.
---
 CHANGES       |  5 +++++
 ssl/s3_clnt.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/CHANGES b/CHANGES
index 872ab107f7..03a626f3ec 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,11 @@
 
  Changes between 1.0.1 and 1.1.0  [xx XXX xxxx]
 
+  *) Add TLS v1.2 client side support for client authentication. Keep cache
+     of handshake records longer as we don't know the hash algorithm to use
+     until after the certificate request message is received.
+     [Steve Henson]
+
   *) Rename FIPS_mode_set and FIPS_mode to FIPS_module_mode_set and
      FIPS_module_mode. FIPS_mode and FIPS_mode_set will be implmeneted
      outside the validated module in the FIPS capable OpenSSL.
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 5d3dfcc389..64fd5ec00f 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -922,9 +922,11 @@ int ssl3_get_server_hello(SSL *s)
 			}
 		}
 	s->s3->tmp.new_cipher=c;
-	if (!ssl3_digest_cached_records(s))
+	/* Don't digest cached records if TLS v1.2: we may need them for
+	 * client authentication.
+	 */
+	if (s->version < TLS1_2_VERSION && !ssl3_digest_cached_records(s))
 		goto f_err;
-
 	/* lets get the compression algorithm */
 	/* COMPRESSION */
 #ifdef OPENSSL_NO_COMP
@@ -1813,6 +1815,14 @@ int ssl3_get_certificate_request(SSL *s)
 	if (s->s3->tmp.message_type == SSL3_MT_SERVER_DONE)
 		{
 		s->s3->tmp.reuse_message=1;
+		/* If we get here we don't need any cached handshake records
+		 * as we wont be doing client auth.
+		 */
+		if (s->s3->handshake_buffer)
+			{
+			if (!ssl3_digest_cached_records(s))
+				goto err;
+			}
 		return(1);
 		}
 
@@ -2854,12 +2864,13 @@ int ssl3_send_client_verify(SSL *s)
 	unsigned char data[MD5_DIGEST_LENGTH+SHA_DIGEST_LENGTH];
 	EVP_PKEY *pkey;
 	EVP_PKEY_CTX *pctx=NULL;
-#ifndef OPENSSL_NO_RSA
+	EVP_MD_CTX mctx;
 	unsigned u=0;
-#endif
 	unsigned long n;
 	int j;
 
+	EVP_MD_CTX_init(&mctx);
+
 	if (s->state == SSL3_ST_CW_CERT_VRFY_A)
 		{
 		d=(unsigned char *)s->init_buf->data;
@@ -2870,7 +2881,8 @@ int ssl3_send_client_verify(SSL *s)
 		EVP_PKEY_sign_init(pctx);
 		if (EVP_PKEY_CTX_set_signature_md(pctx, EVP_sha1())>0)
 			{
-			s->method->ssl3_enc->cert_verify_mac(s,
+			if (s->version < TLS1_2_VERSION)
+				s->method->ssl3_enc->cert_verify_mac(s,
 						NID_sha1,
 						&(data[MD5_DIGEST_LENGTH]));
 			}
@@ -2878,6 +2890,41 @@ int ssl3_send_client_verify(SSL *s)
 			{
 			ERR_clear_error();
 			}
+		/* For TLS v1.2 send signature algorithm and signature
+		 * using agreed digest and cached handshake records.
+		 */
+		if (s->version >= TLS1_2_VERSION)
+			{
+			long hdatalen = 0;
+			void *hdata;
+			const EVP_MD *md = s->cert->key->digest;
+			hdatalen = BIO_get_mem_data(s->s3->handshake_buffer,
+								&hdata);
+			if (hdatalen <= 0 || !tls12_get_sigandhash(p, pkey, md))
+				{
+				SSLerr(SSL_F_SSL3_SEND_CLIENT_VERIFY,
+						ERR_R_INTERNAL_ERROR);
+				goto err;
+				}
+			p += 2;
+#ifdef SSL_DEBUG
+			fprintf(stderr, "Using TLS 1.2 with client alg %s\n",
+							EVP_MD_name(md));
+#endif
+			if (!EVP_SignInit_ex(&mctx, md, NULL)
+				|| !EVP_SignUpdate(&mctx, hdata, hdatalen)
+				|| !EVP_SignFinal(&mctx, p + 2, &u, pkey))
+				{
+				SSLerr(SSL_F_SSL3_SEND_CLIENT_VERIFY,
+						ERR_R_EVP_LIB);
+				goto err;
+				}
+			s2n(u,p);
+			n = u + 4;
+			if (!ssl3_digest_cached_records(s))
+				goto err;
+			}
+		else
 #ifndef OPENSSL_NO_RSA
 		if (pkey->type == EVP_PKEY_RSA)
 			{
@@ -2960,9 +3007,11 @@ int ssl3_send_client_verify(SSL *s)
 		s->init_num=(int)n+4;
 		s->init_off=0;
 		}
+	EVP_MD_CTX_cleanup(&mctx);
 	EVP_PKEY_CTX_free(pctx);
 	return(ssl3_do_write(s,SSL3_RT_HANDSHAKE));
 err:
+	EVP_MD_CTX_cleanup(&mctx);
 	EVP_PKEY_CTX_free(pctx);
 	return(-1);
 	}
-- 
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