gitolite/gl-compile-conf

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#!/usr/bin/perl -w
use strict;
use Data::Dumper;
# === add-auth-keys ===
# part of the gitosis-lite (GL) suite
# (1) - "compiles" ~/.ssh/authorized_keys from the list of pub-keys
# (2) - also "compiles" the user-friendly GL conf file into something easier
# to parse. We're doing this because both the gl-auth-command and the
# (gl-)update hook need this, and it seems easier to do this than
# replicate the parsing code in both those places. As a bonus, it's
# probably more efficient.
# how run: manual, by GL admin
# when:
# - anytime a pubkey is added/deleted
# - anytime gitosis-lite.conf is changed
# input:
# - GL_CONF (default: ~/.gitosis-lite/gitosis-lite.conf)
# - GL_KEYDIR (default: ~/.gitosis-lite/keydir)
# output:
# - ~/.ssh/authorized_keys (dictated by sshd)
# - GL_CONF_COMPILED (default: ~/.gitosis-lite/gitosis-lite.conf-compiled.pm)
# security:
# - touches a very critical system file that manages the restrictions on
# incoming users. Be sure to audit AUTH_COMMAND and AUTH_OPTIONS (see
# below) on any change to this script
# - no security checks within program. The GL admin runs this manually
# warnings:
# - if the "start" line exists, but the "end" line does not, you lose the
# rest of the existing authkey file. In general, "don't do that (TM)",
# but we do have a "vim -d" popping up so you can see the changes being
# made, just in case...
# ----------------------------------------------------------------------------
# common definitions
# ----------------------------------------------------------------------------
our $GL_ADMINDIR;
our $GL_CONF;
our $GL_KEYDIR;
our $GL_CONF_COMPILED;
our $REPO_BASE;
my $glrc = $ENV{HOME} . "/.gitosis-lite.rc";
unless (my $ret = do $glrc)
{
die "parse $glrc failed: $@" if $@;
die "couldn't do $glrc: $!" unless defined $ret;
die "couldn't run $glrc" unless $ret;
}
# ----------------------------------------------------------------------------
# definitions specific to this program
# ----------------------------------------------------------------------------
# command and options for authorized_keys
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my $AUTH_COMMAND="$GL_ADMINDIR/gl-auth-command";
my $AUTH_OPTIONS="no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty";
my $USERNAME_PATT=qr(^\@?[0-9a-zA-Z][0-9a-zA-Z._-]*$); # very simple pattern
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my %groups = ();
my %repos = ();
# set a restrictive umask, just in case
umask(0077);
# ----------------------------------------------------------------------------
# subroutines
# ----------------------------------------------------------------------------
sub my_chdir
{
chdir($_[0]) or die "chdir $_[0] failed: $!";
}
sub expand_userlist
{
my @list = @_;
my @new_list = ();
for my $item (@list)
{
die "bad user $item\n" unless $item =~ $USERNAME_PATT;
if ($item =~ /^@/) # nested group
{
die "undefined group $item" unless $groups{$item};
# add those names to the list
push @new_list, @{ $groups{$item} };
}
else
{
push @new_list, $item;
}
}
return @new_list;
}
# ----------------------------------------------------------------------------
# "compile" GL conf
# ----------------------------------------------------------------------------
open(INF, "<", $GL_CONF)
or die "open GL conf failed: $!";
# the syntax is fairly simple, so we parse it inline
my @repos;
while (<INF>)
{
# normalise whitespace; keeps later regexes very simple
s/=/ = /;
s/\s+/ /g;
s/^ //;
s/ $//;
# kill comments
s/#.*//;
# and blank lines
next unless /\S/;
# user groups
if (/^(@\S+) = (.*)/)
{
push @{ $groups{$1} }, expand_userlist( split(' ', $2) );
die "bad group $1\n" unless $1 =~ $USERNAME_PATT;
}
# repo(s)
elsif (/^repo (.*)/)
{
@repos = split(' ', $1);
}
# actual permission line
elsif (/^(R|RW|RW\+) (.* )?= (.+)/)
{
# split perms to separate out R, W, and +
my @perms = split //, $1;
my @refs; @refs = split(' ', $2) if $2;
my @users = split ' ', $3;
# if no ref is given, this PERM applies to all refs
@refs = qw(refs/.*) unless @refs;
# fully qualify refs that dont start with "refs/"; prefix them with
# "refs/heads/"
@refs = map { m(^refs/) or s(^)(refs/heads/); $_ } @refs;
# expand the user list, unless it is just "@all"
@users = expand_userlist ( @users )
unless (@users == 1 and $users[0] eq '@all');
# ok, we can finally populate the %repos hash
for my $repo (@repos) # each repo in the current stanza
{
for my $perm (@perms)
{
for my $user (@users)
{
push @{ $repos{$repo}{$perm}{$user} }, @refs;
}
}
}
}
else
{
die "can't make head or tail of '$_'\n";
}
}
open(OUT, ">", $GL_CONF_COMPILED)
or die "open GL conf compiled failed: $!";
print OUT Data::Dumper->Dump([\%repos], [qw(*repos)]);
close(OUT);
# ----------------------------------------------------------------------------
# any new repos created?
# ----------------------------------------------------------------------------
# modern gits allow cloning from an empty repo, so we just create it. Gitosis
# did not have that luxury, so it was forced to detect the first push and
# create it then
my_chdir("$ENV{HOME}/$REPO_BASE");
for my $repo (keys %repos)
{
unless (-d "$repo.git")
{
mkdir("$repo.git") or die "mkdir $repo.git failed: $!";
my_chdir("$repo.git");
system("git init --bare");
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system("cp $GL_ADMINDIR/update-hook.pl hooks/update");
system("chmod 755 hooks/update");
my_chdir("$ENV{HOME}/$REPO_BASE");
}
}
# ----------------------------------------------------------------------------
# "compile" ssh authorized_keys
# ----------------------------------------------------------------------------
open(INF, "<", $ENV{HOME} . "/.ssh/authorized_keys") or die "open old authkeys failed: $!";
open(OUT, ">", $ENV{HOME} . "/.ssh/new_authkeys") or die "open new authkeys failed: $!";
# save existing authkeys minus the GL-added stuff
while (<INF>)
{
print OUT unless (/^# gitosis-lite start/../^# gitosis-lite end/);
}
# add our "start" line, each key on its own line (prefixed by command and
# options, in the standard ssh authorized_keys format), then the "end" line.
print OUT "# gitosis-lite start\n";
my_chdir($GL_KEYDIR);
for my $pubkey (glob("*.pub"))
{
my $user = $pubkey; $user =~ s/\.pub$//;
print OUT "command=\"$AUTH_COMMAND $user\",$AUTH_OPTIONS ";
print OUT `cat $pubkey`;
}
print OUT "# gitosis-lite end\n";
close(OUT);
# check what changes are being made; just a comfort factor
# system("vim -d ~/.ssh/authorized_keys ~/.ssh/new_authkeys");
# all done; overwrite the file (use cat to avoid perm changes)
system("cat ~/.ssh/new_authkeys > ~/.ssh/authorized_keys");
system("rm ~/.ssh/new_authkeys");
# if the gl admin directory (~/.gitosis-lite) is itself a git repo, do an
# autocheckin. nothing fancy; this is a "just in case" type of thing.
my_chdir($GL_ADMINDIR);
if (-d ".git")
{
system("git add -A keydir"); # stage all changes in keydir
# and if there are any
if (system("git diff --cached --quiet") )
{
open(COMMIT, "|-", "git commit -F -")
or die "pipe commit failed: $!";
print COMMIT "keydir changed\n\n";
print COMMIT `git diff --cached --name-status`;
close(COMMIT) or die "close commit failed: $!";
}
}