/* R_ENHANC.C - cryptographic enhancements for RSAREF
 */

/* Copyright (C) RSA Laboratories, a division of RSA Data Security,
     Inc., created 1991. All rights reserved.
 */

#include "global.h"
#include "rsaref.h"
#include "r_random.h"
#include "rsa.h"

/* DigestInfo encoding is DIGEST_INFO_A, then 2 or 5 (for MD2/MD5),
   then DIGEST_INFO_B, then 16-byte message digest.
 */

static unsigned char DIGEST_INFO_A[] = {
  0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, 0x2a, 0x86, 0x48, 0x86, 0xf7,
  0x0d, 0x02
};
#define DIGEST_INFO_A_LEN sizeof (DIGEST_INFO_A)

static unsigned char DIGEST_INFO_B[] = { 0x05, 0x00, 0x04, 0x10 };
#define DIGEST_INFO_B_LEN sizeof (DIGEST_INFO_B)

#define DIGEST_INFO_LEN (DIGEST_INFO_A_LEN + 1 + DIGEST_INFO_B_LEN + 16)

static unsigned char *PADDING[] = {
  (unsigned char *)"", (unsigned char *)"\001", (unsigned char *)"\002\002",
  (unsigned char *)"\003\003\003", (unsigned char *)"\004\004\004\004",
  (unsigned char *)"\005\005\005\005\005",
  (unsigned char *)"\006\006\006\006\006\006", 
  (unsigned char *)"\007\007\007\007\007\007\007",
  (unsigned char *)"\010\010\010\010\010\010\010\010"
};

#define MAX_ENCRYPTED_KEY_LEN MAX_RSA_MODULUS_LEN

static void R_EncodeDigestInfo PROTO_LIST
  ((unsigned char *, int, unsigned char *));
static void EncryptPEMUpdateFinal PROTO_LIST
  ((R_ENVELOPE_CTX *, unsigned char *, unsigned int *, unsigned char *,
    unsigned int));
static int DecryptPEMUpdateFinal PROTO_LIST
  ((R_ENVELOPE_CTX *, unsigned char *, unsigned int *, unsigned char *,
    unsigned int));
static int CipherInit PROTO_LIST
  ((R_ENVELOPE_CTX *, int, unsigned char *, unsigned char *, int));
static void CipherUpdate PROTO_LIST
  ((R_ENVELOPE_CTX *, unsigned char *, unsigned char *, unsigned int));
static void CipherRestart PROTO_LIST ((R_ENVELOPE_CTX *));

int R_DigestInit (context, digestAlgorithm)
R_DIGEST_CTX *context;                                       /* new context */
int digestAlgorithm;                            /* message-digest algorithm */
{
  context->digestAlgorithm = digestAlgorithm;

  switch (digestAlgorithm) {
  case DA_MD2:
    MD2Init (&context->context.md2);
    break;

  case DA_MD5:
    MD5Init (&context->context.md5);
    break;
  
  default:
    return (RE_DIGEST_ALGORITHM);
  }

  return (0);
}

int R_DigestUpdate (context, partIn, partInLen)
R_DIGEST_CTX *context;                                           /* context */
unsigned char *partIn;                                    /* next data part */
unsigned int partInLen;                         /* length of next data part */
{
  if (context->digestAlgorithm == DA_MD2)
    MD2Update (&context->context.md2, partIn, partInLen);
  else
    MD5Update (&context->context.md5, partIn, partInLen);
  return (0);
}

int R_DigestFinal (context, digest, digestLen)
R_DIGEST_CTX *context;                                           /* context */
unsigned char *digest;                                    /* message digest */
unsigned int *digestLen;                        /* length of message digest */
{
  *digestLen = 16;
  if (context->digestAlgorithm == DA_MD2)
    MD2Final (digest, &context->context.md2);
  else
    MD5Final (digest, &context->context.md5);

  return (0);
}

int R_SignInit (context, digestAlgorithm)
R_SIGNATURE_CTX *context;                                    /* new context */
int digestAlgorithm;                            /* message-digest algorithm */
{
  return (R_DigestInit (&context->digestContext, digestAlgorithm));
}

int R_SignUpdate (context, partIn, partInLen)
R_SIGNATURE_CTX *context;                                        /* context */
unsigned char *partIn;                                    /* next data part */
unsigned int partInLen;                         /* length of next data part */
{
  return (R_DigestUpdate (&context->digestContext, partIn, partInLen));
}

int R_SignFinal (context, signature, signatureLen, privateKey)
R_SIGNATURE_CTX *context;                                        /* context */
unsigned char *signature;                                      /* signature */
unsigned int *signatureLen;                          /* length of signature */
R_RSA_PRIVATE_KEY *privateKey;                  /* signer's RSA private key */
{
  int status;
  unsigned char digest[MAX_DIGEST_LEN], digestInfo[DIGEST_INFO_LEN];
  unsigned int digestLen;

  do {
    if ((status = R_DigestFinal (&context->digestContext, digest, &digestLen))
        != 0)
      break;

    R_EncodeDigestInfo
      (digestInfo, context->digestContext.digestAlgorithm, digest);
    
    if (RSAPrivateEncrypt
        (signature, signatureLen, digestInfo, DIGEST_INFO_LEN, privateKey)
        != 0) {
      status = RE_PRIVATE_KEY;
      break;
    }

    /* Reset for another verification. Assume Init won't fail */
    R_DigestInit
      (&context->digestContext, context->digestContext.digestAlgorithm);
  } while (0);
  
  /* Zeroize potentially sensitive information.
   */
  R_memset ((POINTER)digest, 0, sizeof (digest));
  R_memset ((POINTER)digestInfo, 0, sizeof (digestInfo));

  return (status);
}

int R_VerifyInit (context, digestAlgorithm)
R_SIGNATURE_CTX *context;                                    /* new context */
int digestAlgorithm;                            /* message-digest algorithm */
{
  return (R_DigestInit (&context->digestContext, digestAlgorithm));
}

int R_VerifyUpdate (context, partIn, partInLen)
R_SIGNATURE_CTX *context;                                        /* context */
unsigned char *partIn;                                    /* next data part */
unsigned int partInLen;                         /* length of next data part */
{
  return (R_DigestUpdate (&context->digestContext, partIn, partInLen));
}

int R_VerifyFinal (context, signature, signatureLen, publicKey)
R_SIGNATURE_CTX *context;                                        /* context */
unsigned char *signature;                                      /* signature */
unsigned int signatureLen;                           /* length of signature */
R_RSA_PUBLIC_KEY *publicKey;                     /* signer's RSA public key */
{
  int status;
  unsigned char digest[MAX_DIGEST_LEN], digestInfo[DIGEST_INFO_LEN],
    originalDigestInfo[MAX_SIGNATURE_LEN];
  unsigned int originalDigestInfoLen, digestLen;
  
  if (signatureLen > MAX_SIGNATURE_LEN)
    return (RE_LEN);

  status = 0;
  do {
    if ((status = R_DigestFinal (&context->digestContext, digest, &digestLen))
        != 0)
      break;

    R_EncodeDigestInfo
      (digestInfo, context->digestContext.digestAlgorithm, digest);
    
    if (RSAPublicDecrypt
        (originalDigestInfo, &originalDigestInfoLen, signature, signatureLen, 
         publicKey) != 0) {
      status = RE_PUBLIC_KEY;
      break;
    }
    
    if ((originalDigestInfoLen != DIGEST_INFO_LEN) ||
        (R_memcmp 
         ((POINTER)originalDigestInfo, (POINTER)digestInfo,
          DIGEST_INFO_LEN))) {
      status = RE_SIGNATURE;
      break;
    }

    /* Reset for another verification. Assume Init won't fail */
    R_DigestInit
      (&context->digestContext, context->digestContext.digestAlgorithm);
  } while (0);
  
  /* Zeroize potentially sensitive information.
   */
  R_memset ((POINTER)digest, 0, sizeof (digest));
  R_memset ((POINTER)digestInfo, 0, sizeof (digestInfo));
  R_memset ((POINTER)originalDigestInfo, 0, sizeof (originalDigestInfo));

  return (status);
}

/* Caller must ASCII recode the encrypted keys if desired.
 */
int R_SealInit
  (context, encryptedKeys, encryptedKeyLens, iv, publicKeyCount, publicKeys,
   encryptionAlgorithm, randomStruct)
R_ENVELOPE_CTX *context;                                     /* new context */
unsigned char **encryptedKeys;                            /* encrypted keys */
unsigned int *encryptedKeyLens;                /* lengths of encrypted keys */
unsigned char iv[8];                               /* initialization vector */
unsigned int publicKeyCount;                       /* number of public keys */
R_RSA_PUBLIC_KEY **publicKeys;                               /* public keys */
int encryptionAlgorithm;                       /* data encryption algorithm */
R_RANDOM_STRUCT *randomStruct;                          /* random structure */
{
  int status;
  unsigned char key[24];
  unsigned int keyLen, i;
  
  do {
    context->encryptionAlgorithm = encryptionAlgorithm;
    
    keyLen = (encryptionAlgorithm == EA_DES_CBC) ? 8 : 24;
    if ((status = R_GenerateBytes (key, keyLen, randomStruct)) != 0)
      break;
    if ((status = R_GenerateBytes (iv, 8, randomStruct)) != 0)
      break;

    if (encryptionAlgorithm == EA_DES_EDE2_CBC)
      /* Make both E keys the same */
      R_memcpy ((POINTER)(key + 16), (POINTER)key, 8);

    if ((status = CipherInit (context, encryptionAlgorithm, key, iv, 1)) != 0)
      break;

    for (i = 0; i < publicKeyCount; ++i) {
      if (RSAPublicEncrypt
          (encryptedKeys[i], &encryptedKeyLens[i], key, keyLen,
           publicKeys[i], randomStruct)) {
        status = RE_PUBLIC_KEY;
        break;
      }
    }
    if (status != 0)
      break;

    context->bufferLen = 0;
  } while (0);
  
  /* Zeroize sensitive information.
   */
  R_memset ((POINTER)key, 0, sizeof (key));

  return (status);
}

/* Assume partOut buffer is at least partInLen + 7, since this may flush
     buffered input.
 */
int R_SealUpdate (context, partOut, partOutLen, partIn, partInLen)
R_ENVELOPE_CTX *context;                                         /* context */
unsigned char *partOut;                         /* next encrypted data part */
unsigned int *partOutLen;             /* length of next encrypted data part */
unsigned char *partIn;                                    /* next data part */
unsigned int partInLen;                         /* length of next data part */
{
  unsigned int tempLen;

  tempLen = 8 - context->bufferLen;
  if (partInLen < tempLen) {
    /* Just accumulate into buffer.
     */
    R_memcpy
      ((POINTER)(context->buffer + context->bufferLen), (POINTER)partIn,
       partInLen);
    context->bufferLen += partInLen;
    *partOutLen = 0;
    return (0);
  }

  /* Fill the buffer and encrypt.
   */
  R_memcpy
    ((POINTER)(context->buffer + context->bufferLen), (POINTER)partIn,
     tempLen);
  CipherUpdate (context, partOut, context->buffer, 8);
  partIn += tempLen;
  partInLen -= tempLen;
  partOut += 8;
  *partOutLen = 8;

  /* Encrypt as many 8-byte blocks as possible.
   */
  tempLen = 8 * (partInLen / 8);
  CipherUpdate (context, partOut, partIn, tempLen);
  partIn += tempLen;
  partInLen -= tempLen;
  *partOutLen += tempLen;

  /* Length is now less than 8, so copy remainder to buffer.
   */
  R_memcpy
    ((POINTER)context->buffer, (POINTER)partIn,