From 5aa0ca9319919f35eb2e1dc4c9e6d8f0385c394e Mon Sep 17 00:00:00 2001
From: Eugene Burkov <e.burkov@adguard.com>
Date: Fri, 5 Mar 2021 19:20:36 +0300
Subject: [PATCH] Pull request: 2582 invalid hostname vol.2

Merge in DNS/adguard-home from 2582-invalid-hostname-2 to master

Updates #2582.

Squashed commit of the following:

commit 9d3ceb289e3869b2c3d12e91ec104fb25d7931ee
Merge: 91c68e46 90054974
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Mar 5 19:11:49 2021 +0300

    Merge branch 'master' into 2582-invalid-hostname-2

commit 91c68e468c5f5b12a2fb509ff391133483c9d915
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Mar 5 18:28:14 2021 +0300

    all: mv trimming from home to dhcpd

commit f51faf35288577b6f610f172b26e7ac13aa24f72
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Fri Mar 5 16:28:00 2021 +0300

    home: add more host sanitizings
---
 internal/dhcpd/v4.go          | 12 +++++++++++-
 internal/home/clients.go      | 13 -------------
 internal/home/clients_test.go | 26 --------------------------
 3 files changed, 11 insertions(+), 40 deletions(-)

diff --git a/internal/dhcpd/v4.go b/internal/dhcpd/v4.go
index 7d24699e..38c0a90d 100644
--- a/internal/dhcpd/v4.go
+++ b/internal/dhcpd/v4.go
@@ -7,6 +7,7 @@ import (
 	"encoding/binary"
 	"fmt"
 	"net"
+	"strings"
 	"sync"
 	"time"
 
@@ -463,7 +464,16 @@ func (s *v4Server) processRequest(req, resp *dhcpv4.DHCPv4) (*Lease, bool) {
 	}
 
 	if lease.Expiry.Unix() != leaseExpireStatic {
-		lease.Hostname = string(hostname)
+		// The trimming is required since some devices include trailing
+		// zero-byte in DHCP option length calculation.
+		//
+		// See https://github.com/AdguardTeam/AdGuardHome/issues/2582.
+		//
+		// TODO(e.burkov): Remove after the trimming for hostname option
+		// will be added into github.com/insomniacslk/dhcp module.
+		hostnameStr := strings.TrimRight(string(hostname), "\x00")
+
+		lease.Hostname = hostnameStr
 		s.commitLease(lease)
 	} else if len(lease.Hostname) != 0 {
 		o := &optFQDN{
diff --git a/internal/home/clients.go b/internal/home/clients.go
index 6c314874..5a9e9eac 100644
--- a/internal/home/clients.go
+++ b/internal/home/clients.go
@@ -586,22 +586,9 @@ func (clients *clientsContainer) SetWhoisInfo(ip string, info [][]string) {
 	log.Debug("clients: set whois info for auto-client with IP %s: %q", ip, info)
 }
 
-// sanitizeHost proccesses a host to remove some special symbols causing errors.
-// Logic may be expanded in the future.
-func sanitizeHost(host string) (processed string) {
-	// cutset brings together all the deprecated sets.
-	//
-	// See https://github.com/AdguardTeam/AdGuardHome/issues/2582.
-	const cutset = "\x00"
-
-	return strings.TrimRight(host, cutset)
-}
-
 // AddHost adds a new IP-hostname pairing.  The priorities of the sources is
 // taken into account.  ok is true if the pairing was added.
 func (clients *clientsContainer) AddHost(ip, host string, src clientSource) (ok bool, err error) {
-	host = sanitizeHost(host)
-
 	clients.lock.Lock()
 	ok = clients.addHostLocked(ip, host, src)
 	clients.lock.Unlock()
diff --git a/internal/home/clients_test.go b/internal/home/clients_test.go
index e6200ddd..a098bf4c 100644
--- a/internal/home/clients_test.go
+++ b/internal/home/clients_test.go
@@ -290,29 +290,3 @@ func TestClientsCustomUpstream(t *testing.T) {
 	assert.Equal(t, 1, len(config.Upstreams))
 	assert.Equal(t, 1, len(config.DomainReservedUpstreams))
 }
-
-func TestProcessHost(t *testing.T) {
-	const (
-		name int = iota
-		host
-		want
-
-		fieldsNum
-	)
-
-	testCases := [][fieldsNum]string{{
-		name: "valid",
-		host: "abc",
-		want: "abc",
-	}, {
-		name: "with_trailing_zero_byte",
-		host: "abc\x00",
-		want: "abc",
-	}}
-
-	for _, tc := range testCases {
-		t.Run(tc[name], func(t *testing.T) {
-			assert.Equal(t, tc[want], sanitizeHost(tc[host]))
-		})
-	}
-}