Yeah but it seems to be the same issue / reason. I wasn't aware that PKISSH is something else. I thought it was an extension/protocol or something

I added "Feature Request", because this is a request to support:

• A feature of bug compatibility, which is implemented wrongly in PKISSH
• for a specific algo of key, which is not considered so useful (== ECDSA)
• PKISSH, which is variant of OpenSSH

In T4563#140184, @idl0r wrote:

I was and I am using OpenSSH on both sides, client and server.

I was and I am using OpenSSH on both sides, client and server.

I do not think that we should support a fork of openssh right now. If we would support it we are bound to maintain that for years - this is not a good idea.

Well, I have no idea about the technical background to be honest but without this patch it doesn't work at all for me, unless I stop using the agent or workaround it by using SSH_AUTH_SOCK=0. With this patch, I can use the agent again. I don't know how many others are affected by this but it made it usable again, which wasn't the case for months already.

In theory, I don't think the patch gnupg.patch works. It just ignore the flag.

I am affected by the same bug and the patch seems to work for me. Login via gpg-agent with ssh support is possible again, which wasn't before, since some openssh and/or gnupg update. Not sure.

No more problems reported, so I assume like @aheinecke that it has been resolved in Windows.

Its done for 2.2 thus changing the tag.

I though about this too but we need to take care about the logging functions of Libgcrypt which are intertwined with nPth (clamp function of libgpg-error).

{F1982353}

Thanks. I understand the situation. Basically, gpg-agent's computation is done by a single thread (in current implementation), although it accepts many requests simultaneously.

In T5137#139066, @werner wrote:

Note that you actually run 30 independent processes with gpg 1.4 but with gpg-agent there is just one process to handle the private key operations (decrypt). To utilize more cores you need to setup several GNUPGHOME with the same private keys.

In T5137#139064, @gniibe wrote:

I think that it is not gpg-agent but pinentry which causes millions of futex syscall errors.
For interactive use case, pinentry may be the point of contention.
I might be wrong if your key is not protected by passphrase.

If possible, please try adding arguments for gpg invocation: --pinentry-mode loopback --passphrase-file YOUR_FILE_FOR_PASSPHRASE
This can avoid the invocation of pinentry entirely.

I change this to a feature request: Allow several processes to run public key decryption using the same set of private keys.

One bug is fixed in rGdd4fb1c8f668: gpg: Fix first zero-byte case for SOS handling..

Fixed in 2.2 branch.
Also, I found another issue of libgcrypt master, which is fixed in rC361a0588489c: ecc: Handle removed zeros at the beginning for Ed25519..
Further, I found different issue, and created T5116: GnuPG master shows an error when importing Ed25519 keys generated.

I think that it may occur with eddsa secret keys generated with 2.2, too. (In the 50% probability)

In short eddsa secret keys generated with current 2.3 can't be imported with 2.2, right? That will lead to a compatibility problem, so we need to fix that in 2.2.

IIUC, it is an issue of GnuPG 2.2.
The condition is where the secret 'd' starts by the first bit = 1 (that is, >= 0x80).
I located the bug in agent/cvt-openpgp.c. The function do_unprotect calls convert_secret_key with skey[1] as usual MPI (not opaque),
and gcry_sexp_build with "(d%m)" will put additional 0x00 at the beginning, which results 33-byte secret in R_KEY. Then, when gcry_pk_testkey is called with R_KEY, when it checks, because 32-byte is expected, it returns GPG_ERR_INV_OBJ. Then, do_unprotect returns GPG_ERR_BAD_PASSPHRASE.

What can be done is to use gpgconf --list-dirs bindir as a fallback for pinentry.

@werner can you confirm if the environment I provided will work with OpenSSH support fully implemented?

So, if there's no support for native OpenSSH yet, I'll wait for it. After it's supported, I should be able to get the scenery I described working, right?

Unfortunately you can't pass extra arguments.

@bvieira You need to set pinentry-mode=loopback for gpg program used in git.

I'm actually trying to do the following:

In the meantime you can use [0]. I have tested with ssh key on yubikey and AuthenticationMethods publickey, win32-ssh (or ssh-portable, which is the new repository name) correctly works with gpg and pinentry is called. Despite it being called wsl, wsl environment is not required.

[These damned typos in commit messages ;-)]

Any news on this?

Change of gpg-agent for ECC-SOS

I t could print a warning for a non-existant homedir

Sure, I personally know that GnuPG requires a homedir to operate.

As you surely known GnuPG requires its home directory; in particular when using the gpgconf to manage the config options. Thus I can't see what to do other than error out. gpgconf needs to know the location of the config file; if it is containign diretcory is not existant it will fail anyway.

The description comes from gpg/gpgsm while the prompts are from gpg-agent. Thus if the agent has been started with the German local but gpgsm without a local this would explain the behaviour.

Although I don't use the ssh client on Windows I had to integrate the Windows ssh server into our release process (GlobalSign sent us a Windows-only token, for the new cert and so we can't anymore use osslsigncode). The ssh server is really stable and so it makes a lot of sense to better integrate our ssh-agent into Windows.

My analysis is that it's not a race condition but... it's about secure memory.
It is true that we have a race condition between putting an entry to cache after pinentry interaction _and_ next examining cache to invoke pinentry. But for this test case, the gpg process of unlock the key (and cache the passphrase) is finished before running the run-threaded command.

That is actually a GnuPG thing. We originally did it this way to help people remember their passphrase before they start using the key. I agree it is annoying and I would like to remove it too. At the same time we should really think about making no-passphrase the default and require it only with certain compliance settings.

OK, I identify the problem.

But this problem remains for several versions for some time. I tried to find out the source of this "new option" in the communication, but I could not find anything about "GPG Agent" in the source code of openssh.

Sorry for the late answer, but I have been busy. Actually this happened against several ssh versions, for some time now.

It was fixed in GnuPG master by rGc395f8315362: agent: Terminate pinentry process gracefully, by watching socket. and rG374a0775546b: agent: Close a dialog cleanly when gpg/ssh is killed for CONFIRM..
Those will be in GnuPG 2.3.

This appears to be https://bugs.debian.org/850946 and it does not appear to be fixed to me.

Please update the documentation for the function in that case.

No, it was not in mind. I introduced this only for backward compatibility. It will be extended iff we have a need for it.

My understanding is: it was introduced by rG370f841a0135: Enhanced last patch. in 2009 to give information to client (for a specific command at that time), possibly in a hope that server side would support the feature for all commands (and client could benefits).

Which SSH client are you using?

gpg-agent side is fixed to relax the error handling.

As I said we do this with all GnuPG components. Pinentry is a bit of exception because it is an external package.
I have also had bug reports which later turned out that a wrong pinentry was used; I prefer to know eactly which pinentry is used. Regarding your concrete problem I suggested to add a note with the full name of the pinentry or to change the error message to something better understandable.

So this is a defense against an adversary capable of creating a pinentry-wrapper somewhere in $PATH, but not capable of modifying gpg-agent.conf? It sounds to me like this is a defense against a very unusually-constrained attacker, at the expense of regular, common bug reports and user confusion.

GnuPG invokes its components always with their absolute file name. We want to mitigate attacks where malware creates a pinentry wrapper somewhere in an improper set PATH.

I'm unlikely to put a windows-specific patch into the debian source, as
i have no good way of testing it, and it wouldn't affect any binary that
we ship.

@dkg, for your patch, it can be improved for Windows by using its event mechanism. You can see gnupg/scd/scdaemon.c.

Hm, T4521 suggests that the two different cases should not be treated differently. If you think that they *should* cause distinct behavior, please do mention it over there!

There are two different cases: (1) By SIGTERM and (2) By KILLAGENT. It's true that the agent stops accepting on the listening socket for (1), but it's not the case for (2).
This particular problem is for the case (2).

@gniibe, thanks for the diagnosis! I agree that restarting or shutting down the backends should be done in the reverse order as a simple workaround.

Correct solution is to implement KILLAGENT synchronously, but it's somehow harder to implement.
Easier workaround is modifying gpgconf like:

I found a race condition between KILLAGENT command and accepting another request.
Here is a patch to replicate the race condition :

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.