Support SSH alias users

[tecosaur]

Feature Description

After setting Gitea up under a gitea user and group, it can be desirable to be able to use git@example.com:user/repo.git. This can be enabled by creating a git user with the same UID, e.g. via useradd -o -u $(id -u gitea) git.

At the moment, this causes issues because the user check is based on the name, not the UID.

gitea/modules/setting/setting.go

Lines 999 to 1005 in ff9b6fa

	// Does not check run user when the install lock is off.
	if InstallLock {
	currentUser, match := IsRunUserMatchCurrentUser(RunUser)
	if !match {
	log.Fatal("Expect user '%s' but current user is: %s", RunUser, currentUser)
	}
	}

gitea/modules/setting/setting.go

Lines 512 to 523 in ff9b6fa

	// IsRunUserMatchCurrentUser returns false if configured run user does not match
	// actual user that runs the app. The first return value is the actual user name.
	// This check is ignored under Windows since SSH remote login is not the main
	// method to login on Windows.
	func IsRunUserMatchCurrentUser(runUser string) (string, bool) {
	if IsWindows || SSH.StartBuiltinServer {
	return "", true
	}
	currentUser := user.CurrentUsername()
	return currentUser, runUser == currentUser
	}

Would it be possible to change this check to be based on the UID?

Screenshots

No response

[balki]

I am using the Builtin ssh server. The service is running as gitea. If I set git for SSH_USER, it does not work. It only works if SSH_USER is also gitea.