From 3fe2c73dd04f7769a9d9673236cb94b79ac45659 Mon Sep 17 00:00:00 2001
From: Francis Lavoie <lavofr@gmail.com>
Date: Thu, 30 Dec 2021 04:15:48 -0500
Subject: [PATCH] caddyhttp: Fix `MatchPath` sanitizing (#4499)
This is a followup to #4407, in response to a report on the forums: https://caddy.community/t/php-fastcgi-phishing-redirection/14542
Turns out that doing `TrimRight` to remove trailing dots, _before_ cleaning the path, will cause double-dots at the end of the path to not be cleaned away as they should. We should instead remove the dots _after_ cleaning.
---
modules/caddyhttp/matchers.go | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/modules/caddyhttp/matchers.go b/modules/caddyhttp/matchers.go
index 439c40730..272c92421 100644
--- a/modules/caddyhttp/matchers.go
+++ b/modules/caddyhttp/matchers.go
@@ -325,6 +325,11 @@ func (m MatchPath) Match(r *http.Request) bool {
lowerPath := strings.ToLower(unescapedPath)
+ // Clean the path, merges doubled slashes, etc.
+ // This ensures maliciously crafted requests can't bypass
+ // the path matcher. See #4407
+ lowerPath = path.Clean(lowerPath)
+
// see #2917; Windows ignores trailing dots and spaces
// when accessing files (sigh), potentially causing a
// security risk (cry) if PHP files end up being served
@@ -332,11 +337,6 @@ func (m MatchPath) Match(r *http.Request) bool {
// being matched by *.php to be treated as PHP scripts
lowerPath = strings.TrimRight(lowerPath, ". ")
- // Clean the path, merges doubled slashes, etc.
- // This ensures maliciously crafted requests can't bypass
- // the path matcher. See #4407
- lowerPath = path.Clean(lowerPath)
-
// Cleaning may remove the trailing slash, but we want to keep it
if lowerPath != "/" && strings.HasSuffix(r.URL.Path, "/") {
lowerPath = lowerPath + "/"