102 lines
2.6 KiB
Go
102 lines
2.6 KiB
Go
package aghnet
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import (
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"fmt"
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"net"
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"strings"
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"github.com/AdguardTeam/AdGuardHome/internal/agherr"
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"golang.org/x/net/idna"
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)
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// ValidateHardwareAddress returns an error if hwa is not a valid EUI-48,
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// EUI-64, or 20-octet InfiniBand link-layer address.
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func ValidateHardwareAddress(hwa net.HardwareAddr) (err error) {
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defer agherr.Annotate("validating hardware address %q: %w", &err, hwa)
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switch l := len(hwa); l {
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case 0:
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return agherr.Error("address is empty")
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case 6, 8, 20:
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return nil
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default:
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return fmt.Errorf("bad len: %d", l)
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}
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}
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// maxDomainLabelLen is the maximum allowed length of a domain name label
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// according to RFC 1035.
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const maxDomainLabelLen = 63
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// maxDomainNameLen is the maximum allowed length of a full domain name
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// according to RFC 1035.
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//
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// See https://stackoverflow.com/a/32294443/1892060.
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const maxDomainNameLen = 253
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const invalidCharMsg = "invalid char %q at index %d in %q"
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// isValidHostFirstRune returns true if r is a valid first rune for a hostname
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// label.
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func isValidHostFirstRune(r rune) (ok bool) {
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return (r >= 'a' && r <= 'z') ||
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(r >= 'A' && r <= 'Z') ||
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(r >= '0' && r <= '9')
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}
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// isValidHostRune returns true if r is a valid rune for a hostname label.
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func isValidHostRune(r rune) (ok bool) {
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return r == '-' || isValidHostFirstRune(r)
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}
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// ValidateDomainNameLabel returns an error if label is not a valid label of
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// a domain name.
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func ValidateDomainNameLabel(label string) (err error) {
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if len(label) > maxDomainLabelLen {
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return fmt.Errorf("%q is too long, max: %d", label, maxDomainLabelLen)
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} else if len(label) == 0 {
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return agherr.Error("label is empty")
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}
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if r := label[0]; !isValidHostFirstRune(rune(r)) {
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return fmt.Errorf(invalidCharMsg, r, 0, label)
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}
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for i, r := range label[1:] {
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if !isValidHostRune(r) {
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return fmt.Errorf(invalidCharMsg, r, i+1, label)
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}
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}
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return nil
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}
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// ValidateDomainName validates the domain name in accordance to RFC 952, RFC
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// 1035, and with RFC-1123's inclusion of digits at the start of the host. It
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// doesn't validate against two or more hyphens to allow punycode and
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// internationalized domains.
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//
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// TODO(a.garipov): After making sure that this works correctly, port this into
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// module golibs.
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func ValidateDomainName(name string) (err error) {
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name, err = idna.ToASCII(name)
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if err != nil {
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return err
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}
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l := len(name)
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if l == 0 || l > maxDomainNameLen {
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return fmt.Errorf("%q is too long, max: %d", name, maxDomainNameLen)
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}
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labels := strings.Split(name, ".")
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for i, l := range labels {
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err = ValidateDomainNameLabel(l)
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if err != nil {
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return fmt.Errorf("invalid domain name label at index %d: %w", i, err)
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}
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}
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return nil
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}
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