asn1: Improved encoding/decoding for OID types

The first identifier in an Object Identifer must be between 0 and 2
inclusive. The range of values that the second one can take depends
on the value of the first one.
The two first identifiers are not necessarily encoded in a single octet,
but in a varint.

R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/10140046

diff --git a/src/pkg/crypto/x509/x509_test.go b/src/pkg/crypto/x509/x509_test.go
index abd4fe84d7eb7efd197a1160d73373d821023089..123b1cfc84e08efe538b34ccbd52c104ff1a8376 100644 (file)
--- a/src/pkg/crypto/x509/x509_test.go
+++ b/src/pkg/crypto/x509/x509_test.go
@@ -308,7 +308,7 @@ func TestCreateSelfSignedCertificate(t *testing.T) {
        }
 
        testExtKeyUsage := []ExtKeyUsage{ExtKeyUsageClientAuth, ExtKeyUsageServerAuth}
-       testUnknownExtKeyUsage := []asn1.ObjectIdentifier{[]int{1, 2, 3}, []int{3, 2, 1}}
+       testUnknownExtKeyUsage := []asn1.ObjectIdentifier{[]int{1, 2, 3}, []int{2, 59, 1}}
 
        for _, test := range tests {
                commonName := "test.example.com"

diff --git a/src/pkg/encoding/asn1/asn1.go b/src/pkg/encoding/asn1/asn1.go
index 453c1743c7b047f0734fd2016b3de5c71cb98345..a9d17a3c14aaf673eb2aa30d195cfd14903f66f6 100644 (file)
--- a/src/pkg/encoding/asn1/asn1.go
+++ b/src/pkg/encoding/asn1/asn1.go
@@ -210,12 +210,24 @@ func parseObjectIdentifier(bytes []byte) (s []int, err error) {
        // encoded differently) and then every varint is a single byte long.
        s = make([]int, len(bytes)+1)
 
-       // The first byte is 40*value1 + value2:
-       s[0] = int(bytes[0]) / 40
-       s[1] = int(bytes[0]) % 40
+       // The first varint is 40*value1 + value2:
+       // According to this packing, value1 can take the values 0, 1 and 2 only.
+       // When value1 = 0 or value1 = 1, then value2 is <= 39. When value1 = 2,
+       // then there are no restrictions on value2.
+       v, offset, err := parseBase128Int(bytes, 0)
+       if err != nil {
+               return
+       }
+       if v < 80 {
+               s[0] = v / 40
+               s[1] = v % 40
+       } else {
+               s[0] = 2
+               s[1] = v - 80
+       }
+
        i := 2
-       for offset := 1; offset < len(bytes); i++ {
-               var v int
+       for ; offset < len(bytes); i++ {
                v, offset, err = parseBase128Int(bytes, offset)
                if err != nil {
                        return

diff --git a/src/pkg/encoding/asn1/asn1_test.go b/src/pkg/encoding/asn1/asn1_test.go
index fb82937b7ee8eac8807a17d350d4fe4c33e07748..f68804ebffd2faff24f4e7cfd7b9f498a8e3ebc8 100644 (file)
--- a/src/pkg/encoding/asn1/asn1_test.go
+++ b/src/pkg/encoding/asn1/asn1_test.go
@@ -209,6 +209,7 @@ var objectIdentifierTestData = []objectIdentifierTest{
        {[]byte{85}, true, []int{2, 5}},
        {[]byte{85, 0x02}, true, []int{2, 5, 2}},
        {[]byte{85, 0x02, 0xc0, 0x00}, true, []int{2, 5, 2, 0x2000}},
+       {[]byte{0x81, 0x34, 0x03}, true, []int{2, 100, 3}},
        {[]byte{85, 0x02, 0xc0, 0x80, 0x80, 0x80, 0x80}, false, []int{}},
 }
 

diff --git a/src/pkg/encoding/asn1/marshal.go b/src/pkg/encoding/asn1/marshal.go
index 7a1f7c23e1d16e889fc58adcdd9959ed2bbf8f5f..d38694d666ef64d9817d4dce05d6a03bc2db1da7 100644 (file)
--- a/src/pkg/encoding/asn1/marshal.go
+++ b/src/pkg/encoding/asn1/marshal.go
@@ -240,11 +240,11 @@ func marshalBitString(out *forkableWriter, b BitString) (err error) {
 }
 
 func marshalObjectIdentifier(out *forkableWriter, oid []int) (err error) {
-       if len(oid) < 2 || oid[0] > 6 || oid[1] >= 40 {
+       if len(oid) < 2 || oid[0] > 2 || (oid[0] < 2 && oid[1] >= 40) {
                return StructuralError{"invalid object identifier"}
        }
 
-       err = out.WriteByte(byte(oid[0]*40 + oid[1]))
+       err = marshalBase128Int(out, int64(oid[0]*40+oid[1]))
        if err != nil {
                return
        }

diff --git a/src/pkg/encoding/asn1/marshal_test.go b/src/pkg/encoding/asn1/marshal_test.go
index b4dbe71ef3c7fe6403757395f8571124ed0ef6d1..763c86da23f5b0b5b2ea7e2cb361fd8e8f6375e0 100644 (file)
--- a/src/pkg/encoding/asn1/marshal_test.go
+++ b/src/pkg/encoding/asn1/marshal_test.go
@@ -87,6 +87,7 @@ var marshalTests = []marshalTest{
        {BitString{[]byte{0x81, 0xf0}, 12}, "03030481f0"},
        {ObjectIdentifier([]int{1, 2, 3, 4}), "06032a0304"},
        {ObjectIdentifier([]int{1, 2, 840, 133549, 1, 1, 5}), "06092a864888932d010105"},
+       {ObjectIdentifier([]int{2, 100, 3}), "0603813403"},
        {"test", "130474657374"},
        {
                "" +