static int GetRSAPublicKeySize(byte[] kv)
{
AsnElt ae = AsnElt.Decode(kv);
ae.CheckTag(AsnElt.SEQUENCE);
ae.CheckNumSub(2);
AsnElt ai = ae.GetSub(0);
ai.CheckTag(AsnElt.INTEGER);
ai.CheckPrimitive();
byte[] v = ai.CopyValue();
if (v.Length > 0 && v[0] >= 0x80)
{
throw new AsnException(
"Invalid RSA modulus (negative)");
}
int bitLen = M.BitLength(v);
if (bitLen < 512)
{
throw new AsnException(string.Format(
"Invalid RSA modulus ({0} bits)", bitLen));
}
else if ((v[v.Length - 1] & 0x01) == 0)
{
throw new AsnException("Invalid RSA modulus (even)");
}
return(bitLen);
}
/*
* This method expects the DSA parameters, as an ASN.1 object.
*/
static int GetDSAPublicKeySize(AsnElt adp)
{
if (adp == null)
{
/*
* No parameters -- this means inheritance from
* the CA, which we do not analyse because we do
* not do chain building.
*/
return(0);
}
adp.CheckTag(AsnElt.SEQUENCE);
adp.CheckNumSub(3);
foreach (AsnElt ai in adp.Sub)
{
ai.CheckTag(AsnElt.INTEGER);
ai.CheckPrimitive();
}
byte[] v = adp.GetSub(0).CopyValue();
if (v.Length > 0 && v[0] >= 0x80)
{
throw new AsnException(
"Invalid RSA modulus (negative)");
}
int bitLen = M.BitLength(v);
/*
* Acceptable modulus sizes for DSA have varied with
* successive versions of FIPS 186:
* 512 to 1024, and multiple of 64 (FIPS 186-1)
* 1024 only (FIPS 186-2)
* 1024, 2048 or 3072 (FIPS 186-3 and 186-4)
*
* Future versions might allow larger lengths. We
* apply the following rules: acceptable sizes are
* either multiple of 1024, or multiple of 64 in
* the 512..1024 range.
*/
bool goodLen;
if (bitLen < 1024)
{
goodLen = (bitLen >= 512 && ((bitLen & 0x3F) == 0));
}
else
{
goodLen = ((bitLen & 0x3FF) == 0);
}
if (!goodLen)
{
throw new AsnException(string.Format(
"Invalid DSA modulus ({0} bits)", bitLen));
}
else if ((v[v.Length - 1] & 0x01) == 0)
{
throw new AsnException("Invalid DSA modulus (even)");
}
return(bitLen);
}
static IPublicKey DecodePublicKeyRSA(byte[] pub)
{
AsnElt ae = AsnElt.Decode(pub);
ae.CheckTag(AsnElt.SEQUENCE);
ae.CheckNumSub(2);
byte[] n = GetPositiveInteger(ae.GetSub(0));
byte[] e = GetPositiveInteger(ae.GetSub(1));
return(new RSAPublicKey(n, e));
}
static ECCurve DecodeCurve(AsnElt acc)
{
/*
* We support only named curves for now. PKIX does not
* want to see any other kind of curve anyway (see RFC
* 5480).
*/
acc.CheckTag(AsnElt.OBJECT_IDENTIFIER);
string oid = acc.GetOID();
return(OIDToCurve(oid));
}
static byte[] GetPositiveInteger(AsnElt ae)
{
ae.CheckTag(AsnElt.INTEGER);
byte[] x = ae.CopyValue();
if (x.Length == 0)
{
throw new AsnException("Invalid integer (empty)");
}
if (x[0] >= 0x80)
{
throw new AsnException("Invalid integer (negative)");
}
return(x);
}
static IPrivateKey DecodePrivateKeyPKCS8(AsnElt ak)
{
ak.CheckNumSub(3);
ak.GetSub(0).CheckTag(AsnElt.INTEGER);
long v = ak.GetSub(0).GetInteger();
if (v != 0)
{
throw new AsnException(
"Unsupported PKCS#8 version: " + v);
}
AsnElt aai = ak.GetSub(1);
aai.CheckTag(AsnElt.SEQUENCE);
aai.CheckNumSubMin(1);
aai.CheckNumSubMin(2);
aai.GetSub(0).CheckTag(AsnElt.OBJECT_IDENTIFIER);
string oid = aai.GetSub(0).GetOID();
ak.GetSub(2).CheckTag(AsnElt.OCTET_STRING);
byte[] rawKey = ak.GetSub(2).CopyValue();
AsnElt ark = AsnElt.Decode(rawKey);
switch (oid)
{
case OID_RSA:
case OID_RSA_OAEP:
case OID_RSA_PSS:
return(DecodePrivateKeyRSA(ark));
/* disabled DSA
* case OID_DSA:
* return DecodePrivateKeyDSA(ark);
*/
case OID_EC:
/*
* For elliptic curves, the parameters may
* include the curve specification.
*/
ECCurve curve = (aai.Sub.Length == 2)
? DecodeCurve(aai.GetSub(1)) : null;
return(DecodePrivateKeyEC(ark, curve));
default:
throw new AsnException(
"Unknown PKCS#8 key type: " + oid);
}
}
/*
* Generic parsing. If 'strictStrings' is true, then the following
* rules are enforced:
* -- Every SET in the sequence of RDN must have size 1.
* -- Every name element is decoded as a string (by tag).
*
* If 'strictStrings' is false, then multiple elements may appear
* in each SET, and values needs not be decodable as string (values
* with a known OID must still be decodable).
*
* This constructor checks that within a single RDN, no two
* attributes may have the same type.
*
* On decoding error, an AsnException is thrown.
*/
public X500Name(AsnElt aDN, bool strictStrings)
{
/*
* Note: the SEQUENCE tag MUST be present, since the
* ASN.1 definition of Name starts with a CHOICE; thus,
* any tag override would have to be explicit, not
* implicit.
*/
aDN.CheckConstructed();
aDN.CheckTag(AsnElt.SEQUENCE);
List <List <DNPart> > r = new List <List <DNPart> >();
foreach (AsnElt aRDN in aDN.Sub)
{
aRDN.CheckConstructed();
aRDN.CheckTag(AsnElt.SET);
aRDN.CheckNumSubMin(1);
int n = aRDN.Sub.Length;
if (n != 1 && strictStrings)
{
throw new AsnException(String.Format(
"several ({0}) values in RDN", n));
}
List <DNPart> r2 = new List <DNPart>();
r.Add(r2);
for (int i = 0; i < n; i++)
{
AsnElt aTV = aRDN.Sub[i];
aTV.CheckConstructed();
aTV.CheckTag(AsnElt.SEQUENCE);
aTV.CheckNumSub(2);
AsnElt aOID = aTV.GetSub(0);
aOID.CheckTag(AsnElt.OBJECT_IDENTIFIER);
AsnElt aVal = aTV.GetSub(1);
string nt = aOID.GetOID();
DNPart dnp = new DNPart(nt, aVal);
if (strictStrings && !dnp.IsString)
{
throw new AsnException(
"RDN is not a string");
}
r2.Add(dnp);
}
}
Init(r);
}
/*
* Decode a public key (SubjectPublicKeyInfo).
*/
public static IPublicKey DecodePublicKey(AsnElt ak)
{
ak.CheckNumSub(2);
AlgorithmIdentifier ai = new AlgorithmIdentifier(ak.GetSub(0));
AsnElt abs = ak.GetSub(1);
abs.CheckTag(AsnElt.BIT_STRING);
byte[] pub = abs.GetBitString();
switch (ai.OID)
{
case OID_RSA:
case OID_RSA_OAEP:
case OID_RSA_PSS:
return(DecodePublicKeyRSA(pub));
/* disabled DSA
* case OID_DSA:
* return DecodePublicKeyDSA(pub);
*/
case OID_EC:
/*
* For elliptic curves, the parameters should
* include the curve specification.
*/
AsnElt ap = ai.Parameters;
if (ap == null)
{
throw new AsnException("No curve specified"
+ " for EC public key");
}
if (ap.TagClass != AsnElt.UNIVERSAL ||
ap.TagValue != AsnElt.OBJECT_IDENTIFIER)
{
throw new AsnException("Unsupported type"
+ " of curve specification");
}
return(new ECPublicKey(OIDToCurve(ap.GetOID()), pub));
default:
throw new AsnException(
"Unknown public key type: " + ai.OID);
}
}
/*
* Create an instance over the provided ASN.1 element. If
* 'checkTag' is true, then the outer tag will be checked to
* match the universal tag for SEQUENCE. Set 'checkTag' to
* false if the tag was already checked, or if it has been
* overwritten with an implicit tag.
*/
internal AlgorithmIdentifier(AsnElt ai, bool checkTag)
{
if (checkTag)
{
ai.CheckTag(AsnElt.SEQUENCE);
}
ai.CheckNumSubMin(1);
ai.CheckNumSubMax(2);
AsnElt ao = ai.GetSub(0);
ao.CheckTag(AsnElt.OBJECT_IDENTIFIER);
oid = ao.GetOID();
if (ai.Sub.Length >= 2)
{
parameters = ai.GetSub(1);
}
else
{
parameters = null;
}
}
void ProcessAltNames(byte[] extVal, bool forIssuer)
{
/*
* Alternative names processing.
*
* If the extension contains an X.500 name, and the
* corresponding DN in the certificate TBS is empty,
* then that X.500 name will be used as subjectDN or
* issuerDN. However, if the extension contains several
* X.500 names, or if the DN in the TBS is non-empty,
* then the X.500 name(s) in the extension will be
* ignored.
*
* For the subject, we also gather dNSNames into
* the "serverNames" array.
*/
List <string> dnsNames = new List <string>();
AsnElt ae = AsnElt.Decode(extVal);
ae.CheckTag(AsnElt.SEQUENCE);
ae.CheckConstructed();
bool foundDN = false;
X500Name dn = null;
foreach (AsnElt agn in ae.Sub)
{
if (agn.TagClass != AsnElt.CONTEXT)
{
continue;
}
switch (agn.TagValue)
{
case 2:
dnsNames.Add(agn.GetString(AsnElt.IA5String));
break;
case 4:
/*
* Since "Name" is a CHOICE, the context
* tag applied on it as part of the
* GeneralName structure is EXPLICIT. We
* have to remove it.
*/
agn.CheckNumSub(1);
AsnElt adn = agn.GetSub(0);
if (!foundDN)
{
dn = new X500Name(adn, false);
}
else
{
dn = null;
}
foundDN = true;
break;
}
}
if (foundDN && dn != null)
{
if (forIssuer)
{
if (issuerDN.IsEmpty)
{
issuerDN = dn;
}
}
else
{
if (subjectDN.IsEmpty)
{
subjectDN = dn;
}
}
}
if (!forIssuer && dnsNames.Count > 0)
{
serverNames = dnsNames.ToArray();
}
}
/*
* Create an instance by decoding the provided object.
* This constructor assumes ASN.1 DER encoding (not Base64,
* not PEM).
*
* On decoding error, an AsnException is thrown.
*/
public X509Cert(byte[] cert)
{
/*
* Compute thumbprint.
*/
thumbprint = M.DoSHA1(cert).ToUpperInvariant();
/*
* Outer layer decoding and extraction of the signature
* hash algorithm.
*/
AsnElt ac = AsnElt.Decode(cert);
ac.CheckTag(AsnElt.SEQUENCE);
ac.CheckNumSub(3);
hashAlgorithm = GetSignHashName(
new AlgorithmIdentifier(ac.GetSub(1)));
/*
* TBS exploration. First field is optional; if present,
* it contains the certificate version.
*/
AsnElt atbs = ac.GetSub(0);
atbs.CheckNumSubMin(6);
atbs.CheckNumSubMax(10);
int off = 0;
if (atbs.GetSub(0).TagValue == 0)
{
off++;
}
/*
* Serial numer: nominally an INTEGER, we extract the
* raw bytes, because some CA wrongly use unsigned
* encoding.
*/
AsnElt aserial = atbs.GetSub(off);
aserial.CheckTag(AsnElt.INTEGER);
byte[] sv = aserial.CopyValue();
int svk = 0;
while (svk < sv.Length && sv[svk] == 0)
{
svk++;
}
if (svk == sv.Length)
{
serialHex = "00";
}
else
{
StringBuilder sb = new StringBuilder();
while (svk < sv.Length)
{
sb.AppendFormat("{0:X2}", sv[svk++]);
}
serialHex = sb.ToString();
}
/*
* Issuer and subject DN.
*/
issuerDN = new X500Name(atbs.GetSub(off + 2));
subjectDN = new X500Name(atbs.GetSub(off + 4));
/*
* Validity dates.
*/
AsnElt adates = atbs.GetSub(off + 3);
adates.CheckTag(AsnElt.SEQUENCE);
adates.CheckNumSub(2);
validFrom = adates.GetSub(0).GetTime();
validTo = adates.GetSub(1).GetTime();
/*
* Public key.
*/
AsnElt aspki = atbs.GetSub(off + 5);
aspki.CheckTag(AsnElt.SEQUENCE);
aspki.CheckNumSub(2);
AlgorithmIdentifier kt =
new AlgorithmIdentifier(aspki.GetSub(0));
AsnElt aktp = kt.Parameters;
AsnElt apkv = aspki.GetSub(1);
apkv.CheckTag(AsnElt.BIT_STRING);
byte[] kv = apkv.GetBitString();
curveOID = null;
keyType = "UNKNOWN";
keySize = 0;
switch (kt.OID)
{
/*
* RSA public keys should use the 'rsaEncryption' OID,
* but some are tagged with the OAEP or the PSS OID,
* to somehow specify that the RSA key should be used
* only with OAEP or PSS.
*/
case "1.2.840.113549.1.1.1":
case "1.2.840.113549.1.1.7":
case "1.2.840.113549.1.1.10":
keyType = "RSA";
keySize = GetRSAPublicKeySize(kv);
break;
/*
* All DSA public keys should use that OID.
*/
case "1.2.840.10040.4.1":
keyType = "DSA";
keySize = GetDSAPublicKeySize(aktp);
break;
/*
* Elliptic curve keys.
* We only support "normal" elliptic curve keys, not
* restricted keys.
* We only supported named curves (RFC 5480 forbids
* explicit curve parameters).
*/
case "1.2.840.10045.2.1":
if (aktp == null)
{
break;
}
if (aktp.TagClass != AsnElt.UNIVERSAL ||
aktp.TagValue != AsnElt.OBJECT_IDENTIFIER)
{
break;
}
keyType = "EC";
curveOID = aktp.GetOID();
keySize = GetCurveSize(curveOID);
break;
/* TODO: GOST R 34.10-94 and GOST R 34.10-2001 */
}
/*
* If there are extensions, process them.
* extract the dNSNames.
*/
serverNames = null;
extensions = new SortedDictionary <string, Extension>(
StringComparer.Ordinal);
for (int i = off + 6; i < atbs.Sub.Length; i++)
{
AsnElt aexts = atbs.GetSub(i);
if (aexts.TagClass != AsnElt.CONTEXT ||
aexts.TagValue != 3)
{
continue;
}
aexts.CheckNumSub(1);
aexts = aexts.GetSub(0);
aexts.CheckTag(AsnElt.SEQUENCE);
foreach (AsnElt aext in aexts.Sub)
{
aext.CheckTag(AsnElt.SEQUENCE);
aext.CheckNumSubMin(2);
aext.CheckNumSubMax(3);
AsnElt aoid = aext.GetSub(0);
aoid.CheckTag(AsnElt.OBJECT_IDENTIFIER);
string oid = aoid.GetOID();
AsnElt av;
bool critical = false;
if (aext.Sub.Length == 2)
{
av = aext.GetSub(1);
}
else
{
AsnElt acrit = aext.GetSub(1);
acrit.CheckTag(AsnElt.BOOLEAN);
critical = acrit.GetBoolean();
av = aext.GetSub(2);
}
av.CheckTag(AsnElt.OCTET_STRING);
Extension ext = new Extension(
oid, critical, av.CopyValue());
if (extensions.ContainsKey(oid))
{
throw new AsnException(
"duplicate extension " + oid);
}
extensions[oid] = ext;
ProcessExtension(ext);
}
}
/*
* If there was no SAN, or no dNSName in the SAN, then
* get the Common Name from the subjectDN.
*/
string cn = null;
foreach (DNPart dnp in subjectDN.Parts)
{
if (dnp.FriendlyType == DNPart.COMMON_NAME)
{
if (cn != null)
{
throw new AsnException(
"multiple CN in subject DN");
}
cn = dnp.Value;
}
}
if (serverNames == null)
{
if (cn == null)
{
serverNames = new string[0];
}
else
{
serverNames = new string[] { cn };
}
}
}
static ECPrivateKey DecodePrivateKeyEC(AsnElt ak, ECCurve curve)
{
ak.CheckNumSubMin(2);
ak.GetSub(0).CheckTag(AsnElt.INTEGER);
ak.GetSub(1).CheckTag(AsnElt.OCTET_STRING);
long kt = ak.GetSub(0).GetInteger();
if (kt != 1)
{
throw new AsnException(
"Unsupported EC key type: " + kt);
}
byte[] x = ak.GetSub(1).CopyValue();
byte[] pub = null;
int n = ak.Sub.Length;
int p = 2;
if (p < n)
{
AsnElt acc = ak.GetSub(p);
if (acc.TagClass == AsnElt.CONTEXT &&
acc.TagValue == 0)
{
acc.CheckNumSub(1);
acc = acc.GetSub(0);
ECCurve curve2 = DecodeCurve(acc);
/*
* Here, we support only named curves.
*/
/* obsolete
*/
if (curve == null)
{
curve = curve2;
}
else if (!curve.Equals(curve2))
{
throw new AsnException(string.Format(
"Inconsistent curve"
+ " specification ({0} / {1})",
curve.Name, curve2.Name));
}
p++;
}
}
if (p < n)
{
AsnElt acc = ak.GetSub(p);
if (acc.TagClass == AsnElt.CONTEXT &&
acc.TagValue == 1)
{
acc.CheckNumSub(1);
acc = acc.GetSub(0);
acc.CheckTag(AsnElt.BIT_STRING);
pub = acc.GetBitString();
}
}
if (curve == null)
{
throw new AsnException("No curve specified for EC key");
}
ECPrivateKey esk = new ECPrivateKey(curve, x);
if (pub != null)
{
ECPublicKey epk = new ECPublicKey(curve, pub);
if (!epk.Equals(esk.PublicKey))
{
throw new CryptoException(
"EC key pair public/private mismatch");
}
}
return(esk);
}
