Don't complain if we receive the cryptopro extension in the ClientHello

The cryptopro extension is supposed to be unsolicited and appears in the
ServerHello only. Additionally it is unofficial and unregistered - therefore
we should really treat it like any other unknown extension if we see it in
the ClientHello.

Fixes #7747
Reviewed-by: NPaul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7984)

(cherry picked from commit 23fed8ba0ec895e1b2a089cae380697f15170afc)

ssl/statem/extensions.c

@@ -348,10 +348,12 @@ static const EXTENSION_DEFINITION ext_defs[] = {
     {
         /*
          * Special unsolicited ServerHello extension only used when
-         * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set
+         * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set. We allow it in a ClientHello but
+         * ignore it.
          */
         TLSEXT_TYPE_cryptopro_bug,
-        SSL_EXT_TLS1_2_SERVER_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
+        SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO
+        | SSL_EXT_TLS1_2_AND_BELOW_ONLY,
         NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL
     },
     {