crypto/rand/randfile.c

   1 /*
   2  * Copyright 1995-2020 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 #if defined (__TANDEM) && defined (_SPT_MODEL_)
  11 /*
  12  * These definitions have to come first in SPT due to scoping of the
  13  * declarations in c99 associated with SPT use of stat.
  14  */
  15 # include <sys/types.h>
  16 # include <sys/stat.h>
  17 #endif
  18
  19 #include "internal/cryptlib.h"
  20
  21 #include <errno.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include <openssl/crypto.h>
  27 #include <openssl/rand.h>
  28 #include <openssl/buffer.h>
  29
  30 #ifdef OPENSSL_SYS_VMS
  31 # include <unixio.h>
  32 #endif
  33 #include <sys/types.h>
  34 #ifndef OPENSSL_NO_POSIX_IO
  35 # include <sys/stat.h>
  36 # include <fcntl.h>
  37 # if defined(_WIN32) && !defined(_WIN32_WCE)
  38 #  include <windows.h>
  39 #  include <io.h>
  40 #  define stat    _stat
  41 #  define chmod   _chmod
  42 #  define open    _open
  43 #  define fdopen  _fdopen
  44 #  define fstat   _fstat
  45 #  define fileno  _fileno
  46 # endif
  47 #endif
  48
  49 /*
  50  * Following should not be needed, and we could have been stricter
  51  * and demand S_IS*. But some systems just don't comply... Formally
  52  * below macros are "anatomically incorrect", because normally they
  53  * would look like ((m) & MASK == TYPE), but since MASK availability
  54  * is as questionable, we settle for this poor-man fallback...
  55  */
  56 # if !defined(S_ISREG)
  57 #   define S_ISREG(m) ((m) & S_IFREG)
  58 # endif
  59
  60 #define RAND_BUF_SIZE 1024
  61 #define RFILE ".rnd"
  62
  63 #ifdef OPENSSL_SYS_VMS
  64 /*
  65  * __FILE_ptr32 is a type provided by DEC C headers (types.h specifically)
  66  * to make sure the FILE* is a 32-bit pointer no matter what.  We know that
  67  * stdio functions return this type (a study of stdio.h proves it).
  68  *
  69  * This declaration is a nasty hack to get around vms' extension to fopen for
  70  * passing in sharing options being disabled by /STANDARD=ANSI89
  71  */
  72 static __FILE_ptr32 (*const vms_fopen)(const char *, const char *, ...) =
  73         (__FILE_ptr32 (*)(const char *, const char *, ...))fopen;
  74 # define VMS_OPEN_ATTRS \
  75         "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0"
  76 # define openssl_fopen(fname, mode) vms_fopen((fname), (mode), VMS_OPEN_ATTRS)
  77 #endif
  78
  79 /*
  80  * Note that these functions are intended for seed files only. Entropy
  81  * devices and EGD sockets are handled in rand_unix.c  If |bytes| is
  82  * -1 read the complete file; otherwise read the specified amount.
  83  */
  84 int RAND_load_file(const char *file, long bytes)
  85 {
  86     /*
  87      * The load buffer size exceeds the chunk size by the comfortable amount
  88      * of 'RAND_DRBG_STRENGTH' bytes (not bits!). This is done on purpose
  89      * to avoid calling RAND_add() with a small final chunk. Instead, such
  90      * a small final chunk will be added together with the previous chunk
  91      * (unless it's the only one).
  92      */
  93 #define RAND_LOAD_BUF_SIZE (RAND_BUF_SIZE + RAND_DRBG_STRENGTH)
  94     unsigned char buf[RAND_LOAD_BUF_SIZE];
  95
  96 #ifndef OPENSSL_NO_POSIX_IO
  97     struct stat sb;
  98 #endif
  99     int i, n, ret = 0;
 100     FILE *in;
 101
 102     if (bytes == 0)
 103         return 0;
 104
 105     if ((in = openssl_fopen(file, "rb")) == NULL) {
 106         ERR_raise_data(ERR_LIB_RAND, RAND_R_CANNOT_OPEN_FILE,
 107                        "Filename=%s", file);
 108         return -1;
 109     }
 110
 111 #ifndef OPENSSL_NO_POSIX_IO
 112     if (fstat(fileno(in), &sb) < 0) {
 113         ERR_raise_data(ERR_LIB_RAND, RAND_R_INTERNAL_ERROR,
 114                        "Filename=%s", file);
 115         fclose(in);
 116         return -1;
 117     }
 118
 119     if (bytes < 0) {
 120         if (S_ISREG(sb.st_mode))
 121             bytes = sb.st_size;
 122         else
 123             bytes = RAND_DRBG_STRENGTH;
 124     }
 125 #endif
 126     /*
 127      * On VMS, setbuf() will only take 32-bit pointers, and a compilation
 128      * with /POINTER_SIZE=64 will give off a MAYLOSEDATA2 warning here.
 129      * However, we trust that the C RTL will never give us a FILE pointer
 130      * above the first 4 GB of memory, so we simply turn off the warning
 131      * temporarily.
 132      */
 133 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 134 # pragma environment save
 135 # pragma message disable maylosedata2
 136 #endif
 137     /*
 138      * Don't buffer, because even if |file| is regular file, we have
 139      * no control over the buffer, so why would we want a copy of its
 140      * contents lying around?
 141      */
 142     setbuf(in, NULL);
 143 #if defined(OPENSSL_SYS_VMS) && defined(__DECC)
 144 # pragma environment restore
 145 #endif
 146
 147     for ( ; ; ) {
 148         if (bytes > 0)
 149             n = (bytes <= RAND_LOAD_BUF_SIZE) ? (int)bytes : RAND_BUF_SIZE;
 150         else
 151             n = RAND_LOAD_BUF_SIZE;
 152         i = fread(buf, 1, n, in);
 153 #ifdef EINTR
 154         if (ferror(in) && errno == EINTR){
 155             clearerr(in);
 156             if (i == 0)
 157                 continue;
 158         }
 159 #endif
 160         if (i == 0)
 161             break;
 162
 163         RAND_add(buf, i, (double)i);
 164         ret += i;
 165
 166         /* If given a bytecount, and we did it, break. */
 167         if (bytes > 0 && (bytes -= i) <= 0)
 168             break;
 169     }
 170
 171     OPENSSL_cleanse(buf, sizeof(buf));
 172     fclose(in);
 173     if (!RAND_status()) {
 174         ERR_raise_data(ERR_LIB_RAND, RAND_R_RESEED_ERROR, "Filename=%s", file);
 175         return -1;
 176     }
 177
 178     return ret;
 179 }
 180
 181 int RAND_write_file(const char *file)
 182 {
 183     unsigned char buf[RAND_BUF_SIZE];
 184     int ret = -1;
 185     FILE *out = NULL;
 186 #ifndef OPENSSL_NO_POSIX_IO
 187     struct stat sb;
 188
 189     if (stat(file, &sb) >= 0 && !S_ISREG(sb.st_mode)) {
 190         ERR_raise_data(ERR_LIB_RAND, RAND_R_NOT_A_REGULAR_FILE,
 191                        "Filename=%s", file);
 192         return -1;
 193     }
 194 #endif
 195
 196     /* Collect enough random data. */
 197     if (RAND_priv_bytes(buf, (int)sizeof(buf)) != 1)
 198         return  -1;
 199
 200 #if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && \
 201     !defined(OPENSSL_SYS_VMS) && !defined(OPENSSL_SYS_WINDOWS)
 202     {
 203 # ifndef O_BINARY
 204 #  define O_BINARY 0
 205 # endif
 206         /*
 207          * chmod(..., 0600) is too late to protect the file, permissions
 208          * should be restrictive from the start
 209          */
 210         int fd = open(file, O_WRONLY | O_CREAT | O_BINARY, 0600);
 211         if (fd != -1)
 212             out = fdopen(fd, "wb");
 213     }
 214 #endif
 215
 216 #ifdef OPENSSL_SYS_VMS
 217     /*
 218      * VMS NOTE: Prior versions of this routine created a _new_ version of
 219      * the rand file for each call into this routine, then deleted all
 220      * existing versions named ;-1, and finally renamed the current version
 221      * as ';1'. Under concurrent usage, this resulted in an RMS race
 222      * condition in rename() which could orphan files (see vms message help
 223      * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares
 224      * the top-level version of the rand file. Note that there may still be
 225      * conditions where the top-level rand file is locked. If so, this code
 226      * will then create a new version of the rand file. Without the delete
 227      * and rename code, this can result in ascending file versions that stop
 228      * at version 32767, and this routine will then return an error. The
 229      * remedy for this is to recode the calling application to avoid
 230      * concurrent use of the rand file, or synchronize usage at the
 231      * application level. Also consider whether or not you NEED a persistent
 232      * rand file in a concurrent use situation.
 233      */
 234     out = openssl_fopen(file, "rb+");
 235 #endif
 236
 237     if (out == NULL)
 238         out = openssl_fopen(file, "wb");
 239     if (out == NULL) {
 240         ERR_raise_data(ERR_LIB_RAND, RAND_R_CANNOT_OPEN_FILE,
 241                        "Filename=%s", file);
 242         return -1;
 243     }
 244
 245 #if !defined(NO_CHMOD) && !defined(OPENSSL_NO_POSIX_IO)
 246     /*
 247      * Yes it's late to do this (see above comment), but better than nothing.
 248      */
 249     chmod(file, 0600);
 250 #endif
 251
 252     ret = fwrite(buf, 1, RAND_BUF_SIZE, out);
 253     fclose(out);
 254     OPENSSL_cleanse(buf, RAND_BUF_SIZE);
 255     return ret;
 256 }
 257
 258 const char *RAND_file_name(char *buf, size_t size)
 259 {
 260     char *s = NULL;
 261     size_t len;
 262     int use_randfile = 1;
 263
 264 #if defined(_WIN32) && defined(CP_UTF8) && !defined(_WIN32_WCE)
 265     DWORD envlen;
 266     WCHAR *var;
 267
 268     /* Look up various environment variables. */
 269     if ((envlen = GetEnvironmentVariableW(var = L"RANDFILE", NULL, 0)) == 0) {
 270         use_randfile = 0;
 271         if ((envlen = GetEnvironmentVariableW(var = L"HOME", NULL, 0)) == 0
 272                 && (envlen = GetEnvironmentVariableW(var = L"USERPROFILE",
 273                                                   NULL, 0)) == 0)
 274             envlen = GetEnvironmentVariableW(var = L"SYSTEMROOT", NULL, 0);
 275     }
 276
 277     /* If we got a value, allocate space to hold it and then get it. */
 278     if (envlen != 0) {
 279         int sz;
 280         WCHAR *val = _alloca(envlen * sizeof(WCHAR));
 281
 282         if (GetEnvironmentVariableW(var, val, envlen) < envlen
 283                 && (sz = WideCharToMultiByte(CP_UTF8, 0, val, -1, NULL, 0,
 284                                              NULL, NULL)) != 0) {
 285             s = _alloca(sz);
 286             if (WideCharToMultiByte(CP_UTF8, 0, val, -1, s, sz,
 287                                     NULL, NULL) == 0)
 288                 s = NULL;
 289         }
 290     }
 291 #else
 292     if ((s = ossl_safe_getenv("RANDFILE")) == NULL || *s == '\0') {
 293         use_randfile = 0;
 294         s = ossl_safe_getenv("HOME");
 295     }
 296 #endif
 297
 298 #ifdef DEFAULT_HOME
 299     if (!use_randfile && s == NULL)
 300         s = DEFAULT_HOME;
 301 #endif
 302     if (s == NULL || *s == '\0')
 303         return NULL;
 304
 305     len = strlen(s);
 306     if (use_randfile) {
 307         if (len + 1 >= size)
 308             return NULL;
 309         strcpy(buf, s);
 310     } else {
 311         if (len + 1 + strlen(RFILE) + 1 >= size)
 312             return NULL;
 313         strcpy(buf, s);
 314 #ifndef OPENSSL_SYS_VMS
 315         strcat(buf, "/");
 316 #endif
 317         strcat(buf, RFILE);
 318     }
 319
 320     return buf;
 321 }