text: /*
   * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  #include <stdio.h>
  #include <limits.h>
  #include "internal/cryptlib.h"
  #include <openssl/evp.h>
  #include "internal/evp_int.h"
  #include "evp_locl.h"
  
  static unsigned char conv_ascii2bin(unsigned char a,
                                      const unsigned char *table);
  static int evp_encodeblock_int(EVP_ENCODE_CTX *ctx, unsigned char *t,
                                 const unsigned char *f, int dlen);
  static int evp_decodeblock_int(EVP_ENCODE_CTX *ctx, unsigned char *t,
                                 const unsigned char *f, int n);
  
  #ifndef CHARSET_EBCDIC
  # define conv_bin2ascii(a, table)       ((table)[(a)&0x3f])
  #else
  /*
   * We assume that PEM encoded files are EBCDIC files (i.e., printable text
   * files). Convert them here while decoding. When encoding, output is EBCDIC
   * (text) format again. (No need for conversion in the conv_bin2ascii macro,
   * as the underlying textstring data_bin2ascii[] is already EBCDIC)
   */
  # define conv_bin2ascii(a, table)       ((table)[(a)&0x3f])
  #endif
  
  /*-
   * 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] =
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  
  /* SRP uses a different base64 alphabet */
  static const unsigned char srpdata_bin2ascii[65] =
      "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz./";
  
  
  /*-
   * 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 const unsigned char srpdata_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, 0xFF, 0xFF, 0xF2, 0x3E, 0x3F,
      0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
      0x08, 0x09, 0xFF, 0xFF, 0xFF, 0x00, 0xFF, 0xFF,
      0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10,
      0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
      0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20,
      0x21, 0x22, 0x23, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
      0xFF, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A,
      0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32,
      0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
      0x3B, 0x3C, 0x3D, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
  };
  
  #ifndef CHARSET_EBCDIC
  static unsigned char conv_ascii2bin(unsigned char a, const unsigned char *table)
  {
      if (a & 0x80)
          return B64_ERROR;
      return table[a];
  }
  #else
  static unsigned char conv_ascii2bin(unsigned char a, const unsigned char *table)
  {
      a = os_toascii[a];
      if (a & 0x80)
          return B64_ERROR;
      return table[a];
  }
  #endif
  
  EVP_ENCODE_CTX *EVP_ENCODE_CTX_new(void)
  {
      return OPENSSL_zalloc(sizeof(EVP_ENCODE_CTX));
  }
  
  void EVP_ENCODE_CTX_free(EVP_ENCODE_CTX *ctx)
  {
      OPENSSL_free(ctx);
  }
  
  int EVP_ENCODE_CTX_copy(EVP_ENCODE_CTX *dctx, EVP_ENCODE_CTX *sctx)
  {
      memcpy(dctx, sctx, sizeof(EVP_ENCODE_CTX));
  
      return 1;
  }
  
  int EVP_ENCODE_CTX_num(EVP_ENCODE_CTX *ctx)
  {
      return ctx->num;
  }
  
  void evp_encode_ctx_set_flags(EVP_ENCODE_CTX *ctx, unsigned int flags)
  {
      ctx->flags = flags;
  }
  
  void EVP_EncodeInit(EVP_ENCODE_CTX *ctx)
  {
      ctx->length = 48;
      ctx->num = 0;
      ctx->line_num = 0;
      ctx->flags = 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_int(ctx, out, ctx->enc_data, ctx->length);
          ctx->num = 0;
          out += j;
          total = j;
          if ((ctx->flags & EVP_ENCODE_CTX_NO_NEWLINES) == 0) {
              *(out++) = '\n';
              total++;
          }
          *out = '\0';
      }
      while (inl >= ctx->length && total <= INT_MAX) {
          j = evp_encodeblock_int(ctx, out, in, ctx->length);
          in += ctx->length;
          inl -= ctx->length;
          out += j;
          total += j;
          if ((ctx->flags & EVP_ENCODE_CTX_NO_NEWLINES) == 0) {
              *(out++) = '\n';
              total++;
          }
          *out = '\0';
      }
      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_int(ctx, out, ctx->enc_data, ctx->num);
          if ((ctx->flags & EVP_ENCODE_CTX_NO_NEWLINES) == 0)
              out[ret++] = '\n';
          out[ret] = '\0';
          ctx->num = 0;
      }
      *outl = ret;
  }
  
  static int evp_encodeblock_int(EVP_ENCODE_CTX *ctx, unsigned char *t,
                                 const unsigned char *f, int dlen)
  {
      int i, ret = 0;
      unsigned long l;
      const unsigned char *table;
  
      if (ctx != NULL && (ctx->flags & EVP_ENCODE_CTX_USE_SRP_ALPHABET) != 0)
          table = srpdata_bin2ascii;
      else
          table = data_bin2ascii;
  
      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, table);
              *(t++) = conv_bin2ascii(l >> 12L, table);
              *(t++) = conv_bin2ascii(l >> 6L, table);
              *(t++) = conv_bin2ascii(l, table);
          } else {
              l = ((unsigned long)f[0]) << 16L;
              if (i == 2)
                  l |= ((unsigned long)f[1] << 8L);
  
              *(t++) = conv_bin2ascii(l >> 18L, table);
              *(t++) = conv_bin2ascii(l >> 12L, table);
              *(t++) = (i == 1) ? '=' : conv_bin2ascii(l >> 6L, table);
              *(t++) = '=';
          }
          ret += 4;
          f += 3;
      }
  
      *t = '\0';
      return ret;
  }
  
  int EVP_EncodeBlock(unsigned char *t, const unsigned char *f, int dlen)
  {
      return evp_encodeblock_int(NULL, t, f, dlen);
  }
  
  void EVP_DecodeInit(EVP_ENCODE_CTX *ctx)
  {
      /* Only ctx->num and ctx->flags are used during decoding. */
      ctx->num = 0;
      ctx->length = 0;
      ctx->line_num = 0;
      ctx->flags = 0;
  }
  
  /*-
   * -1 for error
   *  0 for last line
   *  1 for full line
   *
   * Note: even though EVP_DecodeUpdate attempts to detect and report end of
   * content, the context doesn't currently remember it and will accept more data
   * in the next call. Therefore, the caller is responsible for checking and
   * rejecting a 0 return value in the middle of content.
   *
   * Note: even though EVP_DecodeUpdate has historically tried to detect end of
   * content based on line length, this has never worked properly. Therefore,
   * we now return 0 when one of the following is true:
   *   - Padding or B64_EOF was detected and the last block is complete.
   *   - Input has zero-length.
   * -1 is returned if:
   *   - Invalid characters are detected.
   *   - There is extra trailing padding, or data after padding.
   *   - B64_EOF is detected after an incomplete base64 block.
   */
  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;
      const unsigned char *table;
  
      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;
      }
  
      if ((ctx->flags & EVP_ENCODE_CTX_USE_SRP_ALPHABET) != 0)
          table = srpdata_ascii2bin;
      else
          table = data_ascii2bin;
  
      for (i = 0; i < inl; i++) {
          tmp = *(in++);
          v = conv_ascii2bin(tmp, table);
          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_int(ctx, 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_int(ctx, 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;
  }
  
  static int evp_decodeblock_int(EVP_ENCODE_CTX *ctx, unsigned char *t,
                                 const unsigned char *f, int n)
  {
      int i, ret = 0, a, b, c, d;
      unsigned long l;
      const unsigned char *table;
  
      if (ctx != NULL && (ctx->flags & EVP_ENCODE_CTX_USE_SRP_ALPHABET) != 0)
          table = srpdata_ascii2bin;
      else
          table = data_ascii2bin;
  
      /* trim white space from the start of the line. */
      while ((conv_ascii2bin(*f, table) == 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], table))))
          n--;
  
      if (n % 4 != 0)
          return -1;
  
      for (i = 0; i < n; i += 4) {
          a = conv_ascii2bin(*(f++), table);
          b = conv_ascii2bin(*(f++), table);
          c = conv_ascii2bin(*(f++), table);
          d = conv_ascii2bin(*(f++), table);
          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_DecodeBlock(unsigned char *t, const unsigned char *f, int n)
  {
      return evp_decodeblock_int(NULL, t, f, n);
  }
  
  int EVP_DecodeFinal(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl)
  {
      int i;
  
      *outl = 0;
      if (ctx->num != 0) {
          i = evp_decodeblock_int(ctx, out, ctx->enc_data, ctx->num);
          if (i < 0)
              return -1;
          ctx->num = 0;
          *outl = i;
          return 1;
      } else
          return 1;
  }
  