Use UTC to heck certificate validity

ChangeLog

@@ -16,6 +16,7 @@ Changes
    * x509_crt_info() now prints information about parsed extensions as well
    * pk_verify() now returns a specific error code when the signature is valid
      but shorter than the supplied length.
+   * Use UTC time to check certificate validity.
 
 Security
    * Avoid potential timing leak in ecdsa_sign() by blinding modular division.

library/x509.c

@@ -627,7 +627,7 @@ static void x509_get_current_time( x509_time *now )
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
     SYSTEMTIME st;
 
-    GetLocalTime(&st);
+    GetSystemTime(&st);
 
     now->year = st.wYear;
     now->mon = st.wMonth;
@@ -640,7 +640,7 @@ static void x509_get_current_time( x509_time *now )
     time_t tt;
 
     tt = time( NULL );
-    localtime_r( &tt, &lt );
+    gmtime_r( &tt, &lt );
 
     now->year = lt.tm_year + 1900;
     now->mon = lt.tm_mon + 1;