bio_enc.c revision 296465
1/* crypto/evp/bio_enc.c */ 2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58 59#include <stdio.h> 60#include <errno.h> 61#include "cryptlib.h" 62#include <openssl/buffer.h> 63#include <openssl/evp.h> 64 65static int enc_write(BIO *h, const char *buf, int num); 66static int enc_read(BIO *h, char *buf, int size); 67/* 68 * static int enc_puts(BIO *h, const char *str); 69 */ 70/* 71 * static int enc_gets(BIO *h, char *str, int size); 72 */ 73static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2); 74static int enc_new(BIO *h); 75static int enc_free(BIO *data); 76static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps); 77#define ENC_BLOCK_SIZE (1024*4) 78#define BUF_OFFSET (EVP_MAX_BLOCK_LENGTH*2) 79 80typedef struct enc_struct { 81 int buf_len; 82 int buf_off; 83 int cont; /* <= 0 when finished */ 84 int finished; 85 int ok; /* bad decrypt */ 86 EVP_CIPHER_CTX cipher; 87 /* 88 * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return 89 * up to a block more data than is presented to it 90 */ 91 char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2]; 92} BIO_ENC_CTX; 93 94static BIO_METHOD methods_enc = { 95 BIO_TYPE_CIPHER, "cipher", 96 enc_write, 97 enc_read, 98 NULL, /* enc_puts, */ 99 NULL, /* enc_gets, */ 100 enc_ctrl, 101 enc_new, 102 enc_free, 103 enc_callback_ctrl, 104}; 105 106BIO_METHOD *BIO_f_cipher(void) 107{ 108 return (&methods_enc); 109} 110 111static int enc_new(BIO *bi) 112{ 113 BIO_ENC_CTX *ctx; 114 115 ctx = (BIO_ENC_CTX *)OPENSSL_malloc(sizeof(BIO_ENC_CTX)); 116 if (ctx == NULL) 117 return (0); 118 EVP_CIPHER_CTX_init(&ctx->cipher); 119 120 ctx->buf_len = 0; 121 ctx->buf_off = 0; 122 ctx->cont = 1; 123 ctx->finished = 0; 124 ctx->ok = 1; 125 126 bi->init = 0; 127 bi->ptr = (char *)ctx; 128 bi->flags = 0; 129 return (1); 130} 131 132static int enc_free(BIO *a) 133{ 134 BIO_ENC_CTX *b; 135 136 if (a == NULL) 137 return (0); 138 b = (BIO_ENC_CTX *)a->ptr; 139 EVP_CIPHER_CTX_cleanup(&(b->cipher)); 140 OPENSSL_cleanse(a->ptr, sizeof(BIO_ENC_CTX)); 141 OPENSSL_free(a->ptr); 142 a->ptr = NULL; 143 a->init = 0; 144 a->flags = 0; 145 return (1); 146} 147 148static int enc_read(BIO *b, char *out, int outl) 149{ 150 int ret = 0, i; 151 BIO_ENC_CTX *ctx; 152 153 if (out == NULL) 154 return (0); 155 ctx = (BIO_ENC_CTX *)b->ptr; 156 157 if ((ctx == NULL) || (b->next_bio == NULL)) 158 return (0); 159 160 /* First check if there are bytes decoded/encoded */ 161 if (ctx->buf_len > 0) { 162 i = ctx->buf_len - ctx->buf_off; 163 if (i > outl) 164 i = outl; 165 memcpy(out, &(ctx->buf[ctx->buf_off]), i); 166 ret = i; 167 out += i; 168 outl -= i; 169 ctx->buf_off += i; 170 if (ctx->buf_len == ctx->buf_off) { 171 ctx->buf_len = 0; 172 ctx->buf_off = 0; 173 } 174 } 175 176 /* 177 * At this point, we have room of outl bytes and an empty buffer, so we 178 * should read in some more. 179 */ 180 181 while (outl > 0) { 182 if (ctx->cont <= 0) 183 break; 184 185 /* 186 * read in at IV offset, read the EVP_Cipher documentation about why 187 */ 188 i = BIO_read(b->next_bio, &(ctx->buf[BUF_OFFSET]), ENC_BLOCK_SIZE); 189 190 if (i <= 0) { 191 /* Should be continue next time we are called? */ 192 if (!BIO_should_retry(b->next_bio)) { 193 ctx->cont = i; 194 i = EVP_CipherFinal_ex(&(ctx->cipher), 195 (unsigned char *)ctx->buf, 196 &(ctx->buf_len)); 197 ctx->ok = i; 198 ctx->buf_off = 0; 199 } else { 200 ret = (ret == 0) ? i : ret; 201 break; 202 } 203 } else { 204 EVP_CipherUpdate(&(ctx->cipher), 205 (unsigned char *)ctx->buf, &ctx->buf_len, 206 (unsigned char *)&(ctx->buf[BUF_OFFSET]), i); 207 ctx->cont = 1; 208 /* 209 * Note: it is possible for EVP_CipherUpdate to decrypt zero 210 * bytes because this is or looks like the final block: if this 211 * happens we should retry and either read more data or decrypt 212 * the final block 213 */ 214 if (ctx->buf_len == 0) 215 continue; 216 } 217 218 if (ctx->buf_len <= outl) 219 i = ctx->buf_len; 220 else 221 i = outl; 222 if (i <= 0) 223 break; 224 memcpy(out, ctx->buf, i); 225 ret += i; 226 ctx->buf_off = i; 227 outl -= i; 228 out += i; 229 } 230 231 BIO_clear_retry_flags(b); 232 BIO_copy_next_retry(b); 233 return ((ret == 0) ? ctx->cont : ret); 234} 235 236static int enc_write(BIO *b, const char *in, int inl) 237{ 238 int ret = 0, n, i; 239 BIO_ENC_CTX *ctx; 240 241 ctx = (BIO_ENC_CTX *)b->ptr; 242 ret = inl; 243 244 BIO_clear_retry_flags(b); 245 n = ctx->buf_len - ctx->buf_off; 246 while (n > 0) { 247 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n); 248 if (i <= 0) { 249 BIO_copy_next_retry(b); 250 return (i); 251 } 252 ctx->buf_off += i; 253 n -= i; 254 } 255 /* at this point all pending data has been written */ 256 257 if ((in == NULL) || (inl <= 0)) 258 return (0); 259 260 ctx->buf_off = 0; 261 while (inl > 0) { 262 n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl; 263 EVP_CipherUpdate(&(ctx->cipher), 264 (unsigned char *)ctx->buf, &ctx->buf_len, 265 (unsigned char *)in, n); 266 inl -= n; 267 in += n; 268 269 ctx->buf_off = 0; 270 n = ctx->buf_len; 271 while (n > 0) { 272 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n); 273 if (i <= 0) { 274 BIO_copy_next_retry(b); 275 return (ret == inl) ? i : ret - inl; 276 } 277 n -= i; 278 ctx->buf_off += i; 279 } 280 ctx->buf_len = 0; 281 ctx->buf_off = 0; 282 } 283 BIO_copy_next_retry(b); 284 return (ret); 285} 286 287static long enc_ctrl(BIO *b, int cmd, long num, void *ptr) 288{ 289 BIO *dbio; 290 BIO_ENC_CTX *ctx, *dctx; 291 long ret = 1; 292 int i; 293 EVP_CIPHER_CTX **c_ctx; 294 295 ctx = (BIO_ENC_CTX *)b->ptr; 296 297 switch (cmd) { 298 case BIO_CTRL_RESET: 299 ctx->ok = 1; 300 ctx->finished = 0; 301 EVP_CipherInit_ex(&(ctx->cipher), NULL, NULL, NULL, NULL, 302 ctx->cipher.encrypt); 303 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 304 break; 305 case BIO_CTRL_EOF: /* More to read */ 306 if (ctx->cont <= 0) 307 ret = 1; 308 else 309 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 310 break; 311 case BIO_CTRL_WPENDING: 312 ret = ctx->buf_len - ctx->buf_off; 313 if (ret <= 0) 314 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 315 break; 316 case BIO_CTRL_PENDING: /* More to read in buffer */ 317 ret = ctx->buf_len - ctx->buf_off; 318 if (ret <= 0) 319 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 320 break; 321 case BIO_CTRL_FLUSH: 322 /* do a final write */ 323 again: 324 while (ctx->buf_len != ctx->buf_off) { 325 i = enc_write(b, NULL, 0); 326 if (i < 0) 327 return i; 328 } 329 330 if (!ctx->finished) { 331 ctx->finished = 1; 332 ctx->buf_off = 0; 333 ret = EVP_CipherFinal_ex(&(ctx->cipher), 334 (unsigned char *)ctx->buf, 335 &(ctx->buf_len)); 336 ctx->ok = (int)ret; 337 if (ret <= 0) 338 break; 339 340 /* push out the bytes */ 341 goto again; 342 } 343 344 /* Finally flush the underlying BIO */ 345 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 346 break; 347 case BIO_C_GET_CIPHER_STATUS: 348 ret = (long)ctx->ok; 349 break; 350 case BIO_C_DO_STATE_MACHINE: 351 BIO_clear_retry_flags(b); 352 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 353 BIO_copy_next_retry(b); 354 break; 355 case BIO_C_GET_CIPHER_CTX: 356 c_ctx = (EVP_CIPHER_CTX **)ptr; 357 (*c_ctx) = &(ctx->cipher); 358 b->init = 1; 359 break; 360 case BIO_CTRL_DUP: 361 dbio = (BIO *)ptr; 362 dctx = (BIO_ENC_CTX *)dbio->ptr; 363 memcpy(&(dctx->cipher), &(ctx->cipher), sizeof(ctx->cipher)); 364 dbio->init = 1; 365 break; 366 default: 367 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 368 break; 369 } 370 return (ret); 371} 372 373static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp) 374{ 375 long ret = 1; 376 377 if (b->next_bio == NULL) 378 return (0); 379 switch (cmd) { 380 default: 381 ret = BIO_callback_ctrl(b->next_bio, cmd, fp); 382 break; 383 } 384 return (ret); 385} 386 387/*- 388void BIO_set_cipher_ctx(b,c) 389BIO *b; 390EVP_CIPHER_ctx *c; 391 { 392 if (b == NULL) return; 393 394 if ((b->callback != NULL) && 395 (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0)) 396 return; 397 398 b->init=1; 399 ctx=(BIO_ENC_CTX *)b->ptr; 400 memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX)); 401 402 if (b->callback != NULL) 403 b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L); 404 } 405*/ 406 407void BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k, 408 const unsigned char *i, int e) 409{ 410 BIO_ENC_CTX *ctx; 411 412 if (b == NULL) 413 return; 414 415 if ((b->callback != NULL) && 416 (b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 0L) <= 417 0)) 418 return; 419 420 b->init = 1; 421 ctx = (BIO_ENC_CTX *)b->ptr; 422 EVP_CipherInit_ex(&(ctx->cipher), c, NULL, k, i, e); 423 424 if (b->callback != NULL) 425 b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L); 426} 427