Enforce _X509_CHECK_FLAG_DOT_SUBDOMAINS internal-only

crypto/x509v3/v3_utl.c

@@ -584,13 +584,9 @@ static void skip_prefix(const unsigned char **p, size_t *plen,
 	 * If subject starts with a leading '.' followed by more octets, and
 	 * pattern is longer, compare just an equal-length suffix with the
 	 * full subject (starting at the '.'), provided the prefix contains
-	 * no NULs.  (We check again that subject starts with '.' and
-	 * contains at least one subsequent character, just in case the
-	 * internal _X509_CHECK_FLAG_DOT_SUBDOMAINS flag was erroneously
-	 * set by the user).
+	 * no NULs.
 	 */
-	if ((flags & _X509_CHECK_FLAG_DOT_SUBDOMAINS) == 0 ||
-	    subject_len <= 1 || subject[0] != '.')
+	if ((flags & _X509_CHECK_FLAG_DOT_SUBDOMAINS) == 0)
 		return;
 
 	while (pattern_len > subject_len && *pattern)
@@ -895,6 +891,9 @@ static int do_x509_check(X509 *x, const unsigned char *chk, size_t chklen,
 	int alt_type;
 	int san_present = 0;
 	equal_fn equal;
+
+	/* See below, this flag is internal-only */
+	flags &= ~_X509_CHECK_FLAG_DOT_SUBDOMAINS;
 	if (check_type == GEN_EMAIL)
 		{
 		cnid = NID_pkcs9_emailAddress;