C# Security.SecurityBuffer类代码示例

 internal static SecurityStatusPal CompleteAuthToken(
     ref SafeDeleteContext securityContext,
     SecurityBuffer[] inSecurityBufferArray)
 {
     Interop.SECURITY_STATUS winStatus = (Interop.SECURITY_STATUS)SSPIWrapper.CompleteAuthToken(
         GlobalSSPI.SSPIAuth,
         ref securityContext,
         inSecurityBufferArray);
     return SecurityStatusAdapterPal.GetSecurityStatusPalFromInterop(winStatus);
 }

        public static SecurityStatusPal AcceptSecurityContext(ref SafeFreeCredentials credentialsHandle, ref SafeDeleteContext context, SecurityBuffer inputBuffer, SecurityBuffer outputBuffer, bool remoteCertRequired)
        {
            Interop.SspiCli.ContextFlags unusedAttributes = default(Interop.SspiCli.ContextFlags);

            int errorCode = SSPIWrapper.AcceptSecurityContext(
                GlobalSSPI.SSPISecureChannel,
                ref credentialsHandle,
                ref context,
                ServerRequiredFlags | (remoteCertRequired ? Interop.SspiCli.ContextFlags.MutualAuth : Interop.SspiCli.ContextFlags.Zero),
                Interop.SspiCli.Endianness.SECURITY_NATIVE_DREP,
                inputBuffer,
                outputBuffer,
                ref unusedAttributes);

            return SecurityStatusAdapterPal.GetSecurityStatusPalFromNativeInt(errorCode);
        }

        public static SecurityStatusPal InitializeSecurityContext(SafeFreeCredentials credentialsHandle, ref SafeDeleteContext context, string targetName, SecurityBuffer[] inputBuffers, SecurityBuffer outputBuffer)
        {
            Interop.SspiCli.ContextFlags unusedAttributes = default(Interop.SspiCli.ContextFlags);

            int errorCode = SSPIWrapper.InitializeSecurityContext(
                            GlobalSSPI.SSPISecureChannel,
                            credentialsHandle,
                            ref context,
                            targetName,
                            RequiredFlags | Interop.SspiCli.ContextFlags.InitManualCredValidation,
                            Interop.SspiCli.Endianness.SECURITY_NATIVE_DREP,
                            inputBuffers,
                            outputBuffer,
                            ref unusedAttributes);

            return SecurityStatusAdapterPal.GetSecurityStatusPalFromNativeInt(errorCode);
        }

        internal static SecurityStatusPal InitializeSecurityContext(
            SafeFreeCredentials credentialsHandle,
            ref SafeDeleteContext securityContext,
            string spn,
            ContextFlagsPal requestedContextFlags,
            SecurityBuffer[] inSecurityBufferArray,
            SecurityBuffer outSecurityBuffer,
            ref ContextFlagsPal contextFlags)
        {
            Interop.SspiCli.ContextFlags outContextFlags = Interop.SspiCli.ContextFlags.Zero;
            Interop.SECURITY_STATUS winStatus = (Interop.SECURITY_STATUS)SSPIWrapper.InitializeSecurityContext(
                GlobalSSPI.SSPIAuth,
                credentialsHandle,
                ref securityContext,
                spn,
                ContextFlagsAdapterPal.GetInteropFromContextFlagsPal(requestedContextFlags),
                Interop.SspiCli.Endianness.SECURITY_NETWORK_DREP,
                inSecurityBufferArray,
                outSecurityBuffer,
                ref outContextFlags);

            contextFlags = ContextFlagsAdapterPal.GetContextFlagsPalFromInterop(outContextFlags);
            return SecurityStatusAdapterPal.GetSecurityStatusPalFromInterop(winStatus);
        }

        /*++
            Encrypt - Encrypts our bytes before we send them over the wire

            PERF: make more efficient, this does an extra copy when the offset
            is non-zero.

            Input:
                buffer - bytes for sending
                offset -
                size   -
                output - Encrypted bytes
        --*/
        internal Interop.SecurityStatus Encrypt(byte[] buffer, int offset, int size, ref byte[] output, out int resultSize)
        {
            GlobalLog.Enter("SecureChannel#" + Logging.HashString(this) + "::Encrypt");
            GlobalLog.Print("SecureChannel#" + Logging.HashString(this) + "::Encrypt() - offset: " + offset.ToString() + " size: " + size.ToString() + " buffersize: " + buffer.Length.ToString());
            GlobalLog.Print("SecureChannel#" + Logging.HashString(this) + "::Encrypt() buffer:");
            GlobalLog.Dump(buffer, Math.Min(buffer.Length, 128));

            byte[] writeBuffer;
            try
            {
                if (offset < 0 || offset > (buffer == null ? 0 : buffer.Length))
                {
                    throw new ArgumentOutOfRangeException("offset");
                }

                if (size < 0 || size > (buffer == null ? 0 : buffer.Length - offset))
                {
                    throw new ArgumentOutOfRangeException("size");
                }

                resultSize = 0;

                int bufferSizeNeeded = checked(size + _headerSize + _trailerSize);
                if (output != null && bufferSizeNeeded <= output.Length)
                {
                    writeBuffer = output;
                }
                else
                {
                    writeBuffer = new byte[bufferSizeNeeded];
                }

                Buffer.BlockCopy(buffer, offset, writeBuffer, _headerSize, size);
            }
            catch (Exception e)
            {
                if (!ExceptionCheck.IsFatal(e))
                {
                    GlobalLog.Assert(false, "SecureChannel#" + Logging.HashString(this) + "::Encrypt", "Arguments out of range.");
                }

                throw;
            }

            // Encryption using SCHANNEL requires 4 buffers: header, payload, trailer, empty.
            SecurityBuffer[] securityBuffer = new SecurityBuffer[4];

            securityBuffer[0] = new SecurityBuffer(writeBuffer, 0, _headerSize, SecurityBufferType.Header);
            securityBuffer[1] = new SecurityBuffer(writeBuffer, _headerSize, size, SecurityBufferType.Data);
            securityBuffer[2] = new SecurityBuffer(writeBuffer, _headerSize + size, _trailerSize, SecurityBufferType.Trailer);
            securityBuffer[3] = new SecurityBuffer(null, SecurityBufferType.Empty);

            int errorCode = SSPIWrapper.EncryptMessage(GlobalSSPI.SSPISecureChannel, _securityContext, securityBuffer, 0);

            if (errorCode != 0)
            {
                GlobalLog.Leave("SecureChannel#" + Logging.HashString(this) + "::Encrypt ERROR", errorCode.ToString("x"));
                return (Interop.SecurityStatus)errorCode;
            }
            else
            {
                output = writeBuffer;

                // The full buffer may not be used.
                resultSize = securityBuffer[0].size + securityBuffer[1].size + securityBuffer[2].size;
                GlobalLog.Leave("SecureChannel#" + Logging.HashString(this) + "::Encrypt OK", "data size:" + resultSize.ToString());
                return Interop.SecurityStatus.OK;
            }
        }

		static IBufferOffsetSize GetInputBuffer (SecurityBuffer incoming)
		{
			return incoming != null ? new InputBuffer (incoming.token, incoming.offset, incoming.size) : null;
		}

		static void UpdateOutput (IBufferOffsetSize buffer, SecurityBuffer outputBuffer)
		{
			if (buffer != null) {
				outputBuffer.token = buffer.Buffer;
				outputBuffer.offset = buffer.Offset;
				outputBuffer.size = buffer.Size;
				outputBuffer.type = BufferType.Token;
			} else {
				outputBuffer.token = null;
				outputBuffer.size = outputBuffer.offset = 0;
				outputBuffer.type = BufferType.Empty;
			}
		}

        internal static int Decrypt(
            SafeDeleteContext securityContext,
            byte[] buffer,
            int offset,
            int count,
            bool isConfidential,
            bool isNtlm,
            out int newOffset,
            uint sequenceNumber)
        {
            if (offset < 0 || offset > (buffer == null ? 0 : buffer.Length))
            {
                if (GlobalLog.IsEnabled)
                {
                    GlobalLog.Assert("NTAuthentication#" + LoggingHash.HashString(securityContext) + "::Decrypt", "Argument 'offset' out of range.");
                }

                Debug.Fail("NTAuthentication#" + LoggingHash.HashString(securityContext) + "::Decrypt", "Argument 'offset' out of range.");

                throw new ArgumentOutOfRangeException(nameof(offset));
            }

            if (count < 0 || count > (buffer == null ? 0 : buffer.Length - offset))
            {
                if (GlobalLog.IsEnabled)
                {
                    GlobalLog.Assert("NTAuthentication#" + LoggingHash.HashString(securityContext) + "::Decrypt", "Argument 'count' out of range.");
                }

                Debug.Fail("NTAuthentication#" + LoggingHash.HashString(securityContext) + "::Decrypt", "Argument 'count' out of range.");

                throw new ArgumentOutOfRangeException(nameof(count));
            }

            if (isNtlm)
            {
                return DecryptNtlm(securityContext, buffer, offset, count, isConfidential, out newOffset, sequenceNumber);
            }

            //
            // Kerberos and up
            //
            var securityBuffer = new SecurityBuffer[2];
            securityBuffer[0] = new SecurityBuffer(buffer, offset, count, SecurityBufferType.Stream);
            securityBuffer[1] = new SecurityBuffer(0, SecurityBufferType.Data);

            int errorCode;
            if (isConfidential)
            {
                errorCode = SSPIWrapper.DecryptMessage(GlobalSSPI.SSPIAuth, securityContext, securityBuffer, sequenceNumber);
            }
            else
            {
                errorCode = SSPIWrapper.VerifySignature(GlobalSSPI.SSPIAuth, securityContext, securityBuffer, sequenceNumber);
            }

            if (errorCode != 0)
            {
                if (GlobalLog.IsEnabled)
                {
                    GlobalLog.Print("NTAuthentication#"+ "::Decrypt() throw Error = " + errorCode.ToString("x", NumberFormatInfo.InvariantInfo));
                }
                throw new Win32Exception(errorCode);
            }

            if (securityBuffer[1].type != SecurityBufferType.Data)
            {
                throw new InternalException();
            }

            newOffset = securityBuffer[1].offset;
            return securityBuffer[1].size;
        }

        internal unsafe static int CompleteAuthToken(
            ref SafeDeleteContext refContext,
            SecurityBuffer[] inSecBuffers)
        {
            GlobalLog.Enter("SafeDeleteContext::CompleteAuthToken");
            GlobalLog.Print("    refContext       = " + Logging.ObjectToString(refContext));
#if TRACE_VERBOSE
            GlobalLog.Print("    inSecBuffers[]   = length:" + inSecBuffers.Length);
#endif
            GlobalLog.Assert(inSecBuffers != null, "SafeDeleteContext::CompleteAuthToken()|inSecBuffers == null");
            var inSecurityBufferDescriptor = new Interop.Secur32.SecurityBufferDescriptor(inSecBuffers.Length);

            int errorCode = (int)Interop.SecurityStatus.InvalidHandle;

            // These are pinned user byte arrays passed along with SecurityBuffers.
            GCHandle[] pinnedInBytes = null;

            var inUnmanagedBuffer = new Interop.Secur32.SecurityBufferStruct[inSecurityBufferDescriptor.Count];
            fixed (void* inUnmanagedBufferPtr = inUnmanagedBuffer)
            {
                // Fix Descriptor pointer that points to unmanaged SecurityBuffers.
                inSecurityBufferDescriptor.UnmanagedPointer = inUnmanagedBufferPtr;
                pinnedInBytes = new GCHandle[inSecurityBufferDescriptor.Count];
                SecurityBuffer securityBuffer;
                for (int index = 0; index < inSecurityBufferDescriptor.Count; ++index)
                {
                    securityBuffer = inSecBuffers[index];
                    if (securityBuffer != null)
                    {
                        inUnmanagedBuffer[index].count = securityBuffer.size;
                        inUnmanagedBuffer[index].type = securityBuffer.type;

                        // Use the unmanaged token if it's not null; otherwise use the managed buffer.
                        if (securityBuffer.unmanagedToken != null)
                        {
                            inUnmanagedBuffer[index].token = securityBuffer.unmanagedToken.DangerousGetHandle();
                        }
                        else if (securityBuffer.token == null || securityBuffer.token.Length == 0)
                        {
                            inUnmanagedBuffer[index].token = IntPtr.Zero;
                        }
                        else
                        {
                            pinnedInBytes[index] = GCHandle.Alloc(securityBuffer.token, GCHandleType.Pinned);
                            inUnmanagedBuffer[index].token = Marshal.UnsafeAddrOfPinnedArrayElement(securityBuffer.token, securityBuffer.offset);
                        }
#if TRACE_VERBOSE
                        GlobalLog.Print("SecBuffer: cbBuffer:" + securityBuffer.size + " BufferType:" + securityBuffer.type);
#endif
                    }
                }

                Interop.Secur32.SSPIHandle contextHandle = new Interop.Secur32.SSPIHandle();
                if (refContext != null)
                {
                    contextHandle = refContext._handle;
                }
                try
                {
                    if (refContext == null || refContext.IsInvalid)
                    {
                        refContext = new SafeDeleteContext_SECURITY();
                    }

                    try
                    {
                        bool ignore = false;
                        refContext.DangerousAddRef(ref ignore);
                        errorCode = Interop.Secur32.CompleteAuthToken(contextHandle.IsZero ? null : &contextHandle, inSecurityBufferDescriptor);
                    }
                    finally
                    {
                        refContext.DangerousRelease();
                    }
                }
                finally
                {
                    if (pinnedInBytes != null)
                    {
                        for (int index = 0; index < pinnedInBytes.Length; index++)
                        {
                            if (pinnedInBytes[index].IsAllocated)
                            {
                                pinnedInBytes[index].Free();
                            }
                        }
                    }
                }
            }

            GlobalLog.Leave("SafeDeleteContext::CompleteAuthToken() unmanaged CompleteAuthToken()", "errorCode:0x" + errorCode.ToString("x8") + " refContext:" + Logging.ObjectToString(refContext));

            return errorCode;
        }

        private static int DecryptNtlm(
            SafeDeleteContext securityContext,
            byte[] buffer,
            int offset,
            int count,
            bool isConfidential,
            out int newOffset,
            uint sequenceNumber)
        {
            const int ntlmSignatureLength = 16;
            // For the most part the arguments are verified in Decrypt().
            if (count < ntlmSignatureLength)
            {
                NetEventSource.Fail(null, "Argument 'count' out of range.");
                throw new ArgumentOutOfRangeException(nameof(count));
            }

            var securityBuffer = new SecurityBuffer[2];
            securityBuffer[0] = new SecurityBuffer(buffer, offset, ntlmSignatureLength, SecurityBufferType.SECBUFFER_TOKEN);
            securityBuffer[1] = new SecurityBuffer(buffer, offset + ntlmSignatureLength, count - ntlmSignatureLength, SecurityBufferType.SECBUFFER_DATA);

            int errorCode;
            SecurityBufferType realDataType = SecurityBufferType.SECBUFFER_DATA;

            if (isConfidential)
            {
                errorCode = SSPIWrapper.DecryptMessage(GlobalSSPI.SSPIAuth, securityContext, securityBuffer, sequenceNumber);
            }
            else
            {
                realDataType |= SecurityBufferType.SECBUFFER_READONLY;
                securityBuffer[1].type = realDataType;
                errorCode = SSPIWrapper.VerifySignature(GlobalSSPI.SSPIAuth, securityContext, securityBuffer, sequenceNumber);
            }

            if (errorCode != 0)
            {
                Exception e = new Win32Exception(errorCode);
                if (NetEventSource.IsEnabled) NetEventSource.Error(null, e);
                throw new Win32Exception(errorCode);
            }

            if (securityBuffer[1].type != realDataType)
            {
                throw new InternalException();
            }

            newOffset = securityBuffer[1].offset;
            return securityBuffer[1].size;
        }

        internal static SecurityStatusPal AcceptSecurityContext(
            SafeFreeCredentials credentialsHandle,
            ref SafeDeleteContext securityContext,
            ContextFlagsPal requestedContextFlags,
            SecurityBuffer[] inSecurityBufferArray,
            SecurityBuffer outSecurityBuffer,
            ref ContextFlagsPal contextFlags)
        {
            Interop.SspiCli.ContextFlags outContextFlags = Interop.SspiCli.ContextFlags.Zero;
            Interop.SecurityStatus winStatus = (Interop.SecurityStatus)SSPIWrapper.AcceptSecurityContext(
                GlobalSSPI.SSPIAuth,
                credentialsHandle,
                ref securityContext,
                ContextFlagsAdapterPal.GetInteropFromContextFlagsPal(requestedContextFlags),
                Interop.SspiCli.Endianness.Network,
                inSecurityBufferArray,
                outSecurityBuffer,
                ref outContextFlags);

            contextFlags = ContextFlagsAdapterPal.GetContextFlagsPalFromInterop(outContextFlags);
            return SecurityStatusAdapterPal.GetSecurityStatusPalFromInterop(winStatus);
        }

        internal unsafe static int ApplyControlToken(
            ref SafeDeleteContext refContext,
            SecurityBuffer[] inSecBuffers)
        {
            if (NetEventSource.IsEnabled)
            {
                NetEventSource.Enter(null);
                NetEventSource.Info(null, $"    refContext       = {refContext}");
                NetEventSource.Info(null, $"    inSecBuffers[]   = length:{inSecBuffers.Length}");
            }

            if (inSecBuffers == null)
            {
                NetEventSource.Fail(null, "inSecBuffers == null");
            }

            var inSecurityBufferDescriptor = new Interop.SspiCli.SecBufferDesc(inSecBuffers.Length);

            int errorCode = (int)Interop.SECURITY_STATUS.InvalidHandle;

            // These are pinned user byte arrays passed along with SecurityBuffers.
            GCHandle[] pinnedInBytes = null;

            var inUnmanagedBuffer = new Interop.SspiCli.SecBuffer[inSecurityBufferDescriptor.cBuffers];
            fixed (void* inUnmanagedBufferPtr = inUnmanagedBuffer)
            {
                // Fix Descriptor pointer that points to unmanaged SecurityBuffers.
                inSecurityBufferDescriptor.pBuffers = inUnmanagedBufferPtr;
                pinnedInBytes = new GCHandle[inSecurityBufferDescriptor.cBuffers];
                SecurityBuffer securityBuffer;
                for (int index = 0; index < inSecurityBufferDescriptor.cBuffers; ++index)
                {
                    securityBuffer = inSecBuffers[index];
                    if (securityBuffer != null)
                    {
                        inUnmanagedBuffer[index].cbBuffer = securityBuffer.size;
                        inUnmanagedBuffer[index].BufferType = securityBuffer.type;

                        // Use the unmanaged token if it's not null; otherwise use the managed buffer.
                        if (securityBuffer.unmanagedToken != null)
                        {
                            inUnmanagedBuffer[index].pvBuffer = securityBuffer.unmanagedToken.DangerousGetHandle();
                        }
                        else if (securityBuffer.token == null || securityBuffer.token.Length == 0)
                        {
                            inUnmanagedBuffer[index].pvBuffer = IntPtr.Zero;
                        }
                        else
                        {
                            pinnedInBytes[index] = GCHandle.Alloc(securityBuffer.token, GCHandleType.Pinned);
                            inUnmanagedBuffer[index].pvBuffer = Marshal.UnsafeAddrOfPinnedArrayElement(securityBuffer.token, securityBuffer.offset);
                        }
#if TRACE_VERBOSE
                        if (NetEventSource.IsEnabled) NetEventSource.Info(null, $"SecBuffer: cbBuffer:{securityBuffer.size} BufferType:{securityBuffer.type}");
#endif
                    }
                }
                
                // TODO: (#3114): Optimizations to remove the unnecesary allocation of a CredHandle, remove the AddRef
                // if refContext was previously null, refactor the code to unify CompleteAuthToken and ApplyControlToken.
                Interop.SspiCli.CredHandle contextHandle = new Interop.SspiCli.CredHandle();
                if (refContext != null)
                {
                    contextHandle = refContext._handle;
                }

                try
                {
                    if (refContext == null || refContext.IsInvalid)
                    {
                        refContext = new SafeDeleteContext_SECURITY();
                    }

                    try
                    {
                        bool ignore = false;
                        refContext.DangerousAddRef(ref ignore);
                        errorCode = Interop.SspiCli.ApplyControlToken(contextHandle.IsZero ? null : &contextHandle, ref inSecurityBufferDescriptor);
                    }
                    finally
                    {
                        refContext.DangerousRelease();
                    }
                }
                finally
                {
                    if (pinnedInBytes != null)
                    {
                        for (int index = 0; index < pinnedInBytes.Length; index++)
                        {
                            if (pinnedInBytes[index].IsAllocated)
                            {
                                pinnedInBytes[index].Free();
                            }
                        }
                    }
                }
            }

            if (NetEventSource.IsEnabled) NetEventSource.Exit(null, $"unmanaged ApplyControlToken() errorCode:0x{errorCode:x8} refContext: {refContext}");
//.........这里部分代码省略.........

        /*++
            GenerateToken - Called after each successive state
            in the Client - Server handshake.  This function
            generates a set of bytes that will be sent next to
            the server.  The server responds, each response,
            is pass then into this function, again, and the cycle
            repeats until successful connection, or failure.

            Input:
                input  - bytes from the wire
                output - ref to byte [], what we will send to the
                    server in response
            Return:
                status - error information
        --*/
        private SecurityStatusPal GenerateToken(byte[] input, int offset, int count, ref byte[] output)
        {
#if TRACE_VERBOSE
            if (GlobalLog.IsEnabled)
            {
                GlobalLog.Enter("SecureChannel#" + LoggingHash.HashString(this) + "::GenerateToken, _refreshCredentialNeeded = " + _refreshCredentialNeeded);
            }
#endif

            if (offset < 0 || offset > (input == null ? 0 : input.Length))
            {
                if (GlobalLog.IsEnabled)
                {
                    GlobalLog.Assert("SecureChannel#" + LoggingHash.HashString(this) + "::GenerateToken", "Argument 'offset' out of range.");
                }

                Debug.Fail("SecureChannel#" + LoggingHash.HashString(this) + "::GenerateToken", "Argument 'offset' out of range.");
                throw new ArgumentOutOfRangeException(nameof(offset));
            }

            if (count < 0 || count > (input == null ? 0 : input.Length - offset))
            {
                if (GlobalLog.IsEnabled)
                {
                    GlobalLog.Assert("SecureChannel#" + LoggingHash.HashString(this) + "::GenerateToken", "Argument 'count' out of range.");
                }

                Debug.Fail("SecureChannel#" + LoggingHash.HashString(this) + "::GenerateToken", "Argument 'count' out of range.");
                throw new ArgumentOutOfRangeException(nameof(count));
            }

            SecurityBuffer incomingSecurity = null;
            SecurityBuffer[] incomingSecurityBuffers = null;

            if (input != null)
            {
                incomingSecurity = new SecurityBuffer(input, offset, count, SecurityBufferType.Token);
                incomingSecurityBuffers = new SecurityBuffer[]
                {
                    incomingSecurity,
                    new SecurityBuffer(null, 0, 0, SecurityBufferType.Empty)
                };
            }

            SecurityBuffer outgoingSecurity = new SecurityBuffer(null, SecurityBufferType.Token);

            SecurityStatusPal status = default(SecurityStatusPal);

            bool cachedCreds = false;
            byte[] thumbPrint = null;

            //
            // Looping through ASC or ISC with potentially cached credential that could have been
            // already disposed from a different thread before ISC or ASC dir increment a cred ref count.
            //
            try
            {
                do
                {
                    thumbPrint = null;
                    if (_refreshCredentialNeeded)
                    {
                        cachedCreds = _serverMode
                                        ? AcquireServerCredentials(ref thumbPrint)
                                        : AcquireClientCredentials(ref thumbPrint);
                    }

                    if (_serverMode)
                    {
                        status = SslStreamPal.AcceptSecurityContext(
                                      ref _credentialsHandle,
                                      ref _securityContext,
                                      incomingSecurity,
                                      outgoingSecurity,
                                      _remoteCertRequired);
                    }
                    else
                    {
                        if (incomingSecurity == null)
                        {
                            status = SslStreamPal.InitializeSecurityContext(
                                           ref _credentialsHandle,
                                           ref _securityContext,
                                           _destination,
                                           incomingSecurity,
//.........这里部分代码省略.........

        /*++
            GenerateToken - Called after each successive state
            in the Client - Server handshake.  This function
            generates a set of bytes that will be sent next to
            the server.  The server responds, each response,
            is pass then into this function, again, and the cycle
            repeats until successful connection, or failure.

            Input:
                input  - bytes from the wire
                output - ref to byte [], what we will send to the
                    server in response
            Return:
                errorCode - an SSPI error code
        --*/
        private Interop.SecurityStatus GenerateToken(byte[] input, int offset, int count, ref byte[] output)
        {
#if TRACE_VERBOSE
            GlobalLog.Enter("SecureChannel#" + Logging.HashString(this) + "::GenerateToken, _refreshCredentialNeeded = " + _refreshCredentialNeeded);
#endif

            if (offset < 0 || offset > (input == null ? 0 : input.Length))
            {
                GlobalLog.Assert(false, "SecureChannel#" + Logging.HashString(this) + "::GenerateToken", "Argument 'offset' out of range.");
                throw new ArgumentOutOfRangeException("offset");
            }

            if (count < 0 || count > (input == null ? 0 : input.Length - offset))
            {
                GlobalLog.Assert(false, "SecureChannel#" + Logging.HashString(this) + "::GenerateToken", "Argument 'count' out of range.");
                throw new ArgumentOutOfRangeException("count");
            }

            SecurityBuffer incomingSecurity = null;
            SecurityBuffer[] incomingSecurityBuffers = null;

            if (input != null)
            {
                incomingSecurity = new SecurityBuffer(input, offset, count, SecurityBufferType.Token);
                incomingSecurityBuffers = new SecurityBuffer[]
                {
                    incomingSecurity,
                    new SecurityBuffer(null, 0, 0, SecurityBufferType.Empty)
                };
            }

            SecurityBuffer outgoingSecurity = new SecurityBuffer(null, SecurityBufferType.Token);

            int errorCode = 0;

            bool cachedCreds = false;
            byte[] thumbPrint = null;

            //
            // Looping through ASC or ISC with potentially cached credential that could have been
            // already disposed from a different thread before ISC or ASC dir increment a cred ref count.
            //
            try
            {
                do
                {
                    thumbPrint = null;
                    if (_refreshCredentialNeeded)
                    {
                        cachedCreds = _serverMode
                                        ? AcquireServerCredentials(ref thumbPrint)
                                        : AcquireClientCredentials(ref thumbPrint);
                    }

                    if (_serverMode)
                    {
                        errorCode = SSPIWrapper.AcceptSecurityContext(
                                        GlobalSSPI.SSPISecureChannel,
                                        ref _credentialsHandle,
                                        ref _securityContext,
                                        ServerRequiredFlags | (_remoteCertRequired ? Interop.Secur32.ContextFlags.MutualAuth : Interop.Secur32.ContextFlags.Zero),
                                        Interop.Secur32.Endianness.Native,
                                        incomingSecurity,
                                        outgoingSecurity,
                                        ref _attributes
                                        );
                    }
                    else
                    {
                        if (incomingSecurity == null)
                        {
                            errorCode = SSPIWrapper.InitializeSecurityContext(
                                            GlobalSSPI.SSPISecureChannel,
                                            ref _credentialsHandle,
                                            ref _securityContext,
                                            _destination,
                                            RequiredFlags | Interop.Secur32.ContextFlags.InitManualCredValidation,
                                            Interop.Secur32.Endianness.Native,
                                            incomingSecurity,
                                            outgoingSecurity,
                                            ref _attributes
                                            );
                        }
                        else
                        {
//.........这里部分代码省略.........

        private static SecurityStatusPal EstablishSecurityContext(
          SafeFreeNegoCredentials credential,
          ref SafeDeleteContext context,
          string targetName,
          ContextFlagsPal inFlags,
          SecurityBuffer inputBuffer,
          SecurityBuffer outputBuffer,
          ref ContextFlagsPal outFlags)
        {
            bool isNtlmOnly = credential.IsNtlmOnly;

            if (context == null)
            {
                // Empty target name causes the failure on Linux, hence passing a non-empty string  
                context = isNtlmOnly ? new SafeDeleteNegoContext(credential, credential.UserName) : new SafeDeleteNegoContext(credential, targetName);
            }

            SafeDeleteNegoContext negoContext = (SafeDeleteNegoContext)context;
            try
            {
                Interop.NetSecurityNative.GssFlags inputFlags = ContextFlagsAdapterPal.GetInteropFromContextFlagsPal(inFlags, isServer:false);
                uint outputFlags;
                int isNtlmUsed;
                SafeGssContextHandle contextHandle = negoContext.GssContext;
                bool done = GssInitSecurityContext(
                   ref contextHandle,
                   credential.GssCredential,
                   isNtlmOnly,
                   negoContext.TargetName,
                   inputFlags,
                   inputBuffer?.token,
                   out outputBuffer.token,
                   out outputFlags,
                   out isNtlmUsed);

                Debug.Assert(outputBuffer.token != null, "Unexpected null buffer returned by GssApi");
                outputBuffer.size = outputBuffer.token.Length;
                outputBuffer.offset = 0;
                outFlags = ContextFlagsAdapterPal.GetContextFlagsPalFromInterop((Interop.NetSecurityNative.GssFlags)outputFlags, isServer:false);
                Debug.Assert(negoContext.GssContext == null || contextHandle == negoContext.GssContext);

                // Save the inner context handle for further calls to NetSecurity
                Debug.Assert(negoContext.GssContext == null || contextHandle == negoContext.GssContext);
                if (null == negoContext.GssContext)
                {
                    negoContext.SetGssContext(contextHandle);
                }

                // Populate protocol used for authentication
                if (done)
                {
                    negoContext.SetAuthenticationPackage(Convert.ToBoolean(isNtlmUsed));
                }

                SecurityStatusPalErrorCode errorCode = done ? 
                    (negoContext.IsNtlmUsed && outputBuffer.size > 0 ? SecurityStatusPalErrorCode.OK : SecurityStatusPalErrorCode.CompleteNeeded) :
                    SecurityStatusPalErrorCode.ContinueNeeded;
                return new SecurityStatusPal(errorCode);
            }
            catch(Exception ex)
            {
                if (NetEventSource.IsEnabled) NetEventSource.Error(null, ex);
                return new SecurityStatusPal(SecurityStatusPalErrorCode.InternalError, ex);
            }
        }