From bfda13f16c3a055b30d7e5448dd6640a12898adc Mon Sep 17 00:00:00 2001
From: Joey Hess <joey@kitenet.net>
Date: Mon, 23 Jan 2012 18:36:33 -0400
Subject: [PATCH] recentchangesdiff: truncate extremely large diffs

A diff was already truncated after 200 lines. But it could still be
arbitrarily enormous, if a spammer or other random noise source likes long
lines. That could use a lot of memory to html encode etc the diff and fill
it into the template. Truncating after 100kb seems sufficient; it allows
for 200 lines of up to 512 characters each.
---
 IkiWiki/Plugin/recentchangesdiff.pm | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/IkiWiki/Plugin/recentchangesdiff.pm b/IkiWiki/Plugin/recentchangesdiff.pm
index 71297572d..418822793 100644
--- a/IkiWiki/Plugin/recentchangesdiff.pm
+++ b/IkiWiki/Plugin/recentchangesdiff.pm
@@ -31,13 +31,21 @@ sub pagetemplate (@) {
 		my @lines=IkiWiki::rcs_diff($params{rev}, $maxlines+1);
 		if (@lines) {
 			my $diff;
+			my $trunc=0;
 			if (@lines > $maxlines) {
-				$diff=join("", @lines[0..($maxlines-1)])."\n".
-					gettext("(Diff truncated)");
+				$diff=join("", @lines[0..($maxlines-1)]);
+				$trunc=1;
 			}
 			else {
 				$diff=join("", @lines);
 			}
+			if (length $diff > 102400) {
+				$diff=substr($diff, 0, 10240);
+				$trunc=1;
+			}
+			if ($trunc) {
+				$diff.="\n".gettext("(Diff truncated)");
+			}
 			# escape html
 			$diff = encode_entities($diff);
 			# escape links and preprocessor stuff
-- 
2.26.2