/*++

Copyright (c)  2007 Intel Corporation. All rights reserved
This software and associated documentation (if any) is furnished
under a license and may only be used or copied in accordance
with the terms of the license. Except as permitted by such
license, no part of this software or documentation may be
reproduced, stored in a retrieval system, or transmitted in any
form or by any means without the express written consent of
Intel Corporation.

Module Name:

  IScsiCHAP.c

Abstract:

--*/

#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 (NetCompareMem (VerifyRsp, TargetResponse, ISCSI_CHAP_RSP_LEN)) {
    Status = EFI_SECURITY_VIOLATION;
  }

  return Status;
}

EFI_STATUS
IScsiCHAPOnRspReceived (
  IN ISCSI_CONNECTION  *Conn,
  IN BOOLEAN           Transit
  )
/*++

Routine Description:

  This function checks the received iSCSI Login Response during the security
  negotiation stage.
  
Arguments:

  Conn    - The iSCSI connection.
  Transit - The transit flag of the latest iSCSI Login Response.

Returns:

  EFI_SUCCESS          - The Login Response passed the CHAP validation.
  EFI_OUT_OF_RESOURCES - Failed to allocate memory.
  EFI_PROTOCOL_ERROR   - Some kind of protocol error happend.

--*/
{
  EFI_STATUS                Status;
  ISCSI_SESSION             *Session;
  ISCSI_SESSION_CONFIG_DATA *ConfigData;
  ISCSI_CHAP_AUTH_DATA      *AuthData;
  CHAR8                     *Value;
  UINT8                     *Data;
  UINT32                    Len;
  NET_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;
  ConfigData  = &Session->ConfigData;
  AuthData    = &Session->AuthData;

  Len         = Conn->RspQue.BufSize;
  Data        = NetAllocatePool (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 (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);

  NetFreePool (Data);

  return Status;
}

EFI_STATUS
IScsiCHAPToSendReq (
  IN ISCSI_CONNECTION  *Conn,
  IN NET_BUF           *Pdu
  )
/*++

Routine Description:

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

  Conn - The iSCSI connection.
  Pdu  - The PDU to send out.

Returns:

  EFI_SUCCESS          - All check passed and the phase-related CHAP authentication
                         info is filled into the iSCSI PDU.
  EFI_OUT_OF_RESOURCES - Failed to allocate memory.
  EFI_PROTOCOL_ERROR   - Some kind of protocol error happend.

--*/
{
  EFI_STATUS                Status;
  ISCSI_SESSION             *Session;
  ISCSI_LOGIN_REQUEST       *LoginReq;
  ISCSI_SESSION_CONFIG_DATA *ConfigData;
  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;
  ConfigData  = &Session->ConfigData;
  AuthData    = &Session->AuthData;
  LoginReq    = (ISCSI_LOGIN_REQUEST *) NetbufGetByte (Pdu, 0, 0);
  Status      = EFI_SUCCESS;

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

  ChallengeLen  = 2 * ISCSI_CHAP_RSP_LEN + 3;
  Challenge     = NetAllocatePool (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, (UINT8 *) &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;
  }

  NetFreePool (Response);
  NetFreePool (Challenge);

  return Status;
}