[PATCH 2 of 2 v2] hg-ssh: more flexible permissions for hg-ssh

[Wagner Bruna]

On 21-05-2012 20:29, David Schleimer wrote:
> # HG changeset patch
> # User David Schleimer <dschleimer at fb.com>
> # Date 1337642370 25200
> # Node ID 6be86d4b3a0c424272600164500b6329b43ab946
> # Parent  b52b7fe0dd08b257dfc69c8a5de503cec94f4b76
> hg-ssh: more flexible permissions for hg-ssh
> 
> This allows more flexible control over the permissions granted to a
> ssh key when using hg-ssh as the command in an authorized_keys file.
> 
> Specifically, it allows you to restrict a key to read-only access, as
> well as allowing you to grant a key access to any repo, instead of
> needing to whitelist repos.
> 
> diff --git a/contrib/hg-ssh b/contrib/hg-ssh
> --- a/contrib/hg-ssh
> +++ b/contrib/hg-ssh
> @@ -35,9 +35,21 @@
>  
>  def main():
>      cwd = os.getcwd()
> +    allrepos = False
> +    readonly = False
> +    args = sys.argv[1:]
> +    while len(args):
> +        if args[0] == '--all-repos':
> +            allrepos = True
> +            args.pop(0)
> +        elif args[0] == '--read-only':
> +            readonly = True
> +            args.pop(0)
> +        else:
> +            break
>      allowed_paths = [os.path.normpath(os.path.join(cwd,
>                                                     os.path.expanduser(path)))
> -                     for path in sys.argv[1:]]
> +                     for path in args]
>      orig_cmd = os.getenv('SSH_ORIGINAL_COMMAND', '?')
>      try:
>          cmdargv = shlex.split(orig_cmd)
> @@ -48,10 +60,12 @@
>      if cmdargv[:2] == ['hg', '-R'] and cmdargv[3:] == ['serve', '--stdio']:
>          path = cmdargv[2]
>          repo = os.path.normpath(os.path.join(cwd, os.path.expanduser(path)))
> -        if repo in allowed_paths:
> -            dispatch.dispatch(dispatch.request(['-R', repo,
> -                                                'serve',
> -                                                '--stdio']))
> +        if repo in allowed_paths or allrepos:
> +            cmd = ['-R', repo, 'serve', '--stdio']
> +            if readonly:
> +                cmd += ['--config',
> +                        'hooks.prechangegroup=python:__main__.rejectpush']

I believe a prepushkey hook should be added here as well. Also, I'd suggest
using "hooks.prechangegroup.hg-ssh", to add a bit more information to the
error message.

BTW, an alternative approach could be adding a --user parameter to hg-ssh, to
check it against web.deny_push / web.allow_push for authorization. This would
be simpler for users: each ssh key would simply authenticate a single user,
leaving authorization to the existing (and documented) configuration mechanisms.

Regards,
Wagner

> +            dispatch.dispatch(dispatch.request(cmd))
>          else:
>              sys.stderr.write('Illegal repository "%s"\n' % repo)
>              sys.exit(255)
> @@ -59,5 +73,11 @@
>          sys.stderr.write('Illegal command "%s"\n' % orig_cmd)
>          sys.exit(255)
>  
> +def rejectpush(ui, **kwargs):
> +    ui.warn("Permission denied\n")
> +    # mercurial hooks use unix process conventions for hook return values
> +    # so a truthy return means failure
> +    return True
> +
>  if __name__ == '__main__':
>      main()

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