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 exisiting 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 leting the application to read the data.
85 BIO_f_reliable tries to solve both problems, so that you can
86 read and write arbitraly 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 futher 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 ouput
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 initialy 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.
122 #include "cryptlib.h"
123 #include <openssl/buffer.h>
124 #include <openssl/bio.h>
125 #include <openssl/evp.h>
126 #include <openssl/rand.h>
129 static int ok_write(BIO *h,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,char *arg2);
132 static int ok_new(BIO *h);
133 static int ok_free(BIO *data);
134 static void sig_out(BIO* b);
135 static void sig_in(BIO* b);
136 static void block_out(BIO* b);
137 static void block_in(BIO* b);
139 static int ok_write();
140 static int ok_read();
141 static long ok_ctrl();
143 static int ok_free();
144 static void sig_out();
145 static void sig_in();
146 static void block_out();
147 static void block_in();
150 #define OK_BLOCK_SIZE (1024*4)
151 #define OK_BLOCK_BLOCK 4
152 #define IOBS (OK_BLOCK_SIZE+ OK_BLOCK_BLOCK+ 3*EVP_MAX_MD_SIZE)
153 #define WELLKNOWN "The quick brown fox jumped over the lazy dog's back."
157 ((unsigned long int)((((unsigned long int)(x) & 0x000000ffU) << 24) | \
158 (((unsigned long int)(x) & 0x0000ff00U) << 8) | \
159 (((unsigned long int)(x) & 0x00ff0000U) >> 8) | \
160 (((unsigned long int)(x) & 0xff000000U) >> 24)))
162 #define swapem(x) (x)
165 typedef struct ok_struct
171 int cont; /* <= 0 when finished */
174 int blockout; /* output block is ready */
175 int sigio; /* must process signature */
179 static BIO_METHOD methods_ok=
181 BIO_TYPE_CIPHER,"reliable",
191 BIO_METHOD *BIO_f_reliable(void)
196 static int ok_new(BIO *bi)
200 ctx=(BIO_OK_CTX *)Malloc(sizeof(BIO_OK_CTX));
201 if (ctx == NULL) return(0);
218 static int ok_free(BIO *a)
220 if (a == NULL) return(0);
221 memset(a->ptr,0,sizeof(BIO_OK_CTX));
229 static int ok_read(BIO *b, char *out, int outl)
234 if (out == NULL) return(0);
235 ctx=(BIO_OK_CTX *)b->ptr;
237 if ((ctx == NULL) || (b->next_bio == NULL) || (b->init == 0)) return(0);
242 /* copy clean bytes to output buffer */
245 i=ctx->buf_len-ctx->buf_off;
246 if (i > outl) i=outl;
247 memcpy(out,&(ctx->buf[ctx->buf_off]),i);
253 /* all clean bytes are out */
254 if (ctx->buf_len == ctx->buf_off)
258 /* copy start of the next block into proper place */
259 if(ctx->buf_len_save- ctx->buf_off_save > 0)
261 ctx->buf_len= ctx->buf_len_save- ctx->buf_off_save;
262 memmove(ctx->buf, &(ctx->buf[ctx->buf_off_save]),
273 /* output buffer full -- cancel */
274 if (outl == 0) break;
276 /* no clean bytes in buffer -- fill it */
277 n=IOBS- ctx->buf_len;
278 i=BIO_read(b->next_bio,&(ctx->buf[ctx->buf_len]),n);
280 if (i <= 0) break; /* nothing new */
284 /* no signature yet -- check if we got one */
285 if (ctx->sigio == 1) sig_in(b);
287 /* signature ok -- check if we got block */
288 if (ctx->sigio == 0) block_in(b);
290 /* invalid block -- cancel */
291 if (ctx->cont <= 0) break;
295 BIO_clear_retry_flags(b);
296 BIO_copy_next_retry(b);
300 static int ok_write(BIO *b, char *in, int inl)
305 ctx=(BIO_OK_CTX *)b->ptr;
308 if ((ctx == NULL) || (b->next_bio == NULL) || (b->init == 0)) return(0);
310 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)
317 i=BIO_write(b->next_bio,&(ctx->buf[ctx->buf_off]),n);
320 BIO_copy_next_retry(b);
321 if(!BIO_should_retry(b))
329 /* at this point all pending data has been written */
331 if (ctx->buf_len == ctx->buf_off)
333 ctx->buf_len=OK_BLOCK_BLOCK;
337 if ((in == NULL) || (inl <= 0)) return(0);
339 n= (inl+ ctx->buf_len > OK_BLOCK_SIZE+ OK_BLOCK_BLOCK) ?
340 OK_BLOCK_SIZE+ OK_BLOCK_BLOCK- ctx->buf_len : inl;
342 memcpy((unsigned char *)(&(ctx->buf[ctx->buf_len])),(unsigned char *)in,n);
347 if(ctx->buf_len >= OK_BLOCK_SIZE+ OK_BLOCK_BLOCK)
353 BIO_clear_retry_flags(b);
354 BIO_copy_next_retry(b);
358 static long ok_ctrl(BIO *b, int cmd, long num, char *ptr)
366 ctx=(BIO_OK_CTX *)b->ptr;
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)
398 while (ctx->blockout)
400 i=ok_write(b,NULL,0);
409 ctx->buf_off=ctx->buf_len=0;
412 /* Finally flush the underlying BIO */
413 ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
415 case BIO_C_DO_STATE_MACHINE:
416 BIO_clear_retry_flags(b);
417 ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
418 BIO_copy_next_retry(b);
425 EVP_DigestInit(&(ctx->md),md);
431 ppmd=(const EVP_MD **)ptr;
432 *ppmd=ctx->md.digest;
438 ret=BIO_ctrl(b->next_bio,cmd,num,ptr);
444 static void longswap(void *_ptr, int len)
450 for(i= 0;i < len;i+= 4){
451 *((unsigned long *)&(ptr[i]))= swapem(*((unsigned long *)&(ptr[i])));
456 static void sig_out(BIO* b)
461 ctx=(BIO_OK_CTX *)b->ptr;
464 if(ctx->buf_len+ 2* md->digest->md_size > OK_BLOCK_SIZE) return;
466 EVP_DigestInit(md, md->digest);
467 RAND_bytes(&(md->md.base[0]), md->digest->md_size);
468 memcpy(&(ctx->buf[ctx->buf_len]), &(md->md.base[0]), md->digest->md_size);
469 longswap(&(ctx->buf[ctx->buf_len]), md->digest->md_size);
470 ctx->buf_len+= md->digest->md_size;
472 EVP_DigestUpdate(md, (unsigned char*)WELLKNOWN, strlen(WELLKNOWN));
473 md->digest->final(&(ctx->buf[ctx->buf_len]), &(md->md.base[0]));
474 ctx->buf_len+= md->digest->md_size;
479 static void sig_in(BIO* b)
483 unsigned char tmp[EVP_MAX_MD_SIZE];
486 ctx=(BIO_OK_CTX *)b->ptr;
489 if(ctx->buf_len- ctx->buf_off < 2* md->digest->md_size) return;
491 EVP_DigestInit(md, md->digest);
492 memcpy(&(md->md.base[0]), &(ctx->buf[ctx->buf_off]), md->digest->md_size);
493 longswap(&(md->md.base[0]), md->digest->md_size);
494 ctx->buf_off+= md->digest->md_size;
496 EVP_DigestUpdate(md, (unsigned char*)WELLKNOWN, strlen(WELLKNOWN));
497 md->digest->final(tmp, &(md->md.base[0]));
498 ret= memcmp(&(ctx->buf[ctx->buf_off]), tmp, md->digest->md_size) == 0;
499 ctx->buf_off+= md->digest->md_size;
503 if(ctx->buf_len != ctx->buf_off)
505 memmove(ctx->buf, &(ctx->buf[ctx->buf_off]), ctx->buf_len- ctx->buf_off);
507 ctx->buf_len-= ctx->buf_off;
516 static void block_out(BIO* b)
522 ctx=(BIO_OK_CTX *)b->ptr;
525 tl= ctx->buf_len- OK_BLOCK_BLOCK;
527 memcpy(ctx->buf, &tl, OK_BLOCK_BLOCK);
529 EVP_DigestUpdate(md, (unsigned char*) &(ctx->buf[OK_BLOCK_BLOCK]), tl);
530 md->digest->final(&(ctx->buf[ctx->buf_len]), &(md->md.base[0]));
531 ctx->buf_len+= md->digest->md_size;
535 static void block_in(BIO* b)
540 unsigned char tmp[EVP_MAX_MD_SIZE];
542 ctx=(BIO_OK_CTX *)b->ptr;
545 memcpy(&tl, ctx->buf, OK_BLOCK_BLOCK);
547 if (ctx->buf_len < tl+ OK_BLOCK_BLOCK+ md->digest->md_size) return;
549 EVP_DigestUpdate(md, (unsigned char*) &(ctx->buf[OK_BLOCK_BLOCK]), tl);
550 md->digest->final(tmp, &(md->md.base[0]));
551 if(memcmp(&(ctx->buf[tl+ OK_BLOCK_BLOCK]), tmp, md->digest->md_size) == 0)
553 /* there might be parts from next block lurking around ! */
554 ctx->buf_off_save= tl+ OK_BLOCK_BLOCK+ md->digest->md_size;
555 ctx->buf_len_save= ctx->buf_len;
556 ctx->buf_off= OK_BLOCK_BLOCK;
557 ctx->buf_len= tl+ OK_BLOCK_BLOCK;