git-daemon: fix and de-obfuscate the pkt-line parser.

[userv-utils.git] / git-daemon / git-daemon.pl

diff --git a/git-daemon/git-daemon.pl b/git-daemon/git-daemon.pl
index 4f8a7747cb72aa24d96023dffc8a8e65698eeb91..645cbc5bce9b0f4c7a2cfcc553fd7887d47dbcf2 100755 (executable)
--- a/git-daemon/git-daemon.pl
+++ b/git-daemon/git-daemon.pl
@@ -2,10 +2,6 @@
 #
 # A git daemon with an added userv security boundary.
 #
-# This reads the first packet-line of the protocol, checks the syntax
-# of the pathname and hostname, then uses userv to invoke the
-# git-upload-pack as the target user with safe arguments.
-#
 # This was written by Tony Finch <dot@dotat.at>
 # You may do anything with it, at your own risk.
 # http://creativecommons.org/publicdomain/zero/1.0/
@@ -17,67 +13,53 @@ use POSIX;
 use Socket;
 use Sys::Syslog;
 
-use vars qw{ %vhost_default_user %vhost_user_from_tilde
-             $TILDE $REPO $HOSTNAME };
-
-use lib '/etc/userv';
-require 'git-daemon-vhosts.pl';
-
-my $peer = getpeername STDIN;
-my ($port,$addr);
-if (defined $peer) {
-    ($port,$addr) = sockaddr_in $peer;
+sub ntoa {
+    my $sockaddr = shift;
+    return ('(local)') unless defined $sockaddr;
+    my ($port,$addr) = sockaddr_in $sockaddr;
     $addr = inet_ntoa $addr;
-    $peer = "[$addr]:$port";
-} else {
-    $peer = "[?.?.?.?]:?";
-    undef $!;
+    return ("[$addr]:$port",$addr,$port);
 }
+our ($client,$client_addr,$client_port) = ntoa getpeername STDIN;
+our ($server,$server_addr,$server_port) = ntoa getsockname STDIN;
+our ($service,$path,$host,$user);
 
 openlog 'userv-git-daemon', 'pid', 'daemon';
+sub fail { syslog 'err', "$client @_"; exit }
 
-sub fail {
-    syslog 'err', "$peer @_";
-    exit;
-}
+$SIG{ALRM} = sub { fail "timeout" };
+alarm 30;
 
 sub xread {
     my $length = shift;
     my $buffer = "";
-    # simply die if the client takes too long
-    alarm 30;
     while ($length > length $buffer) {
         my $ret = sysread STDIN, $buffer, $length, length $buffer;
-        fail "short read: expected $length bytes, got " . length $buffer
+        fail "Expected $length bytes, got ".length $buffer
                             if defined $ret and $ret == 0;
         fail "read: $!" if not defined $ret and $! != EINTR and $! != EAGAIN;
-        $ret = 0        if not defined $ret;
     }
-    alarm 0;
     return $buffer;
 }
-
-my $len_hex = xread 4;
-fail "non-hexadecimal packet length" unless $len_hex =~ m{^[0-9a-zA-Z]{4}$};
-my $len = hex $len_hex;
-
-my $line = xread $len;
-unless ($line =~ m{^git-upload-pack (?:~($TILDE)/)?($REPO[.]git)\0host=($HOSTNAME)\0$}) {
-    $line =~ s/[^ -~]+/ /g;
-    fail "could not parse \"$line\""
+my $hex_len = xread 4;
+fail "Bad hex in packet length" unless $hex_len =~ m|^[0-9a-fA-F]{4}$|;
+my $line = xread -4 + hex $hex_len;
+unless (($service,$path,$host) = $line =~
+        m|^(git-[a-z-]+) /*([!-~]+)\0host=([!-~]+)\0$|) {
+    $line =~ s|[^ -~]+| |g;
+    fail "Could not parse \"$line\""
 }
-my ($tilde,$repo,$host) = ($1,$2,$3);
-my $url = $tilde ? "git://$host/~$tilde/$repo" : "git://$host/$repo";
-
-my $user = $vhost_user_from_tilde{$host} ? $tilde : $vhost_default_user{$host};
-fail "no user configuration for $url" unless defined $user;
+our $uri = $_ = "git://$host/$path";
+for my $cf (@ARGV) { do $cf }
 
-syslog 'info', "$peer $user $url";
+fail "No user for $uri" unless defined $user;
+syslog 'notice', "$client $service $uri";
 
-my @opts = ("-DCLIENT=$addr", "-DHOST=$host", "-DREPO=$repo");
-push @opts, "-DTILDE=$tilde" if defined $tilde;
+my @opts = map "-D$_=${$::{$_}}",
+        grep defined ${$::{$_}} && /^[a-z_]+$/, keys %::;
 
-exec 'userv', @opts, $user, 'git-upload-pack'
-    or fail "exec userv: $!";
+my @cmd = ('userv', @opts, $user, $service);
+no warnings; # suppress errors to stderr
+exec @cmd or fail "exec userv: $!";
 
 # end