/* $OpenBSD: encode.c,v 1.29 2021/12/12 21:30:13 tb Exp $ */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 *

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 *

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 *

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 *

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <limits.h>

#include <stdio.h>

#include <string.h>

#include <openssl/evp.h>

#include "evp_locl.h"

static unsigned char conv_ascii2bin(unsigned char a);

#define conv_bin2ascii(a) (data_bin2ascii[(a)&0x3f])

/* 64 char lines

 * pad input with 0

 * left over chars are set to =

 * 1 byte  => xx==

 * 2 bytes => xxx=

 * 3 bytes => xxxx

 */

#define BIN_PER_LINE    (64/4*3)

#define CHUNKS_PER_LINE (64/4)

#define CHAR_PER_LINE   (64+1)

static const unsigned char data_bin2ascii[65] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ\

abcdefghijklmnopqrstuvwxyz0123456789+/";

/* 0xF0 is a EOLN

 * 0xF1 is ignore but next needs to be 0xF0 (for \r\n processing).

 * 0xF2 is EOF

 * 0xE0 is ignore at start of line.

 * 0xFF is error

 */

#define B64_EOLN    0xF0

#define B64_CR      0xF1

#define B64_EOF     0xF2

#define B64_WS      0xE0

#define B64_ERROR         0xFF

#define B64_NOT_BASE64(a) (((a)|0x13) == 0xF3)

#define B64_BASE64(a)   !B64_NOT_BASE64(a)

static const unsigned char data_ascii2bin[128] = {

  0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

  0xFF, 0xE0, 0xF0, 0xFF, 0xFF, 0xF1, 0xFF, 0xFF,

  0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

  0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

  0xE0, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

  0xFF, 0xFF, 0xFF, 0x3E, 0xFF, 0xF2, 0xFF, 0x3F,

  0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B,

  0x3C, 0x3D, 0xFF, 0xFF, 0xFF, 0x00, 0xFF, 0xFF,

  0xFF, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,

  0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,

  0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,

  0x17, 0x18, 0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

  0xFF, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,

  0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,

  0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,

  0x31, 0x32, 0x33, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

};

static unsigned char

conv_ascii2bin(unsigned char a)

{

  if (a & 0x80)

    return B64_ERROR;

  return data_ascii2bin[a];

}

EVP_ENCODE_CTX *

EVP_ENCODE_CTX_new(void)

{

  return calloc(1, sizeof(EVP_ENCODE_CTX));

}

void

EVP_ENCODE_CTX_free(EVP_ENCODE_CTX *ctx)

{

  free(ctx);

}

void

EVP_EncodeInit(EVP_ENCODE_CTX *ctx)

{

  ctx->length = 48;

  ctx->num = 0;

  ctx->line_num = 0;

}

int

EVP_EncodeUpdate(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl,

    const unsigned char *in, int inl)

{

  int i, j;

  size_t total = 0;

  *outl = 0;

  if (inl <= 0)

    return 0;

  OPENSSL_assert(ctx->length <= (int)sizeof(ctx->enc_data));

  if (ctx->length - ctx->num > inl) {

    memcpy(&(ctx->enc_data[ctx->num]), in, inl);

    ctx->num += inl;

    return 1;

  }

  if (ctx->num != 0) {

    i = ctx->length - ctx->num;

    memcpy(&(ctx->enc_data[ctx->num]), in, i);

    in += i;

    inl -= i;

    j = EVP_EncodeBlock(out, ctx->enc_data, ctx->length);

    ctx->num = 0;

    out += j;

    *(out++) = '\n';

    *out = '\0';

    total = j + 1;

  }

  while (inl >= ctx->length && total <= INT_MAX) {

    j = EVP_EncodeBlock(out, in, ctx->length);

    in += ctx->length;

    inl -= ctx->length;

    out += j;

    *(out++) = '\n';

    *out = '\0';

    total += j + 1;

  }

  if (total > INT_MAX) {

    /* Too much output data! */

    *outl = 0;

    return 0;

  }

  if (inl != 0)

    memcpy(&(ctx->enc_data[0]), in, inl);

  ctx->num = inl;

  *outl = total;

  return 1;

}

void

EVP_EncodeFinal(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl)

{

  unsigned int ret = 0;

  if (ctx->num != 0) {

    ret = EVP_EncodeBlock(out, ctx->enc_data, ctx->num);

    out[ret++] = '\n';

    out[ret] = '\0';

    ctx->num = 0;

  }

  *outl = ret;

}

int

EVP_EncodeBlock(unsigned char *t, const unsigned char *f, int dlen)

{

  int i, ret = 0;

  unsigned long l;

  for (i = dlen; i > 0; i -= 3) {

    if (i >= 3) {

      l = (((unsigned long)f[0]) << 16L) |

          (((unsigned long)f[1]) << 8L) | f[2];

      *(t++) = conv_bin2ascii(l >> 18L);

      *(t++) = conv_bin2ascii(l >> 12L);

      *(t++) = conv_bin2ascii(l >> 6L);

      *(t++) = conv_bin2ascii(l     );

    } else {

      l = ((unsigned long)f[0]) << 16L;

      if (i == 2)

        l |= ((unsigned long)f[1] << 8L);

      *(t++) = conv_bin2ascii(l >> 18L);

      *(t++) = conv_bin2ascii(l >> 12L);

      *(t++) = (i == 1) ? '=' : conv_bin2ascii(l >> 6L);

      *(t++) = '=';

    }

    ret += 4;

    f += 3;

  }

  *t = '\0';

  return (ret);

}

void

EVP_DecodeInit(EVP_ENCODE_CTX *ctx)

{

  ctx->num = 0;

  ctx->length = 0;

  ctx->line_num = 0;

  ctx->expect_nl = 0;

}

int

EVP_DecodeUpdate(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl,

    const unsigned char *in, int inl)

{

  int seof = 0, eof = 0, rv = -1, ret = 0, i, v, tmp, n, decoded_len;

  unsigned char *d;

  n = ctx->num;

  d = ctx->enc_data;

  if (n > 0 && d[n - 1] == '=') {

    eof++;

    if (n > 1 && d[n - 2] == '=')

      eof++;

  }

  /* Legacy behaviour: an empty input chunk signals end of input. */

  if (inl == 0) {

    rv = 0;

    goto end;

  }

  for (i = 0; i < inl; i++) {

    tmp = *(in++);

    v = conv_ascii2bin(tmp);

    if (v == B64_ERROR) {

      rv = -1;

      goto end;

    }

    if (tmp == '=') {

      eof++;

    } else if (eof > 0 && B64_BASE64(v)) {

      /* More data after padding. */

      rv = -1;

      goto end;

    }

    if (eof > 2) {

      rv = -1;

      goto end;

    }

    if (v == B64_EOF) {

      seof = 1;

      goto tail;

    }

    /* Only save valid base64 characters. */

    if (B64_BASE64(v)) {

      if (n >= 64) {

        /*

         * We increment n once per loop, and empty the

         * buffer as soon as we reach 64 characters, so

         * this can only happen if someone's manually

         * messed with the ctx. Refuse to write any

         * more data.

         */

        rv = -1;

        goto end;

      }

      OPENSSL_assert(n < (int)sizeof(ctx->enc_data));

      d[n++] = tmp;

    }

    if (n == 64) {

      decoded_len = EVP_DecodeBlock(out, d, n);

      n = 0;

      if (decoded_len < 0 || eof > decoded_len) {

        rv = -1;

        goto end;

      }

      ret += decoded_len - eof;

      out += decoded_len - eof;

    }

  }

  /*

   * Legacy behaviour: if the current line is a full base64-block (i.e.,

   * has 0 mod 4 base64 characters), it is processed immediately. We keep

   * this behaviour as applications may not be calling EVP_DecodeFinal

   * properly.

   */

 tail:

  if (n > 0) {

    if ((n & 3) == 0) {

      decoded_len = EVP_DecodeBlock(out, d, n);

      n = 0;

      if (decoded_len < 0 || eof > decoded_len) {

        rv = -1;

        goto end;

      }

      ret += (decoded_len - eof);

    } else if (seof) {

      /* EOF in the middle of a base64 block. */

      rv = -1;

      goto end;

    }

  }

  rv = seof || (n == 0 && eof) ? 0 : 1;

 end:

  /* Legacy behaviour. This should probably rather be zeroed on error. */

  *outl = ret;

  ctx->num = n;

  return (rv);

}

int

EVP_DecodeBlock(unsigned char *t, const unsigned char *f, int n)

{

  int i, ret = 0, a, b, c, d;

  unsigned long l;

  /* trim white space from the start of the line. */

  while ((conv_ascii2bin(*f) == B64_WS) && (n > 0)) {

    f++;

    n--;

  }

  /* strip off stuff at the end of the line

   * ascii2bin values B64_WS, B64_EOLN, B64_EOLN and B64_EOF */

  while ((n > 3) && (B64_NOT_BASE64(conv_ascii2bin(f[n - 1]))))

    n--;

  if (n % 4 != 0)

    return (-1);

  for (i = 0; i < n; i += 4) {

    a = conv_ascii2bin(*(f++));

    b = conv_ascii2bin(*(f++));

    c = conv_ascii2bin(*(f++));

    d = conv_ascii2bin(*(f++));

    if ((a & 0x80) || (b & 0x80) ||

        (c & 0x80) || (d & 0x80))

      return (-1);

    l = ((((unsigned long)a) << 18L) |

        (((unsigned long)b) << 12L) |

        (((unsigned long)c) << 6L) |

        (((unsigned long)d)));

    *(t++) = (unsigned char)(l >> 16L) & 0xff;

    *(t++) = (unsigned char)(l >> 8L) & 0xff;

    *(t++) = (unsigned char)(l) & 0xff;

    ret += 3;

  }

  return (ret);

}

int

EVP_DecodeFinal(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl)

{

  int i;

  *outl = 0;

  if (ctx->num != 0) {

    i = EVP_DecodeBlock(out, ctx->enc_data, ctx->num);

    if (i < 0)

      return (-1);

    ctx->num = 0;

    *outl = i;

    return (1);

  } else

    return (1);

}