1 /* crypto/evp/bio_ok.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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.
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).
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.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
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)"
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
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.]
60 From: Arne Ansper <arne@cyber.ee>
64 I wrote function which took BIO* as argument, read data from it
65 and processed it. Then I wanted to store the input file in
66 encrypted form. OK I pushed BIO_f_cipher to the BIO stack
67 and everything was OK. BUT if user types wrong password
68 BIO_f_cipher outputs only garbage and my function crashes. Yes
69 I can and I should fix my function, but BIO_f_cipher is
70 easy way to add encryption support to many existing applications
71 and it's hard to debug and fix them all.
73 So I wanted another BIO which would catch the incorrect passwords and
74 file damages which cause garbage on BIO_f_cipher's output.
76 The easy way is to push the BIO_f_md and save the checksum at
77 the end of the file. However there are several problems with this
80 1) you must somehow separate checksum from actual data.
81 2) you need lot's of memory when reading the file, because you
82 must read to the end of the file and verify the checksum before
83 letting the application to read the data.
85 BIO_f_reliable tries to solve both problems, so that you can
86 read and write arbitrary long streams using only fixed amount
89 BIO_f_reliable splits data stream into blocks. Each block is prefixed
90 with it's length and suffixed with it's digest. So you need only
91 several Kbytes of memory to buffer single block before verifying
94 BIO_f_reliable goes further and adds several important capabilities:
96 1) the digest of the block is computed over the whole stream
97 -- so nobody can rearrange the blocks or remove or replace them.
99 2) to detect invalid passwords right at the start BIO_f_reliable
100 adds special prefix to the stream. In order to avoid known plain-text
101 attacks this prefix is generated as follows:
103 *) digest is initialized with random seed instead of
105 *) same seed is written to output
106 *) well-known text is then hashed and the output
107 of the digest is also written to output.
109 reader can now read the seed from stream, hash the same string
110 and then compare the digest output.
112 Bad things: BIO_f_reliable knows what's going on in EVP_Digest. I
113 initially wrote and tested this code on x86 machine and wrote the
114 digests out in machine-dependent order :( There are people using
115 this code and I cannot change this easily without making existing
116 data files unreadable.
123 #include "cryptlib.h"
124 #include <openssl/buffer.h>
125 #include <openssl/bio.h>
126 #include <openssl/evp.h>
127 #include <openssl/rand.h>
129 static int ok_write(BIO *h, const char *buf, int num);
130 static int ok_read(BIO *h, char *buf, int size);
131 static long ok_ctrl(BIO *h, int cmd, long arg1, void *arg2);
132 static int ok_new(BIO *h);
133 static int ok_free(BIO *data);
134 static long ok_callback_ctrl(BIO *h, int cmd, bio_info_cb *fp);
136 static __owur int sig_out(BIO *b);
137 static __owur int sig_in(BIO *b);
138 static __owur int block_out(BIO *b);
139 static __owur int block_in(BIO *b);
140 #define OK_BLOCK_SIZE (1024*4)
141 #define OK_BLOCK_BLOCK 4
142 #define IOBS (OK_BLOCK_SIZE+ OK_BLOCK_BLOCK+ 3*EVP_MAX_MD_SIZE)
143 #define WELLKNOWN "The quick brown fox jumped over the lazy dog's back."
145 typedef struct ok_struct {
150 int cont; /* <= 0 when finished */
153 int blockout; /* output block is ready */
154 int sigio; /* must process signature */
155 unsigned char buf[IOBS];
158 static BIO_METHOD methods_ok = {
159 BIO_TYPE_CIPHER, "reliable",
170 BIO_METHOD *BIO_f_reliable(void)
172 return (&methods_ok);
175 static int ok_new(BIO *bi)
179 ctx = OPENSSL_malloc(sizeof(*ctx));
185 ctx->buf_len_save = 0;
186 ctx->buf_off_save = 0;
192 EVP_MD_CTX_init(&ctx->md);
195 bi->ptr = (char *)ctx;
200 static int ok_free(BIO *a)
204 EVP_MD_CTX_cleanup(&((BIO_OK_CTX *)a->ptr)->md);
205 OPENSSL_clear_free(a->ptr, sizeof(BIO_OK_CTX));
212 static int ok_read(BIO *b, char *out, int outl)
219 ctx = (BIO_OK_CTX *)b->ptr;
221 if ((ctx == NULL) || (b->next_bio == NULL) || (b->init == 0))
226 /* copy clean bytes to output buffer */
228 i = ctx->buf_len - ctx->buf_off;
231 memcpy(out, &(ctx->buf[ctx->buf_off]), i);
237 /* all clean bytes are out */
238 if (ctx->buf_len == ctx->buf_off) {
242 * copy start of the next block into proper place
244 if (ctx->buf_len_save - ctx->buf_off_save > 0) {
245 ctx->buf_len = ctx->buf_len_save - ctx->buf_off_save;
246 memmove(ctx->buf, &(ctx->buf[ctx->buf_off_save]),
255 /* output buffer full -- cancel */
259 /* no clean bytes in buffer -- fill it */
260 n = IOBS - ctx->buf_len;
261 i = BIO_read(b->next_bio, &(ctx->buf[ctx->buf_len]), n);
264 break; /* nothing new */
268 /* no signature yet -- check if we got one */
269 if (ctx->sigio == 1) {
271 BIO_clear_retry_flags(b);
276 /* signature ok -- check if we got block */
277 if (ctx->sigio == 0) {
279 BIO_clear_retry_flags(b);
284 /* invalid block -- cancel */
290 BIO_clear_retry_flags(b);
291 BIO_copy_next_retry(b);
295 static int ok_write(BIO *b, const char *in, int inl)
303 ctx = (BIO_OK_CTX *)b->ptr;
306 if ((ctx == NULL) || (b->next_bio == NULL) || (b->init == 0))
309 if (ctx->sigio && !sig_out(b))
313 BIO_clear_retry_flags(b);
314 n = ctx->buf_len - ctx->buf_off;
315 while (ctx->blockout && n > 0) {
316 i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);
318 BIO_copy_next_retry(b);
319 if (!BIO_should_retry(b))
327 /* at this point all pending data has been written */
329 if (ctx->buf_len == ctx->buf_off) {
330 ctx->buf_len = OK_BLOCK_BLOCK;
334 if ((in == NULL) || (inl <= 0))
337 n = (inl + ctx->buf_len > OK_BLOCK_SIZE + OK_BLOCK_BLOCK) ?
338 (int)(OK_BLOCK_SIZE + OK_BLOCK_BLOCK - ctx->buf_len) : inl;
340 memcpy((unsigned char *)(&(ctx->buf[ctx->buf_len])),
341 (unsigned char *)in, n);
346 if (ctx->buf_len >= OK_BLOCK_SIZE + OK_BLOCK_BLOCK) {
348 BIO_clear_retry_flags(b);
354 BIO_clear_retry_flags(b);
355 BIO_copy_next_retry(b);
359 static long ok_ctrl(BIO *b, int cmd, long num, void *ptr)
373 ctx->buf_len_save = 0;
374 ctx->buf_off_save = 0;
379 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
381 case BIO_CTRL_EOF: /* More to read */
385 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
387 case BIO_CTRL_PENDING: /* More to read in buffer */
388 case BIO_CTRL_WPENDING: /* More to read in buffer */
389 ret = ctx->blockout ? ctx->buf_len - ctx->buf_off : 0;
391 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
394 /* do a final write */
395 if (ctx->blockout == 0)
399 while (ctx->blockout) {
400 i = ok_write(b, NULL, 0);
408 ctx->buf_off = ctx->buf_len = 0;
409 ctx->cont = (int)ret;
411 /* Finally flush the underlying BIO */
412 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
414 case BIO_C_DO_STATE_MACHINE:
415 BIO_clear_retry_flags(b);
416 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
417 BIO_copy_next_retry(b);
420 ret = (long)ctx->cont;
424 if (!EVP_DigestInit_ex(&ctx->md, md, NULL))
431 *ppmd = ctx->md.digest;
436 ret = BIO_ctrl(b->next_bio, cmd, num, ptr);
442 static long ok_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
446 if (b->next_bio == NULL)
450 ret = BIO_callback_ctrl(b->next_bio, cmd, fp);
456 static void longswap(void *_ptr, size_t len)
465 if (is_endian.little) {
467 unsigned char *p = _ptr, c;
469 for (i = 0; i < len; i += 4) {
470 c = p[0], p[0] = p[3], p[3] = c;
471 c = p[1], p[1] = p[2], p[2] = c;
476 static int sig_out(BIO *b)
484 if (ctx->buf_len + 2 * md->digest->md_size > OK_BLOCK_SIZE)
487 if (!EVP_DigestInit_ex(md, md->digest, NULL))
490 * FIXME: there's absolutely no guarantee this makes any sense at all,
491 * particularly now EVP_MD_CTX has been restructured.
493 if (RAND_bytes(md->md_data, md->digest->md_size) <= 0)
495 memcpy(&(ctx->buf[ctx->buf_len]), md->md_data, md->digest->md_size);
496 longswap(&(ctx->buf[ctx->buf_len]), md->digest->md_size);
497 ctx->buf_len += md->digest->md_size;
499 if (!EVP_DigestUpdate(md, WELLKNOWN, strlen(WELLKNOWN)))
501 if (!EVP_DigestFinal_ex(md, &(ctx->buf[ctx->buf_len]), NULL))
503 ctx->buf_len += md->digest->md_size;
508 BIO_clear_retry_flags(b);
512 static int sig_in(BIO *b)
516 unsigned char tmp[EVP_MAX_MD_SIZE];
522 if ((int)(ctx->buf_len - ctx->buf_off) < 2 * md->digest->md_size)
525 if (!EVP_DigestInit_ex(md, md->digest, NULL))
527 memcpy(md->md_data, &(ctx->buf[ctx->buf_off]), md->digest->md_size);
528 longswap(md->md_data, md->digest->md_size);
529 ctx->buf_off += md->digest->md_size;
531 if (!EVP_DigestUpdate(md, WELLKNOWN, strlen(WELLKNOWN)))
533 if (!EVP_DigestFinal_ex(md, tmp, NULL))
535 ret = memcmp(&(ctx->buf[ctx->buf_off]), tmp, md->digest->md_size) == 0;
536 ctx->buf_off += md->digest->md_size;
539 if (ctx->buf_len != ctx->buf_off) {
540 memmove(ctx->buf, &(ctx->buf[ctx->buf_off]),
541 ctx->buf_len - ctx->buf_off);
543 ctx->buf_len -= ctx->buf_off;
550 BIO_clear_retry_flags(b);
554 static int block_out(BIO *b)
563 tl = ctx->buf_len - OK_BLOCK_BLOCK;
564 ctx->buf[0] = (unsigned char)(tl >> 24);
565 ctx->buf[1] = (unsigned char)(tl >> 16);
566 ctx->buf[2] = (unsigned char)(tl >> 8);
567 ctx->buf[3] = (unsigned char)(tl);
568 if (!EVP_DigestUpdate(md,
569 (unsigned char *)&(ctx->buf[OK_BLOCK_BLOCK]), tl))
571 if (!EVP_DigestFinal_ex(md, &(ctx->buf[ctx->buf_len]), NULL))
573 ctx->buf_len += md->digest->md_size;
577 BIO_clear_retry_flags(b);
581 static int block_in(BIO *b)
585 unsigned long tl = 0;
586 unsigned char tmp[EVP_MAX_MD_SIZE];
591 assert(sizeof(tl) >= OK_BLOCK_BLOCK); /* always true */
600 if (ctx->buf_len < tl + OK_BLOCK_BLOCK + md->digest->md_size)
603 if (!EVP_DigestUpdate(md,
604 (unsigned char *)&(ctx->buf[OK_BLOCK_BLOCK]), tl))
606 if (!EVP_DigestFinal_ex(md, tmp, NULL))
608 if (memcmp(&(ctx->buf[tl + OK_BLOCK_BLOCK]), tmp, md->digest->md_size) ==
610 /* there might be parts from next block lurking around ! */
611 ctx->buf_off_save = tl + OK_BLOCK_BLOCK + md->digest->md_size;
612 ctx->buf_len_save = ctx->buf_len;
613 ctx->buf_off = OK_BLOCK_BLOCK;
614 ctx->buf_len = tl + OK_BLOCK_BLOCK;
621 BIO_clear_retry_flags(b);