AdGuardHome/internal/aghnet/addr.go
Ainar Garipov c133b01ef7 Pull request: all: add idna handling, imp domain validation
Updates #2915.

Squashed commit of the following:

commit b907324426c87ee7334edbd61e43c44444ad27a9
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Apr 7 16:26:41 2021 +0300

    all: imp docs, upd

commit c022f75cac006e077095cad283fea0a91d3a0eea
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Apr 7 15:51:30 2021 +0300

    all: add idna handling, imp domain validation
2021-04-07 16:36:38 +03:00

101 lines
2.6 KiB
Go

package aghnet
import (
"fmt"
"net"
"strings"
"github.com/AdguardTeam/AdGuardHome/internal/agherr"
"golang.org/x/net/idna"
)
// 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) {
defer agherr.Annotate("validating hardware address %q: %w", &err, hwa)
switch l := len(hwa); l {
case 0:
return agherr.Error("address is empty")
case 6, 8, 20:
return nil
default:
return fmt.Errorf("bad len: %d", l)
}
}
// maxDomainLabelLen is the maximum allowed length of a domain name label
// according to RFC 1035.
const maxDomainLabelLen = 63
// maxDomainNameLen is the maximum allowed length of a full domain name
// according to RFC 1035.
//
// See https://stackoverflow.com/a/32294443/1892060.
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 {
return fmt.Errorf("%q is too long, max: %d", label, maxDomainLabelLen)
} else if len(label) == 0 {
return agherr.Error("label is empty")
}
if r := label[0]; !isValidHostFirstRune(rune(r)) {
return fmt.Errorf(invalidCharMsg, r, 0, label)
}
for i, r := range label[1:] {
if !isValidHostRune(r) {
return fmt.Errorf(invalidCharMsg, r, i+1, label)
}
}
return nil
}
// ValidateDomainName validates the domain name in accordance to RFC 952, RFC
// 1035, and with RFC-1123's inclusion of digits at the start of the host. It
// doesn't validate against two or more hyphens to allow punycode and
// internationalized domains.
//
// TODO(a.garipov): After making sure that this works correctly, port this into
// module golibs.
func ValidateDomainName(name string) (err error) {
name, err = idna.ToASCII(name)
if err != nil {
return err
}
l := len(name)
if l == 0 || l > maxDomainNameLen {
return fmt.Errorf("%q is too long, max: %d", name, maxDomainNameLen)
}
labels := strings.Split(name, ".")
for i, l := range labels {
err = ValidateDomainNameLabel(l)
if err != nil {
return fmt.Errorf("invalid domain name label at index %d: %w", i, err)
}
}
return nil
}