enc_read.c 7.2 KB

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  1. /* crypto/des/enc_read.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. #include <stdio.h>
  59. #include <errno.h>
  60. #include "cryptlib.h"
  61. #include "des_locl.h"
  62. /* This has some uglies in it but it works - even over sockets. */
  63. /*extern int errno;*/
  64. OPENSSL_IMPLEMENT_GLOBAL(int,DES_rw_mode)=DES_PCBC_MODE;
  65. /*
  66. * WARNINGS:
  67. *
  68. * - The data format used by DES_enc_write() and DES_enc_read()
  69. * has a cryptographic weakness: When asked to write more
  70. * than MAXWRITE bytes, DES_enc_write will split the data
  71. * into several chunks that are all encrypted
  72. * using the same IV. So don't use these functions unless you
  73. * are sure you know what you do (in which case you might
  74. * not want to use them anyway).
  75. *
  76. * - This code cannot handle non-blocking sockets.
  77. *
  78. * - This function uses an internal state and thus cannot be
  79. * used on multiple files.
  80. */
  81. int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,
  82. DES_cblock *iv)
  83. {
  84. #if defined(OPENSSL_NO_POSIX_IO)
  85. return(0);
  86. #else
  87. /* data to be unencrypted */
  88. int net_num=0;
  89. static unsigned char *net=NULL;
  90. /* extra unencrypted data
  91. * for when a block of 100 comes in but is des_read one byte at
  92. * a time. */
  93. static unsigned char *unnet=NULL;
  94. static int unnet_start=0;
  95. static int unnet_left=0;
  96. static unsigned char *tmpbuf=NULL;
  97. int i;
  98. long num=0,rnum;
  99. unsigned char *p;
  100. if (tmpbuf == NULL)
  101. {
  102. tmpbuf=OPENSSL_malloc(BSIZE);
  103. if (tmpbuf == NULL) return(-1);
  104. }
  105. if (net == NULL)
  106. {
  107. net=OPENSSL_malloc(BSIZE);
  108. if (net == NULL) return(-1);
  109. }
  110. if (unnet == NULL)
  111. {
  112. unnet=OPENSSL_malloc(BSIZE);
  113. if (unnet == NULL) return(-1);
  114. }
  115. /* left over data from last decrypt */
  116. if (unnet_left != 0)
  117. {
  118. if (unnet_left < len)
  119. {
  120. /* we still still need more data but will return
  121. * with the number of bytes we have - should always
  122. * check the return value */
  123. memcpy(buf,&(unnet[unnet_start]),
  124. unnet_left);
  125. /* eay 26/08/92 I had the next 2 lines
  126. * reversed :-( */
  127. i=unnet_left;
  128. unnet_start=unnet_left=0;
  129. }
  130. else
  131. {
  132. memcpy(buf,&(unnet[unnet_start]),len);
  133. unnet_start+=len;
  134. unnet_left-=len;
  135. i=len;
  136. }
  137. return(i);
  138. }
  139. /* We need to get more data. */
  140. if (len > MAXWRITE) len=MAXWRITE;
  141. /* first - get the length */
  142. while (net_num < HDRSIZE)
  143. {
  144. i=read(fd,(void *)&(net[net_num]),HDRSIZE-net_num);
  145. #ifdef EINTR
  146. if ((i == -1) && (errno == EINTR)) continue;
  147. #endif
  148. if (i <= 0) return(0);
  149. net_num+=i;
  150. }
  151. /* we now have at net_num bytes in net */
  152. p=net;
  153. /* num=0; */
  154. n2l(p,num);
  155. /* num should be rounded up to the next group of eight
  156. * we make sure that we have read a multiple of 8 bytes from the net.
  157. */
  158. if ((num > MAXWRITE) || (num < 0)) /* error */
  159. return(-1);
  160. rnum=(num < 8)?8:((num+7)/8*8);
  161. net_num=0;
  162. while (net_num < rnum)
  163. {
  164. i=read(fd,(void *)&(net[net_num]),rnum-net_num);
  165. #ifdef EINTR
  166. if ((i == -1) && (errno == EINTR)) continue;
  167. #endif
  168. if (i <= 0) return(0);
  169. net_num+=i;
  170. }
  171. /* Check if there will be data left over. */
  172. if (len < num)
  173. {
  174. if (DES_rw_mode & DES_PCBC_MODE)
  175. DES_pcbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
  176. else
  177. DES_cbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
  178. memcpy(buf,unnet,len);
  179. unnet_start=len;
  180. unnet_left=num-len;
  181. /* The following line is done because we return num
  182. * as the number of bytes read. */
  183. num=len;
  184. }
  185. else
  186. {
  187. /* >output is a multiple of 8 byes, if len < rnum
  188. * >we must be careful. The user must be aware that this
  189. * >routine will write more bytes than he asked for.
  190. * >The length of the buffer must be correct.
  191. * FIXED - Should be ok now 18-9-90 - eay */
  192. if (len < rnum)
  193. {
  194. if (DES_rw_mode & DES_PCBC_MODE)
  195. DES_pcbc_encrypt(net,tmpbuf,num,sched,iv,
  196. DES_DECRYPT);
  197. else
  198. DES_cbc_encrypt(net,tmpbuf,num,sched,iv,
  199. DES_DECRYPT);
  200. /* eay 26/08/92 fix a bug that returned more
  201. * bytes than you asked for (returned len bytes :-( */
  202. memcpy(buf,tmpbuf,num);
  203. }
  204. else
  205. {
  206. if (DES_rw_mode & DES_PCBC_MODE)
  207. DES_pcbc_encrypt(net,buf,num,sched,iv,
  208. DES_DECRYPT);
  209. else
  210. DES_cbc_encrypt(net,buf,num,sched,iv,
  211. DES_DECRYPT);
  212. }
  213. }
  214. return num;
  215. #endif /* OPENSSL_NO_POSIX_IO */
  216. }