From d49e3769a105f4dee639b9dec1112b123b7a23aa Mon Sep 17 00:00:00 2001
From: Eugene Bujak <hmage@hmage.net>
Date: Mon, 10 Sep 2018 20:34:42 +0300
Subject: [PATCH] dnsfilter -- do not check lookup hosts against themselves to
avoid recursion
---
dnsfilter/dnsfilter.go | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/dnsfilter/dnsfilter.go b/dnsfilter/dnsfilter.go
index b9305948..90db03b7 100644
--- a/dnsfilter/dnsfilter.go
+++ b/dnsfilter/dnsfilter.go
@@ -28,7 +28,8 @@ const defaultHTTPMaxIdleConnections = 100
const defaultSafebrowsingServer = "sb.adtidy.org"
const defaultSafebrowsingURL = "http://%s/safebrowsing-lookup-hash.html?prefixes=%s"
-const defaultParentalURL = "http://pctrl.adguard.com/check-parental-control-hash?prefixes=%s&sensitivity=%d"
+const defaultParentalServer = "pctrl.adguard.com"
+const defaultParentalURL = "http://%s/check-parental-control-hash?prefixes=%s&sensitivity=%d"
var ErrInvalidSyntax = errors.New("dnsfilter: invalid rule syntax")
var ErrInvalidParental = errors.New("dnsfilter: invalid parental sensitivity, must be either 3, 10, 13 or 17")
@@ -43,6 +44,7 @@ type Config struct {
safeBrowsingEnabled bool
safeBrowsingServer string
parentalEnabled bool
+ parentalServer string
parentalSensitivity int // must be either 3, 10, 13 or 17
}
@@ -140,6 +142,7 @@ func (d *Dnsfilter) CheckHost(host string) (Result, error) {
if host == "" {
return Result{Reason: FilteredInvalid}, nil
}
+ host = strings.ToLower(host)
// try filter lists first
result, err := d.matchHost(host)
@@ -487,6 +490,10 @@ func hostnameToHashParam(host string, addslash bool) (string, map[string]bool) {
}
func (d *Dnsfilter) checkSafeBrowsing(host string) (Result, error) {
+ // prevent recursion -- checking the host of safebrowsing server makes no sense
+ if host == d.config.safeBrowsingServer {
+ return Result{}, nil
+ }
format := func(hashparam string) string {
url := fmt.Sprintf(defaultSafebrowsingURL, d.config.safeBrowsingServer, hashparam)
return url
@@ -521,8 +528,12 @@ func (d *Dnsfilter) checkSafeBrowsing(host string) (Result, error) {
}
func (d *Dnsfilter) checkParental(host string) (Result, error) {
+ // prevent recursion -- checking the host of parental safety server makes no sense
+ if host == d.config.parentalServer {
+ return Result{}, nil
+ }
format := func(hashparam string) string {
- url := fmt.Sprintf(defaultParentalURL, hashparam, d.config.parentalSensitivity)
+ url := fmt.Sprintf(defaultParentalURL, d.config.parentalServer, hashparam, d.config.parentalSensitivity)
return url
}
handleBody := func(body []byte, hashes map[string]bool) (Result, error) {
@@ -723,6 +734,8 @@ func New() *Dnsfilter {
Timeout: defaultHTTPTimeout,
}
d.config.safeBrowsingServer = defaultSafebrowsingServer
+ d.config.parentalServer = defaultParentalServer
+
return d
}