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Initial implementation of a builtin SSH connection support #1323

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merged 3 commits into from Nov 8, 2023
Merged

Initial implementation of a builtin SSH connection support #1323

merged 3 commits into from Nov 8, 2023

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christianparpart
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@christianparpart christianparpart commented Oct 29, 2023 •
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Main motivation of implementing this is to bypass local PTY (ConPTY) on Windows. But there may be more use to it than that on other platforms maybe as well, so we make it available on all platforms, if possible.

Closes #1319, #1064.

Implement builtin SSH support. While being not THAT useful on Linux desktop or MacOS, it turns out to be a game changer on Windows platform, as we can fully bypass ConPTY with a builtin SSH client in case would simply SSH away only anyways.

Maybe this would also bypass ConPTY on Windows when using to get into WSL / WSL2 (I do not know yet).

Checklist

  • build: make sure it builds on MacOS/X (CI) (currently has linker errors, can't find lib)
  • build: make sure it builds on Windows (CI)
  • build: make sure it builds on Linux (CI)
  • SSH backend (using libssh2, bridging to C++ API: SshClient)
  • vtpty::Pty implementation: SshSession
  • frontend: configuration for login shell over SSH (how could the YAML config look like?)
  • frontend: support SSH session configuration for SSH-agent based authentication
  • frontend: support SSH session configuration for SSH key pair based authentication with password (to be prompted!) (needs code to interactively ask for password within the TE grid)
  • frontend: support username/password based auth
  • configuration additions documented
  • DNS resolution of hostname to IP via getaddr (API matches on UNIX + Win32, yay)
  • support TCP/IPv4
  • support TCP/IPv6
  • properly propagate login shell's exit code
  • server host key verification
  • configurable SSH agent forwarding (current problem: upon ssh-add -l the session terminates - ref)

Postponed post-merge and maybe post-0.4.0-release

Notes

this feature is only built if libssh2 is installed (its development package).

@christianparpart christianparpart added the frontend Contour Terminal Emulator (GUI frontend) label Oct 29, 2023
@christianparpart christianparpart marked this pull request as draft October 29, 2023 18:15
@github-actions github-actions bot added VT: Backend Virtual Terminal Backend (libterminal API) and removed frontend Contour Terminal Emulator (GUI frontend) labels Oct 29, 2023
@christianparpart christianparpart force-pushed the feature/ssh-client branch 2 times, most recently from f3f325d to 5a3abf1 Compare October 29, 2023 19:50
@github-actions github-actions bot added the CI GitHub Actions & CI label Oct 29, 2023
@christianparpart christianparpart force-pushed the feature/ssh-client branch 3 times, most recently from 93ff06d to 82bcf9a Compare October 29, 2023 21:02
@christianparpart christianparpart changed the title [vtpty] Initial implementation of a builtin SSH login session Pty implementation Initial implementation of a builtin SSH login session Pty implementation Oct 29, 2023
@github-actions github-actions bot added documentation Improvements or additions to documentation frontend Contour Terminal Emulator (GUI frontend) labels Oct 30, 2023
@christianparpart christianparpart force-pushed the feature/ssh-client branch 6 times, most recently from 3e158ec to 498f618 Compare October 30, 2023 22:01
@christianparpart christianparpart changed the title Initial implementation of a builtin SSH login session Pty implementation Initial implementation of a builtin SSH login PTY session Oct 31, 2023
@christianparpart christianparpart force-pushed the feature/ssh-client branch 8 times, most recently from 977a89a to b64d840 Compare October 31, 2023 15:52
@christianparpart christianparpart force-pushed the feature/ssh-client branch 2 times, most recently from 7667d3b to 9ad7a29 Compare November 6, 2023 07:00
whisperity

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Right off the bat, here is something weird. When using the build from https://github.com/contour-terminal/contour/actions/runs/6763840917, I immediately get a complete failure when just starting Contour if I let contour create its default configuration:

nice catch. the instant failure is because it tries to connect to SSH (localhost here) via IPv6. apparently that's not working (either not possible or i need to fix IPv6 support, will check).

On the other hand, SSH should not be used when using default config. i'll address that asap. (it's because ssh.hostname defaults to "localhost" and makes the frontend think that it should connect to SSH rather than spawn a local process.

@christianparpart christianparpart force-pushed the feature/ssh-client branch 4 times, most recently from 7492123 to ae99510 Compare November 6, 2023 20:05
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@whisperity I cannot repro what you described. my earlier comment was based on an old state of this PR. :(

I've found some other minor issue though. the default user name on windows was not properly inferred. it was set to "unknown" as fallback. I've just fixed that.

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I cannot repro what you described. my earlier comment was based on an old state of this PR. :(

I linked exactly the build I was using... 😦 Although, yeah, it does not point to a commit.

I will try the latest build of the branch tomorrow!

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Using this build, I can confirm that Contour auto-starts PowerShell on Windows using the default configuration.

Yaraslaut
Yaraslaut requested changes Nov 8, 2023
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contour failed to spawn ssh sessions for me because i dont have .ssh/config file

src/vtpty/SshSession.cpp Outdated Show resolved Hide resolved
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[crispy] Add API: result<T, E=std::error_code>
bc7542c 
Signed-off-by: Christian Parpart <christian@parpart.family>
@christianparpart
[vtpty] Process: cleanup bad implementation of fmtlib override for Ex…
c204a1e 
…itCode

Signed-off-by: Christian Parpart <christian@parpart.family>
@Yaraslaut Yaraslaut self-requested a review November 8, 2023 14:51
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Now it asks password for three times, but if i insert correct password second time it does not work
here is output log for two different runs

~/r/contour feature/ssh-client 20.2s ❱ ./build/src/contour/contour
QML debugging is enabled. Only use this in a safe environment.
Info: libpng warning: iCCP: known incorrect sRGB profile ((null):0, (null))
[2023-11-08 14:52:05.116606663.116606] [ssh] (contour) Resizing PTY to 80x24.
[2023-11-08 14:52:05.116649454.116649] [ssh] Starting SSH session to host: user@192.168.50.20
[2023-11-08 14:52:05.116654083.116654] [ssh] (contour) State transition from Initial to Started.
[2023-11-08 14:52:05.116656448.116656] [ssh] (contour) State transition from Started to Connect.
[2023-11-08 14:52:05.117152308.117152] [ssh] Connected to 192.168.50.20
[2023-11-08 14:52:05.117156336.117156] [ssh] (contour) State transition from Connect to Handshake.
[2023-11-08 14:52:05.255754371.255754] [ssh] (contour) State transition from Handshake to VerifyHostKey.
[2023-11-08 14:52:05.255812912.255812] [ssh] Host key verification succeeded (AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBCvNflTlLiqQTLfsiDJpdiZbqVov9zWXFfnw4EcEGr8WEeeH7UoIkwaQk8pwvs9LOXGDYAOpsDtMO/Aza3cx7oY=).
[2023-11-08 14:52:05.255818603.255818] [ssh] (contour) State transition from VerifyHostKey to AuthenticateAgent.
[error] Failed to connect to SSH agent. Bad use
[error] Failed to authenticate with SSH agent. No more identities available.
[2023-11-08 14:52:05.255828111.255828] [ssh] (contour) State transition from AuthenticateAgent to AuthenticatePasswordStart.
[2023-11-08 14:52:05.255830425.255830] [ssh] (contour) State transition from AuthenticatePasswordStart to AuthenticatePasswordWaitForInput.
[2023-11-08 14:52:05.268786526.268786] [ssh] (contour) Resizing PTY to 80x23.
[2023-11-08 14:52:05.420128299.420128] [ssh] (QSGRenderThread) Resizing PTY to 80x24.
[2023-11-08 14:52:05.469879871.469879] [ssh] (contour) Resizing PTY to 162x24.
[2023-11-08 14:52:05.470018193.470018] [ssh] (contour) Resizing PTY to 162x43.
[2023-11-08 14:52:05.471272903.471272] [ssh] (contour) Resizing PTY to 162x43.
[2023-11-08 14:52:05.471277902.471277] [ssh] (contour) Resizing PTY to 162x43.
[2023-11-08 14:52:05.913383187.913383] [ssh] (contour) Handling pre-authentication input: "s"
[2023-11-08 14:52:06.120066394.120066] [ssh] (contour) Handling pre-authentication input: "t"
[2023-11-08 14:52:06.297095622.297095] [ssh] (contour) Handling pre-authentication input: "a"
[2023-11-08 14:52:06.456843719.456843] [ssh] (contour) Handling pre-authentication input: "r"
[2023-11-08 14:52:06.903854537.903854] [ssh] (contour) Handling pre-authentication input: "f"
[2023-11-08 14:52:07.003769011.003768] [ssh] (contour) Handling pre-authentication input: "i"
[2023-11-08 14:52:07.138722175.138722] [ssh] (contour) Handling pre-authentication input: "v"
[2023-11-08 14:52:07.226831010.226830] [ssh] (contour) Handling pre-authentication input: "e"
[2023-11-08 14:52:07.382814777.382814] [ssh] (contour) Handling pre-authentication input: "\r"
[2023-11-08 14:52:07.382837070.382837] [ssh] (contour) State transition from AuthenticatePasswordWaitForInput to AuthenticatePassword.
[2023-11-08 14:52:07.763370245.763370] [ssh] Successfully authenticated with password.
[2023-11-08 14:52:07.763397417.763397] [ssh] (contour) State transition from AuthenticatePassword to OpenChannel.
[2023-11-08 14:52:09.521277450.521277] [ssh] (contour) State transition from OpenChannel to RequestAuthAgent.
[2023-11-08 14:52:09.521298640.521298] [ssh] (contour) State transition from RequestAuthAgent to RequestPty.
[2023-11-08 14:52:09.535460839.535460] [ssh] (contour) State transition from RequestPty to SetEnv.
[error] Failed to set SSH environment variable "COLORTERM". Request denied
[error] Failed to set SSH environment variable "TERMINAL_NAME". Request denied
[error] Failed to set SSH environment variable "TERMINAL_VERSION_STRING". Request denied
[error] Failed to set SSH environment variable "TERMINAL_VERSION_TRIPLE". Request denied
[2023-11-08 14:52:09.537095809.537095] [ssh] (contour) State transition from SetEnv to StartShell.
[2023-11-08 14:52:09.538545749.538545] [ssh] (contour) State transition from StartShell to Operational.
[2023-11-08 14:52:11.648588210.648588] [ssh] (Terminal.Loop) State transition from Operational to Closed.
Debug[qml]: Client process terminated. Closing the window. (file:///home/yaraslau/repo/contour/src/contour/ui/Terminal.qml:205, expression for onTerminated)
~/r/contour feature/ssh-client 6.7s ❱ ./build/src/contour/contour
QML debugging is enabled. Only use this in a safe environment.
Info: libpng warning: iCCP: known incorrect sRGB profile ((null):0, (null))
[2023-11-08 14:52:16.257187556.257187] [ssh] (contour) Resizing PTY to 80x24.
[2023-11-08 14:52:16.257235167.257235] [ssh] Starting SSH session to host: user@192.168.50.20
[2023-11-08 14:52:16.257240276.257240] [ssh] (contour) State transition from Initial to Started.
[2023-11-08 14:52:16.257242711.257242] [ssh] (contour) State transition from Started to Connect.
[2023-11-08 14:52:16.257757607.257757] [ssh] Connected to 192.168.50.20
[2023-11-08 14:52:16.257761916.257761] [ssh] (contour) State transition from Connect to Handshake.
[2023-11-08 14:52:16.409017837.409017] [ssh] (contour) State transition from Handshake to VerifyHostKey.
[2023-11-08 14:52:16.409078292.409078] [ssh] Host key verification succeeded (AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBCvNflTlLiqQTLfsiDJpdiZbqVov9zWXFfnw4EcEGr8WEeeH7UoIkwaQk8pwvs9LOXGDYAOpsDtMO/Aza3cx7oY=).
[2023-11-08 14:52:16.409085085.409085] [ssh] (contour) State transition from VerifyHostKey to AuthenticateAgent.
[error] Failed to connect to SSH agent. Bad use
[error] Failed to authenticate with SSH agent. No more identities available.
[2023-11-08 14:52:16.409096647.409096] [ssh] (contour) State transition from AuthenticateAgent to AuthenticatePasswordStart.
[2023-11-08 14:52:16.409099613.409099] [ssh] (contour) State transition from AuthenticatePasswordStart to AuthenticatePasswordWaitForInput.
[2023-11-08 14:52:16.422029935.422029] [ssh] (contour) Resizing PTY to 80x23.
[2023-11-08 14:52:16.497921300.497921] [ssh] (QSGRenderThread) Resizing PTY to 80x24.
[2023-11-08 14:52:16.545855757.545855] [ssh] (contour) Resizing PTY to 162x24.
[2023-11-08 14:52:16.545968671.545968] [ssh] (contour) Resizing PTY to 162x43.
[2023-11-08 14:52:16.547079417.547079] [ssh] (contour) Resizing PTY to 162x43.
[2023-11-08 14:52:16.547085208.547085] [ssh] (contour) Resizing PTY to 162x43.
[2023-11-08 14:52:17.405177073.405177] [ssh] (contour) Handling pre-authentication input: "a"
[2023-11-08 14:52:17.797939193.797939] [ssh] (contour) Handling pre-authentication input: "\r"
[2023-11-08 14:52:17.797957808.797957] [ssh] (contour) State transition from AuthenticatePasswordWaitForInput to AuthenticatePassword.
[error] Authentication failed. Authentication failed
[2023-11-08 14:52:20.657258732.657258] [ssh] (contour) State transition from AuthenticatePassword to AuthenticatePasswordStart.
[2023-11-08 14:52:20.657267468.657267] [ssh] (contour) State transition from AuthenticatePasswordStart to AuthenticatePasswordWaitForInput.
[2023-11-08 14:52:21.703121413.703121] [ssh] (contour) Handling pre-authentication input: "s"
[2023-11-08 14:52:22.084141599.084141] [ssh] (contour) Handling pre-authentication input: "t"
[2023-11-08 14:52:22.478187858.478187] [ssh] (contour) Handling pre-authentication input: "a"
[2023-11-08 14:52:22.773196283.773196] [ssh] (contour) Handling pre-authentication input: "r"
[2023-11-08 14:52:23.172443805.172443] [ssh] (contour) Handling pre-authentication input: "f"
[2023-11-08 14:52:23.316162514.316162] [ssh] (contour) Handling pre-authentication input: "i"
[2023-11-08 14:52:23.407145251.407145] [ssh] (contour) Handling pre-authentication input: "v"
[2023-11-08 14:52:23.517153830.517153] [ssh] (contour) Handling pre-authentication input: "e"
[2023-11-08 14:52:23.891107564.891107] [ssh] (contour) Handling pre-authentication input: "\r"
[2023-11-08 14:52:23.891129065.891129] [ssh] (contour) State transition from AuthenticatePasswordWaitForInput to AuthenticatePassword.
[error] Authentication failed. Authentication failed
[2023-11-08 14:52:26.750514333.750514] [ssh] (contour) State transition from AuthenticatePassword to AuthenticatePasswordStart.
[2023-11-08 14:52:26.750523881.750523] [ssh] (contour) State transition from AuthenticatePasswordStart to AuthenticatePasswordWaitForInput.

@christianparpart
[vtpty] Initial implementation of a builtin SSH login session Pty imp…
a9efd73 
…lementation

Signed-off-by: Christian Parpart <christian@parpart.family>
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Now it asks password for three times, but if i insert correct password second time it does not work here is output log for two different runs

we weren't clearing the input buffer on retry. I did not notice, because I only tried success and login failure excess. thx for pointing it out. fixed.

Yaraslaut
Yaraslaut approved these changes Nov 8, 2023
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Tested that things are working

@christianparpart christianparpart merged commit 2ff337e into master Nov 8, 2023
49 of 55 checks passed
@christianparpart christianparpart deleted the feature/ssh-client branch November 8, 2023 15:50
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Bypass conpty when using ssh.
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