git-daemon: move checking to more appropriate place.
[userv-utils] / git-daemon / git-daemon.pl
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1#!/usr/bin/perl
2#
fbde0914 3# A git daemon with an added userv security boundary.
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4#
5# This reads the first packet-line of the protocol, checks the syntax
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6# of the pathname and hostname, then uses userv to invoke the
7# git-upload-pack as the target user with safe arguments.
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8#
9# This was written by Tony Finch <dot@dotat.at>
10# You may do anything with it, at your own risk.
11# http://creativecommons.org/publicdomain/zero/1.0/
12
13use strict;
14use warnings;
15
16use POSIX;
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17use Socket;
18use Sys::Syslog;
d2707bea 19
fbde0914 20use lib '/etc/userv';
fbde0914 21
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22sub ntoa {
23 my $sockaddr = shift;
24 if (defined $sockaddr) {
25 my ($port,$addr) = sockaddr_in $sockaddr;
26 $addr = inet_ntoa $addr;
27 return ($addr,$port,"[$addr]:$port");
28 } else {
29 return (undef,undef,"[?.?.?.?]:?");
30 }
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31}
32
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33my ($client_addr,$client_port,$client) = ntoa getpeername STDIN;
34my ($server_addr,$server_port,$server) = ntoa getsockname STDIN;
35
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36openlog 'userv-git-daemon', 'pid', 'daemon';
37
38sub fail {
6fe98f4a 39 syslog 'err', "$client @_";
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40 exit;
41}
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42
43sub xread {
44 my $length = shift;
45 my $buffer = "";
f14a8627 46 local $SIG{ALRM} = sub { fail "timeout" };
fbde0914 47 alarm 30;
d2707bea 48 while ($length > length $buffer) {
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49 my $ret = sysread STDIN, $buffer, $length, length $buffer;
50 fail "short read: expected $length bytes, got " . length $buffer
51 if defined $ret and $ret == 0;
52 fail "read: $!" if not defined $ret and $! != EINTR and $! != EAGAIN;
53 $ret = 0 if not defined $ret;
d2707bea 54 }
fbde0914 55 alarm 0;
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56 return $buffer;
57}
58
59my $len_hex = xread 4;
6fe98f4a 60fail "non-hex packet length" unless $len_hex =~ m{^[0-9a-fA-F]{4}$};
f14a8627 61my $line = xread hex $len_hex;
6fe98f4a 62unless ($line =~ m{^git-upload-pack ([!-~]+)\0host=([!-~]+)\0$}) {
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63 $line =~ s/[^ -~]+/ /g;
64 fail "could not parse \"$line\""
65}
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66my ($path,$host) = ($1,$2);
67$path =~ s|^/||;
68$_ = my $uri = "git://$host/$path";
69
70my ($user,$repo) = do "git-daemon-urlmap.pl";
71fail "no user configured for $uri" unless defined $user;
72syslog 'info', "$client userv $user git-upload-pack $uri";
fbde0914 73
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74my %vars = (
75 REQUEST_HOST => $host,
76 REQUEST_PATH => $path,
77 REQUEST_URI => $uri,
78 CLIENT_ADDR => $client_addr,
79 CLIENT_PORT => $client_port,
80 SERVER_ADDR => $server_addr,
81 SERVER_PORT => $server_port,
82);
83my @opts = map "-D$_=$vars{$_}", grep defined $vars{$_}, sort keys %vars;
fbde0914 84
11b88dbb 85no warnings; # suppress errors to stderr
fbde0914 86exec 'userv', @opts, $user, 'git-upload-pack'
6fe98f4a 87 or fail "exec userv @opts $user git-upload-pack: $!";
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88
89# end