crypto/rand/randfile.c

   1 /*
   2  * Copyright 1995-2018 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 #include <sys/types.h>
  25 #ifndef OPENSSL_NO_POSIX_IO
  26 # include <sys/stat.h>
  27 # include <fcntl.h>
  28 # ifdef _WIN32
  29 #  include <windows.h>
  30 #  include <io.h>
  31 #  define stat    _stat
  32 #  define chmod   _chmod
  33 #  define open    _open
  34 #  define fdopen  _fdopen
  35 #  define fstat   _fstat
  36 #  define fileno  _fileno
  37 # endif
  38 #endif
  39
  40 /*
  41  * Following should not be needed, and we could have been stricter
  42  * and demand S_IS*. But some systems just don't comply... Formally
  43  * below macros are "anatomically incorrect", because normally they
  44  * would look like ((m) & MASK == TYPE), but since MASK availability
  45  * is as questionable, we settle for this poor-man fallback...
  46  */
  47 # if !defined(S_ISREG)
  48 #   define S_ISREG(m) ((m) & S_IFREG)
  49 # endif
  50
  51 #define RAND_FILE_SIZE 1024
  52 #define RFILE ".rnd"
  53
  54 #ifdef OPENSSL_SYS_VMS
  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 functions return this type (a study of stdio.h proves it).
  59  *
  60  * This declaration is a nasty hack to get around vms' extension to fopen for
  61  * passing in sharing options being disabled by /STANDARD=ANSI89
  62  */
  63 static __FILE_ptr32 (*const vms_fopen)(const char *, const char *, ...) =
  64         (__FILE_ptr32 (*)(const char *, const char *, ...))fopen;
  65 # define VMS_OPEN_ATTRS \
  66         "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0"
  67 # define openssl_fopen(fname, mode) vms_fopen((fname), (mode), VMS_OPEN_ATTRS)
  68 #endif
  69
  70 /*
  71  * Note that these functions are intended for seed files only. Entropy
  72  * devices and EGD sockets are handled in rand_unix.c  If |bytes| is
  73  * -1 read the complete file; otherwise read the specified amount.
  74  */
  75 int RAND_load_file(const char *file, long bytes)
  76 {
  77     unsigned char buf[RAND_FILE_SIZE];
  78 #ifndef OPENSSL_NO_POSIX_IO
  79     struct stat sb;
  80 #endif
  81     int i, n, ret = 0;
  82     FILE *in;
  83
  84     if (bytes == 0)
  85         return 0;
  86
  87     if ((in = openssl_fopen(file, "rb")) == NULL) {
  88         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_CANNOT_OPEN_FILE);
  89         ERR_add_error_data(2, "Filename=", file);
  90         return -1;
  91     }
  92
  93 #ifndef OPENSSL_NO_POSIX_IO
  94     if (fstat(fileno(in), &sb) < 0) {
  95         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_INTERNAL_ERROR);
  96         ERR_add_error_data(2, "Filename=", file);
  97         fclose(in);
  98         return -1;
  99     }
 100
 101     if (!S_ISREG(sb.st_mode) && bytes < 0)
 102         bytes = 256;
 103 #endif
 104     /*
 105      * On VMS, setbuf() will only take 32-bit pointers, and a compilation
 106      * with /POINTER_SIZE=64 will give off a MAYLOSEDATA2 warning here.
 107      * However, we trust that the C RTL will never give us a FILE pointer
 108      * above the first 4 GB of memory, so we simply turn off the warning
 109      * temporarily.
 110      */
 111 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 112 # pragma environment save
 113 # pragma message disable maylosedata2
 114 #endif
 115     /*
 116      * Don't buffer, because even if |file| is regular file, we have
 117      * no control over the buffer, so why would we want a copy of its
 118      * contents lying around?
 119      */
 120     setbuf(in, NULL);
 121 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 122 # pragma environment restore
 123 #endif
 124
 125     for ( ; ; ) {
 126         if (bytes > 0)
 127             n = (bytes < RAND_FILE_SIZE) ? (int)bytes : RAND_FILE_SIZE;
 128         else
 129             n = RAND_FILE_SIZE;
 130         i = fread(buf, 1, n, in);
 131 #ifdef EINTR
 132         if (ferror(in) && errno == EINTR){
 133             clearerr(in);
 134             if (i == 0)
 135                 continue;
 136         }
 137 #endif
 138         if (i == 0)
 139             break;
 140
 141         RAND_add(buf, i, (double)i);
 142         ret += i;
 143
 144         /* If given a bytecount, and we did it, break. */
 145         if (bytes > 0 && (bytes -= i) <= 0)
 146             break;
 147     }
 148
 149     OPENSSL_cleanse(buf, sizeof(buf));
 150     fclose(in);
 151     if (!RAND_status()) {
 152         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_RESEED_ERROR);
 153         ERR_add_error_data(2, "Filename=", file);
 154         return -1;
 155     }
 156
 157     return ret;
 158 }
 159
 160 int RAND_write_file(const char *file)
 161 {
 162     unsigned char buf[RAND_FILE_SIZE];
 163     int ret = -1;
 164     FILE *out = NULL;
 165 #ifndef OPENSSL_NO_POSIX_IO
 166     struct stat sb;
 167
 168     if (stat(file, &sb) >= 0 && !S_ISREG(sb.st_mode)) {
 169         RANDerr(RAND_F_RAND_WRITE_FILE, RAND_R_NOT_A_REGULAR_FILE);
 170         ERR_add_error_data(2, "Filename=", file);
 171         return -1;
 172     }
 173 #endif
 174
 175     /* Collect enough random data. */
 176     if (RAND_priv_bytes(buf, (int)sizeof(buf)) != 1)
 177         return  -1;
 178
 179 #if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && \
 180     !defined(OPENSSL_SYS_VMS) && !defined(OPENSSL_SYS_WINDOWS)
 181     {
 182 # ifndef O_BINARY
 183 #  define O_BINARY 0
 184 # endif
 185         /*
 186          * chmod(..., 0600) is too late to protect the file, permissions
 187          * should be restrictive from the start
 188          */
 189         int fd = open(file, O_WRONLY | O_CREAT | O_BINARY, 0600);
 190         if (fd != -1)
 191             out = fdopen(fd, "wb");
 192     }
 193 #endif
 194
 195 #ifdef OPENSSL_SYS_VMS
 196     /*
 197      * VMS NOTE: Prior versions of this routine created a _new_ version of
 198      * the rand file for each call into this routine, then deleted all
 199      * existing versions named ;-1, and finally renamed the current version
 200      * as ';1'. Under concurrent usage, this resulted in an RMS race
 201      * condition in rename() which could orphan files (see vms message help
 202      * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares
 203      * the top-level version of the rand file. Note that there may still be
 204      * conditions where the top-level rand file is locked. If so, this code
 205      * will then create a new version of the rand file. Without the delete
 206      * and rename code, this can result in ascending file versions that stop
 207      * at version 32767, and this routine will then return an error. The
 208      * remedy for this is to recode the calling application to avoid
 209      * concurrent use of the rand file, or synchronize usage at the
 210      * application level. Also consider whether or not you NEED a persistent
 211      * rand file in a concurrent use situation.
 212      */
 213     out = openssl_fopen(file, "rb+");
 214 #endif
 215
 216     if (out == NULL)
 217         out = openssl_fopen(file, "wb");
 218     if (out == NULL) {
 219         RANDerr(RAND_F_RAND_WRITE_FILE, RAND_R_CANNOT_OPEN_FILE);
 220         ERR_add_error_data(2, "Filename=", file);
 221         return -1;
 222     }
 223
 224 #if !defined(NO_CHMOD) && !defined(OPENSSL_NO_POSIX_IO)
 225     /*
 226      * Yes it's late to do this (see above comment), but better than nothing.
 227      */
 228     chmod(file, 0600);
 229 #endif
 230
 231     ret = fwrite(buf, 1, RAND_FILE_SIZE, out);
 232     fclose(out);
 233     OPENSSL_cleanse(buf, RAND_FILE_SIZE);
 234     return ret;
 235 }
 236
 237 const char *RAND_file_name(char *buf, size_t size)
 238 {
 239     char *s = NULL;
 240     size_t len;
 241     int use_randfile = 1;
 242
 243 #if defined(_WIN32) && defined(CP_UTF8)
 244     DWORD envlen;
 245     WCHAR *var;
 246
 247     /* Look up various environment variables. */
 248     if ((envlen = GetEnvironmentVariableW(var = L"RANDFILE", NULL, 0)) == 0) {
 249         use_randfile = 0;
 250         if ((envlen = GetEnvironmentVariableW(var = L"HOME", NULL, 0)) == 0
 251                 && (envlen = GetEnvironmentVariableW(var = L"USERPROFILE",
 252                                                   NULL, 0)) == 0)
 253             envlen = GetEnvironmentVariableW(var = L"SYSTEMROOT", NULL, 0);
 254     }
 255
 256     /* If we got a value, allocate space to hold it and then get it. */
 257     if (envlen != 0) {
 258         int sz;
 259         WCHAR *val = _alloca(envlen * sizeof(WCHAR));
 260
 261         if (GetEnvironmentVariableW(var, val, envlen) < envlen
 262                 && (sz = WideCharToMultiByte(CP_UTF8, 0, val, -1, NULL, 0,
 263                                              NULL, NULL)) != 0) {
 264             s = _alloca(sz);
 265             if (WideCharToMultiByte(CP_UTF8, 0, val, -1, s, sz,
 266                                     NULL, NULL) == 0)
 267                 s = NULL;
 268         }
 269     }
 270 #else
 271     if ((s = ossl_safe_getenv("RANDFILE")) == NULL || *s == '\0') {
 272         use_randfile = 0;
 273         s = ossl_safe_getenv("HOME");
 274     }
 275 #endif
 276
 277 #ifdef DEFAULT_HOME
 278     if (!use_randfile && s == NULL)
 279         s = DEFAULT_HOME;
 280 #endif
 281     if (s == NULL || *s == '\0')
 282         return NULL;
 283
 284     len = strlen(s);
 285     if (use_randfile) {
 286         if (len + 1 >= size)
 287             return NULL;
 288         strcpy(buf, s);
 289     } else {
 290         if (len + 1 + strlen(RFILE) + 1 >= size)
 291             return NULL;
 292         strcpy(buf, s);
 293 #ifndef OPENSSL_SYS_VMS
 294         strcat(buf, "/");
 295 #endif
 296         strcat(buf, RFILE);
 297     }
 298
 299     return buf;
 300 }