pkcs12: drop PKCS#12 attributes with unknown OIDs

Looking at our own use case as well as people running into the same issue
[1][2], it seems like users usually don't care about decoding unknown
PKCS12Attributes.

[1]: golang/go#24325
[2]: SSLMate/go-pkcs12#4

Fixes golang/go#24325

Change-Id: I4f3700d2551af6dac215c49dd179ce46c4b2a9db
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/241281
Reviewed-by: Filippo Valsorda <[email protected]>
Run-TryBot: Filippo Valsorda <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>

Author: chronologos

pkcs12/pkcs12.go

@@ -30,6 +30,8 @@ var (
 	oidFriendlyName     = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 1, 9, 20})
 	oidLocalKeyID       = asn1.ObjectIdentifier([]int{1, 2, 840, 113549, 1, 9, 21})
 	oidMicrosoftCSPName = asn1.ObjectIdentifier([]int{1, 3, 6, 1, 4, 1, 311, 17, 1})
+
+	errUnknownAttributeOID = errors.New("pkcs12: unknown attribute OID")
 )
 
 type pfxPdu struct {
@@ -104,6 +106,7 @@ func unmarshal(in []byte, out interface{}) error {
 }
 
 // ToPEM converts all "safe bags" contained in pfxData to PEM blocks.
+// Unknown attributes are discarded.
 //
 // Note that although the returned PEM blocks for private keys have type
 // "PRIVATE KEY", the bytes are not encoded according to PKCS #8, but according
@@ -139,6 +142,9 @@ func convertBag(bag *safeBag, password []byte) (*pem.Block, error) {
 
 	for _, attribute := range bag.Attributes {
 		k, v, err := convertAttribute(&attribute)
+		if err == errUnknownAttributeOID {
+			continue
+		}
 		if err != nil {
 			return nil, err
 		}
@@ -192,7 +198,7 @@ func convertAttribute(attribute *pkcs12Attribute) (key, value string, err error)
 		key = "Microsoft CSP Name"
 		isString = true
 	default:
-		return "", "", errors.New("pkcs12: unknown attribute with OID " + attribute.Id.String())
+		return "", "", errUnknownAttributeOID
 	}
 
 	if isString {

pkcs12/pkcs12_test.go

@@ -89,6 +89,9 @@ func ExampleToPEM() {
 var testdata = map[string]string{
 	// 'null' password test case
 	"Windows Azure Tools": `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`,
+	// Windows IAS PEAP & LDAPS certificates test case
+	// Unknown OID 1.3.6.1.4.1.311.17.2 should be dropped
+	"Windows IAS PEAP & LDAPS certificates": `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`,
 	// empty string password test case
 	"[email protected]": `MIIJzgIBAzCCCZQGCSqGSIb3DQEHAaCCCYUEggmBMIIJfTCCA/cGCSqGSIb3DQEHBqCCA+gwggPk
 AgEAMIID3QYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQYwDgQIIszfRGqcmPcCAggAgIIDsOZ9Eg1L