/*
 * Copyright (C) 2017 Denys Vlasenko
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
#include "tls.h"

/* The code below is taken from parts of
 *  matrixssl-3-7-2b-open/crypto/pubkey/pkcs.c
 *  matrixssl-3-7-2b-open/crypto/pubkey/rsa.c
 * and (so far) almost not modified. Changes are flagged with //bbox
 */

#define pkcs1Pad(in, inlen, out, outlen, cryptType, userPtr) \
        pkcs1Pad(in, inlen, out, outlen, cryptType)
static //bbox
int32 pkcs1Pad(unsigned char *in, uint32 inlen, unsigned char *out,
                        uint32 outlen, int32 cryptType, void *userPtr)
{
        unsigned char   *c;
        int32           randomLen;

        randomLen = outlen - 3 - inlen;
        if (randomLen < 8) {
                psTraceCrypto("pkcs1Pad failure\n");
                return PS_LIMIT_FAIL;
        }
        c = out;
        *c = 0x00;
        c++;
        *c = (unsigned char)cryptType;
        c++;
        if (cryptType == PUBKEY_TYPE) {
                while (randomLen-- > 0) {
                        *c++ = 0xFF;
                }
        } else {
                if (matrixCryptoGetPrngData(c, (uint32)randomLen, userPtr) < 0) {
                        return PS_PLATFORM_FAIL;
                }
/*
                SECURITY:  Read through the random data and change all 0x0 to 0x01.
                This is per spec that no random bytes should be 0
*/
                while (randomLen-- > 0) {
                        if (*c == 0x0) {
                                *c = 0x01;
                        }
                        c++;
                }
        }
        *c = 0x00;
        c++;
        memcpy(c, in, inlen);

        return outlen;
}

#define psRsaCrypt(pool, in, inlen, out, outlen, key, type, data) \
        psRsaCrypt(      in, inlen, out, outlen, key, type)
static //bbox
int32 psRsaCrypt(psPool_t *pool, const unsigned char *in, uint32 inlen,
                        unsigned char *out, uint32 *outlen, psRsaKey_t *key, int32 type,
                        void *data)
{
        pstm_int                tmp, tmpa, tmpb;
        int32                   res;
        uint32                  x;

//bbox
//      if (in == NULL || out == NULL || outlen == NULL || key == NULL) {
//              psTraceCrypto("NULL parameter error in psRsaCrypt\n");
//              return PS_ARG_FAIL;
//      }

        tmp.dp = tmpa.dp = tmpb.dp = NULL;

        /* Init and copy into tmp */
        if (pstm_init_for_read_unsigned_bin(pool, &tmp, inlen + sizeof(pstm_digit))
                        != PS_SUCCESS) {
                return PS_FAILURE;
        }
        if (pstm_read_unsigned_bin(&tmp, (unsigned char *)in, inlen) != PS_SUCCESS){
                pstm_clear(&tmp);
                return PS_FAILURE;
        }
        /* Sanity check on the input */
        if (pstm_cmp(&key->N, &tmp) == PSTM_LT) {
                res = PS_LIMIT_FAIL;
                goto done;
        }
        if (type == PRIVKEY_TYPE) {
                if (key->optimized) {
                        if (pstm_init_size(pool, &tmpa, key->p.alloc) != PS_SUCCESS) {
                                res = PS_FAILURE;
                                goto done;
                        }
                        if (pstm_init_size(pool, &tmpb, key->q.alloc) != PS_SUCCESS) {
                                pstm_clear(&tmpa);
                                res = PS_FAILURE;
                                goto done;
                        }
                        if (pstm_exptmod(pool, &tmp, &key->dP, &key->p, &tmpa) !=
                                        PS_SUCCESS) {
                                psTraceCrypto("decrypt error: pstm_exptmod dP, p\n");
                                goto error;
                        }
                        if (pstm_exptmod(pool, &tmp, &key->dQ, &key->q, &tmpb) !=
                                        PS_SUCCESS) {
                                psTraceCrypto("decrypt error: pstm_exptmod dQ, q\n");
                                goto error;
                        }
                        if (pstm_sub(&tmpa, &tmpb, &tmp) != PS_SUCCESS) {
                                psTraceCrypto("decrypt error: sub tmpb, tmp\n");
                                goto error;
                        }
                        if (pstm_mulmod(pool, &tmp, &key->qP, &key->p, &tmp) != PS_SUCCESS) {
                                psTraceCrypto("decrypt error: pstm_mulmod qP, p\n");
                                goto error;
                        }
                        if (pstm_mul_comba(pool, &tmp, &key->q, &tmp, NULL, 0)
                                        != PS_SUCCESS){
                                psTraceCrypto("decrypt error: pstm_mul q \n");
                                goto error;
                        }
                        if (pstm_add(&tmp, &tmpb, &tmp) != PS_SUCCESS) {
                                psTraceCrypto("decrypt error: pstm_add tmp \n");
                                goto error;
                        }
                } else {
                        if (pstm_exptmod(pool, &tmp, &key->d, &key->N, &tmp) !=
                                        PS_SUCCESS) {
                                psTraceCrypto("psRsaCrypt error: pstm_exptmod\n");
                                goto error;
                        }
                }
        } else if (type == PUBKEY_TYPE) {
                if (pstm_exptmod(pool, &tmp, &key->e, &key->N, &tmp) != PS_SUCCESS) {
                        psTraceCrypto("psRsaCrypt error: pstm_exptmod\n");
                        goto error;
                }
        } else {
                psTraceCrypto("psRsaCrypt error: invalid type param\n");
                goto error;
        }
        /* Read it back */
        x = pstm_unsigned_bin_size(&key->N);

        if ((uint32)x > *outlen) {
                res = -1;
                psTraceCrypto("psRsaCrypt error: pstm_unsigned_bin_size\n");
                goto done;
        }
        /* We want the encrypted value to always be the key size.  Pad with 0x0 */
        while ((uint32)x < (unsigned long)key->size) {
                *out++ = 0x0;
                x++;
        }

        *outlen = x;
        /* Convert it */
        memset(out, 0x0, x);

        if (pstm_to_unsigned_bin(pool, &tmp, out+(x-pstm_unsigned_bin_size(&tmp)))
                        != PS_SUCCESS) {
                psTraceCrypto("psRsaCrypt error: pstm_to_unsigned_bin\n");
                goto error;
        }
        /* Clean up and return */
        res = PS_SUCCESS;
        goto done;
error:
        res = PS_FAILURE;
done:
        if (type == PRIVKEY_TYPE && key->optimized) {
                //pstm_clear_multi(&tmpa, &tmpb, NULL, NULL, NULL, NULL, NULL, NULL);
                pstm_clear(&tmpa);
                pstm_clear(&tmpb);
        }
        pstm_clear(&tmp);
        return res;
}

int32 FAST_FUNC psRsaEncryptPub(psPool_t *pool, psRsaKey_t *key,
                                                unsigned char *in, uint32 inlen,
                                                unsigned char *out, uint32 outlen, void *data)
{
        int32   err;
        uint32  size;

        size = key->size;
        if (outlen < size) {
//bbox          psTraceCrypto("Error on bad outlen parameter to psRsaEncryptPub\n");
                bb_error_msg_and_die("RSA crypt outlen:%d < size:%d", outlen, size);
                return PS_ARG_FAIL;
        }

        if ((err = pkcs1Pad(in, inlen, out, size, PRIVKEY_TYPE, data))
                        < PS_SUCCESS) {
                psTraceCrypto("Error padding psRsaEncryptPub. Likely data too long\n");
                return err;
        }
        if ((err = psRsaCrypt(pool, out, size, out, (uint32*)&outlen, key,
                        PUBKEY_TYPE, data)) < PS_SUCCESS) {
                psTraceCrypto("Error performing psRsaEncryptPub\n");
                return err;
        }
        if (outlen != size) {
                psTraceCrypto("Encrypted size error in psRsaEncryptPub\n");
                return PS_FAILURE;
        }
        return size;
}