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all: sync with master; upd chlog

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This commit is contained in:
Ainar Garipov
2023-04-12 14:48:42 +03:00
parent 0dad53b5f7
commit d9c57cdd9a
181 changed files with 6992 additions and 3430 deletions
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144
internal/dnsforward/dns.go
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@@ -4,6 +4,7 @@ import (
"encoding/binary"
"net"
"net/netip"
"strconv"
"strings"
"time"
@@ -21,7 +22,7 @@ import (
// To transfer information between modules
//
// TODO(s.chzhen): Add lowercased, non-FQDN version of the hostname from the
// question of the request.
// question of the request. Add persistent client.
type dnsContext struct {
proxyCtx *proxy.DNSContext
@@ -37,6 +38,8 @@ type dnsContext struct {
// was parsed successfully and belongs to one of the locally served IP
// ranges. It is also filled with unmapped version of the address if it's
// within DNS64 prefixes.
//
// TODO(e.burkov): Use netip.Addr when we switch to netip more fully.
unreversedReqIP net.IP
// err is the error returned from a processing function.
@@ -181,6 +184,21 @@ func (s *Server) processInitial(dctx *dnsContext) (rc resultCode) {
return resultCodeFinish
}
// Handle a reserved domain healthcheck.adguardhome.test.
//
// [Section 6.2 of RFC 6761] states that DNS Registries/Registrars must not
// grant requests to register test names in the normal way to any person or
// entity, making domain names under test. TLD free to use in internal
// purposes.
//
// [Section 6.2 of RFC 6761]: https://www.rfc-editor.org/rfc/rfc6761.html#section-6.2
if q.Name == "healthcheck.adguardhome.test." {
// Generate a NODATA negative response to make nslookup exit with 0.
pctx.Res = s.makeResponse(pctx.Req)
return resultCodeFinish
}
// Get the ClientID, if any, before getting client-specific filtering
// settings.
var key [8]byte
@@ -188,7 +206,7 @@ func (s *Server) processInitial(dctx *dnsContext) (rc resultCode) {
dctx.clientID = string(s.clientIDCache.Get(key[:]))
// Get the client-specific filtering settings.
dctx.protectionEnabled = s.conf.ProtectionEnabled
dctx.protectionEnabled, _ = s.UpdatedProtectionStatus()
dctx.setts = s.getClientRequestFilteringSettings(dctx)
return resultCodeSuccess
@@ -240,17 +258,16 @@ func (s *Server) onDHCPLeaseChanged(flags int) {
lowhost := strings.ToLower(l.Hostname + "." + s.localDomainSuffix)
// Assume that we only process IPv4 now.
//
// TODO(a.garipov): Remove once we switch to netip.Addr more fully.
ip, err := netutil.IPToAddr(l.IP, netutil.AddrFamilyIPv4)
if err != nil {
log.Debug("dnsforward: skipping invalid ip %v from dhcp: %s", l.IP, err)
if !l.IP.Is4() {
log.Debug("dnsforward: skipping invalid ip from dhcp: bad ipv4 net.IP %v", l.IP)
continue
}
ipToHost[ip] = lowhost
hostToIP[lowhost] = ip
leaseIP := l.IP
ipToHost[leaseIP] = lowhost
hostToIP[lowhost] = leaseIP
}
s.setTableHostToIP(hostToIP)
@@ -442,6 +459,88 @@ func (s *Server) processDHCPHosts(dctx *dnsContext) (rc resultCode) {
return resultCodeSuccess
}
// indexFirstV4Label returns the index at which the reversed IPv4 address
// starts, assuming the domain is pre-validated ARPA domain having in-addr and
// arpa labels removed.
func indexFirstV4Label(domain string) (idx int) {
idx = len(domain)
for labelsNum := 0; labelsNum < net.IPv4len && idx > 0; labelsNum++ {
curIdx := strings.LastIndexByte(domain[:idx-1], '.') + 1
_, parseErr := strconv.ParseUint(domain[curIdx:idx-1], 10, 8)
if parseErr != nil {
return idx
}
idx = curIdx
}
return idx
}
// indexFirstV6Label returns the index at which the reversed IPv6 address
// starts, assuming the domain is pre-validated ARPA domain having ip6 and arpa
// labels removed.
func indexFirstV6Label(domain string) (idx int) {
idx = len(domain)
for labelsNum := 0; labelsNum < net.IPv6len*2 && idx > 0; labelsNum++ {
curIdx := idx - len("a.")
if curIdx > 1 && domain[curIdx-1] != '.' {
return idx
}
nibble := domain[curIdx]
if (nibble < '0' || nibble > '9') && (nibble < 'a' || nibble > 'f') {
return idx
}
idx = curIdx
}
return idx
}
// extractARPASubnet tries to convert a reversed ARPA address being a part of
// domain to an IP network. domain must be an FQDN.
//
// TODO(e.burkov): Move to golibs.
func extractARPASubnet(domain string) (pref netip.Prefix, err error) {
err = netutil.ValidateDomainName(strings.TrimSuffix(domain, "."))
if err != nil {
// Don't wrap the error since it's informative enough as is.
return netip.Prefix{}, err
}
const (
v4Suffix = "in-addr.arpa."
v6Suffix = "ip6.arpa."
)
domain = strings.ToLower(domain)
var idx int
switch {
case strings.HasSuffix(domain, v4Suffix):
idx = indexFirstV4Label(domain[:len(domain)-len(v4Suffix)])
case strings.HasSuffix(domain, v6Suffix):
idx = indexFirstV6Label(domain[:len(domain)-len(v6Suffix)])
default:
return netip.Prefix{}, &netutil.AddrError{
Err: netutil.ErrNotAReversedSubnet,
Kind: netutil.AddrKindARPA,
Addr: domain,
}
}
var subnet *net.IPNet
subnet, err = netutil.SubnetFromReversedAddr(domain[idx:])
if err != nil {
// Don't wrap the error since it's informative enough as is.
return netip.Prefix{}, err
}
return netutil.IPNetToPrefixNoMapped(subnet)
}
// processRestrictLocal responds with NXDOMAIN to PTR requests for IP addresses
// in locally served network from external clients.
func (s *Server) processRestrictLocal(dctx *dnsContext) (rc resultCode) {
@@ -453,34 +552,29 @@ func (s *Server) processRestrictLocal(dctx *dnsContext) (rc resultCode) {
return resultCodeSuccess
}
ip, err := netutil.IPFromReversedAddr(q.Name)
subnet, err := extractARPASubnet(q.Name)
if err != nil {
log.Debug("dnsforward: parsing reversed addr: %s", err)
if errors.Is(err, netutil.ErrNotAReversedSubnet) {
log.Debug("dnsforward: request is not for arpa domain")
// DNS-Based Service Discovery uses PTR records having not an ARPA
// format of the domain name in question. Those shouldn't be
// invalidated. See http://www.dns-sd.org/ServerStaticSetup.html and
// RFC 2782.
name := strings.TrimSuffix(q.Name, ".")
if err = netutil.ValidateSRVDomainName(name); err != nil {
log.Debug("dnsforward: validating service domain: %s", err)
return resultCodeError
return resultCodeSuccess
}
log.Debug("dnsforward: request is not for arpa domain")
log.Debug("dnsforward: parsing reversed addr: %s", err)
return resultCodeSuccess
return resultCodeError
}
// 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
// shouldn't be accessible externally.
if !s.privateNets.Contains(ip) {
subnetAddr := subnet.Addr()
addrData := subnetAddr.AsSlice()
if !s.privateNets.Contains(addrData) {
return resultCodeSuccess
}
log.Debug("dnsforward: addr %s is from locally served network", ip)
log.Debug("dnsforward: addr %s is from locally served network", subnetAddr)
if !dctx.isLocalClient {
log.Debug("dnsforward: %q requests an internal ip", pctx.Addr)
@@ -491,7 +585,7 @@ func (s *Server) processRestrictLocal(dctx *dnsContext) (rc resultCode) {
}
// Do not perform unreversing ever again.
dctx.unreversedReqIP = ip
dctx.unreversedReqIP = addrData
// There is no need to filter request from external addresses since this
// code is only executed when the request is for locally served ARPA