commit 03f44b974b1c85804b54af7c3ffb5241d5ffd952
author Dr. Stephen Henson <steve@openssl.org> Wed Feb 22 17:26:44 2017 +0000
committer Dr. Stephen Henson <steve@openssl.org> Mon Feb 27 18:23:18 2017 +0000
tree a5da2267b5cc1e615edb973040fed6c2cfc89aca
parent 013bc448672cbc3c9cd154709400c676c2955229

Initial incomplete TLS 1.3 certificate request support.

This adds partial support for TLS 1.3 certificate request message.

The request context and extensions are currently ignored on receive
and set to zero length on send.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2728)

ssl/statem/statem_clnt.c

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index 6e162fb..5957718 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -2196,27 +2196,45 @@
 MSG_PROCESS_RETURN tls_process_certificate_request(SSL *s, PACKET *pkt)
 {
     int ret = MSG_PROCESS_ERROR;
-    unsigned int list_len, i, name_len;
+    unsigned int i, name_len;
     X509_NAME *xn = NULL;
     const unsigned char *namestart, *namebytes;
     STACK_OF(X509_NAME) *ca_sk = NULL;
-    PACKET ctypes;
+    PACKET cadns;
 
     if ((ca_sk = sk_X509_NAME_new(ca_dn_cmp)) == NULL) {
         SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, ERR_R_MALLOC_FAILURE);
         goto err;
     }
 
-    /* get the certificate types */
-    if (!PACKET_get_length_prefixed_1(pkt, &ctypes)) {
-        ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
-        SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, SSL_R_LENGTH_MISMATCH);
-        goto err;
-    }
+    if (SSL_IS_TLS13(s)) {
+        PACKET reqctx;
 
-    if (!PACKET_memdup(&ctypes, &s->s3->tmp.ctype, &s->s3->tmp.ctype_len)) {
-        SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, ERR_R_INTERNAL_ERROR);
+        /* Free and zero certificate types: it is not present in TLS 1.3 */
+        OPENSSL_free(s->s3->tmp.ctype);
+        s->s3->tmp.ctype = NULL;
+        s->s3->tmp.ctype_len = 0;
+        /* TODO(TLS1.3) need to process request context, for now ignore */
+        if (!PACKET_get_length_prefixed_1(pkt, &reqctx)) {
+            SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
+                   SSL_R_LENGTH_MISMATCH);
             goto err;
+        }
+    } else {
+        PACKET ctypes;
+
+        /* get the certificate types */
+        if (!PACKET_get_length_prefixed_1(pkt, &ctypes)) {
+            ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+            SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
+                   SSL_R_LENGTH_MISMATCH);
+            goto err;
+        }
+
+        if (!PACKET_memdup(&ctypes, &s->s3->tmp.ctype, &s->s3->tmp.ctype_len)) {
+            SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
     }
 
     if (SSL_USE_SIGALGS(s)) {
@@ -2246,16 +2264,15 @@
     }
 
     /* get the CA RDNs */
-    if (!PACKET_get_net_2(pkt, &list_len)
-        || PACKET_remaining(pkt) != list_len) {
+    if (!PACKET_get_length_prefixed_2(pkt, &cadns)) {
         ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
         SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, SSL_R_LENGTH_MISMATCH);
         goto err;
     }
 
-    while (PACKET_remaining(pkt)) {
-        if (!PACKET_get_net_2(pkt, &name_len)
-            || !PACKET_get_bytes(pkt, &namebytes, name_len)) {
+    while (PACKET_remaining(&cadns)) {
+        if (!PACKET_get_net_2(&cadns, &name_len)
+            || !PACKET_get_bytes(&cadns, &namebytes, name_len)) {
             ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
             SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
                    SSL_R_LENGTH_MISMATCH);
@@ -2283,6 +2300,23 @@
         }
         xn = NULL;
     }
+    /* TODO(TLS1.3) need to parse and process extensions, for now ignore */
+    if (SSL_IS_TLS13(s)) {
+        PACKET reqexts;
+
+        if (!PACKET_get_length_prefixed_2(pkt, &reqexts)) {
+            ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+            SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST,
+                   SSL_R_EXT_LENGTH_MISMATCH);
+            goto err;
+        }
+    }
+
+    if (PACKET_remaining(pkt) != 0) {
+        ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+        SSLerr(SSL_F_TLS_PROCESS_CERTIFICATE_REQUEST, SSL_R_LENGTH_MISMATCH);
+        goto err;
+    }
 
     /* we should setup a certificate to return.... */
     s->s3->tmp.cert_req = 1;