community
/
dns
3
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Allow for escaping of dots in domainnames

This commit is contained in:
Miek Gieben 2011-02-21 20:33:36 +01:00
parent 865ba16420
commit c7c4d8061e
2 changed files with 110 additions and 80 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

101
msg.go
View File

@ -22,7 +22,7 @@ import (
"time"
"strconv"
"encoding/base64"
"encoding/base32"
"encoding/base32"
"encoding/hex"
)
@ -76,14 +76,14 @@ var Rr_str = map[uint16]string{
TypeLOC: "LOC",
TypeOPT: "OPT",
TypeDS: "DS",
TypeIPSECKEY: "IPSECKEY",
TypeIPSECKEY: "IPSECKEY",
TypeSSHFP: "SSHFP",
TypeRRSIG: "RRSIG",
TypeNSEC: "NSEC",
TypeDNSKEY: "DNSKEY",
TypeNSEC3: "NSEC3",
TypeNSEC3PARAM: "NSEC3PARAM",
TypeTALINK: "TALINK",
TypeTALINK: "TALINK",
TypeSPF: "SPF",
TypeTKEY: "TKEY", // Meta RR
TypeTSIG: "TSIG", // Meta RR
@ -147,6 +147,7 @@ func packDomainName(s string, msg []byte, off int) (off1 int, ok bool) {
// Each dot ends a segment of the name.
// We trade each dot byte for a length byte.
// Except for escaped dots (\.), which are normal dots.
// There is also a trailing zero.
// Check that we have all the space we need.
tot := len(s) + 1
@ -156,22 +157,32 @@ func packDomainName(s string, msg []byte, off int) (off1 int, ok bool) {
// Emit sequence of counted strings, chopping at dots.
begin := 0
for i := 0; i < len(s); i++ {
if s[i] == '.' {
if i-begin >= 1<<6 { // top two bits of length must be clear
return len(msg), false
}
msg[off] = byte(i - begin)
off++
for j := begin; j < i; j++ {
msg[off] = s[j]
off++
}
begin = i + 1
bs := []byte(s)
ls := len(bs)
for i := 0; i < ls; i++ {
if bs[i] == '\\' {
for j := i; j < len(s)-1; j++ {
bs[j] = bs[j+1]
}
ls--
continue
}
if bs[i] == '.' {
if i-begin >= 1<<6 { // top two bits of length must be clear
return len(msg), false
}
msg[off] = byte(i - begin)
off++
for j := begin; j < i; j++ {
msg[off] = bs[j]
off++
}
begin = i + 1
}
}
// Root label is special
if s == "." {
if string(bs) == "." {
return off, true
}
msg[off] = 0
@ -367,39 +378,39 @@ func packStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int, o
default:
//fmt.Fprintf(os.Stderr, "dns: unknown packing string tag %v", f.Tag)
return len(msg), false
case "base32":
b32, err := packBase32([]byte(s))
case "base32":
b32, err := packBase32([]byte(s))
if err != nil {
//fmt.Fprintf(os.Stderr, "dns: overflow packing base32")
return len(msg), false
}
copy(msg[off:off+len(b32)], b32)
off += len(b32)
copy(msg[off:off+len(b32)], b32)
off += len(b32)
case "base64":
b64, err := packBase64([]byte(s))
b64, err := packBase64([]byte(s))
if err != nil {
//fmt.Fprintf(os.Stderr, "dns: overflow packing base64")
return len(msg), false
}
copy(msg[off:off+len(b64)], b64)
off += len(b64)
/*
b64len := base64.StdEncoding.DecodedLen(len(s))
_, err := base64.StdEncoding.Decode(msg[off:off+b64len], []byte(s))
if err != nil {
//fmt.Fprintf(os.Stderr, "dns: overflow packing base64")
return len(msg), false
}
off += b64len
*/
copy(msg[off:off+len(b64)], b64)
off += len(b64)
/*
b64len := base64.StdEncoding.DecodedLen(len(s))
_, err := base64.StdEncoding.Decode(msg[off:off+b64len], []byte(s))
if err != nil {
//fmt.Fprintf(os.Stderr, "dns: overflow packing base64")
return len(msg), false
}
off += b64len
*/
case "domain-name":
off, ok = packDomainName(s, msg, off)
if !ok {
//fmt.Fprintf(os.Stderr, "dns: overflow packing domain-name")
return len(msg), false
}
case "size-hex":
fallthrough;
case "size-hex":
fallthrough
case "hex":
// There is no length encoded here
h, e := hex.DecodeString(s)
@ -604,8 +615,8 @@ func unpackStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int,
consumed = 2 // Algorithm(1) + Type(1)
case "RR_NSEC3PARAM":
consumed = 5 // Hash(1) + Flags(1) + Iterations(2) + SaltLength(1)
case "RR_RFC3597":
fallthrough; // Rest is the unknown data
case "RR_RFC3597":
fallthrough // Rest is the unknown data
default:
consumed = 0 // return len(msg), false?
}
@ -636,7 +647,7 @@ func unpackStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int,
//fmt.Fprintf(os.Stderr, "dns: failure unpacking domain-name")
return len(msg), false
}
case "size-base32":
case "size-base32":
var size int
switch val.Type().Name() {
case "RR_NSEC3":
@ -645,15 +656,15 @@ func unpackStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int,
name := val.FieldByName("HashLength")
size = int(name.(*reflect.UintValue).Get())
}
}
}
if off+size > len(msg) {
//fmt.Fprintf(os.Stderr, "dns: failure unpacking size-base32 string")
return len(msg), false
}
s = unpackBase32(msg[off : off+size])
off += size
case "size-hex":
// a "size" string, but a it must be encoded in hex in the string
case "size-hex":
// a "size" string, but a it must be encoded in hex in the string
var size int
switch val.Type().Name() {
case "RR_NSEC3":
@ -665,7 +676,7 @@ func unpackStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int,
name := val.FieldByName("HashLength")
size = int(name.(*reflect.UintValue).Get())
}
}
}
if off+size > len(msg) {
//fmt.Fprintf(os.Stderr, "dns: failure unpacking hex-size string")
return len(msg), false
@ -800,11 +811,11 @@ func unpackRR(msg []byte, off int) (rr RR, off1 int, ok bool) {
// make an rr of that type and re-unpack.
// again inefficient but doesn't need to be fast.
mk, known := rr_mk[int(h.Rrtype)]
if !known {
rr = new(RR_RFC3597)
if !known {
rr = new(RR_RFC3597)
} else {
rr = mk()
}
rr = mk()
}
off, ok = unpackStruct(rr, msg, off0)
if off != end {
return &h, end, true

89
parse_test.go
View File

@ -1,8 +1,8 @@
package dns
import (
"fmt"
"net"
"fmt"
"net"
"testing"
"crypto/rsa"
)
@ -75,7 +75,7 @@ Activate: 20110109154937`
k.Hdr.Rrtype = TypeDNSKEY
k.Hdr.Class = ClassINET
k.Hdr.Name = "miek.nl."
k.Hdr.Ttl = 3600
k.Hdr.Ttl = 3600
k.Protocol = 3
k.Flags = 256
p, _ := k.PrivateKeySetString(a)
@ -92,47 +92,66 @@ Activate: 20110109154937`
t.Fail()
}
soa := new(RR_SOA)
soa.Hdr = RR_Header{"miek.nl.", TypeSOA, ClassINET, 14400, 0}
soa.Ns = "open.nlnetlabs.nl."
soa.Mbox = "miekg.atoom.net."
soa.Serial = 1293945905
soa.Refresh = 14400
soa.Retry = 3600
soa.Expire = 604800
soa.Minttl = 86400
soa := new(RR_SOA)
soa.Hdr = RR_Header{"miek.nl.", TypeSOA, ClassINET, 14400, 0}
soa.Ns = "open.nlnetlabs.nl."
soa.Mbox = "miekg.atoom.net."
soa.Serial = 1293945905
soa.Refresh = 14400
soa.Retry = 3600
soa.Expire = 604800
soa.Minttl = 86400
sig := new(RR_RRSIG)
sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
sig.Inception = 1293942305 // date -u '+%s' -d"2011-01-02 04:25:05"
sig.KeyTag = k.KeyTag()
sig.SignerName = k.Hdr.Name
sig.Algorithm = k.Algorithm
sig := new(RR_RRSIG)
sig.Hdr = RR_Header{"miek.nl.", TypeRRSIG, ClassINET, 14400, 0}
sig.Expiration = 1296534305 // date -u '+%s' -d"2011-02-01 04:25:05"
sig.Inception = 1293942305 // date -u '+%s' -d"2011-01-02 04:25:05"
sig.KeyTag = k.KeyTag()
sig.SignerName = k.Hdr.Name
sig.Algorithm = k.Algorithm
sig.Sign(p, []RR{soa})
fmt.Printf("%v\n%v\n%v\n", k, soa, sig)
sig.Sign(p, []RR{soa})
fmt.Printf("%v\n%v\n%v\n", k, soa, sig)
}
func TestA(t *testing.T) {
a := new(RR_A)
a.Hdr = RR_Header{"miek.nl.", TypeA, ClassINET, 14400, 0}
a.A = net.ParseIP("192.168.1.1")
str := a.String()
if str != "miek.nl.\t14400\tIN\tA\t192.168.1.1" {
t.Log(str)
t.Fail()
}
a := new(RR_A)
a.Hdr = RR_Header{"miek.nl.", TypeA, ClassINET, 14400, 0}
a.A = net.ParseIP("192.168.1.1")
str := a.String()
if str != "miek.nl.\t14400\tIN\tA\t192.168.1.1" {
t.Log(str)
t.Fail()
}
}
func TestQuadA(t *testing.T) {
a := new(RR_AAAA)
a.Hdr = RR_Header{"miek.nl.", TypeAAAA, ClassINET, 14400, 0}
a.AAAA = net.ParseIP("::1")
str := a.String()
if str != "miek.nl.\t14400\tIN\tAAAA\t::1" {
t.Log(str)
a := new(RR_AAAA)
a.Hdr = RR_Header{"miek.nl.", TypeAAAA, ClassINET, 14400, 0}
a.AAAA = net.ParseIP("::1")
str := a.String()
if str != "miek.nl.\t14400\tIN\tAAAA\t::1" {
t.Log(str)
t.Fail()
}
}
func TestDotInName(t *testing.T) {
buf := make([]byte, 20)
packDomainName("aa\\.bb.nl", buf, 0)
// index 3 must be a real dot
if buf[3] != '.' {
t.Log("Dot should be a real dot")
t.Fail()
}
if buf[6] != 2 {
t.Log("This must have the value 2")
t.Fail()
}
dom, _, ok := unpackDomainName(buf, 0)
// printing it should yield the backspace again
println(dom)
println(ok)
}