crypto/evp/bio_enc.c

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