Added a wincrypt adapter to read CA trust certs from Windows CA store and feed them into openssl for TLS hostname authentication

m4/acx_getaddrinfo.m4

@@ -32,12 +32,12 @@ dnl see if on windows
 if test "$ac_cv_header_windows_h" = "yes"; then
 	AC_DEFINE(USE_WINSOCK, 1, [Whether the windows socket API is used])
 	USE_WINSOCK="1"
-	LIBS="$LIBS -lws2_32"
+	LIBS="$LIBS -lws2_32 -lcrypt32"
 fi
 ],
 dnl no quick getaddrinfo, try mingw32 and winsock2 library.
 ORIGLIBS="$LIBS"
-LIBS="$LIBS -lws2_32"
+LIBS="$LIBS -lws2_32 -lcrypt32"
 AC_LINK_IFELSE(
 [AC_LANG_PROGRAM(
 [
@@ -62,7 +62,7 @@ AC_LINK_IFELSE(
 )],
 [
 ac_cv_func_getaddrinfo="yes"
-dnl already: LIBS="$LIBS -lws2_32"
+dnl already: LIBS="$LIBS -lws2_32 -lcrypt32"
 AC_DEFINE(USE_WINSOCK, 1, [Whether the windows socket API is used])
 USE_WINSOCK="1"
 ],

src/context.c

@@ -44,6 +44,14 @@
 #include <winsock2.h>
 #include <iphlpapi.h>
 typedef unsigned short in_port_t;
+
+#include <openssl/x509.h>
+#include <openssl/pem.h>
+#include <openssl/bio.h>
+
+#include <stdio.h>
+#include <windows.h>
+#include <Wincrypt.h>
 #endif
 
 #include <sys/stat.h>
@@ -130,6 +138,66 @@ static void set_ub_edns_maximum_udp_payload_size(struct getdns_context*,
 /* Stuff to make it compile pedantically */
 #define RETURN_IF_NULL(ptr, code) if(ptr == NULL) return code;
 
+
+#ifdef USE_WINSOCK
+// For windows, the CA trust store is not read by openssl. 
+// Add code to open the trust store using wincrypt API and add
+// the root certs into openssl trust store
+X509_STORE *store;
+X509_STORE_CTX  *sslctx = NULL;
+void add_cacerts_to_openssl_store(struct getdns_context *context)
+{
+	HCERTSTORE      hSystemStore;
+	PCCERT_CONTEXT  pTargetCert = NULL;
+
+	// Call wincrypt's CertOpenStore to open the CA root store.
+
+	if ((hSystemStore = CertOpenStore(
+		CERT_STORE_PROV_SYSTEM,
+		0,
+		NULL,
+		// mingw does not have this const: replace with 1 << 16 from code
+		// CERT_SYSTEM_STORE_CURRENT_USER,
+		1 << 16,
+		L"root")) == 0)
+	{
+		DEBUG_STUB("*** %s(CertOpenStore failed)\n", __FUNCTION__);
+		return;
+	}
+	store = SSL_CTX_get_cert_store(context->tls_ctx);
+
+	// iterate over the windows cert store and add to openssl store
+	while (pTargetCert = CertEnumCertificatesInStore(
+		hSystemStore,
+		pTargetCert))
+	{
+		BYTE* cert = pTargetCert->pbCertEncoded;
+		X509 *cert1 = d2i_X509(NULL, (const unsigned char **)&pTargetCert->pbCertEncoded, pTargetCert->cbCertEncoded);
+		if (!cert1) {
+			DEBUG_STUB("*** %s(%s)\n", __FUNCTION__,
+				"unable to parse certificate in memory");
+		}
+		else {
+			if (X509_STORE_add_cert(store, cert1) == 0)
+				DEBUG_STUB("*** %s(%s)\n", __FUNCTION__,
+				"error adding certificate");
+			X509_free(cert1);
+		}
+	}
+	// Clean up memory and quit.
+
+	if (pTargetCert)
+		CertFreeCertificateContext(pTargetCert);
+	if (hSystemStore)
+	{
+		if (!CertCloseStore(
+			hSystemStore, 0))
+			DEBUG_STUB("*** %s(%s)\n", __FUNCTION__, "CertCloseStore failed");
+	}
+
+}
+#endif
+
 static void destroy_local_host(_getdns_rbnode_t * node, void *arg)
 {
 	getdns_context *context = (getdns_context *)arg;
@@ -2631,7 +2699,8 @@ _getdns_context_prepare_for_resolution(struct getdns_context *context,
 #ifndef USE_WINSOCK
 				return GETDNS_RETURN_BAD_CONTEXT;
 #else
-				printf("Warning! Bad TLS context, check openssl version on Windows!\n");;
+				printf("Warning! Bad TLS context, check openssl version on Windows!\n");
+			add_cacerts_to_openssl_store(context);
 #endif
 			/* Be strict and only use the cipher suites recommended in RFC7525
 			   Unless we later fallback to opportunistic. */