gitolite/src/gl-auth-command
Sitaram Chamarty 75de6c0438 auth: (WDITOT?) allow special users to get a shell
".../gl-auth-command username" is the normal command that authkeys
forces, and this prevents that key from being used to get a shell.

We now allow the user to get a shell if the forced command has a "-s"
before the "username", like ".../gl-auth-command -s sitaram".

(Now that a plain "ssh gitolite" gets you a shell, there's a new "info"
command that such privileged keys can use to get basic access info).

Thanks to Jesse Keating for the idea!  I can't believe this never
occurred to me before, but I guess I was so enamoured of my "innovation"
in converting what used to be an error into some useful info I didn't
think a bit more :/
2009-12-19 22:47:11 +05:30

164 lines
5.5 KiB
Perl
Executable file

#!/usr/bin/perl
use strict;
use warnings;
# === auth-command ===
# the command that GL users actually run
# part of the gitolite (GL) suite
# how run: via sshd, being listed in "command=" in ssh authkeys
# when: every login by a GL user
# input: $1 is GL username, plus $SSH_ORIGINAL_COMMAND
# output:
# security:
# - currently, we just make some basic checks, copied from gitosis
# robustness:
# other notes:
# ----------------------------------------------------------------------------
# common definitions
# ----------------------------------------------------------------------------
# these are set by the "rc" file
our ($GL_LOGT, $GL_CONF_COMPILED, $REPO_BASE, $GIT_PATH, $REPO_UMASK, $GL_ADMINDIR);
# and these are set by gitolite.pm
our ($R_COMMANDS, $W_COMMANDS, $REPONAME_PATT);
our %repos;
# the common setup module is in the same directory as this running program is
my $bindir = $0;
$bindir =~ s/\/[^\/]+$//;
require "$bindir/gitolite.pm";
# ask where the rc file is, get it, and "do" it
&where_is_rc();
die "parse $ENV{GL_RC} failed: " . ($! or $@) unless do $ENV{GL_RC};
# we need to pass GL_ADMINDIR and the bindir to the child hooks (well only the
# admin repo's post-update hook but still...)
$ENV{GL_ADMINDIR} = $GL_ADMINDIR;
$ENV{GL_BINDIR} = $bindir;
# add a custom path for git binaries, if specified
$ENV{PATH} .= ":$GIT_PATH" if $GIT_PATH;
# set the umask before creating any files
umask($REPO_UMASK);
# ----------------------------------------------------------------------------
# start...
# ----------------------------------------------------------------------------
# if the first argument is a "-s", this user is allowed to get a shell using
# this key
my $shell_allowed = 0;
if ($ARGV[0] eq '-s') {
$shell_allowed = 1;
shift;
}
# first, fix the biggest gripe I have with gitosis, a 1-line change
my $user=$ENV{GL_USER}=shift; # there; now that's available everywhere!
# ----------------------------------------------------------------------------
# sanity checks on SSH_ORIGINAL_COMMAND
# ----------------------------------------------------------------------------
# print basic access info if SSH_ORIGINAL_COMMAND does not exist
unless ($ENV{SSH_ORIGINAL_COMMAND}) {
# unless the user is allowed to use a shell
if ($shell_allowed) {
my $shell = $ENV{SHELL};
$shell =~ s/.*\//-/; # change "/bin/bash" to "-bash"
exec { $ENV{SHELL} } $shell;
}
&report_basic($GL_ADMINDIR, $GL_CONF_COMPILED, $user);
exit 1;
}
my $cmd = $ENV{SSH_ORIGINAL_COMMAND};
# people allowed to get a shell can get basic access info by asking nicely
if ($shell_allowed and $cmd eq 'info') {
&report_basic($GL_ADMINDIR, $GL_CONF_COMPILED, $user);
exit 1;
}
# split into command and arguments; the pattern allows old style as well as
# new style: "git-subcommand arg" or "git subcommand arg", just like gitosis
# does, although I'm not sure how necessary that is
#
# keep in mind this is how git sends across the command:
# git-receive-pack 'reponame.git'
# including the single quotes
my ($verb, $repo) = ($cmd =~ /^\s*(git\s+\S+|\S+)\s+'\/?(.*?)(?:.git)?'/);
unless ( $verb and ( $verb =~ $R_COMMANDS or $verb =~ $W_COMMANDS ) and $repo and $repo =~ $REPONAME_PATT ) {
# if the user is allowed a shell, just run the command
exec $ENV{SHELL}, "-c", $ENV{SSH_ORIGINAL_COMMAND} if $shell_allowed;
# otherwise, whine
die "bad command: $cmd\n";
}
# ----------------------------------------------------------------------------
# first level permissions check
# ----------------------------------------------------------------------------
# parse the compiled acl; goes into %repos (global)
&parse_acl($GL_CONF_COMPILED);
# we know the user and repo; we just need to know what perm he's trying
my $perm = ($verb =~ $R_COMMANDS ? 'R' : 'W');
die "$perm access for $repo DENIED to $user\n"
unless $repos{$repo}{$perm}{$user}
or $repos{$repo}{$perm}{'@all'};
# create the repo if it doesn't already exist and the user has "W" access
my $repo_base_abs = ( $REPO_BASE =~ m(^/) ? $REPO_BASE : "$ENV{HOME}/$REPO_BASE" );
if ( not -d "$repo_base_abs/$repo.git" ) {
if ( $repos{$repo}{W}{$user} or $repos{$repo}{W}{'@all'} ) {
wrap_chdir("$repo_base_abs");
new_repo($repo, "$GL_ADMINDIR/src/hooks");
wrap_chdir($ENV{HOME});
}
}
# ----------------------------------------------------------------------------
# logging, timestamp. also setup env vars for later
# ----------------------------------------------------------------------------
# reponame
$ENV{GL_REPO}=$repo;
# timestamp
my ($s, $min, $h, $d, $m, $y) = (localtime)[0..5];
$y += 1900; $m++; # usual adjustments
for ($s, $min, $h, $d, $m) {
$_ = "0$_" if $_ < 10;
}
$ENV{GL_TS} = "$y-$m-$d.$h:$min:$s";
# substitute template parameters and set the logfile name
$GL_LOGT =~ s/%y/$y/g;
$GL_LOGT =~ s/%m/$m/g;
$GL_LOGT =~ s/%d/$d/g;
$ENV{GL_LOG} = $GL_LOGT;
# if log failure isn't important enough to block access, get rid of all the
# error checking
open my $log_fh, ">>", $ENV{GL_LOG}
or die "open log failed: $!\n";
print $log_fh "$ENV{GL_TS}\t$ENV{SSH_ORIGINAL_COMMAND}\t$user\n";
close $log_fh or die "close log failed: $!\n";
# ----------------------------------------------------------------------------
# over to git now
# ----------------------------------------------------------------------------
$repo = "'$REPO_BASE/$repo.git'";
exec("git", "shell", "-c", "$verb $repo");