crypto/rand/randfile.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include "internal/cryptlib.h"
  11
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16
  17 #include <openssl/crypto.h>
  18 #include <openssl/rand.h>
  19 #include <openssl/buffer.h>
  20
  21 #ifdef OPENSSL_SYS_VMS
  22 # include <unixio.h>
  23 #endif
  24 #ifndef NO_SYS_TYPES_H
  25 # include <sys/types.h>
  26 #endif
  27 #ifndef OPENSSL_NO_POSIX_IO
  28 # include <sys/stat.h>
  29 # include <fcntl.h>
  30 #endif
  31
  32 /*
  33  * Following should not be needed, and we could have been stricter
  34  * and demand S_IS*. But some systems just don't comply... Formally
  35  * below macros are "anatomically incorrect", because normally they
  36  * would look like ((m) & MASK == TYPE), but since MASK availability
  37  * is as questionable, we settle for this poor-man fallback...
  38  */
  39 # if !defined(S_ISREG)
  40 #   define S_ISREG(m) ((m) & S_IFREG)
  41 # endif
  42
  43 #ifdef _WIN32
  44 # define stat    _stat
  45 # define chmod   _chmod
  46 # define open    _open
  47 # define fdopen  _fdopen
  48 #endif
  49
  50 #define RAND_FILE_SIZE 1024
  51
  52 #ifdef OPENSSL_SYS_VMS
  53 /*
  54  * Misc hacks needed for specific cases.
  55  *
  56  * __FILE_ptr32 is a type provided by DEC C headers (types.h specifically)
  57  * to make sure the FILE* is a 32-bit pointer no matter what.  We know that
  58  * stdio function return this type (a study of stdio.h proves it).
  59  */
  60 # if __INITIAL_POINTER_SIZE == 64
  61 #  pragma pointer_size save
  62 #  pragma pointer_size 32
  63 typedef char *char_ptr32;
  64 #  pragma pointer_size restore
  65 # endif
  66
  67 /*
  68  * This declaration is a nasty hack to get around vms' extension to fopen for
  69  * passing in sharing options being disabled by /STANDARD=ANSI89
  70  */
  71 static __FILE_ptr32 (*const vms_fopen)(const char *, const char *, ...) =
  72         (__FILE_ptr32 (*)(const char *, const char *, ...))fopen;
  73 # define VMS_OPEN_ATTRS \
  74         "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0"
  75
  76 # define openssl_fopen(fname,mode) vms_fopen((fname), (mode), VMS_OPEN_ATTRS)
  77 #endif
  78
  79 #define RFILE ".rnd"
  80
  81 /*
  82  * Note that these functions are intended for seed files only. Entropy
  83  * devices and EGD sockets are handled in rand_unix.c  If |bytes| is
  84  * -1 read the complete file; otherwise read the specified amount.
  85  */
  86 int RAND_load_file(const char *file, long bytes)
  87 {
  88     unsigned char buf[RAND_FILE_SIZE];
  89 #ifndef OPENSSL_NO_POSIX_IO
  90     struct stat sb;
  91 #endif
  92     int i, n, ret = 0;
  93     FILE *in;
  94
  95     if (bytes == 0)
  96         return 0;
  97
  98 #ifndef OPENSSL_NO_POSIX_IO
  99     if (stat(file, &sb) < 0 || !S_ISREG(sb.st_mode)) {
 100         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_NOT_A_REGULAR_FILE);
 101         ERR_add_error_data(2, "Filename=", file);
 102         return -1;
 103     }
 104 #endif
 105     if ((in = openssl_fopen(file, "rb")) == NULL) {
 106         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_CANNOT_OPEN_FILE);
 107         ERR_add_error_data(2, "Filename=", file);
 108         return -1;
 109     }
 110
 111     for ( ; ; ) {
 112         if (bytes > 0)
 113             n = (bytes < RAND_FILE_SIZE) ? (int)bytes : RAND_FILE_SIZE;
 114         else
 115             n = RAND_FILE_SIZE;
 116         i = fread(buf, 1, n, in);
 117         if (i <= 0)
 118             break;
 119         RAND_add(buf, i, (double)i);
 120         ret += i;
 121
 122         /* If given a bytecount, and we did it, break. */
 123         if (bytes > 0 && (bytes -= i) <= 0)
 124             break;
 125     }
 126
 127     OPENSSL_cleanse(buf, sizeof(buf));
 128     fclose(in);
 129     return ret;
 130 }
 131
 132 int RAND_write_file(const char *file)
 133 {
 134     unsigned char buf[RAND_FILE_SIZE];
 135     int ret = -1;
 136     FILE *out = NULL;
 137 #ifndef OPENSSL_NO_POSIX_IO
 138     struct stat sb;
 139
 140     if (stat(file, &sb) >= 0 && !S_ISREG(sb.st_mode)) {
 141         RANDerr(RAND_F_RAND_WRITE_FILE, RAND_R_NOT_A_REGULAR_FILE);
 142         ERR_add_error_data(2, "Filename=", file);
 143         return -1;
 144     }
 145 #endif
 146
 147     /* Collect enough random data. */
 148     if (RAND_bytes(buf, (int)sizeof(buf)) != 1)
 149         return  -1;
 150
 151 #if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && \
 152     !defined(OPENSSL_SYS_VMS) && !defined(OPENSSL_SYS_WINDOWS)
 153     {
 154 # ifndef O_BINARY
 155 #  define O_BINARY 0
 156 # endif
 157         /*
 158          * chmod(..., 0600) is too late to protect the file, permissions
 159          * should be restrictive from the start
 160          */
 161         int fd = open(file, O_WRONLY | O_CREAT | O_BINARY, 0600);
 162         if (fd != -1)
 163             out = fdopen(fd, "wb");
 164     }
 165 #endif
 166
 167 #ifdef OPENSSL_SYS_VMS
 168     /*
 169      * VMS NOTE: Prior versions of this routine created a _new_ version of
 170      * the rand file for each call into this routine, then deleted all
 171      * existing versions named ;-1, and finally renamed the current version
 172      * as ';1'. Under concurrent usage, this resulted in an RMS race
 173      * condition in rename() which could orphan files (see vms message help
 174      * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares
 175      * the top-level version of the rand file. Note that there may still be
 176      * conditions where the top-level rand file is locked. If so, this code
 177      * will then create a new version of the rand file. Without the delete
 178      * and rename code, this can result in ascending file versions that stop
 179      * at version 32767, and this routine will then return an error. The
 180      * remedy for this is to recode the calling application to avoid
 181      * concurrent use of the rand file, or synchronize usage at the
 182      * application level. Also consider whether or not you NEED a persistent
 183      * rand file in a concurrent use situation.
 184      */
 185     out = openssl_fopen(file, "rb+");
 186 #endif
 187
 188     if (out == NULL)
 189         out = openssl_fopen(file, "wb");
 190     if (out == NULL)
 191         return -1;
 192
 193 #if !defined(NO_CHMOD) && !defined(OPENSSL_NO_POSIX_IO)
 194     /*
 195      * Yes it's late to do this (see above comment), but better than nothing.
 196      */
 197     chmod(file, 0600);
 198 #endif
 199
 200     ret = fwrite(buf, 1, RAND_FILE_SIZE, out);
 201     fclose(out);
 202     OPENSSL_cleanse(buf, RAND_FILE_SIZE);
 203     return ret;
 204 }
 205
 206 const char *RAND_file_name(char *buf, size_t size)
 207 {
 208     char *s = NULL;
 209     size_t len;
 210     int use_randfile = 1;
 211
 212 #if defined(_WIN32) && defined(CP_UTF8)
 213     DWORD envlen;
 214     WCHAR *var;
 215
 216     /* Look up various environment variables. */
 217     if ((envlen = GetEnvironmentVariableW(var = L"RANDFILE", NULL, 0)) == 0) {
 218         use_randfile = 0;
 219         if ((envlen = GetEnvironmentVariableW(var = L"HOME", NULL, 0)) == 0
 220                 && (envlen = GetEnvironmentVariableW(var = L"USERPROFILE",
 221                                                   NULL, 0)) == 0)
 222             envlen = GetEnvironmentVariableW(var = L"SYSTEMROOT", NULL, 0);
 223     }
 224
 225     /* If we got a value, allocate space to hold it and then get it. */
 226     if (envlen != 0) {
 227         int sz;
 228         WCHAR *val = _alloca(envlen * sizeof(WCHAR));
 229
 230         if (GetEnvironmentVariableW(var, val, envlen) < envlen
 231                 && (sz = WideCharToMultiByte(CP_UTF8, 0, val, -1, NULL, 0,
 232                                              NULL, NULL)) != 0) {
 233             s = _alloca(sz);
 234             if (WideCharToMultiByte(CP_UTF8, 0, val, -1, s, sz,
 235                                     NULL, NULL) == 0)
 236                 s = NULL;
 237         }
 238     }
 239 #else
 240     if (OPENSSL_issetugid() != 0) {
 241         use_randfile = 0;
 242     } else if ((s = getenv("RANDFILE")) == NULL || *s == '\0') {
 243         use_randfile = 0;
 244         s = getenv("HOME");
 245     }
 246 #endif
 247
 248 #ifdef DEFAULT_HOME
 249     if (!use_randfile && s == NULL)
 250         s = DEFAULT_HOME;
 251 #endif
 252     if (s == NULL || *s == '\0')
 253         return NULL;
 254
 255     len = strlen(s);
 256     if (use_randfile) {
 257         if (len + 1 >= size)
 258             return NULL;
 259         strcpy(buf, s);
 260     } else {
 261         if (len + 1 + strlen(RFILE) + 1 >= size)
 262             return NULL;
 263         strcpy(buf, s);
 264 #ifndef OPENSSL_SYS_VMS
 265         strcat(buf, "/");
 266 #endif
 267         strcat(buf, RFILE);
 268     }
 269
 270     return buf;
 271 }