crypto/rand/randfile.c

   1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   2  * All rights reserved.
   3  *
   4  * This package is an SSL implementation written
   5  * by Eric Young (eay@cryptsoft.com).
   6  * The implementation was written so as to conform with Netscapes SSL.
   7  *
   8  * This library is free for commercial and non-commercial use as long as
   9  * the following conditions are aheared to.  The following conditions
  10  * apply to all code found in this distribution, be it the RC4, RSA,
  11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  12  * included with this distribution is covered by the same copyright terms
  13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  14  *
  15  * Copyright remains Eric Young's, and as such any Copyright notices in
  16  * the code are not to be removed.
  17  * If this package is used in a product, Eric Young should be given attribution
  18  * as the author of the parts of the library used.
  19  * This can be in the form of a textual message at program startup or
  20  * in documentation (online or textual) provided with the package.
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  * 3. All advertising materials mentioning features or use of this software
  31  *    must display the following acknowledgement:
  32  *    "This product includes cryptographic software written by
  33  *     Eric Young (eay@cryptsoft.com)"
  34  *    The word 'cryptographic' can be left out if the rouines from the library
  35  *    being used are not cryptographic related :-).
  36  * 4. If you include any Windows specific code (or a derivative thereof) from
  37  *    the apps directory (application code) you must include an acknowledgement:
  38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  *
  52  * The licence and distribution terms for any publically available version or
  53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  54  * copied and put under another distribution licence
  55  * [including the GNU Public Licence.]
  56  */
  57
  58 #include "e_os.h"
  59
  60 /* We need to define this to get macros like S_IFBLK and S_IFCHR */
  61 #if !defined(OPENSSL_SYS_VXWORKS)
  62 # define _XOPEN_SOURCE 500
  63 #endif
  64
  65 #include <errno.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69
  70 #include <openssl/crypto.h>
  71 #include <openssl/rand.h>
  72 #include <openssl/buffer.h>
  73
  74 #ifdef OPENSSL_SYS_VMS
  75 # include <unixio.h>
  76 #endif
  77 #ifndef NO_SYS_TYPES_H
  78 # include <sys/types.h>
  79 #endif
  80 #ifndef OPENSSL_NO_POSIX_IO
  81 # include <sys/stat.h>
  82 # include <fcntl.h>
  83 #endif
  84
  85 #ifdef _WIN32
  86 # define stat    _stat
  87 # define chmod   _chmod
  88 # define open    _open
  89 # define fdopen  _fdopen
  90 #endif
  91
  92 #undef BUFSIZE
  93 #define BUFSIZE 1024
  94 #define RAND_DATA 1024
  95
  96 #ifdef OPENSSL_SYS_VMS
  97 /*
  98  * This declaration is a nasty hack to get around vms' extension to fopen for
  99  * passing in sharing options being disabled by our /STANDARD=ANSI89
 100  */
 101 static FILE *(*const vms_fopen)(const char *, const char *, ...) =
 102     (FILE *(*)(const char *, const char *, ...))fopen;
 103 # define VMS_OPEN_ATTRS "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0"
 104 #endif
 105
 106 /* #define RFILE ".rnd" - defined in ../../e_os.h */
 107
 108 /*
 109  * Note that these functions are intended for seed files only. Entropy
 110  * devices and EGD sockets are handled in rand_unix.c
 111  */
 112
 113 int RAND_load_file(const char *file, long bytes)
 114 {
 115     /*-
 116      * If bytes >= 0, read up to 'bytes' bytes.
 117      * if bytes == -1, read complete file.
 118      */
 119
 120     unsigned char buf[BUFSIZE];
 121 #ifndef OPENSSL_NO_POSIX_IO
 122     struct stat sb;
 123 #endif
 124     int i, ret = 0, n;
 125     FILE *in;
 126
 127     if (file == NULL)
 128         return (0);
 129
 130 #ifndef OPENSSL_NO_POSIX_IO
 131 # ifdef PURIFY
 132     /*
 133      * struct stat can have padding and unused fields that may not be
 134      * initialized in the call to stat(). We need to clear the entire
 135      * structure before calling RAND_add() to avoid complaints from
 136      * applications such as Valgrind.
 137      */
 138     memset(&sb, 0, sizeof(sb));
 139 # endif
 140     if (stat(file, &sb) < 0)
 141         return (0);
 142     RAND_add(&sb, sizeof(sb), 0.0);
 143 #endif
 144     if (bytes == 0)
 145         return (ret);
 146
 147 #ifdef OPENSSL_SYS_VMS
 148     in = vms_fopen(file, "rb", VMS_OPEN_ATTRS);
 149 #else
 150     in = fopen(file, "rb");
 151 #endif
 152     if (in == NULL)
 153         goto err;
 154 #if defined(S_IFBLK) && defined(S_IFCHR) && !defined(OPENSSL_NO_POSIX_IO)
 155     if (sb.st_mode & (S_IFBLK | S_IFCHR)) {
 156         /*
 157          * this file is a device. we don't want read an infinite number of
 158          * bytes from a random device, nor do we want to use buffered I/O
 159          * because we will waste system entropy.
 160          */
 161         bytes = (bytes == -1) ? 2048 : bytes; /* ok, is 2048 enough? */
 162         setbuf(stdin, NULL); /* don't do buffered reads */
 163     }
 164 #endif
 165     for (;;) {
 166         if (bytes > 0)
 167             n = (bytes < BUFSIZE) ? (int)bytes : BUFSIZE;
 168         else
 169             n = BUFSIZE;
 170         i = fread(buf, 1, n, in);
 171         if (i <= 0)
 172             break;
 173 #ifdef PURIFY
 174         RAND_add(buf, i, (double)i);
 175 #else
 176         /* even if n != i, use the full array */
 177         RAND_add(buf, n, (double)i);
 178 #endif
 179         ret += i;
 180         if (bytes > 0) {
 181             bytes -= n;
 182             if (bytes <= 0)
 183                 break;
 184         }
 185     }
 186     fclose(in);
 187     OPENSSL_cleanse(buf, BUFSIZE);
 188  err:
 189     return (ret);
 190 }
 191
 192 int RAND_write_file(const char *file)
 193 {
 194     unsigned char buf[BUFSIZE];
 195     int i, ret = 0, rand_err = 0;
 196     FILE *out = NULL;
 197     int n;
 198 #ifndef OPENSSL_NO_POSIX_IO
 199     struct stat sb;
 200
 201     i = stat(file, &sb);
 202     if (i != -1) {
 203 # if defined(S_ISBLK) && defined(S_ISCHR)
 204         if (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode)) {
 205             /*
 206              * this file is a device. we don't write back to it. we
 207              * "succeed" on the assumption this is some sort of random
 208              * device. Otherwise attempting to write to and chmod the device
 209              * causes problems.
 210              */
 211             return (1);
 212         }
 213 # endif
 214     }
 215 #endif
 216
 217 #if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && !defined(OPENSSL_SYS_VMS)
 218     {
 219 # ifndef O_BINARY
 220 #  define O_BINARY 0
 221 # endif
 222         /*
 223          * chmod(..., 0600) is too late to protect the file, permissions
 224          * should be restrictive from the start
 225          */
 226         int fd = open(file, O_WRONLY | O_CREAT | O_BINARY, 0600);
 227         if (fd != -1)
 228             out = fdopen(fd, "wb");
 229     }
 230 #endif
 231
 232 #ifdef OPENSSL_SYS_VMS
 233     /*
 234      * VMS NOTE: Prior versions of this routine created a _new_ version of
 235      * the rand file for each call into this routine, then deleted all
 236      * existing versions named ;-1, and finally renamed the current version
 237      * as ';1'. Under concurrent usage, this resulted in an RMS race
 238      * condition in rename() which could orphan files (see vms message help
 239      * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares
 240      * the top-level version of the rand file. Note that there may still be
 241      * conditions where the top-level rand file is locked. If so, this code
 242      * will then create a new version of the rand file. Without the delete
 243      * and rename code, this can result in ascending file versions that stop
 244      * at version 32767, and this routine will then return an error. The
 245      * remedy for this is to recode the calling application to avoid
 246      * concurrent use of the rand file, or synchronize usage at the
 247      * application level. Also consider whether or not you NEED a persistent
 248      * rand file in a concurrent use situation.
 249      */
 250
 251     out = vms_fopen(file, "rb+", VMS_OPEN_ATTRS);
 252     if (out == NULL)
 253         out = vms_fopen(file, "wb", VMS_OPEN_ATTRS);
 254 #else
 255     if (out == NULL)
 256         out = fopen(file, "wb");
 257 #endif
 258     if (out == NULL)
 259         goto err;
 260
 261 #ifndef NO_CHMOD
 262     chmod(file, 0600);
 263 #endif
 264     n = RAND_DATA;
 265     for (;;) {
 266         i = (n > BUFSIZE) ? BUFSIZE : n;
 267         n -= BUFSIZE;
 268         if (RAND_bytes(buf, i) <= 0)
 269             rand_err = 1;
 270         i = fwrite(buf, 1, i, out);
 271         if (i <= 0) {
 272             ret = 0;
 273             break;
 274         }
 275         ret += i;
 276         if (n <= 0)
 277             break;
 278     }
 279
 280     fclose(out);
 281     OPENSSL_cleanse(buf, BUFSIZE);
 282  err:
 283     return (rand_err ? -1 : ret);
 284 }
 285
 286 const char *RAND_file_name(char *buf, size_t size)
 287 {
 288     char *s = NULL;
 289 #ifdef __OpenBSD__
 290     struct stat sb;
 291 #endif
 292
 293     if (OPENSSL_issetugid() == 0)
 294         s = getenv("RANDFILE");
 295     if (s != NULL && *s && strlen(s) + 1 < size) {
 296         if (OPENSSL_strlcpy(buf, s, size) >= size)
 297             return NULL;
 298     } else {
 299         if (OPENSSL_issetugid() == 0)
 300             s = getenv("HOME");
 301 #ifdef DEFAULT_HOME
 302         if (s == NULL) {
 303             s = DEFAULT_HOME;
 304         }
 305 #endif
 306         if (s && *s && strlen(s) + strlen(RFILE) + 2 < size) {
 307             OPENSSL_strlcpy(buf, s, size);
 308 #ifndef OPENSSL_SYS_VMS
 309             OPENSSL_strlcat(buf, "/", size);
 310 #endif
 311             OPENSSL_strlcat(buf, RFILE, size);
 312         } else
 313             buf[0] = '\0';      /* no file name */
 314     }
 315
 316 #ifdef __OpenBSD__
 317     /*
 318      * given that all random loads just fail if the file can't be seen on a
 319      * stat, we stat the file we're returning, if it fails, use /dev/arandom
 320      * instead. this allows the user to use their own source for good random
 321      * data, but defaults to something hopefully decent if that isn't
 322      * available.
 323      */
 324
 325     if (!buf[0])
 326         if (OPENSSL_strlcpy(buf, "/dev/arandom", size) >= size) {
 327             return (NULL);
 328         }
 329     if (stat(buf, &sb) == -1)
 330         if (OPENSSL_strlcpy(buf, "/dev/arandom", size) >= size) {
 331             return (NULL);
 332         }
 333 #endif
 334     return (buf);
 335 }