/** @file
  Challenge-Handshake Authentication Protocol (CHAP) Configuration

Copyright (c) 2004 - 2008, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution.  The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php

THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

Module Name:

  IScsiCHAP.c

Abstract:

  This file is for CHAP configuration

**/

#include "IScsiImpl.h"
#include "Md5.h"

EFI_GUID  mIScsiCHAPAuthInfoGuid = ISCSI_CHAP_AUTH_INFO_GUID;

EFI_STATUS
IScsiCHAPCalculateResponse (
  IN  UINT32  ChapIdentifier,
  IN  CHAR8   *ChapSecret,
  IN  UINT32  SecretLength,
  IN  UINT8   *ChapChallenge,
  IN  UINT32  ChallengeLength,
  OUT UINT8   *ChapResponse
  )
{
  MD5_CTX     Md5Ctx;
  CHAR8       IdByte[1];
  EFI_STATUS  Status;

  Status = MD5Init (&Md5Ctx);

  //
  // Hash Identifier - Only calculate 1 byte data (RFC1994)
  //
  IdByte[0] = (CHAR8) ChapIdentifier;
  MD5Update (&Md5Ctx, IdByte, 1);

  //
  // Hash Secret
  //
  if (SecretLength < ISCSI_CHAP_SECRET_MIN_LEN - 1) {
    return EFI_PROTOCOL_ERROR;
  }

  MD5Update (&Md5Ctx, ChapSecret, SecretLength);

  //
  // Hash Challenge received from Target
  //
  MD5Update (&Md5Ctx, ChapChallenge, ChallengeLength);

  Status = MD5Final (&Md5Ctx, ChapResponse);

  return Status;
}

EFI_STATUS
IScsiCHAPAuthTarget (
  IN  ISCSI_CHAP_AUTH_DATA  *AuthData,
  IN  UINT8                 *TargetResponse
  )
{
  EFI_STATUS  Status;
  UINT32      SecretSize;
  UINT8       VerifyRsp[ISCSI_CHAP_RSP_LEN];

  Status      = EFI_SUCCESS;

  SecretSize  = (UINT32) AsciiStrLen (AuthData->AuthConfig.ReverseCHAPSecret);
  Status = IScsiCHAPCalculateResponse (
            AuthData->OutIdentifier,
            AuthData->AuthConfig.ReverseCHAPSecret,
            SecretSize,
            AuthData->OutChallenge,
            AuthData->OutChallengeLength,
            VerifyRsp
            );

  if (CompareMem (VerifyRsp, TargetResponse, ISCSI_CHAP_RSP_LEN)) {
    Status = EFI_SECURITY_VIOLATION;
  }

  return Status;
}

/**
  This function checks the received iSCSI Login Response during the security
  negotiation stage.
  
  @param  Conn[in]             The iSCSI connection.

  @param  Transit[in]          The transit flag of the latest iSCSI Login Response.

  @retval EFI_SUCCESS          The Login Response passed the CHAP validation.

  @retval EFI_OUT_OF_RESOURCES Failed to allocate memory.

  @retval EFI_PROTOCOL_ERROR   Some kind of protocol error happend.

**/
EFI_STATUS
IScsiCHAPOnRspReceived (
  IN ISCSI_CONNECTION  *Conn,
  IN BOOLEAN           Transit
  )
{
  EFI_STATUS                Status;
  ISCSI_SESSION             *Session;
  ISCSI_CHAP_AUTH_DATA      *AuthData;
  CHAR8                     *Value;
  UINT8                     *Data;
  UINT32                    Len;
  LIST_ENTRY                *KeyValueList;
  UINTN                     Algorithm;
  CHAR8                     *Identifier;
  CHAR8                     *Challenge;
  CHAR8                     *Name;
  CHAR8                     *Response;
  UINT8                     TargetRsp[ISCSI_CHAP_RSP_LEN];
  UINT32                    RspLen;

  ASSERT (Conn->CurrentStage == ISCSI_SECURITY_NEGOTIATION);
  ASSERT (Conn->RspQue.BufNum != 0);

  Session     = Conn->Session;
  AuthData    = &Session->AuthData;

  Len         = Conn->RspQue.BufSize;
  Data        = AllocatePool (Len);
  if (Data == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
  //
  // Copy the data in case the data spans over multiple PDUs.
  //
  NetbufQueCopy (&Conn->RspQue, 0, Len, Data);

  //
  // Build the key-value list from the data segment of the Login Response.
  //
  KeyValueList = IScsiBuildKeyValueList ((CHAR8 *) Data, Len);
  if (KeyValueList == NULL) {
    Status = EFI_OUT_OF_RESOURCES;
    goto ON_EXIT;
  }

  Status = EFI_PROTOCOL_ERROR;

  switch (Conn->CHAPStep) {
  case ISCSI_CHAP_INITIAL:
    //
    // The first Login Response.
    //
    Value = IScsiGetValueByKeyFromList (KeyValueList, ISCSI_KEY_TARGET_PORTAL_GROUP_TAG);
    if (Value == NULL) {
      goto ON_EXIT;
    }

    Session->TargetPortalGroupTag = (UINT16) AsciiStrDecimalToUintn (Value);

    Value                         = IScsiGetValueByKeyFromList (KeyValueList, ISCSI_KEY_AUTH_METHOD);
    if (Value == NULL) {
      goto ON_EXIT;
    }
    //
    // Initiator mandates CHAP authentication but target replies without "CHAP" or
    // initiator suggets "None" but target replies with some kind of auth method.
    //
    if (AsciiStrCmp (Value, ISCSI_AUTH_METHOD_CHAP) == 0) {
      if (AuthData->AuthConfig.CHAPType == ISCSI_CHAP_NONE) {
        goto ON_EXIT;
      }
    } else {
      if (AuthData->AuthConfig.CHAPType != ISCSI_CHAP_NONE) {
        goto ON_EXIT;
      }
    }
    //
    // Transit to CHAP step one.
    //
    Conn->CHAPStep  = ISCSI_CHAP_STEP_ONE;
    Status          = EFI_SUCCESS;
    break;

  case ISCSI_CHAP_STEP_TWO:
    //
    // The Target replies with CHAP_A=<A> CHAP_I=<I> CHAP_C=<C>
    //
    Value = IScsiGetValueByKeyFromList (KeyValueList, ISCSI_KEY_CHAP_ALGORITHM);
    if (Value == NULL) {
      goto ON_EXIT;
    }

    Algorithm = AsciiStrDecimalToUintn (Value);
    if (Algorithm != ISCSI_CHAP_ALGORITHM_MD5) {
      //
      // Unsupported algorithm is chosen by target.
      //
      goto ON_EXIT;
    }

    Identifier = IScsiGetValueByKeyFromList (KeyValueList, ISCSI_KEY_CHAP_IDENTIFIER);
    if (Identifier == NULL) {
      goto ON_EXIT;
    }

    Challenge = IScsiGetValueByKeyFromList (KeyValueList, ISCSI_KEY_CHAP_CHALLENGE);
    if (Challenge == NULL) {
      goto ON_EXIT;
    }
    //
    // Process the CHAP identifier and CHAP Challenge from Target
    // Calculate Response value
    //
    AuthData->InIdentifier      = (UINT32) AsciiStrDecimalToUintn (Identifier);
    AuthData->InChallengeLength = ISCSI_CHAP_AUTH_MAX_LEN;
    IScsiHexToBin ((UINT8 *) AuthData->InChallenge, &AuthData->InChallengeLength, Challenge);
    Status = IScsiCHAPCalculateResponse (
              AuthData->InIdentifier,
              AuthData->AuthConfig.CHAPSecret,
              (UINT32) AsciiStrLen (AuthData->AuthConfig.CHAPSecret),
              AuthData->InChallenge,
              AuthData->InChallengeLength,
              AuthData->CHAPResponse
              );

    //
    // Transit to next step.
    //
    Conn->CHAPStep = ISCSI_CHAP_STEP_THREE;
    break;

  case ISCSI_CHAP_STEP_THREE:
    //
    // one way CHAP authentication and the target would like to
    // authenticate us.
    //
    Status = EFI_SUCCESS;
    break;

  case ISCSI_CHAP_STEP_FOUR:
    ASSERT (AuthData->AuthConfig.CHAPType == ISCSI_CHAP_MUTUAL);
    //
    // The forth step, CHAP_N=<N> CHAP_R=<R> is received from Target.
    //
    Name = IScsiGetValueByKeyFromList (KeyValueList, ISCSI_KEY_CHAP_NAME);
    if (Name == NULL) {
      goto ON_EXIT;
    }

    Response = IScsiGetValueByKeyFromList (KeyValueList, ISCSI_KEY_CHAP_RESPONSE);
    if (Response == NULL) {
      goto ON_EXIT;
    }

    RspLen = ISCSI_CHAP_RSP_LEN;
    IScsiHexToBin (TargetRsp, &RspLen, Response);

    //
    // Check the CHAP Name and Response replied by Target.
    //
    Status = IScsiCHAPAuthTarget (AuthData, TargetRsp);
    break;

  default:
    break;
  }

ON_EXIT:

  IScsiFreeKeyValueList (KeyValueList);

  gBS->FreePool (Data);

  return Status;
}

/**
  This function fills the CHAP authentication information into the login PDU
  during the security negotiation stage in the iSCSI connection login.

  @param  Conn[in]             The iSCSI connection.

  @param  Pdu[in]              The PDU to send out.

  @retval EFI_SUCCESS          All check passed and the phase-related CHAP
                               authentication info is filled into the iSCSI PDU.

  @retval EFI_OUT_OF_RESOURCES Failed to allocate memory.

  @retval EFI_PROTOCOL_ERROR   Some kind of protocol error happend.

**/
EFI_STATUS
IScsiCHAPToSendReq (
  IN ISCSI_CONNECTION  *Conn,
  IN NET_BUF           *Pdu
  )
{
  EFI_STATUS                Status;
  ISCSI_SESSION             *Session;
  ISCSI_LOGIN_REQUEST       *LoginReq;
  ISCSI_CHAP_AUTH_DATA      *AuthData;
  CHAR8                     *Value;
  CHAR8                     ValueStr[256];
  CHAR8                     *Response;
  UINT32                    RspLen;
  CHAR8                     *Challenge;
  UINT32                    ChallengeLen;

  ASSERT (Conn->CurrentStage == ISCSI_SECURITY_NEGOTIATION);

  Session     = Conn->Session;
  AuthData    = &Session->AuthData;
  LoginReq    = (ISCSI_LOGIN_REQUEST *) NetbufGetByte (Pdu, 0, 0);
  Status      = EFI_SUCCESS;

  RspLen      = 2 * ISCSI_CHAP_RSP_LEN + 3;
  Response    = AllocatePool (RspLen);
  if (Response == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  ChallengeLen  = 2 * ISCSI_CHAP_RSP_LEN + 3;
  Challenge     = AllocatePool (ChallengeLen);
  if (Challenge == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  switch (Conn->CHAPStep) {
  case ISCSI_CHAP_INITIAL:
    //
    // It's the initial Login Request. Fill in the key=value pairs mandatory
    // for the initial Login Request.
    //
    IScsiAddKeyValuePair (Pdu, ISCSI_KEY_INITIATOR_NAME, Session->InitiatorName);
    IScsiAddKeyValuePair (Pdu, ISCSI_KEY_SESSION_TYPE, "Normal");
    IScsiAddKeyValuePair (Pdu, ISCSI_KEY_TARGET_NAME, Session->ConfigData.NvData.TargetName);

    if (AuthData->AuthConfig.CHAPType == ISCSI_CHAP_NONE) {
      Value = ISCSI_KEY_VALUE_NONE;
      ISCSI_SET_FLAG (LoginReq, ISCSI_LOGIN_REQ_PDU_FLAG_TRANSIT);
    } else {
      Value = ISCSI_AUTH_METHOD_CHAP;
    }

    IScsiAddKeyValuePair (Pdu, ISCSI_KEY_AUTH_METHOD, Value);

    break;

  case ISCSI_CHAP_STEP_ONE:
    //
    // First step, send the Login Request with CHAP_A=<A1,A2...> key-value pair.
    //
    AsciiSPrint (ValueStr, sizeof (ValueStr), "%d", ISCSI_CHAP_ALGORITHM_MD5);
    IScsiAddKeyValuePair (Pdu, ISCSI_KEY_CHAP_ALGORITHM, ValueStr);

    Conn->CHAPStep = ISCSI_CHAP_STEP_TWO;
    break;

  case ISCSI_CHAP_STEP_THREE:
    //
    // Third step, send the Login Request with CHAP_N=<N> CHAP_R=<R> or
    // CHAP_N=<N> CHAP_R=<R> CHAP_I=<I> CHAP_C=<C> if target ahtentication is
    // required too.
    //
    // CHAP_N=<N>
    //
    IScsiAddKeyValuePair (Pdu, ISCSI_KEY_CHAP_NAME, (CHAR8 *) &AuthData->AuthConfig.CHAPName);
    //
    // CHAP_R=<R>
    //
    IScsiBinToHex ((UINT8 *) AuthData->CHAPResponse, ISCSI_CHAP_RSP_LEN, Response, &RspLen);
    IScsiAddKeyValuePair (Pdu, ISCSI_KEY_CHAP_RESPONSE, Response);

    if (AuthData->AuthConfig.CHAPType == ISCSI_CHAP_MUTUAL) {
      //
      // CHAP_I=<I>
      //
      IScsiGenRandom ((UINT8 *) &AuthData->OutIdentifier, 1);
      AsciiSPrint (ValueStr, sizeof (ValueStr), "%d", AuthData->OutIdentifier);
      IScsiAddKeyValuePair (Pdu, ISCSI_KEY_CHAP_IDENTIFIER, ValueStr);
      //
      // CHAP_C=<C>
      //
      IScsiGenRandom ((UINT8 *) AuthData->OutChallenge, ISCSI_CHAP_RSP_LEN);
      AuthData->OutChallengeLength = ISCSI_CHAP_RSP_LEN;
      IScsiBinToHex ((UINT8 *) AuthData->OutChallenge, ISCSI_CHAP_RSP_LEN, Challenge, &ChallengeLen);
      IScsiAddKeyValuePair (Pdu, ISCSI_KEY_CHAP_CHALLENGE, Challenge);

      Conn->CHAPStep = ISCSI_CHAP_STEP_FOUR;
    }
    //
    // set the stage transition flag.
    //
    ISCSI_SET_FLAG (LoginReq, ISCSI_LOGIN_REQ_PDU_FLAG_TRANSIT);
    break;

  default:
    Status = EFI_PROTOCOL_ERROR;
    break;
  }

  gBS->FreePool (Response);
  gBS->FreePool (Challenge);

  return Status;
}