Pull request: 3371 pipe-tailed rules

Merge in DNS/adguard-home from 3371-rules-validation to master

Updates #3371.

Squashed commit of the following:

commit 7881a0b
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Thu Nov 11 15:06:42 2021 +0300

    all: imp code, docs

commit 613775a
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Nov 2 16:50:43 2021 +0300

    all: upd urlfilter

CHANGELOG.md

@@ -121,6 +121,7 @@ In this release, the schema version has changed from 10 to 12.
 
 ### Fixed
 
+- Matching against rules with `|` at the end of the domain name ([#3371]).
 - Incorrect assignment of explicitly configured DHCP options ([#3744]).
 - Occasional panic during shutdown ([#3655]).
 - Addition of IPs into only one as opposed to all matching ipsets on Linux
@@ -195,6 +196,7 @@ In this release, the schema version has changed from 10 to 12.
 [#3335]: https://github.com/AdguardTeam/AdGuardHome/issues/3335
 [#3343]: https://github.com/AdguardTeam/AdGuardHome/issues/3343
 [#3351]: https://github.com/AdguardTeam/AdGuardHome/issues/3351
+[#3371]: https://github.com/AdguardTeam/AdGuardHome/issues/3371
 [#3372]: https://github.com/AdguardTeam/AdGuardHome/issues/3372
 [#3417]: https://github.com/AdguardTeam/AdGuardHome/issues/3417
 [#3419]: https://github.com/AdguardTeam/AdGuardHome/issues/3419

go.mod

@@ -5,7 +5,7 @@ go 1.16
 require (
 	github.com/AdguardTeam/dnsproxy v0.39.9
 	github.com/AdguardTeam/golibs v0.10.2
-	github.com/AdguardTeam/urlfilter v0.14.6
+	github.com/AdguardTeam/urlfilter v0.15.0
 	github.com/NYTimes/gziphandler v1.1.1
 	github.com/ameshkov/dnscrypt/v2 v2.2.2
 	github.com/digineo/go-ipset/v2 v2.2.1
@@ -28,7 +28,7 @@ require (
 	go.etcd.io/bbolt v1.3.6
 	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5
 	golang.org/x/net v0.0.0-20210929193557-e81a3d93ecf6
-	golang.org/x/sys v0.0.0-20210831042530-f4d43177bf5e
+	golang.org/x/sys v0.0.0-20210909193231-528a39cd75f3
 	gopkg.in/natefinch/lumberjack.v2 v2.0.0
 	gopkg.in/yaml.v2 v2.4.0
 	howett.net/plist v0.0.0-20201203080718-1454fab16a06

go.sum

@@ -17,14 +17,14 @@ github.com/AdguardTeam/golibs v0.9.2/go.mod h1:fCAMwPBJ8S7YMYbTWvYS+eeTLblP5E04I
 github.com/AdguardTeam/golibs v0.10.2 h1:TAwnS4Y49sSUa4UX1yz/MWNGbIlXHqafrWr9MxdIh9A=
 github.com/AdguardTeam/golibs v0.10.2/go.mod h1:rSfQRGHIdgfxriDDNgNJ7HmE5zRoURq8R+VdR81Zuzw=
 github.com/AdguardTeam/gomitmproxy v0.2.0/go.mod h1:Qdv0Mktnzer5zpdpi5rAwixNJzW2FN91LjKJCkVbYGU=
-github.com/AdguardTeam/urlfilter v0.14.6 h1:emqoKZElooHACYehRBYENeKVN1a/rspxiqTIMYLuoIo=
-github.com/AdguardTeam/urlfilter v0.14.6/go.mod h1:klx4JbOfc4EaNb5lWLqOwfg+pVcyRukmoJRvO55lL5U=
+github.com/AdguardTeam/urlfilter v0.15.0 h1:K3WWZE0K5nPTHe2l+TRXDFpYWJJnvkHdlWidt6NQUTk=
+github.com/AdguardTeam/urlfilter v0.15.0/go.mod h1:EwXwrYhowP7bedqmOrmKKmQtpBYFyDNEBFQ+lxdUgQU=
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/NYTimes/gziphandler v1.1.1 h1:ZUDjpQae29j0ryrS0u/B8HZfJBtBQHjqw2rQ2cqUQ3I=
 github.com/NYTimes/gziphandler v1.1.1/go.mod h1:n/CVRwUEOgIxrgPvAQhUUr9oeUtvrhMomdKFjzJNB0c=
-github.com/StackExchange/wmi v0.0.0-20190523213315-cbe66965904d h1:G0m3OIz70MZUWq3EgK3CesDbo8upS2Vm9/P3FtgI+Jk=
-github.com/StackExchange/wmi v0.0.0-20190523213315-cbe66965904d/go.mod h1:3eOhrUMpNV+6aFIbp5/iudMxNCF27Vw2OZgy4xEx0Fg=
+github.com/StackExchange/wmi v1.2.1 h1:VIkavFPXSjcnS+O8yTq7NI32k0R5Aj+v39y29VYDOSA=
+github.com/StackExchange/wmi v1.2.1/go.mod h1:rcmrprowKIVzvc+NUiLncP2uuArMWLCbu9SBzvHz7e8=
 github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da h1:KjTM2ks9d14ZYCvmHS9iAKVt9AyzRSqNU1qabPih5BY=
 github.com/aead/chacha20 v0.0.0-20180709150244-8b13a72661da/go.mod h1:eHEWzANqSiWQsof+nXEI9bUVUyV6F53Fp89EuCh2EAA=
 github.com/aead/poly1305 v0.0.0-20180717145839-3fee0db0b635 h1:52m0LGchQBBVqJRyYYufQuIbVqRawmubW3OFGqK1ekw=
@@ -60,8 +60,8 @@ github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4
 github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
 github.com/gliderlabs/ssh v0.1.1/go.mod h1:U7qILu1NlMHj9FlMhZLlkCdDnU1DBEAqr0aevW3Awn0=
 github.com/go-errors/errors v1.0.1/go.mod h1:f4zRHt4oKfwPJE5k8C9vpYG+aDHdBFUsgrm6/TyX73Q=
-github.com/go-ole/go-ole v1.2.4 h1:nNBDSCOigTSiarFpYE9J/KtEA1IOW4CNeqT9TQDqCxI=
-github.com/go-ole/go-ole v1.2.4/go.mod h1:XCwSNxSkXRo4vlyPy93sltvi/qJq0jqQhjqQNIwKuxM=
+github.com/go-ole/go-ole v1.2.5 h1:t4MGB5xEDZvXI+0rMjjsfBsD7yAgp/s9ZDkL1JndXwY=
+github.com/go-ole/go-ole v1.2.5/go.mod h1:pprOEPIfldk/42T2oK7lQ4v4JSDwmV0As9GaiUsvbm0=
 github.com/go-ping/ping v0.0.0-20210506233800-ff8be3320020 h1:mdi6AbCEoKCA1xKCmp7UtRB5fvGFlP92PvlhxgdvXEw=
 github.com/go-ping/ping v0.0.0-20210506233800-ff8be3320020/go.mod h1:KmHOjTUmJh/l04ukqPoBWPEZr9jwN05h5NXQl5C+DyY=
 github.com/go-test/deep v1.0.5 h1:AKODKU3pDH1RzZzm6YZu77YWtEAq6uh1rLIAQlay2qc=
@@ -109,7 +109,6 @@ github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714 h1:/jC7qQFrv8
 github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714/go.mod h1:2Goc3h8EklBH5mspfHFxBnEoURQCGzQQH1ga9Myjvis=
 github.com/jellevandenhooff/dkim v0.0.0-20150330215556-f50fe3d243e1/go.mod h1:E0B/fFc00Y+Rasa88328GlI/XbtyysCtTHZS8h7IrBU=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
-github.com/joomcode/errorx v1.0.1/go.mod h1:kgco15ekB6cs+4Xjzo7SPeXzx38PbJzBwbnu9qfVNHQ=
 github.com/joomcode/errorx v1.0.3 h1:3e1mi0u7/HTPNdg6d6DYyKGBhA5l9XpsfuVE29NxnWw=
 github.com/joomcode/errorx v1.0.3/go.mod h1:eQzdtdlNyN7etw6YCS4W4+lu442waxZYw5yvz0ULrRo=
 github.com/josharian/native v0.0.0-20200817173448-b6b71def0850 h1:uhL5Gw7BINiiPAo24A2sxkcDI0Jt/sqp1v5xQCniEFA=
@@ -170,7 +169,6 @@ github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065/go.mod h1:7EpbotpCmVZ
 github.com/mdlayher/raw v0.0.0-20210412142147-51b895745faf h1:InctQoB89TIkmgIFQeIL4KXNvWc1iebQXdZggqPSwL8=
 github.com/mdlayher/raw v0.0.0-20210412142147-51b895745faf/go.mod h1:7EpbotpCmVZcu+KCX4g9WaRNuu11uyhiW7+Le1dKawg=
 github.com/microcosm-cc/bluemonday v1.0.1/go.mod h1:hsXNsILzKxV+sX77C5b8FSuKF00vh2OMYv+xgHpAMF4=
-github.com/miekg/dns v1.1.35/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/miekg/dns v1.1.40/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
 github.com/miekg/dns v1.1.43 h1:JKfpVSCB84vrAmHzyrsxB5NAr5kLoMXZArPSw7Qlgyg=
 github.com/miekg/dns v1.1.43/go.mod h1:+evo5L0630/F6ca/Z9+GAqzhjGyn8/c+TBaOyfEl0V4=
@@ -205,8 +203,8 @@ github.com/russross/blackfriday v1.5.2/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR
 github.com/satori/go.uuid v1.2.0 h1:0uYX9dsZ2yD7q2RtLRtPSdGDWzjeM3TbMJP9utgA0ww=
 github.com/satori/go.uuid v1.2.0/go.mod h1:dA0hQrYB0VpLJoorglMZABFdXlWrHn1NEOzdhQKdks0=
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
-github.com/shirou/gopsutil v2.20.3+incompatible h1:0JVooMPsT7A7HqEYdydp/OfjSOYSjhXV7w1hkKj/NPQ=
-github.com/shirou/gopsutil v2.20.3+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=
+github.com/shirou/gopsutil/v3 v3.21.8 h1:nKct+uP0TV8DjjNiHanKf8SAuub+GNsbrOtM9Nl9biA=
+github.com/shirou/gopsutil/v3 v3.21.8/go.mod h1:YWp/H8Qs5fVmf17v7JNZzA0mPJ+mS2e9JdiUF9LlKzQ=
 github.com/shurcooL/component v0.0.0-20170202220835-f88ec8f54cc4/go.mod h1:XhFIlyj5a1fBNx5aJTbKoIq0mNaPvOagO+HjB3EtxrY=
 github.com/shurcooL/events v0.0.0-20181021180414-410e4ca65f48/go.mod h1:5u70Mqkb5O5cxEA8nxTsgrgLehJeAw6Oc4Ab1c/P1HM=
 github.com/shurcooL/github_flavored_markdown v0.0.0-20181002035957-2122de532470/go.mod h1:2dOwnU2uBioM+SGy2aZoq1f/Sd1l9OkAeAUvjSyvgU0=
@@ -246,6 +244,10 @@ github.com/tarm/serial v0.0.0-20180830185346-98f6abe2eb07/go.mod h1:kDXzergiv9cb
 github.com/ti-mo/netfilter v0.2.0/go.mod h1:8GbBGsY/8fxtyIdfwy29JiluNcPK4K7wIT+x42ipqUU=
 github.com/ti-mo/netfilter v0.4.0 h1:rTN1nBYULDmMfDeBHZpKuNKX/bWEXQUhe02a/10orzg=
 github.com/ti-mo/netfilter v0.4.0/go.mod h1:V54q75mUx8CNA2JnFl+wv9iZ5+JP9nCcRlaFS5OZSRM=
+github.com/tklauser/go-sysconf v0.3.9 h1:JeUVdAOWhhxVcU6Eqr/ATFHgXk/mmiItdKeJPev3vTo=
+github.com/tklauser/go-sysconf v0.3.9/go.mod h1:11DU/5sG7UexIrp/O6g35hrWzu0JxlwQ3LSFUzyeuhs=
+github.com/tklauser/numcpus v0.3.0 h1:ILuRUQBtssgnxw0XXIjKUC56fgnOrFoQQ/4+DeU2biQ=
+github.com/tklauser/numcpus v0.3.0/go.mod h1:yFGUr7TUHQRAhyqBcEg0Ge34zDBAsIvJJcyE6boqnA8=
 github.com/u-root/u-root v7.0.0+incompatible h1:u+KSS04pSxJGI5E7WE4Bs9+Zd75QjFv+REkjy/aoAc8=
 github.com/u-root/u-root v7.0.0+incompatible/go.mod h1:RYkpo8pTHrNjW08opNd/U6p/RJE7K0D8fXO0d47+3YY=
 github.com/viant/assertly v0.4.8/go.mod h1:aGifi++jvCrUaklKEKT0BU95igDNaqkvz+49uaYMPRU=
@@ -303,6 +305,7 @@ golang.org/x/net v0.0.0-20210119194325-5f4716e94777/go.mod h1:m0MpNAwzfU5UDzcl9v
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
 golang.org/x/net v0.0.0-20210726213435-c6fcb2dbf985/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20210908191846-a5e095526f91/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20210929193557-e81a3d93ecf6 h1:Z04ewVs7JhXaYkmDhBERPi41gnltfQpMWDnTnQbaCqk=
 golang.org/x/net v0.0.0-20210929193557-e81a3d93ecf6/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@@ -330,6 +333,7 @@ golang.org/x/sys v0.0.0-20190418153312-f0ce4c0180be/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20190606122018-79a91cf218c4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190826190057-c7b8b68b1456/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190904154756-749cb33beabd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190916202348-b4ddaad3f8a3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191005200804-aed5e4c7ecf9/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191008105621-543471e840be/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -359,8 +363,9 @@ golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210831042530-f4d43177bf5e h1:XMgFehsDnnLGtjvjOfqWSUzt0alpTR1RSEuznObga2c=
-golang.org/x/sys v0.0.0-20210831042530-f4d43177bf5e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20210816074244-15123e1e1f71/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20210909193231-528a39cd75f3 h1:3Ad41xy2WCESpufXwgs7NpDSu+vjxqLt2UFqUV+20bI=
+golang.org/x/sys v0.0.0-20210909193231-528a39cd75f3/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

internal/aghnet/hostscontainer.go

@@ -112,16 +112,16 @@ func NewHostsContainer(
 }
 
 // MatchRequest is the request processing method to resolve hostnames and
-// addresses from the operating system's hosts files.  Any request not of A/AAAA
-// or PTR type will return with an empty result.  It's safe for concurrent use.
+// addresses from the operating system's hosts files.  res is nil for any
+// request having not an A/AAAA or PTR type.  It's safe for concurrent use.
 func (hc *HostsContainer) MatchRequest(
 	req urlfilter.DNSRequest,
-) (res urlfilter.DNSResult, ok bool) {
+) (res *urlfilter.DNSResult, ok bool) {
 	switch req.DNSType {
 	case dns.TypeA, dns.TypeAAAA, dns.TypePTR:
 		log.Debug("%s: handling the request", hostsContainerPref)
 	default:
-		return urlfilter.DNSResult{}, false
+		return nil, false
 	}
 
 	hc.engLock.RLock()

internal/aghnet/hostscontainer_test.go

@@ -256,39 +256,42 @@ func TestHostsContainer_MatchRequest(t *testing.T) {
 
 	testCase := []struct {
 		name string
-		want interface{}
+		want []interface{}
 		req  urlfilter.DNSRequest
 	}{{
 		name: "a",
-		want: ip4.To16(),
+		want: []interface{}{ip4.To16()},
 		req: urlfilter.DNSRequest{
 			Hostname: hostname4,
 			DNSType:  dns.TypeA,
 		},
 	}, {
 		name: "aaaa",
-		want: ip6,
+		want: []interface{}{ip6},
 		req: urlfilter.DNSRequest{
 			Hostname: hostname6,
-			DNSType:  dns.TypeA,
+			DNSType:  dns.TypeAAAA,
 		},
 	}, {
 		name: "ptr",
-		want: dns.Fqdn(hostname4),
+		want: []interface{}{
+			dns.Fqdn(hostname4),
+			dns.Fqdn(hostname4a),
+		},
 		req: urlfilter.DNSRequest{
 			Hostname: reversed4,
 			DNSType:  dns.TypePTR,
 		},
 	}, {
 		name: "ptr_v6",
-		want: dns.Fqdn(hostname6),
+		want: []interface{}{dns.Fqdn(hostname6)},
 		req: urlfilter.DNSRequest{
 			Hostname: reversed6,
 			DNSType:  dns.TypePTR,
 		},
 	}, {
 		name: "a_alias",
-		want: ip4.To16(),
+		want: []interface{}{ip4.To16()},
 		req: urlfilter.DNSRequest{
 			Hostname: hostname4a,
 			DNSType:  dns.TypeA,
@@ -299,8 +302,19 @@ func TestHostsContainer_MatchRequest(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			res, ok := hc.MatchRequest(tc.req)
 			require.False(t, ok)
+			require.NotNil(t, res)
+
+			rws := res.DNSRewrites()
+			require.Len(t, rws, len(tc.want))
 
-			assert.Equal(t, tc.want, res.DNSRewrites()[0].DNSRewrite.Value)
+			for i, w := range tc.want {
+				require.NotNil(t, rws[i])
+
+				rw := rws[i].DNSRewrite
+				require.NotNil(t, rw)
+
+				assert.Equal(t, w, rw.Value)
+			}
 		})
 	}
 
@@ -311,7 +325,7 @@ func TestHostsContainer_MatchRequest(t *testing.T) {
 		})
 		require.False(t, ok)
 
-		assert.Empty(t, res)
+		assert.Nil(t, res)
 	})
 }
 

internal/dnsforward/dns.go

@@ -341,14 +341,12 @@ func (s *Server) processRestrictLocal(ctx *dnsContext) (rc resultCode) {
 	// Restrict an access to local addresses for external clients.  We also
 	// assume that all the DHCP leases we give are locally-served or at
 	// least don't need to be inaccessible externally.
-	if s.subnetDetector.IsLocallyServedNetwork(ip) {
-		if !ctx.isLocalClient {
-			log.Debug("dns: %q requests for internal ip", d.Addr)
-			d.Res = s.genNXDomain(req)
+	if s.subnetDetector.IsLocallyServedNetwork(ip) && !ctx.isLocalClient {
+		log.Debug("dns: %q requests for internal ip", d.Addr)
+		d.Res = s.genNXDomain(req)
 
-			// Do not even put into query log.
-			return resultCodeFinish
-		}
+		// Do not even put into query log.
+		return resultCodeFinish
 	}
 
 	// Do not perform unreversing ever again.

internal/filtering/filtering.go

@@ -451,7 +451,11 @@ func (d *DNSFilter) CheckHost(
 
 // matchSysHosts tries to match the host against the operating system's hosts
 // database.
-func (d *DNSFilter) matchSysHosts(host string, qtype uint16, setts *Settings) (res Result, err error) {
+func (d *DNSFilter) matchSysHosts(
+	host string,
+	qtype uint16,
+	setts *Settings,
+) (res Result, err error) {
 	if !setts.FilteringEnabled || d.EtcHosts == nil {
 		return Result{}, nil
 	}
@@ -464,6 +468,9 @@ func (d *DNSFilter) matchSysHosts(host string, qtype uint16, setts *Settings) (r
 		ClientName: setts.ClientName,
 		DNSType:    qtype,
 	})
+	if dnsres == nil {
+		return Result{}, nil
+	}
 
 	dnsr := dnsres.DNSRewrites()
 	if len(dnsr) == 0 {
@@ -695,7 +702,7 @@ func hostRulesToRules(netRules []*rules.HostRule) (res []rules.Rule) {
 // matching.
 func (d *DNSFilter) matchHostProcessAllowList(
 	host string,
-	dnsres urlfilter.DNSResult,
+	dnsres *urlfilter.DNSResult,
 ) (res Result, err error) {
 	var matchedRules []rules.Rule
 	if dnsres.NetworkRule != nil {
@@ -718,7 +725,7 @@ func (d *DNSFilter) matchHostProcessAllowList(
 // matchHostProcessDNSResult processes the matched DNS filtering result.
 func (d *DNSFilter) matchHostProcessDNSResult(
 	qtype uint16,
-	dnsres urlfilter.DNSResult,
+	dnsres *urlfilter.DNSResult,
 ) (res Result) {
 	if dnsres.NetworkRule != nil {
 		reason := FilteredBlockList