rebuild => undef,
section => "widget",
},
+ img_allowed_formats => {
+ type => "string",
+ default => [qw(jpeg png gif)],
+ description => "Image formats to process (jpeg, png, gif, pdf, svg or 'everything' to accept all)",
+ # ImageMagick has had arbitrary code execution flaws,
+ # and the whole delegates mechanism is scary from
+ # that perspective
+ safe => 0,
+ rebuild => 0,
+ },
+}
+
+sub allowed {
+ my $format = shift;
+ my $allowed = $config{img_allowed_formats};
+ $allowed = ['jpeg', 'png'] unless defined $allowed && @$allowed;
+
+ foreach my $a (@$allowed) {
+ return 1 if $a eq $format || $a eq 'everything';
+ }
+
+ return 0;
}
sub preprocess (@) {
# Never interpret well-known file extensions as any other format,
# in case the wiki configuration unwisely allows attaching
# arbitrary files named *.jpg, etc.
+ my $magic;
+ my $offset = 0;
+ open(my $in, '<', $srcfile) or error sprintf(gettext("failed to read %s: %s"), $file, $!);
+ binmode($in);
+
if ($extension =~ m/^(jpeg|jpg)$/is) {
$format = 'jpeg';
+ $magic = "\377\330\377";
}
elsif ($extension =~ m/^(png)$/is) {
$format = 'png';
+ $magic = "\211PNG\r\n\032\n";
}
elsif ($extension =~ m/^(gif)$/is) {
$format = 'gif';
+ $magic = "GIF8";
}
elsif ($extension =~ m/^(svg)$/is) {
$format = 'svg';
}
elsif ($extension =~ m/^(pdf)$/is) {
$format = 'pdf';
+ $magic = "%PDF-";
}
else {
# allow ImageMagick to auto-detect (potentially dangerous)
$format = '';
}
+ error sprintf(gettext("%s image processing disabled in img_allowed_formats configuration"), $format ? $format : "\"$extension\"") unless allowed($format ? $format : "everything");
+
+ # Try harder to protect ImageMagick from itself
+ if ($format eq 'svg') {
+ my $content;
+ read($in, $content, 5) or error sprintf(gettext("failed to read %s: %s"), $file, $!);
+ # This is an over-simplification, but ?xml is the check that
+ # ImageMagick uses. We also accept <svg for the simplest
+ # possible SVGs.
+ if ($content !~ m/^(.\?xml|<svg)/is) {
+ error sprintf(gettext("\"%s\" does not seem to be a valid %s file"), $file, $format);
+ }
+ }
+ elsif ($magic) {
+ my $content;
+ read($in, $content, length $magic) or error sprintf(gettext("failed to read %s: %s"), $file, $!);
+ if ($magic ne $content) {
+ error sprintf(gettext("\"%s\" does not seem to be a valid %s file"), $file, $format);
+ }
+ }
+
my $issvg = $base=~s/\.svg$/.png/i;
my $ispdf = $base=~s/\.pdf$/.png/i;
my $pagenumber = exists($params{pagenumber}) ? int($params{pagenumber}) : 0;