gtls: add support for CURLOPT_CAPATH

lib/vtls/gtls.c

@@ -97,6 +97,10 @@ static bool gtls_inited = FALSE;
 #  if (GNUTLS_VERSION_NUMBER >= 0x03020d)
 #    define HAS_OCSP
 #  endif
+
+#  if (GNUTLS_VERSION_NUMBER >= 0x030306)
+#    define HAS_CAPATH
+#  endif
 #endif
 
 #ifdef HAS_OCSP
@@ -462,6 +466,24 @@ gtls_connect_step1(struct connectdata *conn,
             rc, data->set.ssl.CAfile);
   }
 
+#ifdef HAS_CAPATH
+  if(data->set.ssl.CApath) {
+    /* set the trusted CA cert directory */
+    rc = gnutls_certificate_set_x509_trust_dir(conn->ssl[sockindex].cred,
+                                                data->set.ssl.CApath,
+                                                GNUTLS_X509_FMT_PEM);
+    if(rc < 0) {
+      infof(data, "error reading ca cert file %s (%s)\n",
+            data->set.ssl.CAfile, gnutls_strerror(rc));
+      if(data->set.ssl.verifypeer)
+        return CURLE_SSL_CACERT_BADFILE;
+    }
+    else
+      infof(data, "found %d certificates in %s\n",
+            rc, data->set.ssl.CApath);
+  }
+#endif
+
   if(data->set.ssl.CRLfile) {
     /* set the CRL list file */
     rc = gnutls_certificate_set_x509_crl_file(conn->ssl[sockindex].cred,

lib/vtls/gtls.h

@@ -54,6 +54,9 @@ bool Curl_gtls_cert_status_request(void);
 /* Set the API backend definition to GnuTLS */
 #define CURL_SSL_BACKEND CURLSSLBACKEND_GNUTLS
 
+/* this backend supports the CAPATH option */
+#define have_curlssl_ca_path 1
+
 /* API setup for GnuTLS */
 #define curlssl_init Curl_gtls_init
 #define curlssl_cleanup Curl_gtls_cleanup