mosh extension support about chrome-ssh-agent

[ralimi]

This will be released in version 0.0.25, which is now pending review in the Chrome Web Store.

[alexbodn]

i found mosh in secure shell extension.
however, i couldn't use the chrome ssh agent.

[ralimi]

I tried this out, and it seems to hang for me when connecting after detecting that it requires public key authentication.

What I've done so far:

• In the mosh connection setup, I set the SSH agent ID to eechpbnaifiimgajnomdipfaamobdfha
• Installed mosh on the server to which I'm trying to login.
• Validated in the console (under Chrome Developer tools) for this extension (SSH Agent for Google Chrome) that there are messages to and from the SSH agent.

What would be really helpful is to pass -vvv to the ssh client process started by mosh to see where it's getting hung up, but I haven't figured out how to do that. I suspect I'm missing something obvious.

@rpwoodbu do you have any insight on how best to see what's happening inside of mosh? Or, do you have any background on what we should expect here?

[rpwoodbu]

The web-based Mosh implementation actually doesn't use OpenSSH under the hood (uses libssh), so -vvv is not meaningful here. I would try starting an ordinary SSH session from the Secure Shell app to debug authentication issues first, as that does afford more debuggability.

[alexbodn]

hello friends,
my 2 pence.
i have also tried mosh with the agent, and there's a clear error in the chrome dev console.
mosh does expect some object, and it receives an array of bytes from the agent.
since the agent is already working with some extensions, I'd incline to implement in mosh the parsing of that array.
though I've never tried the world of binaries compiled for the web yet.
all my best,
a.

[ralimi]

Thanks @alexbodn - yes, that aligns with my test. The ssh agent extension works correctly for me for ordinary ssh sessions (when not using mosh).

[vapier]

the problem is that the gnubby extension always sends messages using the format:

{
  type: "[email protected]",
  data: [...]   // Array of integers
}

this extension however omits type in its messages.

it woks with Secure Shell because it doesn't care -- it only looks for .data. mosh however has a check:

    this.agentPort_.onMessage.addListener(function(message) {
      if (message['type'] !== '[email protected]') {
        console.error('Got unexpected message from SSH agent:');
        console.error(message);
        return;
      }

so we could omit the .type check in mosh, or, more easier, change this extension to fill out the .type field. then it would just work with mosh.

i don't think the protocol is documented anywhere.

[ralimi]

Ah - thank you @vapier! I can't think of a downside to just also setting the type in the ssh agent extension. I can give that a try.

[alexbodn]

indeed, if changing the agent doesn't do harm, that would be the way to go, and also harden secure shell to check it afterwards. otherwise, mosh would be easier to patch. well i have no such experience yet. thank you very much! alex

…

On Wed, Jan 25, 2023, 05:52 Mike Frysinger ***@***.***> wrote: the problem is that the gnubby extension always sends messages using the format: { type: ***@***.***", data: [...] // Array of integers} this extension however omits type in its messages. it woks with Secure Shell because it doesn't care -- it only looks for .data. mosh however has a check: this.agentPort_.onMessage.addListener(function(message) { if (message['type'] !== ***@***.***') { console.error('Got unexpected message from SSH agent:'); console.error(message); return; } so we could omit the .type check in mosh, or, more easier, change this extension to fill out the .type field. then it would just work with mosh. i don't think the protocol is documented anywhere. — Reply to this email directly, view it on GitHub <#83 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABER7APCXEIBRQPHXAVIAXTWUCPOFANCNFSM6AAAAAATPFG7MU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[alexbodn]

thank you very much rich. alex

…

On Wed, Jan 25, 2023, 06:08 Rich Alimi ***@***.***> wrote: Ah - thank you @vapier <https://github.com/vapier>! I can't think of a downside to just also setting the type in the ssh agent extension. I can give that a try. — Reply to this email directly, view it on GitHub <#83 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABER7AOYR75LJIQOKJ46BXDWUCRKRANCNFSM6AAAAAATPFG7MU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[alexbodn]

thank you rich.
how can i install the review version?

[ralimi]

Once it is published in the web store, you should get the new version automatically.

[alexbodn]

sure that. but i was asking for the preview version. alex

…

On Sun, Jan 29, 2023, 18:24 Rich Alimi ***@***.***> wrote: Once it is published in the web store, you should get the new version automatically. — Reply to this email directly, view it on GitHub <#83 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABER7AJBQHQDEZTDLSJAX33WU2KSJANCNFSM6AAAAAATPFG7MU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[ralimi]

Ah - I see.

If you are okay with installing it locally, you could use the zip file from the releases page (https://github.com/google/chrome-ssh-agent/releases/tag/v0.0.25). There are a number of guides available for installing extensions from zip files.

NOTE: That this would not be a signed copy, as that is only available after being published in the Web Store.

[alexbodn]

thank you rich. it works well for me. as said before, there's a regression with secure shell, that I've reported in the chromium issues list (see below). alex

…

On Sun, Jan 29, 2023, 20:07 Rich Alimi ***@***.***> wrote: Ah - I see. If you are okay with installing it locally, you could use the zip file from the releases page ( https://github.com/google/chrome-ssh-agent/releases/tag/v0.0.25). There are a number of guides available for installing extensions from zip files. NOTE: That this would not be a signed copy, as that is only available after being published in the Web Store. — Reply to this email directly, view it on GitHub <#83 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABER7AMA7UR5BUTOZLQ6F7TWU2WVPANCNFSM6AAAAAATPFG7MU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[ralimi]

It sounds like that is separate from the subject of this issue, right? If so, can you please file a separate issue?

[alexbodn]

I've reported the secure shell dev regression at
https://bugs.chromium.org/p/chromium/issues/detail?id=1411180

thank you very much