randfile.c revision 296465
1/* crypto/rand/randfile.c */ 2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58 59/* We need to define this to get macros like S_IFBLK and S_IFCHR */ 60#define _XOPEN_SOURCE 500 61 62#include <errno.h> 63#include <stdio.h> 64#include <stdlib.h> 65#include <string.h> 66 67#include "e_os.h" 68#include <openssl/crypto.h> 69#include <openssl/rand.h> 70#include <openssl/buffer.h> 71 72#ifdef OPENSSL_SYS_VMS 73# include <unixio.h> 74#endif 75#ifndef NO_SYS_TYPES_H 76# include <sys/types.h> 77#endif 78#ifdef MAC_OS_pre_X 79# include <stat.h> 80#else 81# include <sys/stat.h> 82#endif 83 84#ifdef _WIN32 85# define stat _stat 86# define chmod _chmod 87# define open _open 88# define fdopen _fdopen 89#endif 90 91#undef BUFSIZE 92#define BUFSIZE 1024 93#define RAND_DATA 1024 94 95#ifdef OPENSSL_SYS_VMS 96/* 97 * This declaration is a nasty hack to get around vms' extension to fopen for 98 * passing in sharing options being disabled by our /STANDARD=ANSI89 99 */ 100static FILE *(*const vms_fopen)(const char *, const char *, ...) = 101 (FILE *(*)(const char *, const char *, ...))fopen; 102# define VMS_OPEN_ATTRS "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0" 103#endif 104 105/* #define RFILE ".rnd" - defined in ../../e_os.h */ 106 107/* 108 * Note that these functions are intended for seed files only. Entropy 109 * devices and EGD sockets are handled in rand_unix.c 110 */ 111 112int RAND_load_file(const char *file, long bytes) 113{ 114 /*- 115 * If bytes >= 0, read up to 'bytes' bytes. 116 * if bytes == -1, read complete file. 117 */ 118 119 MS_STATIC unsigned char buf[BUFSIZE]; 120 struct stat sb; 121 int i, ret = 0, n; 122 FILE *in; 123 124 if (file == NULL) 125 return (0); 126 127#ifdef PURIFY 128 /* 129 * struct stat can have padding and unused fields that may not be 130 * initialized in the call to stat(). We need to clear the entire 131 * structure before calling RAND_add() to avoid complaints from 132 * applications such as Valgrind. 133 */ 134 memset(&sb, 0, sizeof(sb)); 135#endif 136 137 if (stat(file, &sb) < 0) 138 return (0); 139 RAND_add(&sb, sizeof(sb), 0.0); 140 if (bytes == 0) 141 return (ret); 142 143#ifdef OPENSSL_SYS_VMS 144 in = vms_fopen(file, "rb", VMS_OPEN_ATTRS); 145#else 146 in = fopen(file, "rb"); 147#endif 148 if (in == NULL) 149 goto err; 150#if defined(S_ISBLK) && defined(S_ISCHR) 151 if (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode)) { 152 /* 153 * this file is a device. we don't want read an infinite number of 154 * bytes from a random device, nor do we want to use buffered I/O 155 * because we will waste system entropy. 156 */ 157 bytes = (bytes == -1) ? 2048 : bytes; /* ok, is 2048 enough? */ 158 setvbuf(in, NULL, _IONBF, 0); /* don't do buffered reads */ 159 } 160#endif 161 for (;;) { 162 if (bytes > 0) 163 n = (bytes < BUFSIZE) ? (int)bytes : BUFSIZE; 164 else 165 n = BUFSIZE; 166 i = fread(buf, 1, n, in); 167 if (i <= 0) 168 break; 169#ifdef PURIFY 170 RAND_add(buf, i, (double)i); 171#else 172 /* even if n != i, use the full array */ 173 RAND_add(buf, n, (double)i); 174#endif 175 ret += i; 176 if (bytes > 0) { 177 bytes -= n; 178 if (bytes <= 0) 179 break; 180 } 181 } 182 fclose(in); 183 OPENSSL_cleanse(buf, BUFSIZE); 184 err: 185 return (ret); 186} 187 188int RAND_write_file(const char *file) 189{ 190 unsigned char buf[BUFSIZE]; 191 int i, ret = 0, rand_err = 0; 192 FILE *out = NULL; 193 int n; 194 struct stat sb; 195 196 i = stat(file, &sb); 197 if (i != -1) { 198#if defined(S_ISBLK) && defined(S_ISCHR) 199 if (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode)) { 200 /* 201 * this file is a device. we don't write back to it. we 202 * "succeed" on the assumption this is some sort of random 203 * device. Otherwise attempting to write to and chmod the device 204 * causes problems. 205 */ 206 return (1); 207 } 208#endif 209 } 210#if defined(O_CREAT) && !defined(OPENSSL_SYS_WIN32) && !defined(OPENSSL_SYS_VMS) 211 { 212 /* For some reason Win32 can't write to files created this way */ 213 214 /* 215 * chmod(..., 0600) is too late to protect the file, permissions 216 * should be restrictive from the start 217 */ 218 int fd = open(file, O_CREAT, 0600); 219 if (fd != -1) 220 out = fdopen(fd, "wb"); 221 } 222#endif 223 224#ifdef OPENSSL_SYS_VMS 225 /* 226 * VMS NOTE: Prior versions of this routine created a _new_ version of 227 * the rand file for each call into this routine, then deleted all 228 * existing versions named ;-1, and finally renamed the current version 229 * as ';1'. Under concurrent usage, this resulted in an RMS race 230 * condition in rename() which could orphan files (see vms message help 231 * for RMS$_REENT). With the fopen() calls below, openssl/VMS now shares 232 * the top-level version of the rand file. Note that there may still be 233 * conditions where the top-level rand file is locked. If so, this code 234 * will then create a new version of the rand file. Without the delete 235 * and rename code, this can result in ascending file versions that stop 236 * at version 32767, and this routine will then return an error. The 237 * remedy for this is to recode the calling application to avoid 238 * concurrent use of the rand file, or synchronize usage at the 239 * application level. Also consider whether or not you NEED a persistent 240 * rand file in a concurrent use situation. 241 */ 242 243 out = vms_fopen(file, "rb+", VMS_OPEN_ATTRS); 244 if (out == NULL) 245 out = vms_fopen(file, "wb", VMS_OPEN_ATTRS); 246#else 247 if (out == NULL) 248 out = fopen(file, "wb"); 249#endif 250 if (out == NULL) 251 goto err; 252 253#ifndef NO_CHMOD 254 chmod(file, 0600); 255#endif 256 n = RAND_DATA; 257 for (;;) { 258 i = (n > BUFSIZE) ? BUFSIZE : n; 259 n -= BUFSIZE; 260 if (RAND_bytes(buf, i) <= 0) 261 rand_err = 1; 262 i = fwrite(buf, 1, i, out); 263 if (i <= 0) { 264 ret = 0; 265 break; 266 } 267 ret += i; 268 if (n <= 0) 269 break; 270 } 271 272 fclose(out); 273 OPENSSL_cleanse(buf, BUFSIZE); 274 err: 275 return (rand_err ? -1 : ret); 276} 277 278const char *RAND_file_name(char *buf, size_t size) 279{ 280 char *s = NULL; 281#ifdef __OpenBSD__ 282 int ok = 0; 283 struct stat sb; 284#endif 285 286 if (OPENSSL_issetugid() == 0) 287 s = getenv("RANDFILE"); 288 if (s != NULL && *s && strlen(s) + 1 < size) { 289 if (BUF_strlcpy(buf, s, size) >= size) 290 return NULL; 291 } else { 292 if (OPENSSL_issetugid() == 0) 293 s = getenv("HOME"); 294#ifdef DEFAULT_HOME 295 if (s == NULL) { 296 s = DEFAULT_HOME; 297 } 298#endif 299 if (s && *s && strlen(s) + strlen(RFILE) + 2 < size) { 300 BUF_strlcpy(buf, s, size); 301#ifndef OPENSSL_SYS_VMS 302 BUF_strlcat(buf, "/", size); 303#endif 304 BUF_strlcat(buf, RFILE, size); 305#ifdef __OpenBSD__ 306 ok = 1; 307#endif 308 } else 309 buf[0] = '\0'; /* no file name */ 310 } 311 312#ifdef __OpenBSD__ 313 /* 314 * given that all random loads just fail if the file can't be seen on a 315 * stat, we stat the file we're returning, if it fails, use /dev/arandom 316 * instead. this allows the user to use their own source for good random 317 * data, but defaults to something hopefully decent if that isn't 318 * available. 319 */ 320 321 if (!ok) 322 if (BUF_strlcpy(buf, "/dev/arandom", size) >= size) { 323 return (NULL); 324 } 325 if (stat(buf, &sb) == -1) 326 if (BUF_strlcpy(buf, "/dev/arandom", size) >= size) { 327 return (NULL); 328 } 329#endif 330 return (buf); 331} 332