msys2 ssh: invalid key format (under Github CI only)

user_761090 0
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I am cloning repoB within GitHub CI workflow of repoA, using deployment key of repoB (stored in repoA). I understand this might not be a good practice, no need to comment on that (thanks).

The workflow tests this procedure natively on ubuntu-20.04 and using MSYS2 on windows-latest. It works on Ubuntu, I can run the commands manually on regular MSYS2 installation, but it fails on GitHub CI. The CI log has all the details, the essential command being

git -c core.sshCommand='ssh -vvv -i repoB_deployment_key -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no' clone -b main git@github.com:eudoxos/repoB.git repoB

The failure under Windows is Load key "repoB_deployment_key": invalid format and I am not able to find out what's wrong. I tried changing permissions for the private key (chmod 600), adding the -o UserKnownHostsFile=/dev/null and -o StrictHostKeyChecking=no, running the key through unix2dos, adding extra trailing newline — nothing helped.

Again, the same command works under Ubuntu and under MSYS2 on desktop Windows.

The repos are publicly accessible fro reading; you are welcome to open a PR to the repoA repository; a PR should trigger the CI run.

msys2 github-actions ssh-keys openssh
2 Answers

Running the key through dos2unix (not unix2dos) fixed the issue. I will file that as an issue with msys2, as this should be documented.

user_7610900

Try in your GitHub workflow to display the key first, in order to visually check its content and its format (as seen here)

Check also which SSH you used when creating the key, the c:\Program Files\OpenSSH-Win64 one, or the one with Git for Windows (c:\Program Files\git\usr\bin\ssh.exe).

VonC_63090
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