diff options
Diffstat (limited to 'vendor/github.com/miekg/dns/tsig.go')
-rw-r--r-- | vendor/github.com/miekg/dns/tsig.go | 456 |
1 files changed, 0 insertions, 456 deletions
diff --git a/vendor/github.com/miekg/dns/tsig.go b/vendor/github.com/miekg/dns/tsig.go deleted file mode 100644 index debfe2dd9..000000000 --- a/vendor/github.com/miekg/dns/tsig.go +++ /dev/null @@ -1,456 +0,0 @@ -package dns - -import ( - "crypto/hmac" - "crypto/sha1" - "crypto/sha256" - "crypto/sha512" - "encoding/binary" - "encoding/hex" - "hash" - "strconv" - "strings" - "time" -) - -// HMAC hashing codes. These are transmitted as domain names. -const ( - HmacSHA1 = "hmac-sha1." - HmacSHA224 = "hmac-sha224." - HmacSHA256 = "hmac-sha256." - HmacSHA384 = "hmac-sha384." - HmacSHA512 = "hmac-sha512." - - HmacMD5 = "hmac-md5.sig-alg.reg.int." // Deprecated: HmacMD5 is no longer supported. -) - -// TsigProvider provides the API to plug-in a custom TSIG implementation. -type TsigProvider interface { - // Generate is passed the DNS message to be signed and the partial TSIG RR. It returns the signature and nil, otherwise an error. - Generate(msg []byte, t *TSIG) ([]byte, error) - // Verify is passed the DNS message to be verified and the TSIG RR. If the signature is valid it will return nil, otherwise an error. - Verify(msg []byte, t *TSIG) error -} - -type tsigHMACProvider string - -func (key tsigHMACProvider) Generate(msg []byte, t *TSIG) ([]byte, error) { - // If we barf here, the caller is to blame - rawsecret, err := fromBase64([]byte(key)) - if err != nil { - return nil, err - } - var h hash.Hash - switch CanonicalName(t.Algorithm) { - case HmacSHA1: - h = hmac.New(sha1.New, rawsecret) - case HmacSHA224: - h = hmac.New(sha256.New224, rawsecret) - case HmacSHA256: - h = hmac.New(sha256.New, rawsecret) - case HmacSHA384: - h = hmac.New(sha512.New384, rawsecret) - case HmacSHA512: - h = hmac.New(sha512.New, rawsecret) - default: - return nil, ErrKeyAlg - } - h.Write(msg) - return h.Sum(nil), nil -} - -func (key tsigHMACProvider) Verify(msg []byte, t *TSIG) error { - b, err := key.Generate(msg, t) - if err != nil { - return err - } - mac, err := hex.DecodeString(t.MAC) - if err != nil { - return err - } - if !hmac.Equal(b, mac) { - return ErrSig - } - return nil -} - -type tsigSecretProvider map[string]string - -func (ts tsigSecretProvider) Generate(msg []byte, t *TSIG) ([]byte, error) { - key, ok := ts[t.Hdr.Name] - if !ok { - return nil, ErrSecret - } - return tsigHMACProvider(key).Generate(msg, t) -} - -func (ts tsigSecretProvider) Verify(msg []byte, t *TSIG) error { - key, ok := ts[t.Hdr.Name] - if !ok { - return ErrSecret - } - return tsigHMACProvider(key).Verify(msg, t) -} - -// TSIG is the RR the holds the transaction signature of a message. -// See RFC 2845 and RFC 4635. -type TSIG struct { - Hdr RR_Header - Algorithm string `dns:"domain-name"` - TimeSigned uint64 `dns:"uint48"` - Fudge uint16 - MACSize uint16 - MAC string `dns:"size-hex:MACSize"` - OrigId uint16 - Error uint16 - OtherLen uint16 - OtherData string `dns:"size-hex:OtherLen"` -} - -// TSIG has no official presentation format, but this will suffice. - -func (rr *TSIG) String() string { - s := "\n;; TSIG PSEUDOSECTION:\n; " // add another semi-colon to signify TSIG does not have a presentation format - s += rr.Hdr.String() + - " " + rr.Algorithm + - " " + tsigTimeToString(rr.TimeSigned) + - " " + strconv.Itoa(int(rr.Fudge)) + - " " + strconv.Itoa(int(rr.MACSize)) + - " " + strings.ToUpper(rr.MAC) + - " " + strconv.Itoa(int(rr.OrigId)) + - " " + strconv.Itoa(int(rr.Error)) + // BIND prints NOERROR - " " + strconv.Itoa(int(rr.OtherLen)) + - " " + rr.OtherData - return s -} - -func (*TSIG) parse(c *zlexer, origin string) *ParseError { - return &ParseError{err: "TSIG records do not have a presentation format"} -} - -// The following values must be put in wireformat, so that the MAC can be calculated. -// RFC 2845, section 3.4.2. TSIG Variables. -type tsigWireFmt struct { - // From RR_Header - Name string `dns:"domain-name"` - Class uint16 - Ttl uint32 - // Rdata of the TSIG - Algorithm string `dns:"domain-name"` - TimeSigned uint64 `dns:"uint48"` - Fudge uint16 - // MACSize, MAC and OrigId excluded - Error uint16 - OtherLen uint16 - OtherData string `dns:"size-hex:OtherLen"` -} - -// If we have the MAC use this type to convert it to wiredata. Section 3.4.3. Request MAC -type macWireFmt struct { - MACSize uint16 - MAC string `dns:"size-hex:MACSize"` -} - -// 3.3. Time values used in TSIG calculations -type timerWireFmt struct { - TimeSigned uint64 `dns:"uint48"` - Fudge uint16 -} - -// TsigGenerate fills out the TSIG record attached to the message. -// The message should contain a "stub" TSIG RR with the algorithm, key name -// (owner name of the RR), time fudge (defaults to 300 seconds) and the current -// time The TSIG MAC is saved in that Tsig RR. When TsigGenerate is called for -// the first time requestMAC should be set to the empty string and timersOnly to -// false. -func TsigGenerate(m *Msg, secret, requestMAC string, timersOnly bool) ([]byte, string, error) { - return TsigGenerateWithProvider(m, tsigHMACProvider(secret), requestMAC, timersOnly) -} - -// TsigGenerateWithProvider is similar to TsigGenerate, but allows for a custom TsigProvider. -func TsigGenerateWithProvider(m *Msg, provider TsigProvider, requestMAC string, timersOnly bool) ([]byte, string, error) { - if m.IsTsig() == nil { - panic("dns: TSIG not last RR in additional") - } - - rr := m.Extra[len(m.Extra)-1].(*TSIG) - m.Extra = m.Extra[0 : len(m.Extra)-1] // kill the TSIG from the msg - mbuf, err := m.Pack() - if err != nil { - return nil, "", err - } - - buf, err := tsigBuffer(mbuf, rr, requestMAC, timersOnly) - if err != nil { - return nil, "", err - } - - t := new(TSIG) - // Copy all TSIG fields except MAC, its size, and time signed which are filled when signing. - *t = *rr - t.TimeSigned = 0 - t.MAC = "" - t.MACSize = 0 - - // Sign unless there is a key or MAC validation error (RFC 8945 5.3.2) - if rr.Error != RcodeBadKey && rr.Error != RcodeBadSig { - mac, err := provider.Generate(buf, rr) - if err != nil { - return nil, "", err - } - t.TimeSigned = rr.TimeSigned - t.MAC = hex.EncodeToString(mac) - t.MACSize = uint16(len(t.MAC) / 2) // Size is half! - } - - tbuf := make([]byte, Len(t)) - off, err := PackRR(t, tbuf, 0, nil, false) - if err != nil { - return nil, "", err - } - mbuf = append(mbuf, tbuf[:off]...) - // Update the ArCount directly in the buffer. - binary.BigEndian.PutUint16(mbuf[10:], uint16(len(m.Extra)+1)) - - return mbuf, t.MAC, nil -} - -// TsigVerify verifies the TSIG on a message. If the signature does not -// validate the returned error contains the cause. If the signature is OK, the -// error is nil. -func TsigVerify(msg []byte, secret, requestMAC string, timersOnly bool) error { - return tsigVerify(msg, tsigHMACProvider(secret), requestMAC, timersOnly, uint64(time.Now().Unix())) -} - -// TsigVerifyWithProvider is similar to TsigVerify, but allows for a custom TsigProvider. -func TsigVerifyWithProvider(msg []byte, provider TsigProvider, requestMAC string, timersOnly bool) error { - return tsigVerify(msg, provider, requestMAC, timersOnly, uint64(time.Now().Unix())) -} - -// actual implementation of TsigVerify, taking the current time ('now') as a parameter for the convenience of tests. -func tsigVerify(msg []byte, provider TsigProvider, requestMAC string, timersOnly bool, now uint64) error { - // Strip the TSIG from the incoming msg - stripped, tsig, err := stripTsig(msg) - if err != nil { - return err - } - - buf, err := tsigBuffer(stripped, tsig, requestMAC, timersOnly) - if err != nil { - return err - } - - if err := provider.Verify(buf, tsig); err != nil { - return err - } - - // Fudge factor works both ways. A message can arrive before it was signed because - // of clock skew. - // We check this after verifying the signature, following draft-ietf-dnsop-rfc2845bis - // instead of RFC2845, in order to prevent a security vulnerability as reported in CVE-2017-3142/3143. - ti := now - tsig.TimeSigned - if now < tsig.TimeSigned { - ti = tsig.TimeSigned - now - } - if uint64(tsig.Fudge) < ti { - return ErrTime - } - - return nil -} - -// Create a wiredata buffer for the MAC calculation. -func tsigBuffer(msgbuf []byte, rr *TSIG, requestMAC string, timersOnly bool) ([]byte, error) { - var buf []byte - if rr.TimeSigned == 0 { - rr.TimeSigned = uint64(time.Now().Unix()) - } - if rr.Fudge == 0 { - rr.Fudge = 300 // Standard (RFC) default. - } - - // Replace message ID in header with original ID from TSIG - binary.BigEndian.PutUint16(msgbuf[0:2], rr.OrigId) - - if requestMAC != "" { - m := new(macWireFmt) - m.MACSize = uint16(len(requestMAC) / 2) - m.MAC = requestMAC - buf = make([]byte, len(requestMAC)) // long enough - n, err := packMacWire(m, buf) - if err != nil { - return nil, err - } - buf = buf[:n] - } - - tsigvar := make([]byte, DefaultMsgSize) - if timersOnly { - tsig := new(timerWireFmt) - tsig.TimeSigned = rr.TimeSigned - tsig.Fudge = rr.Fudge - n, err := packTimerWire(tsig, tsigvar) - if err != nil { - return nil, err - } - tsigvar = tsigvar[:n] - } else { - tsig := new(tsigWireFmt) - tsig.Name = CanonicalName(rr.Hdr.Name) - tsig.Class = ClassANY - tsig.Ttl = rr.Hdr.Ttl - tsig.Algorithm = CanonicalName(rr.Algorithm) - tsig.TimeSigned = rr.TimeSigned - tsig.Fudge = rr.Fudge - tsig.Error = rr.Error - tsig.OtherLen = rr.OtherLen - tsig.OtherData = rr.OtherData - n, err := packTsigWire(tsig, tsigvar) - if err != nil { - return nil, err - } - tsigvar = tsigvar[:n] - } - - if requestMAC != "" { - x := append(buf, msgbuf...) - buf = append(x, tsigvar...) - } else { - buf = append(msgbuf, tsigvar...) - } - return buf, nil -} - -// Strip the TSIG from the raw message. -func stripTsig(msg []byte) ([]byte, *TSIG, error) { - // Copied from msg.go's Unpack() Header, but modified. - var ( - dh Header - err error - ) - off, tsigoff := 0, 0 - - if dh, off, err = unpackMsgHdr(msg, off); err != nil { - return nil, nil, err - } - if dh.Arcount == 0 { - return nil, nil, ErrNoSig - } - - // Rcode, see msg.go Unpack() - if int(dh.Bits&0xF) == RcodeNotAuth { - return nil, nil, ErrAuth - } - - for i := 0; i < int(dh.Qdcount); i++ { - _, off, err = unpackQuestion(msg, off) - if err != nil { - return nil, nil, err - } - } - - _, off, err = unpackRRslice(int(dh.Ancount), msg, off) - if err != nil { - return nil, nil, err - } - _, off, err = unpackRRslice(int(dh.Nscount), msg, off) - if err != nil { - return nil, nil, err - } - - rr := new(TSIG) - var extra RR - for i := 0; i < int(dh.Arcount); i++ { - tsigoff = off - extra, off, err = UnpackRR(msg, off) - if err != nil { - return nil, nil, err - } - if extra.Header().Rrtype == TypeTSIG { - rr = extra.(*TSIG) - // Adjust Arcount. - arcount := binary.BigEndian.Uint16(msg[10:]) - binary.BigEndian.PutUint16(msg[10:], arcount-1) - break - } - } - if rr == nil { - return nil, nil, ErrNoSig - } - return msg[:tsigoff], rr, nil -} - -// Translate the TSIG time signed into a date. There is no -// need for RFC1982 calculations as this date is 48 bits. -func tsigTimeToString(t uint64) string { - ti := time.Unix(int64(t), 0).UTC() - return ti.Format("20060102150405") -} - -func packTsigWire(tw *tsigWireFmt, msg []byte) (int, error) { - // copied from zmsg.go TSIG packing - // RR_Header - off, err := PackDomainName(tw.Name, msg, 0, nil, false) - if err != nil { - return off, err - } - off, err = packUint16(tw.Class, msg, off) - if err != nil { - return off, err - } - off, err = packUint32(tw.Ttl, msg, off) - if err != nil { - return off, err - } - - off, err = PackDomainName(tw.Algorithm, msg, off, nil, false) - if err != nil { - return off, err - } - off, err = packUint48(tw.TimeSigned, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(tw.Fudge, msg, off) - if err != nil { - return off, err - } - - off, err = packUint16(tw.Error, msg, off) - if err != nil { - return off, err - } - off, err = packUint16(tw.OtherLen, msg, off) - if err != nil { - return off, err - } - off, err = packStringHex(tw.OtherData, msg, off) - if err != nil { - return off, err - } - return off, nil -} - -func packMacWire(mw *macWireFmt, msg []byte) (int, error) { - off, err := packUint16(mw.MACSize, msg, 0) - if err != nil { - return off, err - } - off, err = packStringHex(mw.MAC, msg, off) - if err != nil { - return off, err - } - return off, nil -} - -func packTimerWire(tw *timerWireFmt, msg []byte) (int, error) { - off, err := packUint48(tw.TimeSigned, msg, 0) - if err != nil { - return off, err - } - off, err = packUint16(tw.Fudge, msg, off) - if err != nil { - return off, err - } - return off, nil -} |