1 | /*
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2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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3 | *
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4 | * Licensed under the OpenSSL license (the "License"). You may not use
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5 | * this file except in compliance with the License. You can obtain a copy
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6 | * in the file LICENSE in the source distribution or at
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7 | * https://www.openssl.org/source/license.html
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8 | */
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9 |
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10 | #include <stdio.h>
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11 | #include <errno.h>
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12 | #include "internal/cryptlib.h"
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13 | #include <openssl/buffer.h>
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14 | #include <openssl/evp.h>
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15 | #include "internal/bio.h"
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16 |
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17 | static int enc_write(BIO *h, const char *buf, int num);
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18 | static int enc_read(BIO *h, char *buf, int size);
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19 | /*
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20 | * static int enc_puts(BIO *h, const char *str);
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21 | */
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22 | /*
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23 | * static int enc_gets(BIO *h, char *str, int size);
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24 | */
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25 | static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
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26 | static int enc_new(BIO *h);
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27 | static int enc_free(BIO *data);
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28 | static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps);
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29 | #define ENC_BLOCK_SIZE (1024*4)
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30 | #define ENC_MIN_CHUNK (256)
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31 | #define BUF_OFFSET (ENC_MIN_CHUNK + EVP_MAX_BLOCK_LENGTH)
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32 |
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33 | typedef struct enc_struct {
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34 | int buf_len;
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35 | int buf_off;
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36 | int cont; /* <= 0 when finished */
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37 | int finished;
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38 | int ok; /* bad decrypt */
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39 | EVP_CIPHER_CTX *cipher;
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40 | unsigned char *read_start, *read_end;
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41 | /*
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42 | * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return
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43 | * up to a block more data than is presented to it
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44 | */
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45 | unsigned char buf[BUF_OFFSET + ENC_BLOCK_SIZE];
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46 | } BIO_ENC_CTX;
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47 |
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48 | static const BIO_METHOD methods_enc = {
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49 | BIO_TYPE_CIPHER, "cipher",
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50 | enc_write,
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51 | enc_read,
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52 | NULL, /* enc_puts, */
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53 | NULL, /* enc_gets, */
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54 | enc_ctrl,
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55 | enc_new,
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56 | enc_free,
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57 | enc_callback_ctrl,
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58 | };
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59 |
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60 | const BIO_METHOD *BIO_f_cipher(void)
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61 | {
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62 | return (&methods_enc);
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63 | }
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64 |
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65 | static int enc_new(BIO *bi)
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66 | {
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67 | BIO_ENC_CTX *ctx;
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68 |
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69 | ctx = OPENSSL_zalloc(sizeof(*ctx));
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70 | if (ctx == NULL)
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71 | return 0;
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72 |
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73 | ctx->cipher = EVP_CIPHER_CTX_new();
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74 | if (ctx->cipher == NULL) {
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75 | OPENSSL_free(ctx);
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76 | return 0;
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77 | }
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78 | ctx->cont = 1;
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79 | ctx->ok = 1;
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80 | ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
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81 | BIO_set_data(bi, ctx);
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82 | BIO_set_init(bi, 1);
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83 |
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84 | return 1;
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85 | }
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86 |
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87 | static int enc_free(BIO *a)
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88 | {
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89 | BIO_ENC_CTX *b;
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90 |
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91 | if (a == NULL)
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92 | return 0;
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93 |
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94 | b = BIO_get_data(a);
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95 | if (b == NULL)
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96 | return 0;
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97 |
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98 | EVP_CIPHER_CTX_free(b->cipher);
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99 | OPENSSL_clear_free(b, sizeof(BIO_ENC_CTX));
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100 | BIO_set_data(a, NULL);
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101 | BIO_set_init(a, 0);
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102 |
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103 | return 1;
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104 | }
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105 |
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106 | static int enc_read(BIO *b, char *out, int outl)
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107 | {
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108 | int ret = 0, i, blocksize;
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109 | BIO_ENC_CTX *ctx;
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110 | BIO *next;
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111 |
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112 | if (out == NULL)
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113 | return (0);
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114 | ctx = BIO_get_data(b);
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115 |
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116 | next = BIO_next(b);
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117 | if ((ctx == NULL) || (next == NULL))
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118 | return 0;
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119 |
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120 | /* First check if there are bytes decoded/encoded */
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121 | if (ctx->buf_len > 0) {
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122 | i = ctx->buf_len - ctx->buf_off;
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123 | if (i > outl)
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124 | i = outl;
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125 | memcpy(out, &(ctx->buf[ctx->buf_off]), i);
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126 | ret = i;
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127 | out += i;
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128 | outl -= i;
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129 | ctx->buf_off += i;
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130 | if (ctx->buf_len == ctx->buf_off) {
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131 | ctx->buf_len = 0;
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132 | ctx->buf_off = 0;
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133 | }
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134 | }
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135 |
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136 | blocksize = EVP_CIPHER_CTX_block_size(ctx->cipher);
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137 | if (blocksize == 1)
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138 | blocksize = 0;
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139 |
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140 | /*
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141 | * At this point, we have room of outl bytes and an empty buffer, so we
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142 | * should read in some more.
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143 | */
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144 |
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145 | while (outl > 0) {
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146 | if (ctx->cont <= 0)
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147 | break;
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148 |
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149 | if (ctx->read_start == ctx->read_end) { /* time to read more data */
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150 | ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
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151 | i = BIO_read(next, ctx->read_start, ENC_BLOCK_SIZE);
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152 | if (i > 0)
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153 | ctx->read_end += i;
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154 | } else {
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155 | i = ctx->read_end - ctx->read_start;
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156 | }
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157 |
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158 | if (i <= 0) {
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159 | /* Should be continue next time we are called? */
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160 | if (!BIO_should_retry(next)) {
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161 | ctx->cont = i;
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162 | i = EVP_CipherFinal_ex(ctx->cipher,
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163 | ctx->buf, &(ctx->buf_len));
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164 | ctx->ok = i;
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165 | ctx->buf_off = 0;
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166 | } else {
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167 | ret = (ret == 0) ? i : ret;
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168 | break;
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169 | }
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170 | } else {
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171 | if (outl > ENC_MIN_CHUNK) {
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172 | /*
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173 | * Depending on flags block cipher decrypt can write
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174 | * one extra block and then back off, i.e. output buffer
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175 | * has to accommodate extra block...
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176 | */
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177 | int j = outl - blocksize, buf_len;
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178 |
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179 | if (!EVP_CipherUpdate(ctx->cipher,
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180 | (unsigned char *)out, &buf_len,
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181 | ctx->read_start, i > j ? j : i)) {
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182 | BIO_clear_retry_flags(b);
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183 | return 0;
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184 | }
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185 | ret += buf_len;
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186 | out += buf_len;
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187 | outl -= buf_len;
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188 |
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189 | if ((i -= j) <= 0) {
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190 | ctx->read_start = ctx->read_end;
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191 | continue;
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192 | }
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193 | ctx->read_start += j;
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194 | }
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195 | if (i > ENC_MIN_CHUNK)
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196 | i = ENC_MIN_CHUNK;
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197 | if (!EVP_CipherUpdate(ctx->cipher,
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198 | ctx->buf, &ctx->buf_len,
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199 | ctx->read_start, i)) {
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200 | BIO_clear_retry_flags(b);
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201 | ctx->ok = 0;
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202 | return 0;
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203 | }
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204 | ctx->read_start += i;
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205 | ctx->cont = 1;
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206 | /*
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207 | * Note: it is possible for EVP_CipherUpdate to decrypt zero
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208 | * bytes because this is or looks like the final block: if this
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209 | * happens we should retry and either read more data or decrypt
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210 | * the final block
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211 | */
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212 | if (ctx->buf_len == 0)
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213 | continue;
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214 | }
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215 |
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216 | if (ctx->buf_len <= outl)
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217 | i = ctx->buf_len;
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218 | else
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219 | i = outl;
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220 | if (i <= 0)
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221 | break;
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222 | memcpy(out, ctx->buf, i);
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223 | ret += i;
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224 | ctx->buf_off = i;
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225 | outl -= i;
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226 | out += i;
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227 | }
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228 |
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229 | BIO_clear_retry_flags(b);
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230 | BIO_copy_next_retry(b);
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231 | return ((ret == 0) ? ctx->cont : ret);
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232 | }
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233 |
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234 | static int enc_write(BIO *b, const char *in, int inl)
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235 | {
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236 | int ret = 0, n, i;
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237 | BIO_ENC_CTX *ctx;
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238 | BIO *next;
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239 |
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240 | ctx = BIO_get_data(b);
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241 | next = BIO_next(b);
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242 | if ((ctx == NULL) || (next == NULL))
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243 | return 0;
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244 |
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245 | ret = inl;
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246 |
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247 | BIO_clear_retry_flags(b);
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248 | n = ctx->buf_len - ctx->buf_off;
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249 | while (n > 0) {
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250 | i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
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251 | if (i <= 0) {
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252 | BIO_copy_next_retry(b);
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253 | return (i);
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254 | }
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255 | ctx->buf_off += i;
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256 | n -= i;
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257 | }
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258 | /* at this point all pending data has been written */
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259 |
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260 | if ((in == NULL) || (inl <= 0))
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261 | return (0);
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262 |
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263 | ctx->buf_off = 0;
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264 | while (inl > 0) {
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265 | n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
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266 | if (!EVP_CipherUpdate(ctx->cipher,
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267 | ctx->buf, &ctx->buf_len,
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268 | (const unsigned char *)in, n)) {
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269 | BIO_clear_retry_flags(b);
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270 | ctx->ok = 0;
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271 | return 0;
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272 | }
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273 | inl -= n;
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274 | in += n;
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275 |
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276 | ctx->buf_off = 0;
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277 | n = ctx->buf_len;
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278 | while (n > 0) {
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279 | i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
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280 | if (i <= 0) {
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281 | BIO_copy_next_retry(b);
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282 | return (ret == inl) ? i : ret - inl;
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283 | }
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284 | n -= i;
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285 | ctx->buf_off += i;
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286 | }
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287 | ctx->buf_len = 0;
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288 | ctx->buf_off = 0;
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289 | }
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290 | BIO_copy_next_retry(b);
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291 | return (ret);
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292 | }
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293 |
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294 | static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)
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295 | {
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296 | BIO *dbio;
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297 | BIO_ENC_CTX *ctx, *dctx;
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298 | long ret = 1;
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299 | int i;
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300 | EVP_CIPHER_CTX **c_ctx;
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301 | BIO *next;
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302 |
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303 | ctx = BIO_get_data(b);
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304 | next = BIO_next(b);
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305 | if (ctx == NULL)
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306 | return 0;
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307 |
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308 | switch (cmd) {
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309 | case BIO_CTRL_RESET:
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310 | ctx->ok = 1;
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311 | ctx->finished = 0;
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312 | if (!EVP_CipherInit_ex(ctx->cipher, NULL, NULL, NULL, NULL,
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313 | EVP_CIPHER_CTX_encrypting(ctx->cipher)))
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314 | return 0;
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315 | ret = BIO_ctrl(next, cmd, num, ptr);
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316 | break;
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317 | case BIO_CTRL_EOF: /* More to read */
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318 | if (ctx->cont <= 0)
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319 | ret = 1;
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320 | else
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321 | ret = BIO_ctrl(next, cmd, num, ptr);
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322 | break;
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323 | case BIO_CTRL_WPENDING:
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324 | ret = ctx->buf_len - ctx->buf_off;
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325 | if (ret <= 0)
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326 | ret = BIO_ctrl(next, cmd, num, ptr);
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327 | break;
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328 | case BIO_CTRL_PENDING: /* More to read in buffer */
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329 | ret = ctx->buf_len - ctx->buf_off;
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330 | if (ret <= 0)
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331 | ret = BIO_ctrl(next, cmd, num, ptr);
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332 | break;
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333 | case BIO_CTRL_FLUSH:
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334 | /* do a final write */
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335 | again:
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336 | while (ctx->buf_len != ctx->buf_off) {
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337 | i = enc_write(b, NULL, 0);
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338 | if (i < 0)
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339 | return i;
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340 | }
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341 |
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342 | if (!ctx->finished) {
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343 | ctx->finished = 1;
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344 | ctx->buf_off = 0;
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345 | ret = EVP_CipherFinal_ex(ctx->cipher,
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346 | (unsigned char *)ctx->buf,
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347 | &(ctx->buf_len));
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348 | ctx->ok = (int)ret;
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349 | if (ret <= 0)
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350 | break;
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351 |
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352 | /* push out the bytes */
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353 | goto again;
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354 | }
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355 |
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356 | /* Finally flush the underlying BIO */
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357 | ret = BIO_ctrl(next, cmd, num, ptr);
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358 | break;
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359 | case BIO_C_GET_CIPHER_STATUS:
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360 | ret = (long)ctx->ok;
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361 | break;
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362 | case BIO_C_DO_STATE_MACHINE:
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363 | BIO_clear_retry_flags(b);
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364 | ret = BIO_ctrl(next, cmd, num, ptr);
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365 | BIO_copy_next_retry(b);
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366 | break;
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367 | case BIO_C_GET_CIPHER_CTX:
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368 | c_ctx = (EVP_CIPHER_CTX **)ptr;
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369 | *c_ctx = ctx->cipher;
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370 | BIO_set_init(b, 1);
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371 | break;
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372 | case BIO_CTRL_DUP:
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373 | dbio = (BIO *)ptr;
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374 | dctx = BIO_get_data(dbio);
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375 | dctx->cipher = EVP_CIPHER_CTX_new();
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376 | if (dctx->cipher == NULL)
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377 | return 0;
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378 | ret = EVP_CIPHER_CTX_copy(dctx->cipher, ctx->cipher);
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379 | if (ret)
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380 | BIO_set_init(dbio, 1);
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381 | break;
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382 | default:
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383 | ret = BIO_ctrl(next, cmd, num, ptr);
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384 | break;
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385 | }
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386 | return (ret);
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387 | }
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388 |
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389 | static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
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390 | {
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391 | long ret = 1;
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392 | BIO *next = BIO_next(b);
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393 |
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394 | if (next == NULL)
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395 | return (0);
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396 | switch (cmd) {
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397 | default:
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398 | ret = BIO_callback_ctrl(next, cmd, fp);
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399 | break;
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400 | }
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401 | return (ret);
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402 | }
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403 |
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404 | /*-
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405 | void BIO_set_cipher_ctx(b,c)
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406 | BIO *b;
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407 | EVP_CIPHER_ctx *c;
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408 | {
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409 | if (b == NULL) return;
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410 |
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411 | if ((b->callback != NULL) &&
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412 | (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0))
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413 | return;
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414 |
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415 | b->init=1;
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416 | ctx=(BIO_ENC_CTX *)b->ptr;
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417 | memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX));
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418 |
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419 | if (b->callback != NULL)
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420 | b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L);
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421 | }
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422 | */
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423 |
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424 | int BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
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425 | const unsigned char *i, int e)
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426 | {
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427 | BIO_ENC_CTX *ctx;
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428 | long (*callback) (struct bio_st *, int, const char *, int, long, long);
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429 |
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430 | ctx = BIO_get_data(b);
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431 | if (ctx == NULL)
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432 | return 0;
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433 |
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434 | callback = BIO_get_callback(b);
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435 |
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436 | if ((callback != NULL) &&
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437 | (callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e,
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438 | 0L) <= 0))
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439 | return 0;
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440 |
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441 | BIO_set_init(b, 1);
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442 |
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443 | if (!EVP_CipherInit_ex(ctx->cipher, c, NULL, k, i, e))
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444 | return 0;
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445 |
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446 | if (callback != NULL)
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447 | return callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);
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448 | return 1;
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449 | }
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