Re: avoiding anonymous commits from root/shared accounts

At Mon May 10 13:05:17 -0400 2010, Nick wrote:

At work, we have a number of repositories which we store server configurations in, most of which are only writable as root. We use the script below to ensure that git mostly doesn't lie about the authors of commits. This won't solve your problem of people logging in under shared credentials -- and it also _does_ allow commits as 'root' if you logged in directly as root -- but it's perhaps a partial solution for you.

 - Alex

-------------------->8-------------------- #!/usr/bin/perl

use strict; use warnings; use constant EMAIL_DOMAIN => "example.com";

setenv( get_user($$) ); exec("/usr/bin/git", @ARGV);

sub setenv {
    my $user = shift;

    # If they're _really_ _really_ root, just bail now
    return if $user eq "root";

    # Ditto if we can't find the user (?!)
    my @getpw = getpwnam($user);
    return unless @getpw;

    my $name;
    my $email;

    # See if we can pull from the user's config
    my $gitconfig = "$getpw[7]/.gitconfig";
    if (-r $gitconfig) {
        $name  = `/usr/bin/git config --file $gitconfig user.name`;
        chomp $name;
        $email = `/usr/bin/git config --file $gitconfig user.email`;
        chomp $email;
    }

    # Fall back to getent
    $name  ||= $getpw[6] || $user;
    $email ||= $user . '@' . EMAIL_DOMAIN;

    $ENV{GIT_AUTHOR_NAME} = $name;
    $ENV{GIT_AUTHOR_EMAIL} = $email;
}

sub get_user {
    my $pid = shift;

    # See if the PID is bogus
    return "root" unless $pid and kill 0, $pid;

    # Pull out the env from it
    my %env = getenv($pid);

    # Simplest case -- check USER first
    if ($env{USER} and $env{USER} ne "root") {
        return $env{USER};
    }

    # Or we're running under sudo
    if ($env{SUDO_USER} and $env{SUDO_USER} ne "root") {
        return $env{SUDO_USER};
    }

    # They did something like `sudo su -`
    return get_user(parent_pid($pid));
}

sub getenv {
    my $pid = shift;
    my $env = do {local @ARGV = ("/proc/$pid/environ"); local $/; <>};
    my @lines = split /\0/, $env;
    return () unless grep {/=/} @lines;
    my %env = map {split /=/, $_, 2} @lines;
    return %env;
}

sub parent_pid {
    my $pid = shift;
    my $stat = do {local @ARGV = ("/proc/$pid/stat"); local $/; <>};
    my (undef, undef, undef, $ppid) = split ' ', $stat;
    return $ppid;
}