From 8f91c777559748fa6e857d9fc1f4ae079a532813 Mon Sep 17 00:00:00 2001 From: Christopher Speller Date: Mon, 3 Oct 2016 16:03:15 -0400 Subject: Adding ability to serve TLS directly from Mattermost server (#4119) --- vendor/github.com/miekg/dns/dnssec.go | 721 ++++++++++++++++++++++++++++++++++ 1 file changed, 721 insertions(+) create mode 100644 vendor/github.com/miekg/dns/dnssec.go (limited to 'vendor/github.com/miekg/dns/dnssec.go') diff --git a/vendor/github.com/miekg/dns/dnssec.go b/vendor/github.com/miekg/dns/dnssec.go new file mode 100644 index 000000000..f5f3fbdd8 --- /dev/null +++ b/vendor/github.com/miekg/dns/dnssec.go @@ -0,0 +1,721 @@ +package dns + +import ( + "bytes" + "crypto" + "crypto/dsa" + "crypto/ecdsa" + "crypto/elliptic" + _ "crypto/md5" + "crypto/rand" + "crypto/rsa" + _ "crypto/sha1" + _ "crypto/sha256" + _ "crypto/sha512" + "encoding/asn1" + "encoding/binary" + "encoding/hex" + "math/big" + "sort" + "strings" + "time" +) + +// DNSSEC encryption algorithm codes. +const ( + _ uint8 = iota + RSAMD5 + DH + DSA + _ // Skip 4, RFC 6725, section 2.1 + RSASHA1 + DSANSEC3SHA1 + RSASHA1NSEC3SHA1 + RSASHA256 + _ // Skip 9, RFC 6725, section 2.1 + RSASHA512 + _ // Skip 11, RFC 6725, section 2.1 + ECCGOST + ECDSAP256SHA256 + ECDSAP384SHA384 + INDIRECT uint8 = 252 + PRIVATEDNS uint8 = 253 // Private (experimental keys) + PRIVATEOID uint8 = 254 +) + +// Map for algorithm names. +var AlgorithmToString = map[uint8]string{ + RSAMD5: "RSAMD5", + DH: "DH", + DSA: "DSA", + RSASHA1: "RSASHA1", + DSANSEC3SHA1: "DSA-NSEC3-SHA1", + RSASHA1NSEC3SHA1: "RSASHA1-NSEC3-SHA1", + RSASHA256: "RSASHA256", + RSASHA512: "RSASHA512", + ECCGOST: "ECC-GOST", + ECDSAP256SHA256: "ECDSAP256SHA256", + ECDSAP384SHA384: "ECDSAP384SHA384", + INDIRECT: "INDIRECT", + PRIVATEDNS: "PRIVATEDNS", + PRIVATEOID: "PRIVATEOID", +} + +// Map of algorithm strings. +var StringToAlgorithm = reverseInt8(AlgorithmToString) + +// Map of algorithm crypto hashes. +var AlgorithmToHash = map[uint8]crypto.Hash{ + RSAMD5: crypto.MD5, // Deprecated in RFC 6725 + RSASHA1: crypto.SHA1, + RSASHA1NSEC3SHA1: crypto.SHA1, + RSASHA256: crypto.SHA256, + ECDSAP256SHA256: crypto.SHA256, + ECDSAP384SHA384: crypto.SHA384, + RSASHA512: crypto.SHA512, +} + +// DNSSEC hashing algorithm codes. +const ( + _ uint8 = iota + SHA1 // RFC 4034 + SHA256 // RFC 4509 + GOST94 // RFC 5933 + SHA384 // Experimental + SHA512 // Experimental +) + +// Map for hash names. +var HashToString = map[uint8]string{ + SHA1: "SHA1", + SHA256: "SHA256", + GOST94: "GOST94", + SHA384: "SHA384", + SHA512: "SHA512", +} + +// Map of hash strings. +var StringToHash = reverseInt8(HashToString) + +// DNSKEY flag values. +const ( + SEP = 1 + REVOKE = 1 << 7 + ZONE = 1 << 8 +) + +// The RRSIG needs to be converted to wireformat with some of the rdata (the signature) missing. +type rrsigWireFmt struct { + TypeCovered uint16 + Algorithm uint8 + Labels uint8 + OrigTtl uint32 + Expiration uint32 + Inception uint32 + KeyTag uint16 + SignerName string `dns:"domain-name"` + /* No Signature */ +} + +// Used for converting DNSKEY's rdata to wirefmt. +type dnskeyWireFmt struct { + Flags uint16 + Protocol uint8 + Algorithm uint8 + PublicKey string `dns:"base64"` + /* Nothing is left out */ +} + +func divRoundUp(a, b int) int { + return (a + b - 1) / b +} + +// KeyTag calculates the keytag (or key-id) of the DNSKEY. +func (k *DNSKEY) KeyTag() uint16 { + if k == nil { + return 0 + } + var keytag int + switch k.Algorithm { + case RSAMD5: + // Look at the bottom two bytes of the modules, which the last + // item in the pubkey. We could do this faster by looking directly + // at the base64 values. But I'm lazy. + modulus, _ := fromBase64([]byte(k.PublicKey)) + if len(modulus) > 1 { + x := binary.BigEndian.Uint16(modulus[len(modulus)-2:]) + keytag = int(x) + } + default: + keywire := new(dnskeyWireFmt) + keywire.Flags = k.Flags + keywire.Protocol = k.Protocol + keywire.Algorithm = k.Algorithm + keywire.PublicKey = k.PublicKey + wire := make([]byte, DefaultMsgSize) + n, err := packKeyWire(keywire, wire) + if err != nil { + return 0 + } + wire = wire[:n] + for i, v := range wire { + if i&1 != 0 { + keytag += int(v) // must be larger than uint32 + } else { + keytag += int(v) << 8 + } + } + keytag += (keytag >> 16) & 0xFFFF + keytag &= 0xFFFF + } + return uint16(keytag) +} + +// ToDS converts a DNSKEY record to a DS record. +func (k *DNSKEY) ToDS(h uint8) *DS { + if k == nil { + return nil + } + ds := new(DS) + ds.Hdr.Name = k.Hdr.Name + ds.Hdr.Class = k.Hdr.Class + ds.Hdr.Rrtype = TypeDS + ds.Hdr.Ttl = k.Hdr.Ttl + ds.Algorithm = k.Algorithm + ds.DigestType = h + ds.KeyTag = k.KeyTag() + + keywire := new(dnskeyWireFmt) + keywire.Flags = k.Flags + keywire.Protocol = k.Protocol + keywire.Algorithm = k.Algorithm + keywire.PublicKey = k.PublicKey + wire := make([]byte, DefaultMsgSize) + n, err := packKeyWire(keywire, wire) + if err != nil { + return nil + } + wire = wire[:n] + + owner := make([]byte, 255) + off, err1 := PackDomainName(strings.ToLower(k.Hdr.Name), owner, 0, nil, false) + if err1 != nil { + return nil + } + owner = owner[:off] + // RFC4034: + // digest = digest_algorithm( DNSKEY owner name | DNSKEY RDATA); + // "|" denotes concatenation + // DNSKEY RDATA = Flags | Protocol | Algorithm | Public Key. + + // digest buffer + digest := append(owner, wire...) // another copy + + var hash crypto.Hash + switch h { + case SHA1: + hash = crypto.SHA1 + case SHA256: + hash = crypto.SHA256 + case SHA384: + hash = crypto.SHA384 + case SHA512: + hash = crypto.SHA512 + default: + return nil + } + + s := hash.New() + s.Write(digest) + ds.Digest = hex.EncodeToString(s.Sum(nil)) + return ds +} + +// ToCDNSKEY converts a DNSKEY record to a CDNSKEY record. +func (k *DNSKEY) ToCDNSKEY() *CDNSKEY { + c := &CDNSKEY{DNSKEY: *k} + c.Hdr = *k.Hdr.copyHeader() + c.Hdr.Rrtype = TypeCDNSKEY + return c +} + +// ToCDS converts a DS record to a CDS record. +func (d *DS) ToCDS() *CDS { + c := &CDS{DS: *d} + c.Hdr = *d.Hdr.copyHeader() + c.Hdr.Rrtype = TypeCDS + return c +} + +// Sign signs an RRSet. The signature needs to be filled in with the values: +// Inception, Expiration, KeyTag, SignerName and Algorithm. The rest is copied +// from the RRset. Sign returns a non-nill error when the signing went OK. +// There is no check if RRSet is a proper (RFC 2181) RRSet. If OrigTTL is non +// zero, it is used as-is, otherwise the TTL of the RRset is used as the +// OrigTTL. +func (rr *RRSIG) Sign(k crypto.Signer, rrset []RR) error { + if k == nil { + return ErrPrivKey + } + // s.Inception and s.Expiration may be 0 (rollover etc.), the rest must be set + if rr.KeyTag == 0 || len(rr.SignerName) == 0 || rr.Algorithm == 0 { + return ErrKey + } + + rr.Hdr.Rrtype = TypeRRSIG + rr.Hdr.Name = rrset[0].Header().Name + rr.Hdr.Class = rrset[0].Header().Class + if rr.OrigTtl == 0 { // If set don't override + rr.OrigTtl = rrset[0].Header().Ttl + } + rr.TypeCovered = rrset[0].Header().Rrtype + rr.Labels = uint8(CountLabel(rrset[0].Header().Name)) + + if strings.HasPrefix(rrset[0].Header().Name, "*") { + rr.Labels-- // wildcard, remove from label count + } + + sigwire := new(rrsigWireFmt) + sigwire.TypeCovered = rr.TypeCovered + sigwire.Algorithm = rr.Algorithm + sigwire.Labels = rr.Labels + sigwire.OrigTtl = rr.OrigTtl + sigwire.Expiration = rr.Expiration + sigwire.Inception = rr.Inception + sigwire.KeyTag = rr.KeyTag + // For signing, lowercase this name + sigwire.SignerName = strings.ToLower(rr.SignerName) + + // Create the desired binary blob + signdata := make([]byte, DefaultMsgSize) + n, err := packSigWire(sigwire, signdata) + if err != nil { + return err + } + signdata = signdata[:n] + wire, err := rawSignatureData(rrset, rr) + if err != nil { + return err + } + signdata = append(signdata, wire...) + + hash, ok := AlgorithmToHash[rr.Algorithm] + if !ok { + return ErrAlg + } + + h := hash.New() + h.Write(signdata) + + signature, err := sign(k, h.Sum(nil), hash, rr.Algorithm) + if err != nil { + return err + } + + rr.Signature = toBase64(signature) + + return nil +} + +func sign(k crypto.Signer, hashed []byte, hash crypto.Hash, alg uint8) ([]byte, error) { + signature, err := k.Sign(rand.Reader, hashed, hash) + if err != nil { + return nil, err + } + + switch alg { + case RSASHA1, RSASHA1NSEC3SHA1, RSASHA256, RSASHA512: + return signature, nil + + case ECDSAP256SHA256, ECDSAP384SHA384: + ecdsaSignature := &struct { + R, S *big.Int + }{} + if _, err := asn1.Unmarshal(signature, ecdsaSignature); err != nil { + return nil, err + } + + var intlen int + switch alg { + case ECDSAP256SHA256: + intlen = 32 + case ECDSAP384SHA384: + intlen = 48 + } + + signature := intToBytes(ecdsaSignature.R, intlen) + signature = append(signature, intToBytes(ecdsaSignature.S, intlen)...) + return signature, nil + + // There is no defined interface for what a DSA backed crypto.Signer returns + case DSA, DSANSEC3SHA1: + // t := divRoundUp(divRoundUp(p.PublicKey.Y.BitLen(), 8)-64, 8) + // signature := []byte{byte(t)} + // signature = append(signature, intToBytes(r1, 20)...) + // signature = append(signature, intToBytes(s1, 20)...) + // rr.Signature = signature + } + + return nil, ErrAlg +} + +// Verify validates an RRSet with the signature and key. This is only the +// cryptographic test, the signature validity period must be checked separately. +// This function copies the rdata of some RRs (to lowercase domain names) for the validation to work. +func (rr *RRSIG) Verify(k *DNSKEY, rrset []RR) error { + // First the easy checks + if !IsRRset(rrset) { + return ErrRRset + } + if rr.KeyTag != k.KeyTag() { + return ErrKey + } + if rr.Hdr.Class != k.Hdr.Class { + return ErrKey + } + if rr.Algorithm != k.Algorithm { + return ErrKey + } + if strings.ToLower(rr.SignerName) != strings.ToLower(k.Hdr.Name) { + return ErrKey + } + if k.Protocol != 3 { + return ErrKey + } + + // IsRRset checked that we have at least one RR and that the RRs in + // the set have consistent type, class, and name. Also check that type and + // class matches the RRSIG record. + if rrset[0].Header().Class != rr.Hdr.Class { + return ErrRRset + } + if rrset[0].Header().Rrtype != rr.TypeCovered { + return ErrRRset + } + + // RFC 4035 5.3.2. Reconstructing the Signed Data + // Copy the sig, except the rrsig data + sigwire := new(rrsigWireFmt) + sigwire.TypeCovered = rr.TypeCovered + sigwire.Algorithm = rr.Algorithm + sigwire.Labels = rr.Labels + sigwire.OrigTtl = rr.OrigTtl + sigwire.Expiration = rr.Expiration + sigwire.Inception = rr.Inception + sigwire.KeyTag = rr.KeyTag + sigwire.SignerName = strings.ToLower(rr.SignerName) + // Create the desired binary blob + signeddata := make([]byte, DefaultMsgSize) + n, err := packSigWire(sigwire, signeddata) + if err != nil { + return err + } + signeddata = signeddata[:n] + wire, err := rawSignatureData(rrset, rr) + if err != nil { + return err + } + signeddata = append(signeddata, wire...) + + sigbuf := rr.sigBuf() // Get the binary signature data + if rr.Algorithm == PRIVATEDNS { // PRIVATEOID + // TODO(miek) + // remove the domain name and assume its ours? + } + + hash, ok := AlgorithmToHash[rr.Algorithm] + if !ok { + return ErrAlg + } + + switch rr.Algorithm { + case RSASHA1, RSASHA1NSEC3SHA1, RSASHA256, RSASHA512, RSAMD5: + // TODO(mg): this can be done quicker, ie. cache the pubkey data somewhere?? + pubkey := k.publicKeyRSA() // Get the key + if pubkey == nil { + return ErrKey + } + + h := hash.New() + h.Write(signeddata) + return rsa.VerifyPKCS1v15(pubkey, hash, h.Sum(nil), sigbuf) + + case ECDSAP256SHA256, ECDSAP384SHA384: + pubkey := k.publicKeyECDSA() + if pubkey == nil { + return ErrKey + } + + // Split sigbuf into the r and s coordinates + r := new(big.Int).SetBytes(sigbuf[:len(sigbuf)/2]) + s := new(big.Int).SetBytes(sigbuf[len(sigbuf)/2:]) + + h := hash.New() + h.Write(signeddata) + if ecdsa.Verify(pubkey, h.Sum(nil), r, s) { + return nil + } + return ErrSig + + default: + return ErrAlg + } +} + +// ValidityPeriod uses RFC1982 serial arithmetic to calculate +// if a signature period is valid. If t is the zero time, the +// current time is taken other t is. Returns true if the signature +// is valid at the given time, otherwise returns false. +func (rr *RRSIG) ValidityPeriod(t time.Time) bool { + var utc int64 + if t.IsZero() { + utc = time.Now().UTC().Unix() + } else { + utc = t.UTC().Unix() + } + modi := (int64(rr.Inception) - utc) / year68 + mode := (int64(rr.Expiration) - utc) / year68 + ti := int64(rr.Inception) + (modi * year68) + te := int64(rr.Expiration) + (mode * year68) + return ti <= utc && utc <= te +} + +// Return the signatures base64 encodedig sigdata as a byte slice. +func (rr *RRSIG) sigBuf() []byte { + sigbuf, err := fromBase64([]byte(rr.Signature)) + if err != nil { + return nil + } + return sigbuf +} + +// publicKeyRSA returns the RSA public key from a DNSKEY record. +func (k *DNSKEY) publicKeyRSA() *rsa.PublicKey { + keybuf, err := fromBase64([]byte(k.PublicKey)) + if err != nil { + return nil + } + + // RFC 2537/3110, section 2. RSA Public KEY Resource Records + // Length is in the 0th byte, unless its zero, then it + // it in bytes 1 and 2 and its a 16 bit number + explen := uint16(keybuf[0]) + keyoff := 1 + if explen == 0 { + explen = uint16(keybuf[1])<<8 | uint16(keybuf[2]) + keyoff = 3 + } + pubkey := new(rsa.PublicKey) + + pubkey.N = big.NewInt(0) + shift := uint64((explen - 1) * 8) + expo := uint64(0) + for i := int(explen - 1); i > 0; i-- { + expo += uint64(keybuf[keyoff+i]) << shift + shift -= 8 + } + // Remainder + expo += uint64(keybuf[keyoff]) + if expo > 2<<31 { + // Larger expo than supported. + // println("dns: F5 primes (or larger) are not supported") + return nil + } + pubkey.E = int(expo) + + pubkey.N.SetBytes(keybuf[keyoff+int(explen):]) + return pubkey +} + +// publicKeyECDSA returns the Curve public key from the DNSKEY record. +func (k *DNSKEY) publicKeyECDSA() *ecdsa.PublicKey { + keybuf, err := fromBase64([]byte(k.PublicKey)) + if err != nil { + return nil + } + pubkey := new(ecdsa.PublicKey) + switch k.Algorithm { + case ECDSAP256SHA256: + pubkey.Curve = elliptic.P256() + if len(keybuf) != 64 { + // wrongly encoded key + return nil + } + case ECDSAP384SHA384: + pubkey.Curve = elliptic.P384() + if len(keybuf) != 96 { + // Wrongly encoded key + return nil + } + } + pubkey.X = big.NewInt(0) + pubkey.X.SetBytes(keybuf[:len(keybuf)/2]) + pubkey.Y = big.NewInt(0) + pubkey.Y.SetBytes(keybuf[len(keybuf)/2:]) + return pubkey +} + +func (k *DNSKEY) publicKeyDSA() *dsa.PublicKey { + keybuf, err := fromBase64([]byte(k.PublicKey)) + if err != nil { + return nil + } + if len(keybuf) < 22 { + return nil + } + t, keybuf := int(keybuf[0]), keybuf[1:] + size := 64 + t*8 + q, keybuf := keybuf[:20], keybuf[20:] + if len(keybuf) != 3*size { + return nil + } + p, keybuf := keybuf[:size], keybuf[size:] + g, y := keybuf[:size], keybuf[size:] + pubkey := new(dsa.PublicKey) + pubkey.Parameters.Q = big.NewInt(0).SetBytes(q) + pubkey.Parameters.P = big.NewInt(0).SetBytes(p) + pubkey.Parameters.G = big.NewInt(0).SetBytes(g) + pubkey.Y = big.NewInt(0).SetBytes(y) + return pubkey +} + +type wireSlice [][]byte + +func (p wireSlice) Len() int { return len(p) } +func (p wireSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] } +func (p wireSlice) Less(i, j int) bool { + _, ioff, _ := UnpackDomainName(p[i], 0) + _, joff, _ := UnpackDomainName(p[j], 0) + return bytes.Compare(p[i][ioff+10:], p[j][joff+10:]) < 0 +} + +// Return the raw signature data. +func rawSignatureData(rrset []RR, s *RRSIG) (buf []byte, err error) { + wires := make(wireSlice, len(rrset)) + for i, r := range rrset { + r1 := r.copy() + r1.Header().Ttl = s.OrigTtl + labels := SplitDomainName(r1.Header().Name) + // 6.2. Canonical RR Form. (4) - wildcards + if len(labels) > int(s.Labels) { + // Wildcard + r1.Header().Name = "*." + strings.Join(labels[len(labels)-int(s.Labels):], ".") + "." + } + // RFC 4034: 6.2. Canonical RR Form. (2) - domain name to lowercase + r1.Header().Name = strings.ToLower(r1.Header().Name) + // 6.2. Canonical RR Form. (3) - domain rdata to lowercase. + // NS, MD, MF, CNAME, SOA, MB, MG, MR, PTR, + // HINFO, MINFO, MX, RP, AFSDB, RT, SIG, PX, NXT, NAPTR, KX, + // SRV, DNAME, A6 + // + // RFC 6840 - Clarifications and Implementation Notes for DNS Security (DNSSEC): + // Section 6.2 of [RFC4034] also erroneously lists HINFO as a record + // that needs conversion to lowercase, and twice at that. Since HINFO + // records contain no domain names, they are not subject to case + // conversion. + switch x := r1.(type) { + case *NS: + x.Ns = strings.ToLower(x.Ns) + case *CNAME: + x.Target = strings.ToLower(x.Target) + case *SOA: + x.Ns = strings.ToLower(x.Ns) + x.Mbox = strings.ToLower(x.Mbox) + case *MB: + x.Mb = strings.ToLower(x.Mb) + case *MG: + x.Mg = strings.ToLower(x.Mg) + case *MR: + x.Mr = strings.ToLower(x.Mr) + case *PTR: + x.Ptr = strings.ToLower(x.Ptr) + case *MINFO: + x.Rmail = strings.ToLower(x.Rmail) + x.Email = strings.ToLower(x.Email) + case *MX: + x.Mx = strings.ToLower(x.Mx) + case *NAPTR: + x.Replacement = strings.ToLower(x.Replacement) + case *KX: + x.Exchanger = strings.ToLower(x.Exchanger) + case *SRV: + x.Target = strings.ToLower(x.Target) + case *DNAME: + x.Target = strings.ToLower(x.Target) + } + // 6.2. Canonical RR Form. (5) - origTTL + wire := make([]byte, r1.len()+1) // +1 to be safe(r) + off, err1 := PackRR(r1, wire, 0, nil, false) + if err1 != nil { + return nil, err1 + } + wire = wire[:off] + wires[i] = wire + } + sort.Sort(wires) + for i, wire := range wires { + if i > 0 && bytes.Equal(wire, wires[i-1]) { + continue + } + buf = append(buf, wire...) + } + return buf, nil +} + +func packSigWire(sw *rrsigWireFmt, msg []byte) (int, error) { + // copied from zmsg.go RRSIG packing + off, err := packUint16(sw.TypeCovered, msg, 0) + if err != nil { + return off, err + } + off, err = packUint8(sw.Algorithm, msg, off) + if err != nil { + return off, err + } + off, err = packUint8(sw.Labels, msg, off) + if err != nil { + return off, err + } + off, err = packUint32(sw.OrigTtl, msg, off) + if err != nil { + return off, err + } + off, err = packUint32(sw.Expiration, msg, off) + if err != nil { + return off, err + } + off, err = packUint32(sw.Inception, msg, off) + if err != nil { + return off, err + } + off, err = packUint16(sw.KeyTag, msg, off) + if err != nil { + return off, err + } + off, err = PackDomainName(sw.SignerName, msg, off, nil, false) + if err != nil { + return off, err + } + return off, nil +} + +func packKeyWire(dw *dnskeyWireFmt, msg []byte) (int, error) { + // copied from zmsg.go DNSKEY packing + off, err := packUint16(dw.Flags, msg, 0) + if err != nil { + return off, err + } + off, err = packUint8(dw.Protocol, msg, off) + if err != nil { + return off, err + } + off, err = packUint8(dw.Algorithm, msg, off) + if err != nil { + return off, err + } + off, err = packStringBase64(dw.PublicKey, msg, off) + if err != nil { + return off, err + } + return off, nil +} -- cgit v1.2.3-1-g7c22