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     return ret;
 152 }
 153
 154 int RAND_write_file(const char *file)
 155 {
 156     unsigned char buf[RAND_FILE_SIZE];
 157     int ret = -1;
 158     FILE *out = NULL;
 159 #ifndef OPENSSL_NO_POSIX_IO
 160     struct stat sb;
 161
 162     if (stat(file, &sb) >= 0 && !S_ISREG(sb.st_mode)) {
 163         RANDerr(RAND_F_RAND_WRITE_FILE, RAND_R_NOT_A_REGULAR_FILE);
 164         ERR_add_error_data(2, "Filename=", file);
 165         return -1;
 166     }
 167 #endif
 168
 169     /* Collect enough random data. */
 170     if (RAND_priv_bytes(buf, (int)sizeof(buf)) != 1)
 171         return  -1;
 172
 173 #if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && \
 174     !defined(OPENSSL_SYS_VMS) && !defined(OPENSSL_SYS_WINDOWS)
 175     {
 176 # ifndef O_BINARY
 177 #  define O_BINARY 0
 178 # endif
 179         /*
 180          * chmod(..., 0600) is too late to protect the file, permissions
 181          * should be restrictive from the start
 182          */
 183         int fd = open(file, O_WRONLY | O_CREAT | O_BINARY, 0600);
 184         if (fd != -1)
 185             out = fdopen(fd, "wb");
 186     }
 187 #endif
 188
 189 #ifdef OPENSSL_SYS_VMS
 190     /*
 191      * VMS NOTE: Prior versions of this routine created a _new_ version of
 192      * the rand file for each call into this routine, then deleted all
 193      * existing versions named ;-1, and finally renamed the current version
 194      * as ';1'. Under concurrent usage, this resulted in an RMS race
 195      * condition in rename() which could orphan files (see vms message help
 196      * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares
 197      * the top-level version of the rand file. Note that there may still be
 198      * conditions where the top-level rand file is locked. If so, this code
 199      * will then create a new version of the rand file. Without the delete
 200      * and rename code, this can result in ascending file versions that stop
 201      * at version 32767, and this routine will then return an error. The
 202      * remedy for this is to recode the calling application to avoid
 203      * concurrent use of the rand file, or synchronize usage at the
 204      * application level. Also consider whether or not you NEED a persistent
 205      * rand file in a concurrent use situation.
 206      */
 207     out = openssl_fopen(file, "rb+");
 208 #endif
 209
 210     if (out == NULL)
 211         out = openssl_fopen(file, "wb");
 212     if (out == NULL) {
 213         RANDerr(RAND_F_RAND_WRITE_FILE, RAND_R_CANNOT_OPEN_FILE);
 214         ERR_add_error_data(2, "Filename=", file);
 215         return -1;
 216     }
 217
 218 #if !defined(NO_CHMOD) && !defined(OPENSSL_NO_POSIX_IO)
 219     /*
 220      * Yes it's late to do this (see above comment), but better than nothing.
 221      */
 222     chmod(file, 0600);
 223 #endif
 224
 225     ret = fwrite(buf, 1, RAND_FILE_SIZE, out);
 226     fclose(out);
 227     OPENSSL_cleanse(buf, RAND_FILE_SIZE);
 228     return ret;
 229 }
 230
 231 const char *RAND_file_name(char *buf, size_t size)
 232 {
 233     char *s = NULL;
 234     size_t len;
 235     int use_randfile = 1;
 236
 237 #if defined(_WIN32) && defined(CP_UTF8)
 238     DWORD envlen;
 239     WCHAR *var;
 240
 241     /* Look up various environment variables. */
 242     if ((envlen = GetEnvironmentVariableW(var = L"RANDFILE", NULL, 0)) == 0) {
 243         use_randfile = 0;
 244         if ((envlen = GetEnvironmentVariableW(var = L"HOME", NULL, 0)) == 0
 245                 && (envlen = GetEnvironmentVariableW(var = L"USERPROFILE",
 246                                                   NULL, 0)) == 0)
 247             envlen = GetEnvironmentVariableW(var = L"SYSTEMROOT", NULL, 0);
 248     }
 249
 250     /* If we got a value, allocate space to hold it and then get it. */
 251     if (envlen != 0) {
 252         int sz;
 253         WCHAR *val = _alloca(envlen * sizeof(WCHAR));
 254
 255         if (GetEnvironmentVariableW(var, val, envlen) < envlen
 256                 && (sz = WideCharToMultiByte(CP_UTF8, 0, val, -1, NULL, 0,
 257                                              NULL, NULL)) != 0) {
 258             s = _alloca(sz);
 259             if (WideCharToMultiByte(CP_UTF8, 0, val, -1, s, sz,
 260                                     NULL, NULL) == 0)
 261                 s = NULL;
 262         }
 263     }
 264 #else
 265     if (OPENSSL_issetugid() != 0) {
 266         use_randfile = 0;
 267     } else if ((s = getenv("RANDFILE")) == NULL || *s == '\0') {
 268         use_randfile = 0;
 269         s = getenv("HOME");
 270     }
 271 #endif
 272
 273 #ifdef DEFAULT_HOME
 274     if (!use_randfile && s == NULL)
 275         s = DEFAULT_HOME;
 276 #endif
 277     if (s == NULL || *s == '\0')
 278         return NULL;
 279
 280     len = strlen(s);
 281     if (use_randfile) {
 282         if (len + 1 >= size)
 283             return NULL;
 284         strcpy(buf, s);
 285     } else {
 286         if (len + 1 + strlen(RFILE) + 1 >= size)
 287             return NULL;
 288         strcpy(buf, s);
 289 #ifndef OPENSSL_SYS_VMS
 290         strcat(buf, "/");
 291 #endif
 292         strcat(buf, RFILE);
 293     }
 294
 295     return buf;
 296 }