TLS: fix SRP detection by using the proper #ifdefs

USE_TLS_SRP will be true if *any* selected TLS backend can use SRP

HAVE_OPENSSL_SRP is defined when OpenSSL can use it

HAVE_GNUTLS_SRP is defined when GnuTLS can use it

Clarify in the curl_verison_info docs that CURL_VERSION_TLSAUTH_SRP is
set if at least one of the supported backends offers SRP.

Reported-by: Stefan Strogin
Fixes #5865
Closes #5870

docs/libcurl/curl_version_info.3

@@ -192,7 +192,8 @@ makes libcurl use Windows-provided functions for Kerberos, NTLM, SPNEGO and
 Digest authentication. It also allows libcurl to use the current user
 credentials without the app having to pass them on. (Added in 7.13.2)
 .IP CURL_VERSION_TLSAUTH_SRP
-libcurl was built with support for TLS-SRP. (Added in 7.21.4)
+libcurl was built with support for TLS-SRP (in one or more of the built-in TLS
+backends). (Added in 7.21.4)
 .IP CURL_VERSION_UNIX_SOCKETS
 libcurl was built with support for Unix domain sockets.
 (Added in 7.40.0)

lib/vtls/gtls.c

@@ -81,7 +81,7 @@ static bool gtls_inited = FALSE;
 struct ssl_backend_data {
   gnutls_session_t session;
   gnutls_certificate_credentials_t cred;
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
   gnutls_srp_client_credentials_t srp_client_cred;
 #endif
 };
@@ -434,7 +434,7 @@ gtls_connect_step1(struct connectdata *conn,
     return CURLE_SSL_CONNECT_ERROR;
   }
 
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
   if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP) {
     infof(data, "Using TLS-SRP username: %s\n", SSL_SET_OPTION(username));
 
@@ -588,7 +588,7 @@ gtls_connect_step1(struct connectdata *conn,
       return CURLE_SSL_CONNECT_ERROR;
   }
 
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
   /* Only add SRP to the cipher list if SRP is requested. Otherwise
    * GnuTLS will disable TLS 1.3 support. */
   if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP) {
@@ -610,7 +610,7 @@ gtls_connect_step1(struct connectdata *conn,
   else {
 #endif
     rc = gnutls_priority_set_direct(session, prioritylist, &err);
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
   }
 #endif
 
@@ -681,7 +681,7 @@ gtls_connect_step1(struct connectdata *conn,
     }
   }
 
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
   /* put the credentials to the current session */
   if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP) {
     rc = gnutls_credentials_set(session, GNUTLS_CRD_SRP,
@@ -868,7 +868,7 @@ gtls_connect_step3(struct connectdata *conn,
     if(SSL_CONN_CONFIG(verifypeer) ||
        SSL_CONN_CONFIG(verifyhost) ||
        SSL_SET_OPTION(issuercert)) {
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
       if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP
          && SSL_SET_OPTION(username) != NULL
          && !SSL_CONN_CONFIG(verifypeer)
@@ -881,7 +881,7 @@ gtls_connect_step3(struct connectdata *conn,
         failf(data, "failed to get server cert");
         *certverifyresult = GNUTLS_E_NO_CERTIFICATE_FOUND;
         return CURLE_PEER_FAILED_VERIFICATION;
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
       }
 #endif
     }
@@ -1448,7 +1448,7 @@ static void close_one(struct ssl_connect_data *connssl)
     gnutls_certificate_free_credentials(backend->cred);
     backend->cred = NULL;
   }
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
   if(backend->srp_client_cred) {
     gnutls_srp_free_client_credentials(backend->srp_client_cred);
     backend->srp_client_cred = NULL;
@@ -1530,7 +1530,7 @@ static int Curl_gtls_shutdown(struct connectdata *conn, int sockindex)
   }
   gnutls_certificate_free_credentials(backend->cred);
 
-#ifdef USE_TLS_SRP
+#ifdef HAVE_GNUTLS_SRP
   if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP
      && SSL_SET_OPTION(username) != NULL)
     gnutls_srp_free_client_credentials(backend->srp_client_cred);

lib/vtls/openssl.c

@@ -2486,7 +2486,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
   long * const certverifyresult = &data->set.ssl.certverifyresult;
 #endif
   const long int ssl_version = SSL_CONN_CONFIG(version);
-#ifdef USE_TLS_SRP
+#ifdef HAVE_OPENSSL_SRP
   const enum CURL_TLSAUTH ssl_authtype = SSL_SET_OPTION(authtype);
 #endif
   char * const ssl_cert = SSL_SET_OPTION(cert);
@@ -2531,7 +2531,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     failf(data, OSSL_PACKAGE " was built without SSLv2 support");
     return CURLE_NOT_BUILT_IN;
 #else
-#ifdef USE_TLS_SRP
+#ifdef HAVE_OPENSSL_SRP
     if(ssl_authtype == CURL_TLSAUTH_SRP)
       return CURLE_SSL_CONNECT_ERROR;
 #endif
@@ -2544,7 +2544,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     failf(data, OSSL_PACKAGE " was built without SSLv3 support");
     return CURLE_NOT_BUILT_IN;
 #else
-#ifdef USE_TLS_SRP
+#ifdef HAVE_OPENSSL_SRP
     if(ssl_authtype == CURL_TLSAUTH_SRP)
       return CURLE_SSL_CONNECT_ERROR;
 #endif
@@ -2800,7 +2800,7 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
   SSL_CTX_set_post_handshake_auth(backend->ctx, 1);
 #endif
 
-#ifdef USE_TLS_SRP
+#ifdef HAVE_OPENSSL_SRP
   if(ssl_authtype == CURL_TLSAUTH_SRP) {
     char * const ssl_username = SSL_SET_OPTION(username);