wks: Do not use compression for the encrypted data.

* tools/gpg-wks-client.c (encrypt_response): Add arg -z0.
* tools/gpg-wks-server.c (encrypt_stream): Ditto.
--

If for example a server was built without the development packages of
the compression libraries installed, the server will not be able to
decrypt a request.  In theory this can't happen due to the preference
system but it is just to easy to create the server's key using a
different version of gpg and then use gpg-wks-server built
differently.

For the short messages we exchange compression is not really required
and thus we better do without to make the system more robust.

Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit 70a8db0333)

tools/gpg-wks-client.c

@@ -1151,6 +1151,7 @@ encrypt_response (estream_t *r_output, estream_t input, const char *addrspec,
   ccparray_put (&ccp, "--status-fd=2");
   ccparray_put (&ccp, "--always-trust");
   ccparray_put (&ccp, "--armor");
+  ccparray_put (&ccp, "-z0");  /* No compression for improved robustness.  */
   if (fake_submission_addr)
     ccparray_put (&ccp, "--auto-key-locate=clear,local");
   else

tools/gpg-wks-server.c

@@ -586,6 +586,7 @@ encrypt_stream (estream_t *r_output, estream_t input, const char *keyfile)
   ccparray_put (&ccp, "--always-trust");
   ccparray_put (&ccp, "--no-keyring");
   ccparray_put (&ccp, "--armor");
+  ccparray_put (&ccp, "-z0");  /* No compression for improved robustness.  */
   ccparray_put (&ccp, "--recipient-file");
   ccparray_put (&ccp, keyfile);
   ccparray_put (&ccp, "--encrypt");