From 4605e7c90e509be2a7117dfee282a6b34f3e921c Mon Sep 17 00:00:00 2001
From: Stanislav Chzhen <s.chzhen@adguard.com>
Date: Wed, 21 Feb 2024 13:04:58 +0300
Subject: [PATCH] Pull request 2153: 6610-hostsfile-enabled

Updates #6610.

Squashed commit of the following:

commit 13522f0768fe0a4f6abe3fc82ffb7ddf3f4df9bf
Merge: befa3bd1d 6fd0a624c
Author: Stanislav Chzhen <s.chzhen@adguard.com>
Date:   Wed Feb 21 12:53:08 2024 +0300

    Merge branch 'master' into 6610-hostsfile-enabled

commit befa3bd1dedcd2853ef299c06d5c14c9ed7f2c84
Author: Stanislav Chzhen <s.chzhen@adguard.com>
Date:   Mon Feb 19 15:56:20 2024 +0300

    all: upd chlog

commit c1954306fe7c4d7af164f599b298374ab983216f
Author: Stanislav Chzhen <s.chzhen@adguard.com>
Date:   Thu Feb 15 20:52:52 2024 +0300

    home: hostsfile enabled
---
 CHANGELOG.md             |  3 +++
 internal/home/config.go  | 11 ++++++++---
 internal/home/home.go    |  2 +-
 internal/home/options.go | 12 +++++++-----
 4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0fc8b003..e3c03584 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -30,6 +30,8 @@ NOTE: Add new changes BELOW THIS COMMENT.
 
 ### Added
 
+- Ability to disable the use of system hosts file information for query
+  resolution ([#6610]).
 - Ability to define custom directories for storage of query log files and
   statistics ([#5992]).
 - Context menu item in the Query Log to add a Client to the Persistent client
@@ -66,6 +68,7 @@ NOTE: Add new changes BELOW THIS COMMENT.
 - Go 1.20 support, as it has reached end of life.
 
 [#5992]: https://github.com/AdguardTeam/AdGuardHome/issues/5992
+[#6610]: https://github.com/AdguardTeam/AdGuardHome/issues/6610
 [#6679]: https://github.com/AdguardTeam/AdGuardHome/issues/6679
 [#6711]: https://github.com/AdguardTeam/AdGuardHome/issues/6711
 
diff --git a/internal/home/config.go b/internal/home/config.go
index 17a5661d..1619d083 100644
--- a/internal/home/config.go
+++ b/internal/home/config.go
@@ -232,6 +232,10 @@ type dnsConfig struct {
 
 	// ServePlainDNS defines if plain DNS is allowed for incoming requests.
 	ServePlainDNS bool `yaml:"serve_plain_dns"`
+
+	// HostsFileEnabled defines whether to use information from the system hosts
+	// file to resolve queries.
+	HostsFileEnabled bool `yaml:"hostsfile_enabled"`
 }
 
 type tlsConfigSettings struct {
@@ -349,9 +353,10 @@ var config = &configuration{
 			// was later increased to 300 due to https://github.com/AdguardTeam/AdGuardHome/issues/2257
 			MaxGoroutines: 300,
 		},
-		UpstreamTimeout: timeutil.Duration{Duration: dnsforward.DefaultTimeout},
-		UsePrivateRDNS:  true,
-		ServePlainDNS:   true,
+		UpstreamTimeout:  timeutil.Duration{Duration: dnsforward.DefaultTimeout},
+		UsePrivateRDNS:   true,
+		ServePlainDNS:    true,
+		HostsFileEnabled: true,
 	},
 	TLS: tlsConfigSettings{
 		PortHTTPS:       defaultPortHTTPS,
diff --git a/internal/home/home.go b/internal/home/home.go
index 22f6130c..90949f07 100644
--- a/internal/home/home.go
+++ b/internal/home/home.go
@@ -361,7 +361,7 @@ func setupDNSFilteringConf(conf *filtering.Config) (err error) {
 
 	conf.EtcHosts = Context.etcHosts
 	// TODO(s.chzhen):  Use empty interface.
-	if Context.etcHosts == nil {
+	if Context.etcHosts == nil || !config.DNS.HostsFileEnabled {
 		conf.EtcHosts = nil
 	}
 
diff --git a/internal/home/options.go b/internal/home/options.go
index d32aaa1c..35f26303 100644
--- a/internal/home/options.go
+++ b/internal/home/options.go
@@ -270,15 +270,17 @@ var cmdLineOpts = []cmdLineOpt{{
 		log.Info(
 			"warning: --no-etc-hosts flag is deprecated " +
 				"and will be removed in the future versions; " +
-				"set clients.runtime_sources.hosts in the configuration file to false instead",
+				"set clients.runtime_sources.hosts and dns.hostsfile_enabled " +
+				"in the configuration file to false instead",
 		)
 
 		return nil, nil
 	},
-	serialize:   func(o options) (val string, ok bool) { return "", o.noEtcHosts },
-	description: "Deprecated: use clients.runtime_sources.hosts instead.  Do not use the OS-provided hosts.",
-	longName:    "no-etc-hosts",
-	shortName:   "",
+	serialize: func(o options) (val string, ok bool) { return "", o.noEtcHosts },
+	description: "Deprecated: use clients.runtime_sources.hosts and dns.hostsfile_enabled " +
+		"instead.  Do not use the OS-provided hosts.",
+	longName:  "no-etc-hosts",
+	shortName: "",
 }, {
 	updateWithValue: nil,
 	updateNoValue:   func(o options) (options, error) { o.localFrontend = true; return o, nil },