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 #include "e_os.h"
  60
  61 /* We need to define this to get macros like S_IFBLK and S_IFCHR */
  62 #if !defined(OPENSSL_SYS_VXWORKS)
  63 # define _XOPEN_SOURCE 500
  64 #endif
  65
  66 #include <errno.h>
  67 #include <stdio.h>
  68 #include <stdlib.h>
  69 #include <string.h>
  70
  71 #include <openssl/crypto.h>
  72 #include <openssl/rand.h>
  73 #include <openssl/buffer.h>
  74
  75 #ifdef OPENSSL_SYS_VMS
  76 # include <unixio.h>
  77 #endif
  78 #ifndef NO_SYS_TYPES_H
  79 # include <sys/types.h>
  80 #endif
  81 #ifndef OPENSSL_NO_POSIX_IO
  82 # include <sys/stat.h>
  83 # include <fcntl.h>
  84 #endif
  85
  86 #ifdef _WIN32
  87 # define stat    _stat
  88 # define chmod   _chmod
  89 # define open    _open
  90 # define fdopen  _fdopen
  91 #endif
  92
  93 #undef BUFSIZE
  94 #define BUFSIZE 1024
  95 #define RAND_DATA 1024
  96
  97 #ifdef OPENSSL_SYS_VMS
  98 /*
  99  * This declaration is a nasty hack to get around vms' extension to fopen for
 100  * passing in sharing options being disabled by our /STANDARD=ANSI89
 101  */
 102 static FILE *(*const vms_fopen)(const char *, const char *, ...) =
 103     (FILE *(*)(const char *, const char *, ...))fopen;
 104 # define VMS_OPEN_ATTRS "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0"
 105 #endif
 106
 107 /* #define RFILE ".rnd" - defined in ../../e_os.h */
 108
 109 /*
 110  * Note that these functions are intended for seed files only. Entropy
 111  * devices and EGD sockets are handled in rand_unix.c
 112  */
 113
 114 int RAND_load_file(const char *file, long bytes)
 115 {
 116     /*-
 117      * If bytes >= 0, read up to 'bytes' bytes.
 118      * if bytes == -1, read complete file.
 119      */
 120
 121     unsigned char buf[BUFSIZE];
 122 #ifndef OPENSSL_NO_POSIX_IO
 123     struct stat sb;
 124 #endif
 125     int i, ret = 0, n;
 126     FILE *in;
 127
 128     if (file == NULL)
 129         return (0);
 130
 131 #ifndef OPENSSL_NO_POSIX_IO
 132 # ifdef PURIFY
 133     /*
 134      * struct stat can have padding and unused fields that may not be
 135      * initialized in the call to stat(). We need to clear the entire
 136      * structure before calling RAND_add() to avoid complaints from
 137      * applications such as Valgrind.
 138      */
 139     memset(&sb, 0, sizeof(sb));
 140 # endif
 141     if (stat(file, &sb) < 0)
 142         return (0);
 143     RAND_add(&sb, sizeof(sb), 0.0);
 144 #endif
 145     if (bytes == 0)
 146         return (ret);
 147
 148 #ifdef OPENSSL_SYS_VMS
 149     in = vms_fopen(file, "rb", VMS_OPEN_ATTRS);
 150 #else
 151     in = fopen(file, "rb");
 152 #endif
 153     if (in == NULL)
 154         goto err;
 155 #if defined(S_IFBLK) && defined(S_IFCHR) && !defined(OPENSSL_NO_POSIX_IO)
 156     if (sb.st_mode & (S_IFBLK | S_IFCHR)) {
 157         /*
 158          * this file is a device. we don't want read an infinite number of
 159          * bytes from a random device, nor do we want to use buffered I/O
 160          * because we will waste system entropy.
 161          */
 162         bytes = (bytes == -1) ? 2048 : bytes; /* ok, is 2048 enough? */
 163         setbuf(stdin, NULL); /* don't do buffered reads */
 164     }
 165 #endif
 166     for (;;) {
 167         if (bytes > 0)
 168             n = (bytes < BUFSIZE) ? (int)bytes : BUFSIZE;
 169         else
 170             n = BUFSIZE;
 171         i = fread(buf, 1, n, in);
 172         if (i <= 0)
 173             break;
 174 #ifdef PURIFY
 175         RAND_add(buf, i, (double)i);
 176 #else
 177         /* even if n != i, use the full array */
 178         RAND_add(buf, n, (double)i);
 179 #endif
 180         ret += i;
 181         if (bytes > 0) {
 182             bytes -= n;
 183             if (bytes <= 0)
 184                 break;
 185         }
 186     }
 187     fclose(in);
 188     OPENSSL_cleanse(buf, BUFSIZE);
 189  err:
 190     return (ret);
 191 }
 192
 193 int RAND_write_file(const char *file)
 194 {
 195     unsigned char buf[BUFSIZE];
 196     int i, ret = 0, rand_err = 0;
 197     FILE *out = NULL;
 198     int n;
 199 #ifndef OPENSSL_NO_POSIX_IO
 200     struct stat sb;
 201
 202     i = stat(file, &sb);
 203     if (i != -1) {
 204 # if defined(S_ISBLK) && defined(S_ISCHR)
 205         if (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode)) {
 206             /*
 207              * this file is a device. we don't write back to it. we
 208              * "succeed" on the assumption this is some sort of random
 209              * device. Otherwise attempting to write to and chmod the device
 210              * causes problems.
 211              */
 212             return (1);
 213         }
 214 # endif
 215     }
 216 #endif
 217
 218 #if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && !defined(OPENSSL_SYS_VMS)
 219     {
 220 # ifndef O_BINARY
 221 #  define O_BINARY 0
 222 # endif
 223         /*
 224          * chmod(..., 0600) is too late to protect the file, permissions
 225          * should be restrictive from the start
 226          */
 227         int fd = open(file, O_WRONLY | O_CREAT | O_BINARY, 0600);
 228         if (fd != -1)
 229             out = fdopen(fd, "wb");
 230     }
 231 #endif
 232
 233 #ifdef OPENSSL_SYS_VMS
 234     /*
 235      * VMS NOTE: Prior versions of this routine created a _new_ version of
 236      * the rand file for each call into this routine, then deleted all
 237      * existing versions named ;-1, and finally renamed the current version
 238      * as ';1'. Under concurrent usage, this resulted in an RMS race
 239      * condition in rename() which could orphan files (see vms message help
 240      * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares
 241      * the top-level version of the rand file. Note that there may still be
 242      * conditions where the top-level rand file is locked. If so, this code
 243      * will then create a new version of the rand file. Without the delete
 244      * and rename code, this can result in ascending file versions that stop
 245      * at version 32767, and this routine will then return an error. The
 246      * remedy for this is to recode the calling application to avoid
 247      * concurrent use of the rand file, or synchronize usage at the
 248      * application level. Also consider whether or not you NEED a persistent
 249      * rand file in a concurrent use situation.
 250      */
 251
 252     out = vms_fopen(file, "rb+", VMS_OPEN_ATTRS);
 253     if (out == NULL)
 254         out = vms_fopen(file, "wb", VMS_OPEN_ATTRS);
 255 #else
 256     if (out == NULL)
 257         out = fopen(file, "wb");
 258 #endif
 259     if (out == NULL)
 260         goto err;
 261
 262 #ifndef NO_CHMOD
 263     chmod(file, 0600);
 264 #endif
 265     n = RAND_DATA;
 266     for (;;) {
 267         i = (n > BUFSIZE) ? BUFSIZE : n;
 268         n -= BUFSIZE;
 269         if (RAND_bytes(buf, i) <= 0)
 270             rand_err = 1;
 271         i = fwrite(buf, 1, i, out);
 272         if (i <= 0) {
 273             ret = 0;
 274             break;
 275         }
 276         ret += i;
 277         if (n <= 0)
 278             break;
 279     }
 280
 281     fclose(out);
 282     OPENSSL_cleanse(buf, BUFSIZE);
 283  err:
 284     return (rand_err ? -1 : ret);
 285 }
 286
 287 const char *RAND_file_name(char *buf, size_t size)
 288 {
 289     char *s = NULL;
 290 #ifdef __OpenBSD__
 291     struct stat sb;
 292 #endif
 293
 294     if (OPENSSL_issetugid() == 0)
 295         s = getenv("RANDFILE");
 296     if (s != NULL && *s && strlen(s) + 1 < size) {
 297         if (OPENSSL_strlcpy(buf, s, size) >= size)
 298             return NULL;
 299     } else {
 300         if (OPENSSL_issetugid() == 0)
 301             s = getenv("HOME");
 302 #ifdef DEFAULT_HOME
 303         if (s == NULL) {
 304             s = DEFAULT_HOME;
 305         }
 306 #endif
 307         if (s && *s && strlen(s) + strlen(RFILE) + 2 < size) {
 308             OPENSSL_strlcpy(buf, s, size);
 309 #ifndef OPENSSL_SYS_VMS
 310             OPENSSL_strlcat(buf, "/", size);
 311 #endif
 312             OPENSSL_strlcat(buf, RFILE, size);
 313         } else
 314             buf[0] = '\0';      /* no file name */
 315     }
 316
 317 #ifdef __OpenBSD__
 318     /*
 319      * given that all random loads just fail if the file can't be seen on a
 320      * stat, we stat the file we're returning, if it fails, use /dev/arandom
 321      * instead. this allows the user to use their own source for good random
 322      * data, but defaults to something hopefully decent if that isn't
 323      * available.
 324      */
 325
 326     if (!buf[0])
 327         if (OPENSSL_strlcpy(buf, "/dev/arandom", size) >= size) {
 328             return (NULL);
 329         }
 330     if (stat(buf, &sb) == -1)
 331         if (OPENSSL_strlcpy(buf, "/dev/arandom", size) >= size) {
 332             return (NULL);
 333         }
 334 #endif
 335     return (buf);
 336 }