internal static GeneralName Read(DerSequenceReader reader)
{
var tag = reader.PeekTag();
// Per RFC 2634 section 5.4.1 (https://tools.ietf.org/html/rfc2634#section-5.4.1)
// only the directory name choice (#4) is allowed.
if (tag == DerSequenceReader.ContextSpecificConstructedTag4)
{
var value = reader.ReadValue((DerSequenceReader.DerTag)DerSequenceReader.ContextSpecificConstructedTag4);
if (reader.HasData)
{
throw new SignatureException(Strings.InvalidAsn1);
}
var directoryName = new X500DistinguishedName(value);
return(new GeneralName(directoryName));
}
while (reader.HasData)
{
reader.ValidateAndSkipDerValue();
}
throw new SignatureException(Strings.UnsupportedAsn1);
}
public static void NoSupportForMultiByteTags(string caseName, string hexInput)
{
byte[] bytes = hexInput.HexToByteArray();
DerSequenceReader reader = DerSequenceReader.CreateForPayload(bytes);
Assert.Throws <CryptographicException>(() => reader.PeekTag());
Assert.Throws <CryptographicException>(() => reader.SkipValue());
Assert.Throws <CryptographicException>(() => reader.ReadNextEncodedValue());
}
public static void InvalidLengthSpecified(string hexInput)
{
byte[] bytes = hexInput.HexToByteArray();
DerSequenceReader reader = DerSequenceReader.CreateForPayload(bytes);
// Doesn't throw.
reader.PeekTag();
// Since EatTag will have succeeded the reader needs to be reconstructed after each test.
Assert.Throws <CryptographicException>(() => reader.SkipValue());
reader = DerSequenceReader.CreateForPayload(bytes);
Assert.Throws <CryptographicException>(() => reader.ReadOctetString());
reader = DerSequenceReader.CreateForPayload(bytes);
Assert.Throws <CryptographicException>(() => reader.ReadNextEncodedValue());
}
public void FindByTemplateName(string templateName)
{
FindCore(
cert =>
{
X509Extension ext = FindExtension(cert, Oids.EnrollCertTypeExtension);
if (ext != null)
{
// Try a V1 template structure, just a string:
string decodedName = Interop.Crypto.DerStringToManagedString(ext.RawData);
// If this doesn't match, maybe a V2 template will
if (StringComparer.OrdinalIgnoreCase.Equals(templateName, decodedName))
{
return true;
}
}
ext = FindExtension(cert, Oids.CertificateTemplate);
if (ext != null)
{
DerSequenceReader reader = new DerSequenceReader(ext.RawData);
// SEQUENCE (
// OID oid,
// INTEGER major,
// INTEGER minor OPTIONAL
// )
if (reader.PeekTag() == (byte)DerSequenceReader.DerTag.ObjectIdentifier)
{
Oid oid = reader.ReadOid();
if (StringComparer.Ordinal.Equals(templateName, oid.Value))
{
return true;
}
}
}
return false;
});
}
private static void ReadCertPolicyConstraintsExtension(X509Extension extension, CertificatePolicy policy)
{
DerSequenceReader reader = new DerSequenceReader(extension.RawData);
while (reader.HasData)
{
// Policy Constraints context specific tag values are defined in RFC 3280 4.2.1.12,
// and restated (unchanged) in RFC 5280 4.2.1.11.
switch (reader.PeekTag())
{
case DerSequenceReader.ContextSpecificTagFlag | 0:
policy.RequireExplicitPolicyDepth = reader.ReadInteger();
break;
case DerSequenceReader.ContextSpecificTagFlag | 1:
policy.InhibitMappingDepth = reader.ReadInteger();
break;
default:
if (extension.Critical)
{
// If an unknown value is read, but we're marked as critical,
// then we don't know what we're doing and MUST fail validation
// (RFC 3280).
// If it isn't critical then it means we're allowed to be ignorant
// of data defined more recently than we understand.
throw new CryptographicException();
}
break;
}
}
}
private string FormatSubjectAlternativeName(byte[] rawData)
{
// Because SubjectAlternativeName is a commonly parsed structure, we'll
// specifically format this one. And we'll match the OpenSSL format, which
// includes not localizing any of the values (or respecting the multiLine boolean)
//
// The intent here is to be functionally equivalent to OpenSSL GENERAL_NAME_print.
// The end size of this string is hard to predict.
// * dNSName values have a tag that takes four characters to represent ("DNS:")
// and then their payload is ASCII encoded (so one byte -> one char), so they
// work out to be about equal (in chars) to their DER encoded length (in bytes).
// * iPAddress values have a tag that takes 11 characters ("IP Address:") and then
// grow from 4 bytes to up to 15 characters for IPv4, or 16 bytes to 47 characters
// for IPv6
//
// So use a List<string> and just Concat them all when we're done, and we reduce the
// number of times we copy the header values (vs pointers to the header values).
List <string> segments = new List <string>();
try
{
// SubjectAltName ::= GeneralNames
//
// GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName
//
// GeneralName ::= CHOICE {
// otherName [0] OtherName,
// rfc822Name [1] IA5String,
// dNSName [2] IA5String,
// x400Address [3] ORAddress,
// directoryName [4] Name,
// ediPartyName [5] EDIPartyName,
// uniformResourceIdentifier [6] IA5String,
// iPAddress [7] OCTET STRING,
// registeredID [8] OBJECT IDENTIFIER }
//
// OtherName::= SEQUENCE {
// type - id OBJECT IDENTIFIER,
// value[0] EXPLICIT ANY DEFINED BY type - id }
DerSequenceReader altNameReader = new DerSequenceReader(rawData);
while (altNameReader.HasData)
{
if (segments.Count != 0)
{
segments.Add(CommaSpace);
}
byte tag = altNameReader.PeekTag();
if ((tag & DerSequenceReader.ContextSpecificTagFlag) == 0)
{
// All GeneralName values need the ContextSpecific flag.
return(null);
}
GeneralNameType nameType = (GeneralNameType)(tag & DerSequenceReader.TagNumberMask);
bool needsConstructedFlag = false;
switch (nameType)
{
case GeneralNameType.OtherName:
case GeneralNameType.X400Address:
case GeneralNameType.DirectoryName:
case GeneralNameType.EdiPartyName:
needsConstructedFlag = true;
break;
}
if (needsConstructedFlag &&
(tag & DerSequenceReader.ConstructedFlag) == 0)
{
// All of the SEQUENCE types require the constructed bit,
// or OpenSSL will have refused to print it.
return(null);
}
switch (nameType)
{
case GeneralNameType.OtherName:
segments.Add("othername:<unsupported>");
altNameReader.SkipValue();
break;
case GeneralNameType.Rfc822Name:
segments.Add("email:");
segments.Add(altNameReader.ReadIA5String());
break;
case GeneralNameType.DnsName:
segments.Add("DNS:");
segments.Add(altNameReader.ReadIA5String());
break;
case GeneralNameType.X400Address:
segments.Add("X400Name:<unsupported>");
altNameReader.SkipValue();
break;
case GeneralNameType.DirectoryName:
// OpenSSL supports printing one of these, but the logic lives in X509Certificates,
// and it isn't very common. So we'll skip this one until someone asks for it.
segments.Add("DirName:<unsupported>");
altNameReader.SkipValue();
break;
case GeneralNameType.EdiPartyName:
segments.Add("EdiPartyName:<unsupported>");
altNameReader.SkipValue();
break;
case GeneralNameType.UniformResourceIdentifier:
segments.Add("URI:");
segments.Add(altNameReader.ReadIA5String());
break;
case GeneralNameType.IPAddress:
segments.Add("IP Address");
byte[] ipAddressBytes = altNameReader.ReadOctetString();
if (ipAddressBytes.Length == 4)
{
// Add the colon and dotted-decimal representation of IPv4.
segments.Add(
$":{ipAddressBytes[0]}.{ipAddressBytes[1]}.{ipAddressBytes[2]}.{ipAddressBytes[3]}");
}
else if (ipAddressBytes.Length == 16)
{
// Print the IP Address value as colon separated UInt16 hex values without leading zeroes.
// 20 01 0D B8 AC 10 FE 01 00 00 00 00 00 00 00 00
//
// IP Address:2001:DB8:AC10:FE01:0:0:0:0
for (int i = 0; i < ipAddressBytes.Length; i += 2)
{
segments.Add($":{ipAddressBytes[i] << 8 | ipAddressBytes[i + 1]:X}");
}
}
else
{
segments.Add(":<invalid>");
}
break;
case GeneralNameType.RegisteredId:
segments.Add("Registered ID:");
segments.Add(altNameReader.ReadOidAsString());
break;
default:
// A new extension to GeneralName could legitimately hit this,
// but it's correct to say that until we know what that is that
// the pretty-print has failed, and we should fall back to hex.
//
// But it could also simply be poorly encoded user data.
return(null);
}
}
return(string.Concat(segments));
}
catch (CryptographicException)
{
return(null);
}
}
internal static DerSequenceReader SecKeyExport(
SafeSecKeyRefHandle key,
bool exportPrivate)
{
// Apple requires all private keys to be exported encrypted, but since we're trying to export
// as parsed structures we will need to decrypt it for the user.
const string ExportPassword = "******";
SafeCreateHandle exportPassword = exportPrivate
? CoreFoundation.CFStringCreateWithCString(ExportPassword)
: s_nullExportString;
int ret;
SafeCFDataHandle cfData;
int osStatus;
try
{
ret = AppleCryptoNative_SecKeyExport(
key,
exportPrivate ? 1 : 0,
exportPassword,
out cfData,
out osStatus);
}
finally
{
if (exportPassword != s_nullExportString)
{
exportPassword.Dispose();
}
}
byte[] exportedData;
using (cfData)
{
if (ret == 0)
{
throw CreateExceptionForOSStatus(osStatus);
}
if (ret != 1)
{
Debug.Fail($"AppleCryptoNative_SecKeyExport returned {ret}");
throw new CryptographicException();
}
exportedData = CoreFoundation.CFGetData(cfData);
}
DerSequenceReader reader = new DerSequenceReader(exportedData);
if (!exportPrivate)
{
return(reader);
}
byte tag = reader.PeekTag();
// PKCS#8 defines two structures, PrivateKeyInfo, which starts with an integer,
// and EncryptedPrivateKey, which starts with an encryption algorithm (DER sequence).
if (tag == (byte)DerSequenceReader.DerTag.Integer)
{
return(reader);
}
const byte ConstructedSequence =
DerSequenceReader.ConstructedFlag | (byte)DerSequenceReader.DerTag.Sequence;
if (tag == ConstructedSequence)
{
return(ReadEncryptedPkcs8Blob(ExportPassword, reader));
}
Debug.Fail($"Data was neither PrivateKey or EncryptedPrivateKey: {tag:X2}");
throw new CryptographicException();
}
private static DerSequenceReader ReadEncryptedPkcs8Blob(string passphrase, DerSequenceReader reader)
{
// EncryptedPrivateKeyInfo::= SEQUENCE {
// encryptionAlgorithm EncryptionAlgorithmIdentifier,
// encryptedData EncryptedData }
//
// EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier
//
// EncryptedData ::= OCTET STRING
DerSequenceReader algorithmIdentifier = reader.ReadSequence();
string algorithmOid = algorithmIdentifier.ReadOidAsString();
// PBES2 (Password-Based Encryption Scheme 2)
if (algorithmOid != OidPbes2)
{
Debug.Fail($"Expected PBES2 ({OidPbes2}), got {algorithmOid}");
throw new CryptographicException();
}
// PBES2-params ::= SEQUENCE {
// keyDerivationFunc AlgorithmIdentifier { { PBES2 - KDFs} },
// encryptionScheme AlgorithmIdentifier { { PBES2 - Encs} }
// }
DerSequenceReader pbes2Params = algorithmIdentifier.ReadSequence();
algorithmIdentifier = pbes2Params.ReadSequence();
string kdfOid = algorithmIdentifier.ReadOidAsString();
// PBKDF2 (Password-Based Key Derivation Function 2)
if (kdfOid != OidPbkdf2)
{
Debug.Fail($"Expected PBKDF2 ({OidPbkdf2}), got {kdfOid}");
throw new CryptographicException();
}
// PBKDF2-params ::= SEQUENCE {
// salt CHOICE {
// specified OCTET STRING,
// otherSource AlgorithmIdentifier { { PBKDF2 - SaltSources} }
// },
// iterationCount INTEGER (1..MAX),
// keyLength INTEGER(1..MAX) OPTIONAL,
// prf AlgorithmIdentifier { { PBKDF2 - PRFs} } DEFAULT algid - hmacWithSHA1
// }
DerSequenceReader pbkdf2Params = algorithmIdentifier.ReadSequence();
byte[] salt = pbkdf2Params.ReadOctetString();
int iterCount = pbkdf2Params.ReadInteger();
int keySize = -1;
if (pbkdf2Params.HasData && pbkdf2Params.PeekTag() == (byte)DerSequenceReader.DerTag.Integer)
{
keySize = pbkdf2Params.ReadInteger();
}
if (pbkdf2Params.HasData)
{
string prfOid = pbkdf2Params.ReadOidAsString();
// SHA-1 is the only hash algorithm our PBKDF2 supports.
if (prfOid != OidSha1)
{
Debug.Fail($"Expected SHA1 ({OidSha1}), got {prfOid}");
throw new CryptographicException();
}
}
DerSequenceReader encryptionScheme = pbes2Params.ReadSequence();
string cipherOid = encryptionScheme.ReadOidAsString();
// DES-EDE3-CBC (TripleDES in CBC mode)
if (cipherOid != OidTripleDesCbc)
{
Debug.Fail($"Expected DES-EDE3-CBC ({OidTripleDesCbc}), got {cipherOid}");
throw new CryptographicException();
}
byte[] decrypted;
using (TripleDES des3 = TripleDES.Create())
{
if (keySize == -1)
{
foreach (KeySizes keySizes in des3.LegalKeySizes)
{
keySize = Math.Max(keySize, keySizes.MaxSize);
}
}
byte[] iv = encryptionScheme.ReadOctetString();
using (Rfc2898DeriveBytes pbkdf2 = new Rfc2898DeriveBytes(passphrase, salt, iterCount))
using (ICryptoTransform decryptor = des3.CreateDecryptor(pbkdf2.GetBytes(keySize / 8), iv))
{
byte[] encrypted = reader.ReadOctetString();
decrypted = decryptor.TransformFinalBlock(encrypted, 0, encrypted.Length);
}
}
DerSequenceReader pkcs8Reader = new DerSequenceReader(decrypted);
return(pkcs8Reader);
}