More complete input validation of X509_check_mumble.

(Imported from upstream's 3d15d58e55b97207188e87708a0e7f49b4bfd7fd.)

Change-Id: Iae9e3f839e03c22dc45ac2151884e7afcf31af7b

crypto/x509v3/v3_utl.c

diff --git a/crypto/x509v3/v3_utl.c b/crypto/x509v3/v3_utl.c
index 8174103..a85a2a6 100644
--- a/crypto/x509v3/v3_utl.c
+++ b/crypto/x509v3/v3_utl.c
@@ -971,20 +971,28 @@
 int X509_check_host(X509 *x, const unsigned char *chk, size_t chklen,
 					unsigned int flags)
 	{
-	if (chk && memchr(chk, '\0', chklen))
-		return 0;
+	if (chk == NULL)
+		return -2;
+	if (memchr(chk, '\0', chklen))
+		return -2;
 	return do_x509_check(x, chk, chklen, flags, GEN_DNS);
 	}
 
 int X509_check_email(X509 *x, const unsigned char *chk, size_t chklen,
 					unsigned int flags)
 	{
+	if (chk == NULL)
+		return -2;
+	if (memchr(chk, '\0', chklen))
+		return -2;
 	return do_x509_check(x, chk, chklen, flags, GEN_EMAIL);
 	}
 
 int X509_check_ip(X509 *x, const unsigned char *chk, size_t chklen,
 					unsigned int flags)
 	{
+	if (chk == NULL)
+		return -2;
 	return do_x509_check(x, chk, chklen, flags, GEN_IPADD);
 	}
 
@@ -992,6 +1000,8 @@
 	{
 	unsigned char ipout[16];
 	int iplen;
+	if (ipasc == NULL)
+		return -2;
 	iplen = a2i_ipadd(ipout, ipasc);
 	if (iplen == 0)
 		return -2;