[securedrop-proxy] Downloading submissions give empty file

[kushaldas]

While I am trying to download submissions, the client vm, which talks to the proxy vm over qrexec, is getting empty files copied into ~/QubesIncoming/ directory.

I tried to download the same using the standard securedrop-sdk in the proxy vm itself, I can download the submissions properly.

[kushaldas]

Same goes with downloading replies, empty files.

[redshiftzero]

Steps to Reproduce

1. Configure securedrop-proxy manually as described in README (but with a test journalist interface on a staging server in config.yaml)
2. Try to download any non-JSON content, here the HTML of the index of the journalist interface:

$ echo '{"method":"GET","path_query":""}' | /usr/lib/qubes/qrexec-client-vm securedrop-proxy securedrop.Proxy

3. Inspect filename in response in ~/QubesIncoming on the sd-svs AppVM

Expected Behavior

File contains HTML of journalist interface index

Actual Behavior

File exists but is empty