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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
// <OWNER>Microsoft</OWNER>
//
//
// X509Utils.cs
//
namespace System.Security.Cryptography.X509Certificates {
using System;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
using System.Security.Permissions;
using System.Text;
using _FILETIME = System.Runtime.InteropServices.ComTypes.FILETIME;
internal class X509Utils {
private X509Utils () {}
// this method maps X509RevocationFlag to crypto API flags.
internal static uint MapRevocationFlags (X509RevocationMode revocationMode, X509RevocationFlag revocationFlag) {
uint dwFlags = 0;
if (revocationMode == X509RevocationMode.NoCheck)
return dwFlags;
if (revocationMode == X509RevocationMode.Offline)
dwFlags |= CAPI.CERT_CHAIN_REVOCATION_CHECK_CACHE_ONLY;
if (revocationFlag == X509RevocationFlag.EndCertificateOnly)
dwFlags |= CAPI.CERT_CHAIN_REVOCATION_CHECK_END_CERT;
else if (revocationFlag == X509RevocationFlag.EntireChain)
dwFlags |= CAPI.CERT_CHAIN_REVOCATION_CHECK_CHAIN;
else
dwFlags |= CAPI.CERT_CHAIN_REVOCATION_CHECK_CHAIN_EXCLUDE_ROOT;
return dwFlags;
}
private static readonly char[] hexValues = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
internal static string EncodeHexString (byte[] sArray) {
return EncodeHexString(sArray, 0, (uint) sArray.Length);
}
internal static string EncodeHexString (byte[] sArray, uint start, uint end) {
String result = null;
if (sArray != null) {
char[] hexOrder = new char[(end - start) * 2];
uint digit;
for (uint i = start, j = 0; i < end; i++) {
digit = (uint) ((sArray[i] & 0xf0) >> 4);
hexOrder[j++] = hexValues[digit];
digit = (uint) (sArray[i] & 0x0f);
hexOrder[j++] = hexValues[digit];
}
result = new String(hexOrder);
}
return result;
}
internal static string EncodeHexStringFromInt (byte[] sArray) {
return EncodeHexStringFromInt(sArray, 0, (uint) sArray.Length);
}
internal static string EncodeHexStringFromInt (byte[] sArray, uint start, uint end) {
String result = null;
if(sArray != null) {
char[] hexOrder = new char[(end - start) * 2];
uint i = end;
uint digit, j=0;
while (i-- > start) {
digit = (uint) (sArray[i] & 0xf0) >> 4;
hexOrder[j++] = hexValues[digit];
digit = (uint) (sArray[i] & 0x0f);
hexOrder[j++] = hexValues[digit];
}
result = new String(hexOrder);
}
return result;
}
internal static byte HexToByte (char val) {
if (val <= '9' && val >= '0')
return (byte) (val - '0');
else if (val >= 'a' && val <= 'f')
return (byte) ((val - 'a') + 10);
else if (val >= 'A' && val <= 'F')
return (byte) ((val - 'A') + 10);
else
return 0xFF;
}
internal static byte[] DecodeHexString (string s) {
string hexString = Utils.DiscardWhiteSpaces(s);
uint cbHex = (uint) hexString.Length / 2;
byte[] hex = new byte[cbHex];
int i = 0;
for (int index = 0; index < cbHex; index++) {
hex[index] = (byte) ((HexToByte(hexString[i]) << 4) | HexToByte(hexString[i+1]));
i += 2;
}
return hex;
}
[SecurityCritical]
internal static unsafe bool MemEqual (byte * pbBuf1, uint cbBuf1, byte * pbBuf2, uint cbBuf2) {
if (cbBuf1 != cbBuf2)
return false;
while (cbBuf1-- > 0) {
if (*pbBuf1++ != *pbBuf2++) {
return false;
}
}
return true;
}
[SecurityCritical]
internal static SafeLocalAllocHandle StringToAnsiPtr (string s) {
byte[] arr = new byte[s.Length + 1];
Encoding.ASCII.GetBytes(s, 0, s.Length, arr, 0);
SafeLocalAllocHandle pb = CAPI.LocalAlloc(CAPI.LMEM_FIXED, new IntPtr(arr.Length));
Marshal.Copy(arr, 0, pb.DangerousGetHandle(), arr.Length);
return pb;
}
[SecurityCritical]
internal static SafeCertContextHandle GetCertContext (X509Certificate2 certificate) {
SafeCertContextHandle safeCertContext = CAPI.CertDuplicateCertificateContext(certificate.Handle);
GC.KeepAlive(certificate);
return safeCertContext;
}
[SecurityCritical]
internal static bool GetPrivateKeyInfo (SafeCertContextHandle safeCertContext, ref CspParameters parameters) {
SafeLocalAllocHandle ptr = SafeLocalAllocHandle.InvalidHandle;
uint cbData = 0;
if (!CAPI.CAPISafe.CertGetCertificateContextProperty(safeCertContext,
CAPI.CERT_KEY_PROV_INFO_PROP_ID,
ptr,
ref cbData)) {
int dwErrorCode = Marshal.GetLastWin32Error();
if (dwErrorCode == CAPI.CRYPT_E_NOT_FOUND)
return false;
else
throw new CryptographicException(Marshal.GetLastWin32Error());
}
ptr = CAPI.LocalAlloc(CAPI.LMEM_FIXED, new IntPtr(cbData));
if (!CAPI.CAPISafe.CertGetCertificateContextProperty(safeCertContext,
CAPI.CERT_KEY_PROV_INFO_PROP_ID,
ptr,
ref cbData)) {
int dwErrorCode = Marshal.GetLastWin32Error();
if (dwErrorCode == CAPI.CRYPT_E_NOT_FOUND)
return false;
else
throw new CryptographicException(Marshal.GetLastWin32Error());
}
CAPI.CRYPT_KEY_PROV_INFO pKeyProvInfo = (CAPI.CRYPT_KEY_PROV_INFO) Marshal.PtrToStructure(ptr.DangerousGetHandle(), typeof(CAPI.CRYPT_KEY_PROV_INFO));
parameters.ProviderName = pKeyProvInfo.pwszProvName;
parameters.KeyContainerName = pKeyProvInfo.pwszContainerName;
parameters.ProviderType = (int) pKeyProvInfo.dwProvType;
parameters.KeyNumber = (int) pKeyProvInfo.dwKeySpec;
parameters.Flags = (CspProviderFlags) ((pKeyProvInfo.dwFlags & CAPI.CRYPT_MACHINE_KEYSET) == CAPI.CRYPT_MACHINE_KEYSET ? CspProviderFlags.UseMachineKeyStore : 0);
ptr.Dispose();
return true;
}
// this method create a memory store from a certificate collection
[SecurityCritical]
internal static SafeCertStoreHandle ExportToMemoryStore (X509Certificate2Collection collection,
X509Certificate2Collection collection2 = null) {
//
// We need to Assert all StorePermission flags since this is a memory store and we want
// semi-trusted code to be able to export certificates to a memory store.
//
StorePermission sp = new StorePermission(StorePermissionFlags.AllFlags);
sp.Assert();
SafeCertStoreHandle safeCertStoreHandle;
// we always want to use CERT_STORE_ENUM_ARCHIVED_FLAG since we want to preserve the collection in this operation.
// By default, Archived certificates will not be included.
safeCertStoreHandle = CAPI.CertOpenStore(new IntPtr(CAPI.CERT_STORE_PROV_MEMORY),
CAPI.X509_ASN_ENCODING | CAPI.PKCS_7_ASN_ENCODING,
IntPtr.Zero,
CAPI.CERT_STORE_ENUM_ARCHIVED_FLAG | CAPI.CERT_STORE_CREATE_NEW_FLAG,
null);
if (safeCertStoreHandle == null || safeCertStoreHandle.IsInvalid)
throw new CryptographicException(Marshal.GetLastWin32Error());
AddToStore(safeCertStoreHandle, collection);
if (collection2 != null) {
AddToStore(safeCertStoreHandle, collection2);
}
return safeCertStoreHandle;
}
[SecurityCritical]
private static void AddToStore(SafeCertStoreHandle safeCertStoreHandle, X509Certificate2Collection collection)
{
//
// We use CertAddCertificateLinkToStore to keep a link to the original store, so any property changes get
// applied to the original store. This has a limit of 99 links per cert context however.
//
// X509Store.Add(Range) uses CertAddCertificateContextToStore, which would lose information like ephemeral
// private key associations.
foreach (X509Certificate2 x509 in collection) {
using (SafeCertContextHandle ctx = X509Utils.GetCertContext(x509)) {
if (!CAPI.CertAddCertificateLinkToStore(safeCertStoreHandle,
ctx,
CAPI.CERT_STORE_ADD_ALWAYS,
SafeCertContextHandle.InvalidHandle))
throw new CryptographicException(Marshal.GetLastWin32Error());
}
}
}
[SecuritySafeCritical]
internal static uint OidToAlgId (string value) {
SafeLocalAllocHandle pszOid = StringToAnsiPtr(value);
CAPI.CRYPT_OID_INFO pOIDInfo = CAPI.CryptFindOIDInfo(CAPI.CRYPT_OID_INFO_OID_KEY, pszOid, 0);
return pOIDInfo.Algid;
}
internal static bool IsSelfSigned (X509Chain chain) {
X509ChainElementCollection elements = chain.ChainElements;
if (elements.Count != 1)
return false;
X509Certificate2 certificate = elements[0].Certificate;
if (String.Compare(certificate.SubjectName.Name, certificate.IssuerName.Name, StringComparison.OrdinalIgnoreCase) == 0)
return true;
return false;
}
[SecurityCritical]
internal static SafeLocalAllocHandle CopyOidsToUnmanagedMemory (OidCollection oids) {
SafeLocalAllocHandle safeLocalAllocHandle = SafeLocalAllocHandle.InvalidHandle;
if (oids == null || oids.Count == 0)
return safeLocalAllocHandle;
int ptrSize = oids.Count * Marshal.SizeOf(typeof(IntPtr));
int oidSize = 0;
foreach (Oid oid in oids) {
oidSize += (oid.Value.Length + 1);
}
safeLocalAllocHandle = CAPI.LocalAlloc(CAPI.LPTR, new IntPtr((uint) ptrSize + (uint) oidSize));
IntPtr pOid = new IntPtr((long)safeLocalAllocHandle.DangerousGetHandle() + ptrSize);
for (int index=0; index < oids.Count; index++) {
Marshal.WriteIntPtr(new IntPtr((long) safeLocalAllocHandle.DangerousGetHandle() + index * Marshal.SizeOf(typeof(IntPtr))), pOid);
byte[] ansiOid = Encoding.ASCII.GetBytes(oids[index].Value);
Marshal.Copy(ansiOid, 0, pOid, ansiOid.Length);
pOid = new IntPtr((long) pOid + oids[index].Value.Length + 1);
}
return safeLocalAllocHandle;
}
//
// Builds a certificate chain.
//
[SecurityCritical]
internal static X509Certificate2Collection GetCertificates(SafeCertStoreHandle safeCertStoreHandle) {
X509Certificate2Collection collection = new X509Certificate2Collection();
IntPtr pEnumContext = CAPI.CertEnumCertificatesInStore(safeCertStoreHandle, IntPtr.Zero);
while (pEnumContext != IntPtr.Zero) {
X509Certificate2 certificate = new X509Certificate2(pEnumContext);
collection.Add(certificate);
pEnumContext = CAPI.CertEnumCertificatesInStore(safeCertStoreHandle, pEnumContext);
}
return collection;
}
[SecurityCritical]
internal static unsafe int BuildChain (IntPtr hChainEngine,
SafeCertContextHandle pCertContext,
X509Certificate2Collection extraStore,
OidCollection applicationPolicy,
OidCollection certificatePolicy,
X509RevocationMode revocationMode,
X509RevocationFlag revocationFlag,
DateTime verificationTime,
TimeSpan timeout,
ref SafeCertChainHandle ppChainContext) {
if (pCertContext == null || pCertContext.IsInvalid)
throw new ArgumentException(SecurityResources.GetResourceString("Cryptography_InvalidContextHandle"), "pCertContext");
SafeCertStoreHandle hCertStore = SafeCertStoreHandle.InvalidHandle;
if (extraStore != null && extraStore.Count > 0)
hCertStore = X509Utils.ExportToMemoryStore(extraStore);
CAPI.CERT_CHAIN_PARA ChainPara = new CAPI.CERT_CHAIN_PARA();
// Initialize the structure size.
ChainPara.cbSize = (uint) Marshal.SizeOf(ChainPara);
// Application policy
SafeLocalAllocHandle applicationPolicyHandle = SafeLocalAllocHandle.InvalidHandle;
if (applicationPolicy != null && applicationPolicy.Count > 0) {
ChainPara.RequestedUsage.dwType = CAPI.USAGE_MATCH_TYPE_AND;
ChainPara.RequestedUsage.Usage.cUsageIdentifier = (uint) applicationPolicy.Count;
applicationPolicyHandle = X509Utils.CopyOidsToUnmanagedMemory(applicationPolicy);
ChainPara.RequestedUsage.Usage.rgpszUsageIdentifier = applicationPolicyHandle.DangerousGetHandle();
}
// Certificate policy
SafeLocalAllocHandle certificatePolicyHandle = SafeLocalAllocHandle.InvalidHandle;
if (certificatePolicy != null && certificatePolicy.Count > 0) {
ChainPara.RequestedIssuancePolicy.dwType = CAPI.USAGE_MATCH_TYPE_AND;
ChainPara.RequestedIssuancePolicy.Usage.cUsageIdentifier = (uint) certificatePolicy.Count;
certificatePolicyHandle = X509Utils.CopyOidsToUnmanagedMemory(certificatePolicy);
ChainPara.RequestedIssuancePolicy.Usage.rgpszUsageIdentifier = certificatePolicyHandle.DangerousGetHandle();
}
ChainPara.dwUrlRetrievalTimeout = (uint) timeout.Milliseconds;
_FILETIME ft = new _FILETIME();
*((long*) &ft) = verificationTime.ToFileTime();
uint flags = X509Utils.MapRevocationFlags(revocationMode, revocationFlag);
// Build the chain.
if (!CAPI.CAPISafe.CertGetCertificateChain(hChainEngine,
pCertContext,
ref ft,
hCertStore,
ref ChainPara,
flags,
IntPtr.Zero,
ref ppChainContext))
return Marshal.GetHRForLastWin32Error();
applicationPolicyHandle.Dispose();
certificatePolicyHandle.Dispose();
return CAPI.S_OK;
}
//
// Verifies whether a certificate is valid for the specified policy.
// S_OK means the certificate is valid for the specified policy.
// S_FALSE means the certificate is invalid for the specified policy.
// Anything else is an error.
//
[SecurityCritical]
internal static unsafe int VerifyCertificate (SafeCertContextHandle pCertContext,
OidCollection applicationPolicy,
OidCollection certificatePolicy,
X509RevocationMode revocationMode,
X509RevocationFlag revocationFlag,
DateTime verificationTime,
TimeSpan timeout,
X509Certificate2Collection extraStore,
IntPtr pszPolicy,
IntPtr pdwErrorStatus) {
if (pCertContext == null || pCertContext.IsInvalid)
throw new ArgumentException("pCertContext");
CAPI.CERT_CHAIN_POLICY_PARA PolicyPara = new CAPI.CERT_CHAIN_POLICY_PARA(Marshal.SizeOf(typeof(CAPI.CERT_CHAIN_POLICY_PARA)));
CAPI.CERT_CHAIN_POLICY_STATUS PolicyStatus = new CAPI.CERT_CHAIN_POLICY_STATUS(Marshal.SizeOf(typeof(CAPI.CERT_CHAIN_POLICY_STATUS)));
// Build the chain.
SafeCertChainHandle pChainContext = SafeCertChainHandle.InvalidHandle;
int hr = X509Utils.BuildChain(new IntPtr(CAPI.HCCE_CURRENT_USER),
pCertContext,
extraStore,
applicationPolicy,
certificatePolicy,
revocationMode,
revocationFlag,
verificationTime,
timeout,
ref pChainContext);
if (hr != CAPI.S_OK)
return hr;
// Verify the chain using the specified policy.
if (CAPI.CAPISafe.CertVerifyCertificateChainPolicy(pszPolicy, pChainContext, ref PolicyPara, ref PolicyStatus)) {
if (pdwErrorStatus != IntPtr.Zero)
*(uint*) pdwErrorStatus = PolicyStatus.dwError;
if (PolicyStatus.dwError != 0)
return CAPI.S_FALSE;
} else {
// The API failed.
return Marshal.GetHRForLastWin32Error();
}
return CAPI.S_OK;
}
}
}
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