Add a new unsolicited extension error code and add enum tag

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3418)

include/openssl/ssl.h

@@ -2829,6 +2829,7 @@ int ERR_load_SSL_strings(void);
 # define SSL_R_UNKNOWN_SSL_VERSION                        254
 # define SSL_R_UNKNOWN_STATE                              255
 # define SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED       338
+# define SSL_R_UNSOLICITED_EXTENSION                      217
 # define SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM          257
 # define SSL_R_UNSUPPORTED_ELLIPTIC_CURVE                 315
 # define SSL_R_UNSUPPORTED_PROTOCOL                       258

ssl/ssl_err.c

@@ -843,6 +843,7 @@ static ERR_STRING_DATA SSL_str_reasons[] = {
     {ERR_REASON(SSL_R_UNKNOWN_STATE), "unknown state"},
     {ERR_REASON(SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED),
      "unsafe legacy renegotiation disabled"},
+    {ERR_REASON(SSL_R_UNSOLICITED_EXTENSION), "unsolicited extension"},
     {ERR_REASON(SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM),
      "unsupported compression algorithm"},
     {ERR_REASON(SSL_R_UNSUPPORTED_ELLIPTIC_CURVE),

ssl/statem/extensions.c

@@ -510,7 +510,7 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
                 && type != TLSEXT_TYPE_renegotiate
                 && type != TLSEXT_TYPE_signed_certificate_timestamp
                 && (s->ext.extflags[idx] & SSL_EXT_FLAG_SENT) == 0) {
-            SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_BAD_EXTENSION);
+            SSLerr(SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_UNSOLICITED_EXTENSION);
             *al = SSL_AD_UNSUPPORTED_EXTENSION;
             goto err;
         }

ssl/statem/statem_locl.h

@@ -156,7 +156,7 @@ MSG_PROCESS_RETURN tls_process_end_of_early_data(SSL *s, PACKET *pkt);
 
 /* Extension processing */
 
-typedef enum {
+typedef enum ext_return_en {
     EXT_RETURN_FAIL,
     EXT_RETURN_SENT,
     EXT_RETURN_NOT_SENT