pinentry-tty, gpg-agent, and no way to enter password

pinentry-tty, gpg-agent, and no way to enter password

[David Dombrowsky]

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Back in 2018, I mentioned that there was reliable way to enter a gpg
password on the cygwin console:
http://cygwin.1069669.n5.nabble.com/pinentry-curses-not-available-td143121.html

From there I was able to cobble together a solution using a locally
patched version of pinentry-curses.  Somewhere along the line, that
stopped working.

I am now back where I started.

Does anyone have a solution for the following:
1. ssh into a windows box running cygwin sshd
2. run `echo hello | gpg -sab`

This worked until recently.  Now I get:

gpg: using "01D5A625A30C0E6A" as default secret key for signing
gpg: signing failed: Invalid IPC response
gpg: signing failed: Invalid IPC response

checking the output of gpg-agent, I see:

gpg-agent[2261]: gpg-agent (GnuPG) 2.2.13-unknown started
gpg-agent[2261]: handler 0x200549e0 for fd 7 started
gpg-agent[2261]: starting a new PIN Entry
cbreak failure, exiting
gpg-agent[2261]: failed to unprotect the secret key: Operation cancelled


pinentry-w32 works, but it pops up a GUI window and thus requires an RDP
session.  Does anyone have a working solution that doesn't require
access to the windows console?

-- 
David Dombrowsky, Software Engineer
davek@6thstreetradio.org | 518-374-3204
https://www.linkedin.com/in/david-dombrowsky-94334415


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Re: pinentry-tty, gpg-agent, and no way to enter password

[David Dombrowsky]

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On 4/16/19 12:29 PM, David Dombrowsky wrote:
> From there I was able to cobble together a solution using a locally
> patched version of pinentry-curses.  Somewhere along the line, that
> stopped working.

I put debug prints in pinentry-tty, and it is opening the correct tty.
However, running the command to set the terminal into the right mode
will fail.  If I comment that out, something interesting happens:

tty/pinentry-tty.c
356       c = fgetc (ttyfi);
357       switch (c)

This call to `fgetc`, while it points to a FILE handle opened to the
correct tty, will read NOTHING.  My session is on /dev/pty0, but a
subprocess that opens that terminal for reading neither fail, nor read
anything.

Any ideas?

-- 
David Dombrowsky, Software Engineer
davek@6thstreetradio.org | 518-374-3204
https://www.linkedin.com/in/david-dombrowsky-94334415


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