435c0d9fc8
This PR switches the Nomad repository from using govendor to Go modules for managing dependencies. Aspects of the Nomad workflow remain pretty much the same. The usual Makefile targets should continue to work as they always did. The API submodule simply defers to the parent Nomad version on the repository, keeping the semantics of API versioning that currently exists.
691 lines
18 KiB
Go
691 lines
18 KiB
Go
package dns
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import (
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"encoding/base32"
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"encoding/base64"
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"encoding/binary"
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"encoding/hex"
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"net"
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"strings"
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)
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// helper functions called from the generated zmsg.go
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// These function are named after the tag to help pack/unpack, if there is no tag it is the name
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// of the type they pack/unpack (string, int, etc). We prefix all with unpackData or packData, so packDataA or
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// packDataDomainName.
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func unpackDataA(msg []byte, off int) (net.IP, int, error) {
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if off+net.IPv4len > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking a"}
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}
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a := append(make(net.IP, 0, net.IPv4len), msg[off:off+net.IPv4len]...)
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off += net.IPv4len
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return a, off, nil
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}
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func packDataA(a net.IP, msg []byte, off int) (int, error) {
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switch len(a) {
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case net.IPv4len, net.IPv6len:
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// It must be a slice of 4, even if it is 16, we encode only the first 4
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if off+net.IPv4len > len(msg) {
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return len(msg), &Error{err: "overflow packing a"}
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}
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copy(msg[off:], a.To4())
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off += net.IPv4len
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case 0:
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// Allowed, for dynamic updates.
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default:
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return len(msg), &Error{err: "overflow packing a"}
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}
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return off, nil
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}
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func unpackDataAAAA(msg []byte, off int) (net.IP, int, error) {
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if off+net.IPv6len > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking aaaa"}
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}
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aaaa := append(make(net.IP, 0, net.IPv6len), msg[off:off+net.IPv6len]...)
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off += net.IPv6len
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return aaaa, off, nil
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}
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func packDataAAAA(aaaa net.IP, msg []byte, off int) (int, error) {
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switch len(aaaa) {
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case net.IPv6len:
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if off+net.IPv6len > len(msg) {
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return len(msg), &Error{err: "overflow packing aaaa"}
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}
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copy(msg[off:], aaaa)
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off += net.IPv6len
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case 0:
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// Allowed, dynamic updates.
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default:
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return len(msg), &Error{err: "overflow packing aaaa"}
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}
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return off, nil
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}
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// unpackHeader unpacks an RR header, returning the offset to the end of the header and a
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// re-sliced msg according to the expected length of the RR.
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func unpackHeader(msg []byte, off int) (rr RR_Header, off1 int, truncmsg []byte, err error) {
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hdr := RR_Header{}
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if off == len(msg) {
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return hdr, off, msg, nil
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}
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hdr.Name, off, err = UnpackDomainName(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Rrtype, off, err = unpackUint16(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Class, off, err = unpackUint16(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Ttl, off, err = unpackUint32(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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hdr.Rdlength, off, err = unpackUint16(msg, off)
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if err != nil {
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return hdr, len(msg), msg, err
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}
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msg, err = truncateMsgFromRdlength(msg, off, hdr.Rdlength)
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return hdr, off, msg, err
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}
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// packHeader packs an RR header, returning the offset to the end of the header.
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// See PackDomainName for documentation about the compression.
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func (hdr RR_Header) packHeader(msg []byte, off int, compression compressionMap, compress bool) (int, error) {
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if off == len(msg) {
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return off, nil
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}
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off, err := packDomainName(hdr.Name, msg, off, compression, compress)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint16(hdr.Rrtype, msg, off)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint16(hdr.Class, msg, off)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint32(hdr.Ttl, msg, off)
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if err != nil {
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return len(msg), err
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}
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off, err = packUint16(0, msg, off) // The RDLENGTH field will be set later in packRR.
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if err != nil {
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return len(msg), err
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}
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return off, nil
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}
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// helper helper functions.
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// truncateMsgFromRdLength truncates msg to match the expected length of the RR.
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// Returns an error if msg is smaller than the expected size.
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func truncateMsgFromRdlength(msg []byte, off int, rdlength uint16) (truncmsg []byte, err error) {
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lenrd := off + int(rdlength)
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if lenrd > len(msg) {
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return msg, &Error{err: "overflowing header size"}
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}
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return msg[:lenrd], nil
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}
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var base32HexNoPadEncoding = base32.HexEncoding.WithPadding(base32.NoPadding)
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func fromBase32(s []byte) (buf []byte, err error) {
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for i, b := range s {
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if b >= 'a' && b <= 'z' {
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s[i] = b - 32
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}
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}
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buflen := base32HexNoPadEncoding.DecodedLen(len(s))
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buf = make([]byte, buflen)
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n, err := base32HexNoPadEncoding.Decode(buf, s)
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buf = buf[:n]
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return
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}
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func toBase32(b []byte) string {
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return base32HexNoPadEncoding.EncodeToString(b)
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}
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func fromBase64(s []byte) (buf []byte, err error) {
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buflen := base64.StdEncoding.DecodedLen(len(s))
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buf = make([]byte, buflen)
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n, err := base64.StdEncoding.Decode(buf, s)
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buf = buf[:n]
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return
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}
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func toBase64(b []byte) string { return base64.StdEncoding.EncodeToString(b) }
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// dynamicUpdate returns true if the Rdlength is zero.
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func noRdata(h RR_Header) bool { return h.Rdlength == 0 }
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func unpackUint8(msg []byte, off int) (i uint8, off1 int, err error) {
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if off+1 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint8"}
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}
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return msg[off], off + 1, nil
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}
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func packUint8(i uint8, msg []byte, off int) (off1 int, err error) {
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if off+1 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint8"}
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}
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msg[off] = i
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return off + 1, nil
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}
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func unpackUint16(msg []byte, off int) (i uint16, off1 int, err error) {
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if off+2 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint16"}
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}
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return binary.BigEndian.Uint16(msg[off:]), off + 2, nil
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}
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func packUint16(i uint16, msg []byte, off int) (off1 int, err error) {
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if off+2 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint16"}
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}
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binary.BigEndian.PutUint16(msg[off:], i)
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return off + 2, nil
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}
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func unpackUint32(msg []byte, off int) (i uint32, off1 int, err error) {
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if off+4 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint32"}
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}
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return binary.BigEndian.Uint32(msg[off:]), off + 4, nil
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}
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func packUint32(i uint32, msg []byte, off int) (off1 int, err error) {
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if off+4 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint32"}
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}
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binary.BigEndian.PutUint32(msg[off:], i)
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return off + 4, nil
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}
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func unpackUint48(msg []byte, off int) (i uint64, off1 int, err error) {
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if off+6 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint64 as uint48"}
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}
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// Used in TSIG where the last 48 bits are occupied, so for now, assume a uint48 (6 bytes)
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i = uint64(msg[off])<<40 | uint64(msg[off+1])<<32 | uint64(msg[off+2])<<24 | uint64(msg[off+3])<<16 |
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uint64(msg[off+4])<<8 | uint64(msg[off+5])
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off += 6
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return i, off, nil
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}
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func packUint48(i uint64, msg []byte, off int) (off1 int, err error) {
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if off+6 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint64 as uint48"}
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}
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msg[off] = byte(i >> 40)
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msg[off+1] = byte(i >> 32)
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msg[off+2] = byte(i >> 24)
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msg[off+3] = byte(i >> 16)
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msg[off+4] = byte(i >> 8)
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msg[off+5] = byte(i)
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off += 6
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return off, nil
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}
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func unpackUint64(msg []byte, off int) (i uint64, off1 int, err error) {
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if off+8 > len(msg) {
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return 0, len(msg), &Error{err: "overflow unpacking uint64"}
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}
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return binary.BigEndian.Uint64(msg[off:]), off + 8, nil
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}
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func packUint64(i uint64, msg []byte, off int) (off1 int, err error) {
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if off+8 > len(msg) {
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return len(msg), &Error{err: "overflow packing uint64"}
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}
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binary.BigEndian.PutUint64(msg[off:], i)
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off += 8
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return off, nil
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}
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func unpackString(msg []byte, off int) (string, int, error) {
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if off+1 > len(msg) {
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return "", off, &Error{err: "overflow unpacking txt"}
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}
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l := int(msg[off])
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off++
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if off+l > len(msg) {
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return "", off, &Error{err: "overflow unpacking txt"}
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}
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var s strings.Builder
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consumed := 0
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for i, b := range msg[off : off+l] {
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switch {
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case b == '"' || b == '\\':
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if consumed == 0 {
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s.Grow(l * 2)
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}
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s.Write(msg[off+consumed : off+i])
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s.WriteByte('\\')
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s.WriteByte(b)
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consumed = i + 1
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case b < ' ' || b > '~': // unprintable
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if consumed == 0 {
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s.Grow(l * 2)
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}
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s.Write(msg[off+consumed : off+i])
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s.WriteString(escapeByte(b))
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consumed = i + 1
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}
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}
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if consumed == 0 { // no escaping needed
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return string(msg[off : off+l]), off + l, nil
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}
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s.Write(msg[off+consumed : off+l])
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return s.String(), off + l, nil
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}
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func packString(s string, msg []byte, off int) (int, error) {
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txtTmp := make([]byte, 256*4+1)
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off, err := packTxtString(s, msg, off, txtTmp)
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if err != nil {
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return len(msg), err
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}
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return off, nil
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}
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func unpackStringBase32(msg []byte, off, end int) (string, int, error) {
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking base32"}
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}
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s := toBase32(msg[off:end])
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return s, end, nil
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}
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func packStringBase32(s string, msg []byte, off int) (int, error) {
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b32, err := fromBase32([]byte(s))
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if err != nil {
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return len(msg), err
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}
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if off+len(b32) > len(msg) {
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return len(msg), &Error{err: "overflow packing base32"}
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}
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copy(msg[off:off+len(b32)], b32)
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off += len(b32)
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return off, nil
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}
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func unpackStringBase64(msg []byte, off, end int) (string, int, error) {
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// Rest of the RR is base64 encoded value, so we don't need an explicit length
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// to be set. Thus far all RR's that have base64 encoded fields have those as their
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// last one. What we do need is the end of the RR!
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking base64"}
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}
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s := toBase64(msg[off:end])
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return s, end, nil
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}
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func packStringBase64(s string, msg []byte, off int) (int, error) {
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b64, err := fromBase64([]byte(s))
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if err != nil {
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return len(msg), err
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}
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if off+len(b64) > len(msg) {
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return len(msg), &Error{err: "overflow packing base64"}
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}
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copy(msg[off:off+len(b64)], b64)
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off += len(b64)
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return off, nil
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}
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func unpackStringHex(msg []byte, off, end int) (string, int, error) {
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// Rest of the RR is hex encoded value, so we don't need an explicit length
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// to be set. NSEC and TSIG have hex fields with a length field.
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// What we do need is the end of the RR!
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking hex"}
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}
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s := hex.EncodeToString(msg[off:end])
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return s, end, nil
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}
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func packStringHex(s string, msg []byte, off int) (int, error) {
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h, err := hex.DecodeString(s)
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if err != nil {
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return len(msg), err
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}
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if off+len(h) > len(msg) {
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return len(msg), &Error{err: "overflow packing hex"}
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}
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copy(msg[off:off+len(h)], h)
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off += len(h)
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return off, nil
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}
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func unpackStringAny(msg []byte, off, end int) (string, int, error) {
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if end > len(msg) {
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return "", len(msg), &Error{err: "overflow unpacking anything"}
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}
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return string(msg[off:end]), end, nil
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}
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func packStringAny(s string, msg []byte, off int) (int, error) {
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if off+len(s) > len(msg) {
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return len(msg), &Error{err: "overflow packing anything"}
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}
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copy(msg[off:off+len(s)], s)
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off += len(s)
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return off, nil
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}
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func unpackStringTxt(msg []byte, off int) ([]string, int, error) {
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txt, off, err := unpackTxt(msg, off)
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if err != nil {
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return nil, len(msg), err
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}
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return txt, off, nil
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}
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func packStringTxt(s []string, msg []byte, off int) (int, error) {
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txtTmp := make([]byte, 256*4+1) // If the whole string consists out of \DDD we need this many.
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off, err := packTxt(s, msg, off, txtTmp)
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if err != nil {
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return len(msg), err
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}
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return off, nil
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}
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func unpackDataOpt(msg []byte, off int) ([]EDNS0, int, error) {
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var edns []EDNS0
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Option:
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var code uint16
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if off+4 > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking opt"}
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}
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code = binary.BigEndian.Uint16(msg[off:])
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off += 2
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optlen := binary.BigEndian.Uint16(msg[off:])
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off += 2
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if off+int(optlen) > len(msg) {
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return nil, len(msg), &Error{err: "overflow unpacking opt"}
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}
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switch code {
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case EDNS0NSID:
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e := new(EDNS0_NSID)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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case EDNS0SUBNET:
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e := new(EDNS0_SUBNET)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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case EDNS0COOKIE:
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e := new(EDNS0_COOKIE)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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case EDNS0EXPIRE:
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e := new(EDNS0_EXPIRE)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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case EDNS0UL:
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e := new(EDNS0_UL)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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case EDNS0LLQ:
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e := new(EDNS0_LLQ)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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case EDNS0DAU:
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e := new(EDNS0_DAU)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
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off += int(optlen)
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case EDNS0DHU:
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e := new(EDNS0_DHU)
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if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
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return nil, len(msg), err
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}
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edns = append(edns, e)
|
|
off += int(optlen)
|
|
case EDNS0N3U:
|
|
e := new(EDNS0_N3U)
|
|
if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
|
|
return nil, len(msg), err
|
|
}
|
|
edns = append(edns, e)
|
|
off += int(optlen)
|
|
case EDNS0PADDING:
|
|
e := new(EDNS0_PADDING)
|
|
if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
|
|
return nil, len(msg), err
|
|
}
|
|
edns = append(edns, e)
|
|
off += int(optlen)
|
|
default:
|
|
e := new(EDNS0_LOCAL)
|
|
e.Code = code
|
|
if err := e.unpack(msg[off : off+int(optlen)]); err != nil {
|
|
return nil, len(msg), err
|
|
}
|
|
edns = append(edns, e)
|
|
off += int(optlen)
|
|
}
|
|
|
|
if off < len(msg) {
|
|
goto Option
|
|
}
|
|
|
|
return edns, off, nil
|
|
}
|
|
|
|
func packDataOpt(options []EDNS0, msg []byte, off int) (int, error) {
|
|
for _, el := range options {
|
|
b, err := el.pack()
|
|
if err != nil || off+4 > len(msg) {
|
|
return len(msg), &Error{err: "overflow packing opt"}
|
|
}
|
|
binary.BigEndian.PutUint16(msg[off:], el.Option()) // Option code
|
|
binary.BigEndian.PutUint16(msg[off+2:], uint16(len(b))) // Length
|
|
off += 4
|
|
if off+len(b) > len(msg) {
|
|
copy(msg[off:], b)
|
|
off = len(msg)
|
|
continue
|
|
}
|
|
// Actual data
|
|
copy(msg[off:off+len(b)], b)
|
|
off += len(b)
|
|
}
|
|
return off, nil
|
|
}
|
|
|
|
func unpackStringOctet(msg []byte, off int) (string, int, error) {
|
|
s := string(msg[off:])
|
|
return s, len(msg), nil
|
|
}
|
|
|
|
func packStringOctet(s string, msg []byte, off int) (int, error) {
|
|
txtTmp := make([]byte, 256*4+1)
|
|
off, err := packOctetString(s, msg, off, txtTmp)
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
return off, nil
|
|
}
|
|
|
|
func unpackDataNsec(msg []byte, off int) ([]uint16, int, error) {
|
|
var nsec []uint16
|
|
length, window, lastwindow := 0, 0, -1
|
|
for off < len(msg) {
|
|
if off+2 > len(msg) {
|
|
return nsec, len(msg), &Error{err: "overflow unpacking nsecx"}
|
|
}
|
|
window = int(msg[off])
|
|
length = int(msg[off+1])
|
|
off += 2
|
|
if window <= lastwindow {
|
|
// RFC 4034: Blocks are present in the NSEC RR RDATA in
|
|
// increasing numerical order.
|
|
return nsec, len(msg), &Error{err: "out of order NSEC block"}
|
|
}
|
|
if length == 0 {
|
|
// RFC 4034: Blocks with no types present MUST NOT be included.
|
|
return nsec, len(msg), &Error{err: "empty NSEC block"}
|
|
}
|
|
if length > 32 {
|
|
return nsec, len(msg), &Error{err: "NSEC block too long"}
|
|
}
|
|
if off+length > len(msg) {
|
|
return nsec, len(msg), &Error{err: "overflowing NSEC block"}
|
|
}
|
|
|
|
// Walk the bytes in the window and extract the type bits
|
|
for j, b := range msg[off : off+length] {
|
|
// Check the bits one by one, and set the type
|
|
if b&0x80 == 0x80 {
|
|
nsec = append(nsec, uint16(window*256+j*8+0))
|
|
}
|
|
if b&0x40 == 0x40 {
|
|
nsec = append(nsec, uint16(window*256+j*8+1))
|
|
}
|
|
if b&0x20 == 0x20 {
|
|
nsec = append(nsec, uint16(window*256+j*8+2))
|
|
}
|
|
if b&0x10 == 0x10 {
|
|
nsec = append(nsec, uint16(window*256+j*8+3))
|
|
}
|
|
if b&0x8 == 0x8 {
|
|
nsec = append(nsec, uint16(window*256+j*8+4))
|
|
}
|
|
if b&0x4 == 0x4 {
|
|
nsec = append(nsec, uint16(window*256+j*8+5))
|
|
}
|
|
if b&0x2 == 0x2 {
|
|
nsec = append(nsec, uint16(window*256+j*8+6))
|
|
}
|
|
if b&0x1 == 0x1 {
|
|
nsec = append(nsec, uint16(window*256+j*8+7))
|
|
}
|
|
}
|
|
off += length
|
|
lastwindow = window
|
|
}
|
|
return nsec, off, nil
|
|
}
|
|
|
|
// typeBitMapLen is a helper function which computes the "maximum" length of
|
|
// a the NSEC Type BitMap field.
|
|
func typeBitMapLen(bitmap []uint16) int {
|
|
var l int
|
|
var lastwindow, lastlength uint16
|
|
for _, t := range bitmap {
|
|
window := t / 256
|
|
length := (t-window*256)/8 + 1
|
|
if window > lastwindow && lastlength != 0 { // New window, jump to the new offset
|
|
l += int(lastlength) + 2
|
|
lastlength = 0
|
|
}
|
|
if window < lastwindow || length < lastlength {
|
|
// packDataNsec would return Error{err: "nsec bits out of order"} here, but
|
|
// when computing the length, we want do be liberal.
|
|
continue
|
|
}
|
|
lastwindow, lastlength = window, length
|
|
}
|
|
l += int(lastlength) + 2
|
|
return l
|
|
}
|
|
|
|
func packDataNsec(bitmap []uint16, msg []byte, off int) (int, error) {
|
|
if len(bitmap) == 0 {
|
|
return off, nil
|
|
}
|
|
var lastwindow, lastlength uint16
|
|
for _, t := range bitmap {
|
|
window := t / 256
|
|
length := (t-window*256)/8 + 1
|
|
if window > lastwindow && lastlength != 0 { // New window, jump to the new offset
|
|
off += int(lastlength) + 2
|
|
lastlength = 0
|
|
}
|
|
if window < lastwindow || length < lastlength {
|
|
return len(msg), &Error{err: "nsec bits out of order"}
|
|
}
|
|
if off+2+int(length) > len(msg) {
|
|
return len(msg), &Error{err: "overflow packing nsec"}
|
|
}
|
|
// Setting the window #
|
|
msg[off] = byte(window)
|
|
// Setting the octets length
|
|
msg[off+1] = byte(length)
|
|
// Setting the bit value for the type in the right octet
|
|
msg[off+1+int(length)] |= byte(1 << (7 - t%8))
|
|
lastwindow, lastlength = window, length
|
|
}
|
|
off += int(lastlength) + 2
|
|
return off, nil
|
|
}
|
|
|
|
func unpackDataDomainNames(msg []byte, off, end int) ([]string, int, error) {
|
|
var (
|
|
servers []string
|
|
s string
|
|
err error
|
|
)
|
|
if end > len(msg) {
|
|
return nil, len(msg), &Error{err: "overflow unpacking domain names"}
|
|
}
|
|
for off < end {
|
|
s, off, err = UnpackDomainName(msg, off)
|
|
if err != nil {
|
|
return servers, len(msg), err
|
|
}
|
|
servers = append(servers, s)
|
|
}
|
|
return servers, off, nil
|
|
}
|
|
|
|
func packDataDomainNames(names []string, msg []byte, off int, compression compressionMap, compress bool) (int, error) {
|
|
var err error
|
|
for _, name := range names {
|
|
off, err = packDomainName(name, msg, off, compression, compress)
|
|
if err != nil {
|
|
return len(msg), err
|
|
}
|
|
}
|
|
return off, nil
|
|
}
|