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Pull request: 3381 check private domains

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Merge in DNS/adguard-home from 3381-validate-privateness to master

Closes #3381.

Squashed commit of the following:

commit 21cb12d10b07bb0bf0578db74ca9ac7b3ac5ae14
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Feb 14 16:29:59 2022 +0300

    all: imp code, docs

commit 39793551438cbea71e6ec78d0e05bee2d8dba3e5
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Feb 14 15:08:36 2022 +0300

    all: imp code, docs

commit 6b71848fd0980582b1bfe24a34f48608795e9b7d
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Feb 14 14:22:00 2022 +0300

    all: check private domains
This commit is contained in:
Eugene Burkov
2022-02-14 16:56:14 +03:00
parent b43aa86cae
commit f131067278
7 changed files with 262 additions and 109 deletions
Download Patch File Download Diff File Expand all files Collapse all files

251
internal/dnsforward/http.go
View File

@@ -5,10 +5,12 @@ import (
"fmt"
"net"
"net/http"
"sort"
"strings"
"time"
"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
"github.com/AdguardTeam/dnsproxy/proxy"
"github.com/AdguardTeam/dnsproxy/upstream"
"github.com/AdguardTeam/golibs/errors"
@@ -41,7 +43,7 @@ type dnsConfig struct {
LocalPTRUpstreams *[]string `json:"local_ptr_upstreams"`
}
func (s *Server) getDNSConfig() dnsConfig {
func (s *Server) getDNSConfig() (c *dnsConfig) {
s.serverLock.RLock()
defer s.serverLock.RUnlock()
@@ -70,7 +72,7 @@ func (s *Server) getDNSConfig() dnsConfig {
upstreamMode = "parallel"
}
return dnsConfig{
return &dnsConfig{
Upstreams: &upstreams,
UpstreamsFile: &upstreamFile,
Bootstraps: &bootstraps,
@@ -106,7 +108,7 @@ func (s *Server) handleGetConfig(w http.ResponseWriter, r *http.Request) {
// since there is no need to omit it while decoding from JSON.
DefautLocalPTRUpstreams []string `json:"default_local_ptr_upstreams,omitempty"`
}{
dnsConfig: s.getDNSConfig(),
dnsConfig: *s.getDNSConfig(),
DefautLocalPTRUpstreams: defLocalPTRUps,
}
@@ -138,39 +140,63 @@ func (req *dnsConfig) checkBlockingMode() bool {
}
func (req *dnsConfig) checkUpstreamsMode() bool {
if req.UpstreamMode == nil {
return true
}
valid := []string{"", "fastest_addr", "parallel"}
for _, valid := range []string{
"",
"fastest_addr",
"parallel",
} {
if *req.UpstreamMode == valid {
return true
}
}
return false
return req.UpstreamMode == nil || stringutil.InSlice(valid, *req.UpstreamMode)
}
func (req *dnsConfig) checkBootstrap() (string, error) {
func (req *dnsConfig) checkBootstrap() (err error) {
if req.Bootstraps == nil {
return "", nil
return nil
}
for _, boot := range *req.Bootstraps {
if boot == "" {
return boot, fmt.Errorf("invalid bootstrap server address: empty")
var b string
defer func() { err = errors.Annotate(err, "checking bootstrap %s: invalid address: %w", b) }()
for _, b = range *req.Bootstraps {
if b == "" {
return errors.Error("empty")
}
if _, err := upstream.NewResolver(boot, nil); err != nil {
return boot, fmt.Errorf("invalid bootstrap server address: %w", err)
if _, err = upstream.NewResolver(b, nil); err != nil {
return err
}
}
return "", nil
return nil
}
// validate returns an error if any field of req is invalid.
func (req *dnsConfig) validate(snd *aghnet.SubnetDetector) (err error) {
if req.Upstreams != nil {
err = ValidateUpstreams(*req.Upstreams)
if err != nil {
return fmt.Errorf("validating upstream servers: %w", err)
}
}
if req.LocalPTRUpstreams != nil {
err = ValidateUpstreamsPrivate(*req.LocalPTRUpstreams, snd)
if err != nil {
return fmt.Errorf("validating private upstream servers: %w", err)
}
}
err = req.checkBootstrap()
if err != nil {
return err
}
switch {
case !req.checkBlockingMode():
return errors.Error("blocking_mode: incorrect value")
case !req.checkUpstreamsMode():
return errors.Error("upstream_mode: incorrect value")
case !req.checkCacheTTL():
return errors.Error("cache_ttl_min must be less or equal than cache_ttl_max")
default:
return nil
}
}
func (req *dnsConfig) checkCacheTTL() bool {
@@ -190,69 +216,33 @@ func (req *dnsConfig) checkCacheTTL() bool {
}
func (s *Server) handleSetConfig(w http.ResponseWriter, r *http.Request) {
req := dnsConfig{}
err := json.NewDecoder(r.Body).Decode(&req)
req := &dnsConfig{}
err := json.NewDecoder(r.Body).Decode(req)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "json Encode: %s", err)
aghhttp.Error(r, w, http.StatusBadRequest, "decoding request: %s", err)
return
}
if req.Upstreams != nil {
if err = ValidateUpstreams(*req.Upstreams); err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "wrong upstreams specification: %s", err)
return
}
}
var errBoot string
if errBoot, err = req.checkBootstrap(); err != nil {
aghhttp.Error(
r,
w,
http.StatusBadRequest,
"%s can not be used as bootstrap dns cause: %s",
errBoot,
err,
)
err = req.validate(s.subnetDetector)
if err != nil {
aghhttp.Error(r, w, http.StatusBadRequest, "%s", err)
return
}
switch {
case !req.checkBlockingMode():
aghhttp.Error(r, w, http.StatusBadRequest, "blocking_mode: incorrect value")
return
case !req.checkUpstreamsMode():
aghhttp.Error(r, w, http.StatusBadRequest, "upstream_mode: incorrect value")
return
case !req.checkCacheTTL():
aghhttp.Error(
r,
w,
http.StatusBadRequest,
"cache_ttl_min must be less or equal than cache_ttl_max",
)
return
default:
// Go on.
}
restart := s.setConfig(req)
s.conf.ConfigModified()
if restart {
if err = s.Reconfigure(nil); err != nil {
err = s.Reconfigure(nil)
if err != nil {
aghhttp.Error(r, w, http.StatusInternalServerError, "%s", err)
}
}
}
func (s *Server) setConfigRestartable(dc dnsConfig) (restart bool) {
func (s *Server) setConfigRestartable(dc *dnsConfig) (restart bool) {
if dc.Upstreams != nil {
s.conf.UpstreamDNS = *dc.Upstreams
restart = true
@@ -273,9 +263,9 @@ func (s *Server) setConfigRestartable(dc dnsConfig) (restart bool) {
restart = true
}
if dc.RateLimit != nil {
restart = restart || s.conf.Ratelimit != *dc.RateLimit
if dc.RateLimit != nil && s.conf.Ratelimit != *dc.RateLimit {
s.conf.Ratelimit = *dc.RateLimit
restart = true
}
if dc.EDNSCSEnabled != nil {
@@ -306,7 +296,7 @@ func (s *Server) setConfigRestartable(dc dnsConfig) (restart bool) {
return restart
}
func (s *Server) setConfig(dc dnsConfig) (restart bool) {
func (s *Server) setConfig(dc *dnsConfig) (restart bool) {
s.serverLock.Lock()
defer s.serverLock.Unlock()
@@ -353,52 +343,117 @@ type upstreamJSON struct {
PrivateUpstreams []string `json:"private_upstream"`
}
// IsCommentOrEmpty returns true of the string starts with a "#" character or is
// an empty string. This function is useful for filtering out non-upstream
// lines from upstream configs.
// IsCommentOrEmpty returns true if s starts with a "#" character or is empty.
// This function is useful for filtering out non-upstream lines from upstream
// configs.
func IsCommentOrEmpty(s string) (ok bool) {
return len(s) == 0 || s[0] == '#'
}
// LocalNetChecker is used to check if the IP address belongs to a local
// network.
type LocalNetChecker interface {
// IsLocallyServedNetwork returns true if ip is contained in any of address
// registries defined by RFC 6303.
IsLocallyServedNetwork(ip net.IP) (ok bool)
}
// type check
var _ LocalNetChecker = (*aghnet.SubnetDetector)(nil)
// newUpstreamConfig validates upstreams and returns an appropriate upstream
// configuration or nil if it can't be built.
//
// TODO(e.burkov): Perhaps proxy.ParseUpstreamsConfig should validate upstreams
// slice already so that this function may be considered useless.
func newUpstreamConfig(upstreams []string) (conf *proxy.UpstreamConfig, err error) {
// No need to validate comments and empty lines.
upstreams = stringutil.FilterOut(upstreams, IsCommentOrEmpty)
if len(upstreams) == 0 {
// Consider this case valid since it means the default server should be
// used.
return nil, nil
}
conf, err = proxy.ParseUpstreamsConfig(
upstreams,
&upstream.Options{Bootstrap: []string{}, Timeout: DefaultTimeout},
)
if err != nil {
return nil, err
} else if len(conf.Upstreams) == 0 {
return nil, errors.Error("no default upstreams specified")
}
for _, u := range upstreams {
_, err = validateUpstream(u)
if err != nil {
return nil, err
}
}
return conf, nil
}
// ValidateUpstreams validates each upstream and returns an error if any
// upstream is invalid or if there are no default upstreams specified.
//
// TODO(e.burkov): Move into aghnet or even into dnsproxy.
// TODO(e.burkov): Move into aghnet or even into dnsproxy.
func ValidateUpstreams(upstreams []string) (err error) {
// No need to validate comments
upstreams = stringutil.FilterOut(upstreams, IsCommentOrEmpty)
_, err = newUpstreamConfig(upstreams)
// Consider this case valid because defaultDNS will be used
if len(upstreams) == 0 {
return nil
return err
}
// stringKeysSorted returns the sorted slice of string keys of m.
//
// TODO(e.burkov): Use generics in Go 1.18. Move into golibs.
func stringKeysSorted(m map[string][]upstream.Upstream) (sorted []string) {
sorted = make([]string, 0, len(m))
for s := range m {
sorted = append(sorted, s)
}
_, err = proxy.ParseUpstreamsConfig(
upstreams,
&upstream.Options{
Bootstrap: []string{},
Timeout: DefaultTimeout,
},
)
sort.Strings(sorted)
return sorted
}
// ValidateUpstreamsPrivate validates each upstream and returns an error if any
// upstream is invalid or if there are no default upstreams specified. It also
// checks each domain of domain-specific upstreams for being ARPA pointing to
// a locally-served network. lnc must not be nil.
func ValidateUpstreamsPrivate(upstreams []string, lnc LocalNetChecker) (err error) {
conf, err := newUpstreamConfig(upstreams)
if err != nil {
return err
}
var defaultUpstreamFound bool
for _, u := range upstreams {
var useDefault bool
useDefault, err = validateUpstream(u)
if conf == nil {
return nil
}
var errs []error
for _, domain := range stringKeysSorted(conf.DomainReservedUpstreams) {
var subnet *net.IPNet
subnet, err = netutil.SubnetFromReversedAddr(domain)
if err != nil {
return err
errs = append(errs, err)
continue
}
if !defaultUpstreamFound {
defaultUpstreamFound = useDefault
if !lnc.IsLocallyServedNetwork(subnet.IP) {
errs = append(
errs,
fmt.Errorf("arpa domain %q should point to a locally-served network", domain),
)
}
}
if !defaultUpstreamFound {
return fmt.Errorf("no default upstreams specified")
if len(errs) > 0 {
return errors.List("checking domain-specific upstreams", errs...)
}
return nil