| 1 | # vim: set syntax=perl ts=4 ai si: |
| 2 | |
| 3 | use MIME::Base64(); |
| 4 | use Digest::SHA1(); |
| 5 | use Digest::HMAC_SHA1(); |
| 6 | |
| 7 | # |
| 8 | # local_filter_cancel |
| 9 | # |
| 10 | sub local_filter_cancel { |
| 11 | unless($hdr{Control} =~ m/^cancel\s+(<[^>]+>)/i) { |
| 12 | return "Cancel with broken target ID"; |
| 13 | } |
| 14 | return verify_cancel(\%hdr, $1, 'Cancel'); |
| 15 | } |
| 16 | |
| 17 | sub local_filter_after_emp { |
| 18 | if (exists( $hdr{'Supersedes'} )) { |
| 19 | #return verify_cancel(\%hdr, $hdr{'Supersedes'}, 'Supersedes'); |
| 20 | # verify_cancel is called, but not returned, so the |
| 21 | # posting is unconditionally accepted |
| 22 | # verify_cancel calls INN:cancel() if verification suceeds |
| 23 | verify_cancel(\%hdr, $hdr{'Supersedes'}, 'Supersedes'); |
| 24 | } |
| 25 | |
| 26 | return undef; |
| 27 | } |
| 28 | |
| 29 | sub verify_cancel($$$) { |
| 30 | my $r_hdr = shift || die; |
| 31 | my $target = shift; |
| 32 | my $descr = shift; |
| 33 | |
| 34 | my $headers = INN::head($target) || return "$descr of non-existing ID $target"; |
| 35 | |
| 36 | my %headers; |
| 37 | for my $line(split(/\s*\n/, $headers)) { |
| 38 | if ($line =~ m/^([[:alnum:]-]+):\s+(.*)/) { |
| 39 | $headers{$1} = $2; |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | my $lock = $headers{'Cancel-Lock'}; |
| 44 | if (defined($lock)) { |
| 45 | my $key = $r_hdr->{'Cancel-Key'} || return "$descr of $target without Cancel-Key"; |
| 46 | #return verify_cancel_key($key, $lock, ' target=' . $target); |
| 47 | return verify_cancel_key($key, $lock, $target); |
| 48 | } else { |
| 49 | # -thh |
| 50 | # no cancel-lock: go ahead and cancel anyway! |
| 51 | INN::cancel($target); |
| 52 | } |
| 53 | |
| 54 | return undef; |
| 55 | } |
| 56 | |
| 57 | sub verify_cancel_key($$$) { |
| 58 | my $cancel_key = shift; |
| 59 | my $cancel_lock = shift; |
| 60 | my $msg = shift; |
| 61 | |
| 62 | $msg = '' unless(defined($msg)); |
| 63 | # -thh |
| 64 | my $target = $msg; |
| 65 | $msg = ' target=' . $msg; |
| 66 | |
| 67 | my %lock; |
| 68 | for my $l(split(/\s+/, $cancel_lock)) { |
| 69 | next unless($l =~ m/^(sha1|md5):(\S+)/); |
| 70 | $lock{$2} = $1; |
| 71 | } |
| 72 | |
| 73 | for my $k(split(/\s+/, $cancel_key)) { |
| 74 | unless($k =~ m/^(sha1|md5):(\S+)/) { |
| 75 | INN::syslog('notice', "Invalid Cancel-Key syntax '$k'.$msg"); |
| 76 | next; |
| 77 | } |
| 78 | |
| 79 | my $key; |
| 80 | if ($1 eq 'sha1') { |
| 81 | $key = Digest::SHA1::sha1($2); } |
| 82 | elsif ($1 eq 'md5') { |
| 83 | $key = Digest::MD5::md5($2); |
| 84 | } |
| 85 | $key = MIME::Base64::encode_base64($key, ''); |
| 86 | |
| 87 | if (exists($lock{$key})) { |
| 88 | # INN::syslog('notice', "Valid Cancel-Key $key found.$msg"); |
| 89 | # -thh |
| 90 | # article is canceled now |
| 91 | INN::cancel($target) if ($target); |
| 92 | return undef; |
| 93 | } |
| 94 | } |
| 95 | |
| 96 | INN::syslog('notice', |
| 97 | "No Cancel-Key[$cancel_key] matches Cancel-Lock[$cancel_lock]$msg" |
| 98 | ); |
| 99 | return "No Cancel-Key matches Cancel-Lock.$msg"; |
| 100 | } |
| 101 | |
| 102 | 1; |