crypto/openssl/crypto/rand/randfile.c

   1 /* crypto/rand/randfile.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
  59 /* We need to define this to get macros like S_IFBLK and S_IFCHR */
  60 #define _XOPEN_SOURCE 500
  61
  62 #include <errno.h>
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <string.h>
  66
  67 #include "e_os.h"
  68 #include <openssl/crypto.h>
  69 #include <openssl/rand.h>
  70 #include <openssl/buffer.h>
  71
  72 #ifdef OPENSSL_SYS_VMS
  73 #include <unixio.h>
  74 #endif
  75 #ifndef NO_SYS_TYPES_H
  76 # include <sys/types.h>
  77 #endif
  78 #ifdef MAC_OS_pre_X
  79 # include <stat.h>
  80 #else
  81 # include <sys/stat.h>
  82 #endif
  83
  84 #undef BUFSIZE
  85 #define BUFSIZE 1024
  86 #define RAND_DATA 1024
  87
  88 /* #define RFILE ".rnd" - defined in ../../e_os.h */
  89
  90 /* Note that these functions are intended for seed files only.
  91  * Entropy devices and EGD sockets are handled in rand_unix.c */
  92
  93 int RAND_load_file(const char *file, long bytes)
  94         {
  95         /* If bytes >= 0, read up to 'bytes' bytes.
  96          * if bytes == -1, read complete file. */
  97
  98         MS_STATIC unsigned char buf[BUFSIZE];
  99         struct stat sb;
 100         int i,ret=0,n;
 101         FILE *in;
 102
 103         if (file == NULL) return(0);
 104
 105         if (stat(file,&sb) < 0) return(0);
 106         RAND_add(&sb,sizeof(sb),0.0);
 107         if (bytes == 0) return(ret);
 108
 109         in=fopen(file,"rb");
 110         if (in == NULL) goto err;
 111 #if defined(S_IFBLK) && defined(S_IFCHR)
 112         if (sb.st_mode & (S_IFBLK | S_IFCHR)) {
 113           /* this file is a device. we don't want read an infinite number
 114            * of bytes from a random device, nor do we want to use buffered
 115            * I/O because we will waste system entropy.
 116            */
 117           bytes = (bytes == -1) ? 2048 : bytes; /* ok, is 2048 enough? */
 118           setvbuf(in, NULL, _IONBF, 0); /* don't do buffered reads */
 119         }
 120 #endif
 121         for (;;)
 122                 {
 123                 if (bytes > 0)
 124                         n = (bytes < BUFSIZE)?(int)bytes:BUFSIZE;
 125                 else
 126                         n = BUFSIZE;
 127                 i=fread(buf,1,n,in);
 128                 if (i <= 0) break;
 129 #ifdef PURIFY
 130                 RAND_add(buf,i,(double)i);
 131 #else
 132                 /* even if n != i, use the full array */
 133                 RAND_add(buf,n,(double)i);
 134 #endif
 135                 ret+=i;
 136                 if (bytes > 0)
 137                         {
 138                         bytes-=n;
 139                         if (bytes <= 0) break;
 140                         }
 141                 }
 142         fclose(in);
 143         OPENSSL_cleanse(buf,BUFSIZE);
 144 err:
 145         return(ret);
 146         }
 147
 148 int RAND_write_file(const char *file)
 149         {
 150         unsigned char buf[BUFSIZE];
 151         int i,ret=0,rand_err=0;
 152         FILE *out = NULL;
 153         int n;
 154         struct stat sb;
 155
 156         i=stat(file,&sb);
 157         if (i != -1) {
 158 #if defined(S_IFBLK) && defined(S_IFCHR)
 159           if (sb.st_mode & (S_IFBLK | S_IFCHR)) {
 160             /* this file is a device. we don't write back to it.
 161              * we "succeed" on the assumption this is some sort
 162              * of random device. Otherwise attempting to write to
 163              * and chmod the device causes problems.
 164              */
 165             return(1);
 166           }
 167 #endif
 168         }
 169
 170 #if defined(O_CREAT) && !defined(OPENSSL_SYS_WIN32)
 171         {
 172         /* For some reason Win32 can't write to files created this way */
 173
 174         /* chmod(..., 0600) is too late to protect the file,
 175          * permissions should be restrictive from the start */
 176         int fd = open(file, O_CREAT, 0600);
 177         if (fd != -1)
 178                 out = fdopen(fd, "wb");
 179         }
 180 #endif
 181         if (out == NULL)
 182                 out = fopen(file,"wb");
 183         if (out == NULL) goto err;
 184
 185 #ifndef NO_CHMOD
 186         chmod(file,0600);
 187 #endif
 188         n=RAND_DATA;
 189         for (;;)
 190                 {
 191                 i=(n > BUFSIZE)?BUFSIZE:n;
 192                 n-=BUFSIZE;
 193                 if (RAND_bytes(buf,i) <= 0)
 194                         rand_err=1;
 195                 i=fwrite(buf,1,i,out);
 196                 if (i <= 0)
 197                         {
 198                         ret=0;
 199                         break;
 200                         }
 201                 ret+=i;
 202                 if (n <= 0) break;
 203                 }
 204 #ifdef OPENSSL_SYS_VMS
 205         /* Try to delete older versions of the file, until there aren't
 206            any */
 207         {
 208         char *tmpf;
 209
 210         tmpf = OPENSSL_malloc(strlen(file) + 4);  /* to add ";-1" and a nul */
 211         if (tmpf)
 212                 {
 213                 strcpy(tmpf, file);
 214                 strcat(tmpf, ";-1");
 215                 while(delete(tmpf) == 0)
 216                         ;
 217                 rename(file,";1"); /* Make sure it's version 1, or we
 218                                       will reach the limit (32767) at
 219                                       some point... */
 220                 }
 221         }
 222 #endif /* OPENSSL_SYS_VMS */
 223
 224         fclose(out);
 225         OPENSSL_cleanse(buf,BUFSIZE);
 226 err:
 227         return (rand_err ? -1 : ret);
 228         }
 229
 230 const char *RAND_file_name(char *buf, size_t size)
 231         {
 232         char *s=NULL;
 233         int ok = 0;
 234 #ifdef __OpenBSD__
 235         struct stat sb;
 236 #endif
 237
 238         if (OPENSSL_issetugid() == 0)
 239                 s=getenv("RANDFILE");
 240         if (s != NULL && *s && strlen(s) + 1 < size)
 241                 {
 242                 if (BUF_strlcpy(buf,s,size) >= size)
 243                         return NULL;
 244                 }
 245         else
 246                 {
 247                 if (OPENSSL_issetugid() == 0)
 248                         s=getenv("HOME");
 249 #ifdef DEFAULT_HOME
 250                 if (s == NULL)
 251                         {
 252                         s = DEFAULT_HOME;
 253                         }
 254 #endif
 255                 if (s && *s && strlen(s)+strlen(RFILE)+2 < size)
 256                         {
 257                         BUF_strlcpy(buf,s,size);
 258 #ifndef OPENSSL_SYS_VMS
 259                         BUF_strlcat(buf,"/",size);
 260 #endif
 261                         BUF_strlcat(buf,RFILE,size);
 262                         ok = 1;
 263                         }
 264                 else
 265                         buf[0] = '\0'; /* no file name */
 266                 }
 267
 268 #ifdef __OpenBSD__
 269         /* given that all random loads just fail if the file can't be
 270          * seen on a stat, we stat the file we're returning, if it
 271          * fails, use /dev/arandom instead. this allows the user to
 272          * use their own source for good random data, but defaults
 273          * to something hopefully decent if that isn't available.
 274          */
 275
 276         if (!ok)
 277                 if (BUF_strlcpy(buf,"/dev/arandom",size) >= size) {
 278                         return(NULL);
 279                 }
 280         if (stat(buf,&sb) == -1)
 281                 if (BUF_strlcpy(buf,"/dev/arandom",size) >= size) {
 282                         return(NULL);
 283                 }
 284
 285 #endif
 286         return(buf);
 287         }