Commit e5f5008e authored by Chris Lamb's avatar Chris Lamb 👀
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Catch invalid ZIP "local" field lengths; we were previously inherently blindly... 

Catch invalid ZIP "local" field lengths; we were previously inherently blindly the value supplied in the ZIP file. Thanks to Daniel Stender for the report. (Closes: #803503)
parent 9c7e0949

lib/File/StripNondeterminism/handlers/zip.pm

+13 −12
Original line number Diff line number Diff line
@@ -76,11 +76,6 @@ sub normalize_member($$) { 
	return 1;

}



use constant {

	CENTRAL_HEADER => 0,

	LOCAL_HEADER => 1

};



sub unixtime_to_winnt($) {

	my $unixtime = shift || 0;
@@ -91,11 +86,10 @@ sub unixtime_to_winnt($) { 
	return $unixtime + $secondsdiff;

}



sub normalize_extra_fields($$$) {

sub normalize_extra_fields($$) {

	# See http://sources.debian.net/src/zip/3.0-6/proginfo/extrafld.txt for extra field documentation

	# $header_type is CENTRAL_HEADER or LOCAL_HEADER.

	# WARNING: some fields have a different format depending on the header type

	my ($canonical_time, $field, $header_type) = @_;

	my ($canonical_time, $field) = @_;



	my $result = "";

	my $pos = 0;
@@ -149,6 +143,12 @@ sub normalize_extra_fields($$$) { 
				$result .= substr($field, $pos + 4, $len);

			}

		} else {

			# Catch invalid field lengths by calculating whether we would

			# read beyond the end of the file.

			if ($pos + $len >= length($field)) {

				warn "strip-nondeterminism: invalid extra field length ($len)";

				return;

			}

			# use the current extra field unmodified.

			$result .= substr($field, $pos, $len+4);

		}
@@ -209,10 +209,11 @@ sub normalize { 
				? oct(755)

				: oct(644));

		}

		$member->cdExtraField(

			normalize_extra_fields($canonical_time, $member->cdExtraField(), CENTRAL_HEADER));

		$member->localExtraField(

			normalize_extra_fields($canonical_time, $member->localExtraField(), LOCAL_HEADER));

		foreach my $x (qw(cdExtraField localExtraField)) {

			my $result = normalize_extra_fields($canonical_time, $member->$x);

			return 0 unless defined $result;

			$member->$x($result);

		}

	}

	my $old_perms = (stat($zip_filename))[2] & oct(7777);

	$zip->overwrite();

t/fixtures/zip/bug_803503.zip.in

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+344 B

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t/fixtures/zip/bug_803503.zip.out

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+1 −0
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bug_803503.zip.in
 
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