crypto/rand/randfile.c

   1 /*
   2  * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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/rand_drbg.h>
  20 #include <openssl/buffer.h>
  21
  22 #ifdef OPENSSL_SYS_VMS
  23 # include <unixio.h>
  24 #endif
  25 #include <sys/types.h>
  26 #ifndef OPENSSL_NO_POSIX_IO
  27 # include <sys/stat.h>
  28 # include <fcntl.h>
  29 # ifdef _WIN32
  30 #  include <windows.h>
  31 #  include <io.h>
  32 #  define stat    _stat
  33 #  define chmod   _chmod
  34 #  define open    _open
  35 #  define fdopen  _fdopen
  36 #  define fstat   _fstat
  37 #  define fileno  _fileno
  38 # endif
  39 #endif
  40
  41 /*
  42  * Following should not be needed, and we could have been stricter
  43  * and demand S_IS*. But some systems just don't comply... Formally
  44  * below macros are "anatomically incorrect", because normally they
  45  * would look like ((m) & MASK == TYPE), but since MASK availability
  46  * is as questionable, we settle for this poor-man fallback...
  47  */
  48 # if !defined(S_ISREG)
  49 #   define S_ISREG(m) ((m) & S_IFREG)
  50 # endif
  51
  52 #define RAND_BUF_SIZE 1024
  53 #define RFILE ".rnd"
  54
  55 #ifdef OPENSSL_SYS_VMS
  56 /*
  57  * __FILE_ptr32 is a type provided by DEC C headers (types.h specifically)
  58  * to make sure the FILE* is a 32-bit pointer no matter what.  We know that
  59  * stdio functions return this type (a study of stdio.h proves it).
  60  *
  61  * This declaration is a nasty hack to get around vms' extension to fopen for
  62  * passing in sharing options being disabled by /STANDARD=ANSI89
  63  */
  64 static __FILE_ptr32 (*const vms_fopen)(const char *, const char *, ...) =
  65         (__FILE_ptr32 (*)(const char *, const char *, ...))fopen;
  66 # define VMS_OPEN_ATTRS \
  67         "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0"
  68 # define openssl_fopen(fname, mode) vms_fopen((fname), (mode), VMS_OPEN_ATTRS)
  69 #endif
  70
  71 /*
  72  * Note that these functions are intended for seed files only. Entropy
  73  * devices and EGD sockets are handled in rand_unix.c  If |bytes| is
  74  * -1 read the complete file; otherwise read the specified amount.
  75  */
  76 int RAND_load_file(const char *file, long bytes)
  77 {
  78     /*
  79      * The load buffer size exceeds the chunk size by the comfortable amount
  80      * of 'RAND_DRBG_STRENGTH' bytes (not bits!). This is done on purpose
  81      * to avoid calling RAND_add() with a small final chunk. Instead, such
  82      * a small final chunk will be added together with the previous chunk
  83      * (unless it's the only one).
  84      */
  85 #define RAND_LOAD_BUF_SIZE (RAND_BUF_SIZE + RAND_DRBG_STRENGTH)
  86     unsigned char buf[RAND_LOAD_BUF_SIZE];
  87
  88 #ifndef OPENSSL_NO_POSIX_IO
  89     struct stat sb;
  90 #endif
  91     int i, n, ret = 0;
  92     FILE *in;
  93
  94     if (bytes == 0)
  95         return 0;
  96
  97     if ((in = openssl_fopen(file, "rb")) == NULL) {
  98         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_CANNOT_OPEN_FILE);
  99         ERR_add_error_data(2, "Filename=", file);
 100         return -1;
 101     }
 102
 103 #ifndef OPENSSL_NO_POSIX_IO
 104     if (fstat(fileno(in), &sb) < 0) {
 105         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_INTERNAL_ERROR);
 106         ERR_add_error_data(2, "Filename=", file);
 107         fclose(in);
 108         return -1;
 109     }
 110
 111     if (bytes < 0) {
 112         if (S_ISREG(sb.st_mode))
 113             bytes = sb.st_size;
 114         else
 115             bytes = RAND_DRBG_STRENGTH;
 116     }
 117 #endif
 118     /*
 119      * On VMS, setbuf() will only take 32-bit pointers, and a compilation
 120      * with /POINTER_SIZE=64 will give off a MAYLOSEDATA2 warning here.
 121      * However, we trust that the C RTL will never give us a FILE pointer
 122      * above the first 4 GB of memory, so we simply turn off the warning
 123      * temporarily.
 124      */
 125 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 126 # pragma environment save
 127 # pragma message disable maylosedata2
 128 #endif
 129     /*
 130      * Don't buffer, because even if |file| is regular file, we have
 131      * no control over the buffer, so why would we want a copy of its
 132      * contents lying around?
 133      */
 134     setbuf(in, NULL);
 135 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 136 # pragma environment restore
 137 #endif
 138
 139     for ( ; ; ) {
 140         if (bytes > 0)
 141             n = (bytes <= RAND_LOAD_BUF_SIZE) ? (int)bytes : RAND_BUF_SIZE;
 142         else
 143             n = RAND_LOAD_BUF_SIZE;
 144         i = fread(buf, 1, n, in);
 145 #ifdef EINTR
 146         if (ferror(in) && errno == EINTR){
 147             clearerr(in);
 148             if (i == 0)
 149                 continue;
 150         }
 151 #endif
 152         if (i == 0)
 153             break;
 154
 155         RAND_add(buf, i, (double)i);
 156         ret += i;
 157
 158         /* If given a bytecount, and we did it, break. */
 159         if (bytes > 0 && (bytes -= i) <= 0)
 160             break;
 161     }
 162
 163     OPENSSL_cleanse(buf, sizeof(buf));
 164     fclose(in);
 165     if (!RAND_status()) {
 166         RANDerr(RAND_F_RAND_LOAD_FILE, RAND_R_RESEED_ERROR);
 167         ERR_add_error_data(2, "Filename=", file);
 168         return -1;
 169     }
 170
 171     return ret;
 172 }
 173
 174 int RAND_write_file(const char *file)
 175 {
 176     unsigned char buf[RAND_BUF_SIZE];
 177     int ret = -1;
 178     FILE *out = NULL;
 179 #ifndef OPENSSL_NO_POSIX_IO
 180     struct stat sb;
 181
 182     if (stat(file, &sb) >= 0 && !S_ISREG(sb.st_mode)) {
 183         RANDerr(RAND_F_RAND_WRITE_FILE, RAND_R_NOT_A_REGULAR_FILE);
 184         ERR_add_error_data(2, "Filename=", file);
 185         return -1;
 186     }
 187 #endif
 188
 189     /* Collect enough random data. */
 190     if (RAND_priv_bytes(buf, (int)sizeof(buf)) != 1)
 191         return  -1;
 192
 193 #if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && \
 194     !defined(OPENSSL_SYS_VMS) && !defined(OPENSSL_SYS_WINDOWS)
 195     {
 196 # ifndef O_BINARY
 197 #  define O_BINARY 0
 198 # endif
 199         /*
 200          * chmod(..., 0600) is too late to protect the file, permissions
 201          * should be restrictive from the start
 202          */
 203         int fd = open(file, O_WRONLY | O_CREAT | O_BINARY, 0600);
 204         if (fd != -1)
 205             out = fdopen(fd, "wb");
 206     }
 207 #endif
 208
 209 #ifdef OPENSSL_SYS_VMS
 210     /*
 211      * VMS NOTE: Prior versions of this routine created a _new_ version of
 212      * the rand file for each call into this routine, then deleted all
 213      * existing versions named ;-1, and finally renamed the current version
 214      * as ';1'. Under concurrent usage, this resulted in an RMS race
 215      * condition in rename() which could orphan files (see vms message help
 216      * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares
 217      * the top-level version of the rand file. Note that there may still be
 218      * conditions where the top-level rand file is locked. If so, this code
 219      * will then create a new version of the rand file. Without the delete
 220      * and rename code, this can result in ascending file versions that stop
 221      * at version 32767, and this routine will then return an error. The
 222      * remedy for this is to recode the calling application to avoid
 223      * concurrent use of the rand file, or synchronize usage at the
 224      * application level. Also consider whether or not you NEED a persistent
 225      * rand file in a concurrent use situation.
 226      */
 227     out = openssl_fopen(file, "rb+");
 228 #endif
 229
 230     if (out == NULL)
 231         out = openssl_fopen(file, "wb");
 232     if (out == NULL) {
 233         RANDerr(RAND_F_RAND_WRITE_FILE, RAND_R_CANNOT_OPEN_FILE);
 234         ERR_add_error_data(2, "Filename=", file);
 235         return -1;
 236     }
 237
 238 #if !defined(NO_CHMOD) && !defined(OPENSSL_NO_POSIX_IO)
 239     /*
 240      * Yes it's late to do this (see above comment), but better than nothing.
 241      */
 242     chmod(file, 0600);
 243 #endif
 244
 245     ret = fwrite(buf, 1, RAND_BUF_SIZE, out);
 246     fclose(out);
 247     OPENSSL_cleanse(buf, RAND_BUF_SIZE);
 248     return ret;
 249 }
 250
 251 const char *RAND_file_name(char *buf, size_t size)
 252 {
 253     char *s = NULL;
 254     size_t len;
 255     int use_randfile = 1;
 256
 257 #if defined(_WIN32) && defined(CP_UTF8) && !defined(_WIN32_WCE)
 258     DWORD envlen;
 259     WCHAR *var;
 260
 261     /* Look up various environment variables. */
 262     if ((envlen = GetEnvironmentVariableW(var = L"RANDFILE", NULL, 0)) == 0) {
 263         use_randfile = 0;
 264         if ((envlen = GetEnvironmentVariableW(var = L"HOME", NULL, 0)) == 0
 265                 && (envlen = GetEnvironmentVariableW(var = L"USERPROFILE",
 266                                                   NULL, 0)) == 0)
 267             envlen = GetEnvironmentVariableW(var = L"SYSTEMROOT", NULL, 0);
 268     }
 269
 270     /* If we got a value, allocate space to hold it and then get it. */
 271     if (envlen != 0) {
 272         int sz;
 273         WCHAR *val = _alloca(envlen * sizeof(WCHAR));
 274
 275         if (GetEnvironmentVariableW(var, val, envlen) < envlen
 276                 && (sz = WideCharToMultiByte(CP_UTF8, 0, val, -1, NULL, 0,
 277                                              NULL, NULL)) != 0) {
 278             s = _alloca(sz);
 279             if (WideCharToMultiByte(CP_UTF8, 0, val, -1, s, sz,
 280                                     NULL, NULL) == 0)
 281                 s = NULL;
 282         }
 283     }
 284 #else
 285     if ((s = ossl_safe_getenv("RANDFILE")) == NULL || *s == '\0') {
 286         use_randfile = 0;
 287         s = ossl_safe_getenv("HOME");
 288     }
 289 #endif
 290
 291 #ifdef DEFAULT_HOME
 292     if (!use_randfile && s == NULL)
 293         s = DEFAULT_HOME;
 294 #endif
 295     if (s == NULL || *s == '\0')
 296         return NULL;
 297
 298     len = strlen(s);
 299     if (use_randfile) {
 300         if (len + 1 >= size)
 301             return NULL;
 302         strcpy(buf, s);
 303     } else {
 304         if (len + 1 + strlen(RFILE) + 1 >= size)
 305             return NULL;
 306         strcpy(buf, s);
 307 #ifndef OPENSSL_SYS_VMS
 308         strcat(buf, "/");
 309 #endif
 310         strcat(buf, RFILE);
 311     }
 312
 313     return buf;
 314 }