I also tried adding this to my gpg-agent.conf file:

Oh, in case it wasn't clear, the idea that another application (GNU emacs) is receiving keystrokes meant for the gpg-agent prompt is probably a security risk....

Simply sending "KILLSCD" is implemented.

Also fixed for 2.2

The behaviour related to ssh key access is due to the way ssh works: After a connection has been established to a server ssh presents to to the server all identities (public keys) it has access to (meaning it has a corresponding private key). Thus we can't tell ssh all the keys we have because that would be an information leak and may also take too long. Because the user may in some cases not want to use the ssh-agent but resort to ssh command line input of the passphrase, we do not insist on using a key known by gpg-agent.

I located the bug in agent/command-ssh.c.
Our practice is two calls of gcry_sexp_sprint; One to determine the length including last NUL byte, and another to actually fills the buffer.
The first call return +1 for NUL byte.
The second call fills NUL at the end, but returns +0 length (length sans last NUL).

I spent a lot of time trying to figure out how to automate the interface between my preferred password store (gnome-keyring, via libsecret), but with the loopback pinentry mode changes in gpg 2.1, it is much harder (if not impossible) to do. Having passphrase caching is the only thing preventing me from choosing a weaker passphrase on my gpg keyring.

Disallowing passphrase caching is likely to have the unintended consequence of users choosing weaker passphrases that are more easily memorized and/or typed. Caching should be permitted, IMO. This puts more decisions about passphrase management into the control of the user.

And yet, that interface is already being used by the agent-transfer utility in monkeysphere. The interface exists, it is not marked in any way as unusable or deprecated or off-limits, so it is used.

That is on purpose. Exporting of a secret key should in theory not be possible at all via gpg. In practice we need a way to export a key, but that should be the exception and thus we do not want any caches for passphrases to have an effect.

trigger what command? i'm pretty sure it does not trigger updatestartuptty. And it should not do so, afaict -- if you think it should, i'd be interested in hearing the rationale for it.

Does gpgconf --reload gpg-agent trigger that command? that's the ExecReload setting in the systemd service unit I'm looking at.

This doesn't sound systemd-specific to me, fwiw, though i don't understand how to reproduce the problem from the given description here.

I often put an extra nul byte at the end of binary data so that accidental printing the data (e.g. in gdb) assures that there is a string terminator. But right, it should not go out to a file.

As this update lists multiple issues and following fixes for them, maybe it was resolved by Microsoft?

Since 2.1 the standard use of gpg-agent is to have it started on demand by the components which require it. The use of
"gpg-agent --daemon /bin/sh " should be used for debugging only.

I've applied your patch with an additional comment to our master branch. Thanks!

I did lot of tests in the last weeks while working on gpg-card.

Sorry, this did not make it into 3.1.6. But I'll definitely see about it for the next release. If it is an institutional / corporate issue you could also contract us through www.gnupg.com

In T4427#123774, @werner wrote:

Can you please run

gpg --debug ipc -vK

which will also start gpg-agent and print some diagnostics. You may want to redact the output. You can also run

From: aheinecke (Andre Heinecke)
Sent: Montag, 28. Januar 2019 19:25

fwiw. Your patch is beautiful in which it follows our coding style and
debug output. I'm confident that we will accept it but currently I have
to read up on Job's a bit.

Is there a way I could help you with this? This issue is hampering adoption
of GnuPG 2 here.

--

Jan Echternach

Trying to install the update manually (according to windows update my windows is fully updated) it says "This update is not meant for your computer" and aborts.

Can you please run

gpg --debug ipc -vK

which will also start gpg-agent and print some diagnostics. You may want to redact the output. You can also run

gpg-agent -v --daemon

which should also print some more info.

Thanks for fixing that.

That's my badness. In wait_child_thread, assuan_release may cause thread context switch to agent_reset_scd which accesses scd_local_list; This access should be serialized.
And... in start_scd, calling unlock_scd should be after unlocking start_scd_lock.