Pull request: 2582 invalid hostname

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

Updates #2582.

Squashed commit of the following:

commit 909598d
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Thu Mar 4 17:32:58 2021 +0300

    all: imp code quality, log changes

commit b3b9708
Author: Eugene Burkov <e.burkov@adguard.com>
Date:   Thu Mar 4 16:56:28 2021 +0300

    home: add host processing logic

CHANGELOG.md

@@ -19,6 +19,7 @@ and this project adheres to
 
 ### Fixed
 
+- Incomplete hostnames with trailing zero-bytes handling ([#2582]).
 - Wrong DNS-over-TLS ALPN configuration ([#2681]).
 - Inconsistent responses for messages with EDNS0 and AD when DNS caching is
   enabled ([#2600]).
@@ -27,6 +28,7 @@ and this project adheres to
 - Incomplete DNS upstreams validation ([#2674]).
 - Wrong parsing of DHCP options of the `ip` type ([#2688]).
 
+[#2582]: https://github.com/AdguardTeam/AdGuardHome/issues/2582
 [#2600]: https://github.com/AdguardTeam/AdGuardHome/issues/2600
 [#2674]: https://github.com/AdguardTeam/AdGuardHome/issues/2674
 [#2681]: https://github.com/AdguardTeam/AdGuardHome/issues/2681

internal/home/clients.go

@@ -586,9 +586,22 @@ 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()

internal/home/clients_test.go

@@ -290,3 +290,29 @@ 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]))
+		})
+	}
+}