Add basic support for none cipher and MACs

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/libgcrypt.c

@@ -881,6 +881,17 @@ out:
 }
 #endif /* HAVE_GCRYPT_CHACHA_POLY */
 
+#ifdef WITH_INSECURE_NONE
+static void
+none_crypt(UNUSED_PARAM(struct ssh_cipher_struct *cipher),
+           void *in,
+           void *out,
+           size_t len)
+{
+    memcpy(out, in, len);
+}
+#endif /* WITH_INSECURE_NONE */
+
 /* the table of supported ciphers */
 static struct ssh_cipher_struct ssh_ciphertab[] = {
 #ifdef WITH_BLOWFISH_CIPHER
@@ -1020,6 +1031,15 @@ static struct ssh_cipher_struct ssh_ciphertab[] = {
     .name = "chacha20-poly1305@openssh.com"
 #endif
   },
+#ifdef WITH_INSECURE_NONE
+  {
+    .name            = "none",
+    .blocksize       = 8,
+    .keysize         = 0,
+    .encrypt         = none_crypt,
+    .decrypt         = none_crypt
+  },
+#endif /* WITH_INSECURE_NONE */
   {
     .name            = NULL,
     .blocksize       = 0,