Separate ca_names handling for client and server

SSL(_CTX)?_set_client_CA_list() was a server side only function in 1.1.0.
If it was called on the client side then it was ignored. In 1.1.1 it now
makes sense to have a CA list defined for both client and server (the
client now sends it the the TLSv1.3 certificate_authorities extension).
Unfortunately some applications were using the same SSL_CTX for both
clients and servers and this resulted in some client ClientHellos being
excessively large due to the number of certificate authorities being sent.

This commit seperates out the CA list updated by
SSL(_CTX)?_set_client_CA_list() and the more generic
SSL(_CTX)?_set0_CA_list(). This means that SSL(_CTX)?_set_client_CA_list()
still has no effect on the client side. If both CA lists are set then
SSL(_CTX)?_set_client_CA_list() takes priority.

Fixes #7411

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7503)

1 files changed, 7 insertions, 6 deletions

diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 7d7357fb3a..3314507896 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -501,17 +501,17 @@ const STACK_OF(X509_NAME) *SSL_get0_CA_list(const SSL *s)
 
 void SSL_CTX_set_client_CA_list(SSL_CTX *ctx, STACK_OF(X509_NAME) *name_list)
 {
-    SSL_CTX_set0_CA_list(ctx, name_list);
+    set0_CA_list(&ctx->client_ca_names, name_list);
 }
 
 STACK_OF(X509_NAME) *SSL_CTX_get_client_CA_list(const SSL_CTX *ctx)
 {
-    return ctx->ca_names;
+    return ctx->client_ca_names;
 }
 
 void SSL_set_client_CA_list(SSL *s, STACK_OF(X509_NAME) *name_list)
 {
-    SSL_set0_CA_list(s, name_list);
+    set0_CA_list(&s->client_ca_names, name_list);
 }
 
 const STACK_OF(X509_NAME) *SSL_get0_peer_CA_list(const SSL *s)
@@ -523,7 +523,8 @@ STACK_OF(X509_NAME) *SSL_get_client_CA_list(const SSL *s)
 {
     if (!s->server)
         return s->s3 != NULL ?  s->s3->tmp.peer_ca_names : NULL;
-    return s->ca_names != NULL ?  s->ca_names : s->ctx->ca_names;
+    return s->client_ca_names != NULL ?  s->client_ca_names
+                                      : s->ctx->client_ca_names;
 }
 
 static int add_ca_name(STACK_OF(X509_NAME) **sk, const X509 *x)
@@ -561,12 +562,12 @@ int SSL_CTX_add1_to_CA_list(SSL_CTX *ctx, const X509 *x)
  */
 int SSL_add_client_CA(SSL *ssl, X509 *x)
 {
-    return add_ca_name(&ssl->ca_names, x);
+    return add_ca_name(&ssl->client_ca_names, x);
 }
 
 int SSL_CTX_add_client_CA(SSL_CTX *ctx, X509 *x)
 {
-    return add_ca_name(&ctx->ca_names, x);
+    return add_ca_name(&ctx->client_ca_names, x);
 }
 
 static int xname_cmp(const X509_NAME *a, const X509_NAME *b)