1 /* $OpenBSD: bio_enc.c,v 1.18 2014/07/11 08:44:48 jsing Exp $ */ 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 <errno.h> 60 #include <stdio.h> 61 #include <string.h> 62 63 #include <openssl/buffer.h> 64 #include <openssl/evp.h> 65 66 static int enc_write(BIO *h, const char *buf, int num); 67 static int enc_read(BIO *h, char *buf, int size); 68 /*static int enc_puts(BIO *h, const char *str); */ 69 /*static int enc_gets(BIO *h, char *str, int size); */ 70 static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2); 71 static int enc_new(BIO *h); 72 static int enc_free(BIO *data); 73 static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps); 74 #define ENC_BLOCK_SIZE (1024*4) 75 #define BUF_OFFSET (EVP_MAX_BLOCK_LENGTH*2) 76 77 typedef struct enc_struct { 78 int buf_len; 79 int buf_off; 80 int cont; /* <= 0 when finished */ 81 int finished; 82 int ok; /* bad decrypt */ 83 EVP_CIPHER_CTX cipher; 84 /* buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate 85 * can return up to a block more data than is presented to it 86 */ 87 char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2]; 88 } BIO_ENC_CTX; 89 90 static BIO_METHOD methods_enc = { 91 .type = BIO_TYPE_CIPHER, 92 .name = "cipher", 93 .bwrite = enc_write, 94 .bread = enc_read, 95 .ctrl = enc_ctrl, 96 .create = enc_new, 97 .destroy = enc_free, 98 .callback_ctrl = enc_callback_ctrl 99 }; 100 101 BIO_METHOD * 102 BIO_f_cipher(void) 103 { 104 return (&methods_enc); 105 } 106 107 static int 108 enc_new(BIO *bi) 109 { 110 BIO_ENC_CTX *ctx; 111 112 ctx = malloc(sizeof(BIO_ENC_CTX)); 113 if (ctx == NULL) 114 return (0); 115 EVP_CIPHER_CTX_init(&ctx->cipher); 116 117 ctx->buf_len = 0; 118 ctx->buf_off = 0; 119 ctx->cont = 1; 120 ctx->finished = 0; 121 ctx->ok = 1; 122 123 bi->init = 0; 124 bi->ptr = (char *)ctx; 125 bi->flags = 0; 126 return (1); 127 } 128 129 static int 130 enc_free(BIO *a) 131 { 132 BIO_ENC_CTX *b; 133 134 if (a == NULL) 135 return (0); 136 b = (BIO_ENC_CTX *)a->ptr; 137 EVP_CIPHER_CTX_cleanup(&(b->cipher)); 138 explicit_bzero(a->ptr, sizeof(BIO_ENC_CTX)); 139 free(a->ptr); 140 a->ptr = NULL; 141 a->init = 0; 142 a->flags = 0; 143 return (1); 144 } 145 146 static int 147 enc_read(BIO *b, char *out, int outl) 148 { 149 int ret = 0, i; 150 BIO_ENC_CTX *ctx; 151 152 if (out == NULL) 153 return (0); 154 ctx = (BIO_ENC_CTX *)b->ptr; 155 156 if ((ctx == NULL) || (b->next_bio == NULL)) 157 return (0); 158 159 /* First check if there are bytes decoded/encoded */ 160 if (ctx->buf_len > 0) { 161 i = ctx->buf_len - ctx->buf_off; 162 if (i > outl) 163 i = outl; 164 memcpy(out, &(ctx->buf[ctx->buf_off]), i); 165 ret = i; 166 out += i; 167 outl -= i; 168 ctx->buf_off += i; 169 if (ctx->buf_len == ctx->buf_off) { 170 ctx->buf_len = 0; 171 ctx->buf_off = 0; 172 } 173 } 174 175 /* At this point, we have room of outl bytes and an empty 176 * buffer, so we should read in some more. */ 177 178 while (outl > 0) { 179 if (ctx->cont <= 0) 180 break; 181 182 /* read in at IV offset, read the EVP_Cipher 183 * documentation about why */ 184 i = BIO_read(b->next_bio, &(ctx->buf[BUF_OFFSET]), ENC_BLOCK_SIZE); 185 186 if (i <= 0) { 187 /* Should be continue next time we are called? */ 188 if (!BIO_should_retry(b->next_bio)) { 189 ctx->cont = i; 190 i = EVP_CipherFinal_ex(&(ctx->cipher), 191 (unsigned char *)ctx->buf, 192 &(ctx->buf_len)); 193 ctx->ok = i; 194 ctx->buf_off = 0; 195 } else { 196 ret = (ret == 0) ? i : ret; 197 break; 198 } 199 } else { 200 EVP_CipherUpdate(&(ctx->cipher), 201 (unsigned char *)ctx->buf, &ctx->buf_len, 202 (unsigned char *)&(ctx->buf[BUF_OFFSET]), i); 203 ctx->cont = 1; 204 /* Note: it is possible for EVP_CipherUpdate to 205 * decrypt zero bytes because this is or looks like 206 * the final block: if this happens we should retry 207 * and either read more data or decrypt the final 208 * block 209 */ 210 if (ctx->buf_len == 0) 211 continue; 212 } 213 214 if (ctx->buf_len <= outl) 215 i = ctx->buf_len; 216 else 217 i = outl; 218 if (i <= 0) 219 break; 220 memcpy(out, ctx->buf, i); 221 ret += i; 222 ctx->buf_off = i; 223 outl -= i; 224 out += i; 225 } 226 227 BIO_clear_retry_flags(b); 228 BIO_copy_next_retry(b); 229 return ((ret == 0) ? ctx->cont : ret); 230 } 231 232 static int 233 enc_write(BIO *b, const char *in, int inl) 234 { 235 int ret = 0, n, i; 236 BIO_ENC_CTX *ctx; 237 238 ctx = (BIO_ENC_CTX *)b->ptr; 239 ret = inl; 240 241 BIO_clear_retry_flags(b); 242 n = ctx->buf_len - ctx->buf_off; 243 while (n > 0) { 244 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n); 245 if (i <= 0) { 246 BIO_copy_next_retry(b); 247 return (i); 248 } 249 ctx->buf_off += i; 250 n -= i; 251 } 252 /* at this point all pending data has been written */ 253 254 if ((in == NULL) || (inl <= 0)) 255 return (0); 256 257 ctx->buf_off = 0; 258 while (inl > 0) { 259 n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl; 260 EVP_CipherUpdate(&(ctx->cipher), 261 (unsigned char *)ctx->buf, &ctx->buf_len, 262 (unsigned char *)in, n); 263 inl -= n; 264 in += n; 265 266 ctx->buf_off = 0; 267 n = ctx->buf_len; 268 while (n > 0) { 269 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n); 270 if (i <= 0) { 271 BIO_copy_next_retry(b); 272 return (ret == inl) ? i : ret - inl; 273 } 274 n -= i; 275 ctx->buf_off += i; 276 } 277 ctx->buf_len = 0; 278 ctx->buf_off = 0; 279 } 280 BIO_copy_next_retry(b); 281 return (ret); 282 } 283 284 static long 285 enc_ctrl(BIO *b, int cmd, long num, void *ptr) 286 { 287 BIO *dbio; 288 BIO_ENC_CTX *ctx, *dctx; 289 long ret = 1; 290 int i; 291 EVP_CIPHER_CTX **c_ctx; 292 293 ctx = (BIO_ENC_CTX *)b->ptr; 294 295 switch (cmd) { 296 case BIO_CTRL_RESET: 297 ctx->ok = 1; 298 ctx->finished = 0; 299 EVP_CipherInit_ex(&(ctx->cipher), NULL, NULL, NULL, NULL, 300 ctx->cipher.encrypt); 301 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 302 break; 303 case BIO_CTRL_EOF: /* More to read */ 304 if (ctx->cont <= 0) 305 ret = 1; 306 else 307 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 308 break; 309 case BIO_CTRL_WPENDING: 310 ret = ctx->buf_len - ctx->buf_off; 311 if (ret <= 0) 312 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 313 break; 314 case BIO_CTRL_PENDING: /* More to read in buffer */ 315 ret = ctx->buf_len - ctx->buf_off; 316 if (ret <= 0) 317 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 318 break; 319 case BIO_CTRL_FLUSH: 320 /* do a final write */ 321 again: 322 while (ctx->buf_len != ctx->buf_off) { 323 i = enc_write(b, NULL, 0); 324 if (i < 0) 325 return i; 326 } 327 328 if (!ctx->finished) { 329 ctx->finished = 1; 330 ctx->buf_off = 0; 331 ret = EVP_CipherFinal_ex(&(ctx->cipher), 332 (unsigned char *)ctx->buf, 333 &(ctx->buf_len)); 334 ctx->ok = (int)ret; 335 if (ret <= 0) 336 break; 337 338 /* push out the bytes */ 339 goto again; 340 } 341 342 /* Finally flush the underlying BIO */ 343 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 344 break; 345 case BIO_C_GET_CIPHER_STATUS: 346 ret = (long)ctx->ok; 347 break; 348 case BIO_C_DO_STATE_MACHINE: 349 BIO_clear_retry_flags(b); 350 ret = BIO_ctrl(b->next_bio, cmd, num, ptr); 351 BIO_copy_next_retry(b); 352 break; 353 case BIO_C_GET_CIPHER_CTX: 354 c_ctx = (EVP_CIPHER_CTX **)ptr; 355 (*c_ctx) = &(ctx->cipher); 356 b->init = 1; 357 break; 358 case BIO_CTRL_DUP: 359 dbio = (BIO *)ptr; 360 dctx = (BIO_ENC_CTX *)dbio->ptr; 361 EVP_CIPHER_CTX_init(&dctx->cipher); 362 ret = EVP_CIPHER_CTX_copy(&dctx->cipher, &ctx->cipher); 363 if (ret) 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 } 372 373 static long 374 enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp) 375 { 376 long ret = 1; 377 378 if (b->next_bio == NULL) 379 return (0); 380 switch (cmd) { 381 default: 382 ret = BIO_callback_ctrl(b->next_bio, cmd, fp); 383 break; 384 } 385 return (ret); 386 } 387 388 /* 389 void BIO_set_cipher_ctx(b,c) 390 BIO *b; 391 EVP_CIPHER_ctx *c; 392 { 393 if (b == NULL) return; 394 395 if ((b->callback != NULL) && 396 (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0)) 397 return; 398 399 b->init=1; 400 ctx=(BIO_ENC_CTX *)b->ptr; 401 memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX)); 402 403 if (b->callback != NULL) 404 b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L); 405 } 406 */ 407 408 void 409 BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k, 410 const unsigned char *i, int e) 411 { 412 BIO_ENC_CTX *ctx; 413 414 if (b == NULL) 415 return; 416 417 if ((b->callback != NULL) && 418 (b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 0L) <= 0)) 419 return; 420 421 b->init = 1; 422 ctx = (BIO_ENC_CTX *)b->ptr; 423 EVP_CipherInit_ex(&(ctx->cipher), c, NULL, k, i, e); 424 425 if (b->callback != NULL) 426 b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L); 427 } 428