ssl: set engine implicitly when a PKCS#11 URI is provided

This allows the use of PKCS#11 URI for certificates and keys without
setting the corresponding type as "ENG" and the engine as "pkcs11"
explicitly. If a PKCS#11 URI is provided for certificate, key,
proxy_certificate or proxy_key, the corresponding type is set as "ENG"
if not provided and the engine is set to "pkcs11" if not provided.

Acked-by: Nikos Mavrogiannopoulos
Closes #2333

1 files changed, 38 insertions, 0 deletions

diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index d5b474771..9ce1ae5ab 100644
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -558,8 +558,25 @@ static int ssl_ui_writer(UI *ui, UI_STRING *uis)
   }
   return (UI_method_get_writer(UI_OpenSSL()))(ui, uis);
 }
+
+/*
+ * Check if a given string is a PKCS#11 URI
+ */
+static bool is_pkcs11_uri(const char *string)
+{
+  if(strncasecompare(string, "pkcs11:", 7)) {
+    return TRUE;
+  }
+  else {
+    return FALSE;
+  }
+}
+
 #endif
 
+static CURLcode Curl_ossl_set_engine(struct Curl_easy *data,
+                                     const char *engine);
+
 static
 int cert_stuff(struct connectdata *conn,
                SSL_CTX* ctx,
@@ -622,6 +639,16 @@ int cert_stuff(struct connectdata *conn,
     case SSL_FILETYPE_ENGINE:
 #if defined(USE_OPENSSL_ENGINE) && defined(ENGINE_CTRL_GET_CMD_FROM_NAME)
       {
+        /* Implicitly use pkcs11 engine if none was provided and the
+         * cert_file is a PKCS#11 URI */
+        if(!data->state.engine) {
+          if(is_pkcs11_uri(cert_file)) {
+            if(Curl_ossl_set_engine(data, "pkcs11") != CURLE_OK) {
+              return 0;
+            }
+          }
+        }
+
         if(data->state.engine) {
           const char *cmd_name = "LOAD_CERT_CTRL";
           struct {
@@ -798,6 +825,17 @@ int cert_stuff(struct connectdata *conn,
 #ifdef USE_OPENSSL_ENGINE
       {                         /* XXXX still needs some work */
         EVP_PKEY *priv_key = NULL;
+
+        /* Implicitly use pkcs11 engine if none was provided and the
+         * key_file is a PKCS#11 URI */
+        if(!data->state.engine) {
+          if(is_pkcs11_uri(key_file)) {
+            if(Curl_ossl_set_engine(data, "pkcs11") != CURLE_OK) {
+              return 0;
+            }
+          }
+        }
+
         if(data->state.engine) {
           UI_METHOD *ui_method =
             UI_create_method((char *)"curl user interface");