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Pull request: all: imp dhcp client hostname normalization

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Updates #2952.
Updates #2978.

Squashed commit of the following:

commit 20e379b94ccf8140fd9056429315945c17f711a5
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 19 15:58:37 2021 +0300

    all: imp naming

commit ed300e0563fa37e161406a97991b26a89e23903a
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 19 15:43:09 2021 +0300

    all: imp dhcp client hostname normalization
This commit is contained in:
Ainar Garipov 2021-04-19 16:04:40 +03:00
parent 91304663b7
commit d707f8b1d1
6 changed files with 127 additions and 73 deletions
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3
CHANGELOG.md
View File

@ -33,7 +33,7 @@ and this project adheres to
### Changed
- Quality of logging ([#2954]).
- Normalization of hostnames with spaces sent by DHCP clients ([#2945]).
- Normalization of hostnames sent by DHCP clients ([#2945], [#2952]).
- The access to the private hosts is now forbidden for users from external
networks ([#2889]).
- The reverse lookup for local addresses is now performed via local resolvers
@ -82,6 +82,7 @@ and this project adheres to
[#2934]: https://github.com/AdguardTeam/AdGuardHome/issues/2934
[#2945]: https://github.com/AdguardTeam/AdGuardHome/issues/2945
[#2947]: https://github.com/AdguardTeam/AdGuardHome/issues/2947
[#2952]: https://github.com/AdguardTeam/AdGuardHome/issues/2952
[#2954]: https://github.com/AdguardTeam/AdGuardHome/issues/2954
[#2961]: https://github.com/AdguardTeam/AdGuardHome/issues/2961

49
internal/aghnet/addr.go
View File

@ -10,6 +10,19 @@ import (
"golang.org/x/net/idna"
)
// IsValidHostOuterRune returns true if r is a valid initial or final rune for
// a hostname label.
func IsValidHostOuterRune(r rune) (ok bool) {
return (r >= 'a' && r <= 'z') ||
(r >= 'A' && r <= 'Z') ||
(r >= '0' && r <= '9')
}
// isValidHostRune returns true if r is a valid rune for a hostname label.
func isValidHostRune(r rune) (ok bool) {
return r == '-' || IsValidHostOuterRune(r)
}
// ValidateHardwareAddress returns an error if hwa is not a valid EUI-48,
// EUI-64, or 20-octet InfiniBand link-layer address.
func ValidateHardwareAddress(hwa net.HardwareAddr) (err error) {
@ -37,38 +50,32 @@ const maxDomainNameLen = 253
const invalidCharMsg = "invalid char %q at index %d in %q"
// isValidHostFirstRune returns true if r is a valid first rune for a hostname
// label.
func isValidHostFirstRune(r rune) (ok bool) {
return (r >= 'a' && r <= 'z') ||
(r >= 'A' && r <= 'Z') ||
(r >= '0' && r <= '9')
}
// isValidHostRune returns true if r is a valid rune for a hostname label.
func isValidHostRune(r rune) (ok bool) {
return r == '-' || isValidHostFirstRune(r)
}
// ValidateDomainNameLabel returns an error if label is not a valid label of
// a domain name.
func ValidateDomainNameLabel(label string) (err error) {
if len(label) > maxDomainLabelLen {
l := len(label)
if l > maxDomainLabelLen {
return fmt.Errorf("%q is too long, max: %d", label, maxDomainLabelLen)
} else if len(label) == 0 {
} else if l == 0 {
return agherr.Error("label is empty")
}
if r := label[0]; !isValidHostFirstRune(rune(r)) {
if r := label[0]; !IsValidHostOuterRune(rune(r)) {
return fmt.Errorf(invalidCharMsg, r, 0, label)
} else if l == 1 {
return nil
}
for i, r := range label[1:] {
for i, r := range label[1 : l-1] {
if !isValidHostRune(r) {
return fmt.Errorf(invalidCharMsg, r, i+1, label)
}
}
if r := label[l-1]; !IsValidHostOuterRune(rune(r)) {
return fmt.Errorf(invalidCharMsg, r, l-1, label)
}
return nil
}
@ -86,7 +93,9 @@ func ValidateDomainName(name string) (err error) {
}
l := len(name)
if l == 0 || l > maxDomainNameLen {
if l == 0 {
return agherr.Error("domain name is empty")
} else if l > maxDomainNameLen {
return fmt.Errorf("%q is too long, max: %d", name, maxDomainNameLen)
}
@ -138,7 +147,7 @@ func generateIPv6Hostname(ipv6 net.IP) (hostname string) {
return string(hnData)
}
// GenerateHostName generates the hostname from ip. In case of using IPv4 the
// GenerateHostname generates the hostname from ip. In case of using IPv4 the
// result should be like:
//
// 192-168-10-1
@ -147,7 +156,7 @@ func generateIPv6Hostname(ipv6 net.IP) (hostname string) {
//
// ff80-f076-0000-0000-0000-0000-0000-0010
//
func GenerateHostName(ip net.IP) (hostname string) {
func GenerateHostname(ip net.IP) (hostname string) {
if ipv4 := ip.To4(); ipv4 != nil {
return generateIPv4Hostname(ipv4)
} else if ipv6 := ip.To16(); ipv6 != nil {

15
internal/aghnet/addr_test.go
View File

@ -88,6 +88,14 @@ func TestValidateDomainName(t *testing.T) {
name: "success_idna",
in: "пример.рф",
wantErrMsg: "",
}, {
name: "success_one",
in: "e",
wantErrMsg: "",
}, {
name: "empty",
in: "",
wantErrMsg: `domain name is empty`,
}, {
name: "bad_symbol",
in: "!!!",
@ -111,6 +119,11 @@ func TestValidateDomainName(t *testing.T) {
in: "example.-aa.com",
wantErrMsg: `invalid domain name label at index 1:` +
` invalid char '-' at index 0 in "-aa"`,
}, {
name: "bad_label_last_symbol",
in: "example-.aa.com",
wantErrMsg: `invalid domain name label at index 0:` +
` invalid char '-' at index 7 in "example-"`,
}, {
name: "bad_label_symbol",
in: "example.a!!!.com",
@ -166,7 +179,7 @@ func TestGenerateHostName(t *testing.T) {
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
hostname := GenerateHostName(tc.ip)
hostname := GenerateHostname(tc.ip)
assert.Equal(t, tc.want, hostname)
})
}

66
internal/dhcpd/v4.go
View File

@ -558,34 +558,45 @@ func (o *optFQDN) ToBytes() []byte {
return b
}
// normalizeHostname normalizes and validates a hostname sent by the client.
//
// TODO(a.garipov): Add client hostname uniqueness validations and rename the
// method to validateHostname.
func (s *v4Server) normalizeHostname(name string) (norm string, err error) {
// normalizeHostname normalizes a hostname sent by the client.
func normalizeHostname(name string) (norm string, err error) {
if name == "" {
return "", nil
}
// Some devices send hostnames with spaces, but we still want to accept
// them, so replace them with dashes and issue a warning.
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/2946.
norm = strings.ReplaceAll(name, " ", "-")
state := "non-normalized"
if name != norm {
log.Debug("dhcpv4: normalized hostname %q into %q", name, norm)
state = "normalized"
parts := strings.FieldsFunc(name, func(c rune) (ok bool) {
return c != '.' && !aghnet.IsValidHostOuterRune(c)
})
if len(parts) == 0 {
return "", fmt.Errorf("normalizing hostname %q: no valid parts", name)
}
err = aghnet.ValidateDomainName(norm)
if err != nil {
return "", fmt.Errorf("validating %s hostname: %w", state, err)
}
norm = strings.Join(parts, "-")
norm = strings.TrimSuffix(norm, "-")
return norm, nil
}
// validateHostname validates a hostname sent by the client.
func (s *v4Server) validateHostname(name string) (err error) {
if name == "" {
return nil
}
err = aghnet.ValidateDomainName(name)
if err != nil {
return fmt.Errorf("validating hostname: %w", err)
}
// TODO(a.garipov): Add client hostname uniqueness validation either
// here or into method processRequest. This is not as easy as it might
// look like, because the process of adding and releasing a lease is
// currently non-straightforward.
return nil
}
// Process Request request and return lease
// Return false if we don't need to reply
func (s *v4Server) processRequest(req, resp *dhcpv4.DHCPv4) (lease *Lease, ok bool) {
@ -634,16 +645,29 @@ func (s *v4Server) processRequest(req, resp *dhcpv4.DHCPv4) (lease *Lease, ok bo
}
if !lease.IsStatic() {
cliHostname := req.HostName()
var hostname string
hostname, err = s.normalizeHostname(req.HostName())
hostname, err = normalizeHostname(cliHostname)
if err != nil {
log.Error("dhcpv4: cannot normalize hostname for %s: %s", mac, err)
return nil, false
// Go on and assign a hostname made from the IP.
}
if hostname != "" && cliHostname != hostname {
log.Debug("dhcpv4: normalized hostname %q into %q", cliHostname, hostname)
}
err = s.validateHostname(hostname)
if err != nil {
log.Error("dhcpv4: validating hostname for %s: %s", mac, err)
// Go on and assign a hostname made from the IP.
}
if hostname == "" {
hostname = aghnet.GenerateHostName(reqIP)
hostname = aghnet.GenerateHostname(reqIP)
}
lease.Hostname = hostname

39
internal/dhcpd/v4_test.go
View File

@ -290,7 +290,7 @@ func TestV4DynamicLease_Get(t *testing.T) {
})
}
func TestV4Server_normalizeHostname(t *testing.T) {
func TestNormalizeHostname(t *testing.T) {
testCases := []struct {
name string
hostname string
@ -312,24 +312,35 @@ func TestV4Server_normalizeHostname(t *testing.T) {
wantErrMsg: "",
want: "my-device-01",
}, {
name: "error",
hostname: "!!!",
wantErrMsg: `validating non-normalized hostname: ` +
`invalid domain name label at index 0: ` +
`invalid char '!' at index 0 in "!!!"`,
want: "",
name: "success_underscores",
hostname: "my_device_01",
wantErrMsg: "",
want: "my-device-01",
}, {
name: "error_spaces",
hostname: "! ! !",
wantErrMsg: `validating normalized hostname: ` +
`invalid domain name label at index 0: ` +
`invalid char '!' at index 0 in "!-!-!"`,
want: "",
name: "error_part",
hostname: "device !!!",
wantErrMsg: "",
want: "device",
}, {
name: "error_part_spaces",
hostname: "device ! ! !",
wantErrMsg: "",
want: "device",
}, {
name: "error",
hostname: "!!!",
wantErrMsg: `normalizing hostname "!!!": no valid parts`,
want: "",
}, {
name: "error_spaces",
hostname: "! ! !",
wantErrMsg: `normalizing hostname "! ! !": no valid parts`,
want: "",
}}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
got, err := (&v4Server{}).normalizeHostname(tc.hostname)
got, err := normalizeHostname(tc.hostname)
if tc.wantErrMsg == "" {
assert.NoError(t, err)
} else {

28
internal/dnsforward/dns.go
View File

@ -140,20 +140,6 @@ func processInitial(ctx *dnsContext) (rc resultCode) {
return resultCodeSuccess
}
// Return TRUE if host names doesn't contain disallowed characters
func isHostnameOK(hostname string) bool {
for _, c := range hostname {
if !((c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c >= '0' && c <= '9') ||
c == '.' || c == '-') {
log.Debug("dns: skipping invalid hostname %s from DHCP", hostname)
return false
}
}
return true
}
func (s *Server) setTableHostToIP(t hostToIPTable) {
s.tableHostToIPLock.Lock()
defer s.tableHostToIPLock.Unlock()
@ -169,6 +155,8 @@ func (s *Server) setTableIPToHost(t ipToHostTable) {
}
func (s *Server) onDHCPLeaseChanged(flags int) {
var err error
add := true
switch flags {
case dhcpd.LeaseChangedAdded,
@ -190,8 +178,16 @@ func (s *Server) onDHCPLeaseChanged(flags int) {
ll := s.dhcpServer.Leases(dhcpd.LeasesAll)
for _, l := range ll {
if len(l.Hostname) == 0 || !isHostnameOK(l.Hostname) {
continue
// TODO(a.garipov): Remove this after we're finished
// with the client hostname validations in the DHCP
// server code.
err = aghnet.ValidateDomainName(l.Hostname)
if err != nil {
log.Debug(
"dns: skipping invalid hostname %q from dhcp: %s",
l.Hostname,
err,
)
}
lowhost := strings.ToLower(l.Hostname)