randfile.c 9.73 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329
/* crypto/rand/randfile.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

/* We need to define this to get macros like S_IFBLK and S_IFCHR */
#if !defined(OPENSSL_SYS_VXWORKS)
#define _XOPEN_SOURCE 500
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "e_os.h"
#include <openssl/crypto.h>
#include <openssl/rand.h>
#include <openssl/buffer.h>

#ifdef OPENSSL_SYS_VMS
#include <unixio.h>
#endif
#ifndef NO_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifndef OPENSSL_NO_POSIX_IO
# include <sys/stat.h>
# include <fcntl.h>
#endif

#ifdef _WIN32
#define stat	_stat
#define chmod	_chmod
#define open	_open
#define fdopen	_fdopen
#endif

#undef BUFSIZE
#define BUFSIZE	1024
#define RAND_DATA 1024

#ifdef OPENSSL_SYS_VMS
/* This declaration is a nasty hack to get around vms' extension to fopen
 * for passing in sharing options being disabled by our /STANDARD=ANSI89 */
static FILE *(*const vms_fopen)(const char *, const char *, ...) =
    (FILE *(*)(const char *, const char *, ...))fopen;
#define VMS_OPEN_ATTRS "shr=get,put,upd,del","ctx=bin,stm","rfm=stm","rat=none","mrs=0"
#endif

/* #define RFILE ".rnd" - defined in ../../e_os.h */

/* Note that these functions are intended for seed files only.
 * Entropy devices and EGD sockets are handled in rand_unix.c */

int RAND_load_file(const char *file, long bytes)
	{
	/* If bytes >= 0, read up to 'bytes' bytes.
	 * if bytes == -1, read complete file. */

	MS_STATIC unsigned char buf[BUFSIZE];
#ifndef OPENSSL_NO_POSIX_IO
	struct stat sb;
#endif
	int i,ret=0,n;
	FILE *in;

	if (file == NULL) return(0);

#ifndef OPENSSL_NO_POSIX_IO
#ifdef PURIFY
	/* struct stat can have padding and unused fields that may not be
	 * initialized in the call to stat(). We need to clear the entire
	 * structure before calling RAND_add() to avoid complaints from
	 * applications such as Valgrind.
	 */
	memset(&sb, 0, sizeof(sb));
#endif
	if (stat(file,&sb) < 0) return(0);
	RAND_add(&sb,sizeof(sb),0.0);
#endif
	if (bytes == 0) return(ret);

#ifdef OPENSSL_SYS_VMS
	in=vms_fopen(file,"rb",VMS_OPEN_ATTRS);
#else
	in=fopen(file,"rb");
#endif
	if (in == NULL) goto err;
#if defined(S_IFBLK) && defined(S_IFCHR) && !defined(OPENSSL_NO_POSIX_IO)
	if (sb.st_mode & (S_IFBLK | S_IFCHR)) {
	  /* this file is a device. we don't want read an infinite number
	   * of bytes from a random device, nor do we want to use buffered
	   * I/O because we will waste system entropy. 
	   */
	  bytes = (bytes == -1) ? 2048 : bytes; /* ok, is 2048 enough? */
#ifndef OPENSSL_NO_SETVBUF_IONBF
	  setvbuf(in, NULL, _IONBF, 0); /* don't do buffered reads */
#endif /* ndef OPENSSL_NO_SETVBUF_IONBF */
	}
#endif
	for (;;)
		{
		if (bytes > 0)
			n = (bytes < BUFSIZE)?(int)bytes:BUFSIZE;
		else
			n = BUFSIZE;
		i=fread(buf,1,n,in);
		if (i <= 0) break;
#ifdef PURIFY
		RAND_add(buf,i,(double)i);
#else
		/* even if n != i, use the full array */
		RAND_add(buf,n,(double)i);
#endif
		ret+=i;
		if (bytes > 0)
			{
			bytes-=n;
			if (bytes <= 0) break;
			}
		}
	fclose(in);
	OPENSSL_cleanse(buf,BUFSIZE);
err:
	return(ret);
	}

int RAND_write_file(const char *file)
	{
	unsigned char buf[BUFSIZE];
	int i,ret=0,rand_err=0;
	FILE *out = NULL;
	int n;
#ifndef OPENSSL_NO_POSIX_IO
	struct stat sb;
	
	i=stat(file,&sb);
	if (i != -1) { 
#if defined(S_ISBLK) && defined(S_ISCHR)
	  if (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode)) {
	    /* this file is a device. we don't write back to it. 
	     * we "succeed" on the assumption this is some sort 
	     * of random device. Otherwise attempting to write to 
	     * and chmod the device causes problems.
	     */
	    return(1); 
	  }
#endif
	}
#endif

#if defined(O_CREAT) && !defined(OPENSSL_NO_POSIX_IO) && !defined(OPENSSL_SYS_VMS)
	{
#ifndef O_BINARY
#define O_BINARY 0
#endif
	/* chmod(..., 0600) is too late to protect the file,
	 * permissions should be restrictive from the start */
	int fd = open(file, O_WRONLY|O_CREAT|O_BINARY, 0600);
	if (fd != -1)
		out = fdopen(fd, "wb");
	}
#endif

#ifdef OPENSSL_SYS_VMS
	/* VMS NOTE: Prior versions of this routine created a _new_
	 * version of the rand file for each call into this routine, then
	 * deleted all existing versions named ;-1, and finally renamed
	 * the current version as ';1'. Under concurrent usage, this
	 * resulted in an RMS race condition in rename() which could
	 * orphan files (see vms message help for RMS$_REENT). With the
	 * fopen() calls below, openssl/VMS now shares the top-level
	 * version of the rand file. Note that there may still be
	 * conditions where the top-level rand file is locked. If so, this
	 * code will then create a new version of the rand file. Without
	 * the delete and rename code, this can result in ascending file
	 * versions that stop at version 32767, and this routine will then
	 * return an error. The remedy for this is to recode the calling
	 * application to avoid concurrent use of the rand file, or
	 * synchronize usage at the application level. Also consider
	 * whether or not you NEED a persistent rand file in a concurrent
	 * use situation. 
	 */

	out = vms_fopen(file,"rb+",VMS_OPEN_ATTRS);
	if (out == NULL)
		out = vms_fopen(file,"wb",VMS_OPEN_ATTRS);
#else
	if (out == NULL)
		out = fopen(file,"wb");
#endif
	if (out == NULL) goto err;

#ifndef NO_CHMOD
	chmod(file,0600);
#endif
	n=RAND_DATA;
	for (;;)
		{
		i=(n > BUFSIZE)?BUFSIZE:n;
		n-=BUFSIZE;
		if (RAND_bytes(buf,i) <= 0)
			rand_err=1;
		i=fwrite(buf,1,i,out);
		if (i <= 0)
			{
			ret=0;
			break;
			}
		ret+=i;
		if (n <= 0) break;
                }

	fclose(out);
	OPENSSL_cleanse(buf,BUFSIZE);
err:
	return (rand_err ? -1 : ret);
	}

const char *RAND_file_name(char *buf, size_t size)
	{
	char *s=NULL;
#ifdef __OpenBSD__
	struct stat sb;
#endif

	if (OPENSSL_issetugid() == 0)
		s=getenv("RANDFILE");
	if (s != NULL && *s && strlen(s) + 1 < size)
		{
		if (BUF_strlcpy(buf,s,size) >= size)
			return NULL;
		}
	else
		{
		if (OPENSSL_issetugid() == 0)
			s=getenv("HOME");
#ifdef DEFAULT_HOME
		if (s == NULL)
			{
			s = DEFAULT_HOME;
			}
#endif
		if (s && *s && strlen(s)+strlen(RFILE)+2 < size)
			{
			BUF_strlcpy(buf,s,size);
#ifndef OPENSSL_SYS_VMS
			BUF_strlcat(buf,"/",size);
#endif
			BUF_strlcat(buf,RFILE,size);
			}
		else
		  	buf[0] = '\0'; /* no file name */
		}

#ifdef __OpenBSD__
	/* given that all random loads just fail if the file can't be 
	 * seen on a stat, we stat the file we're returning, if it
	 * fails, use /dev/arandom instead. this allows the user to 
	 * use their own source for good random data, but defaults
	 * to something hopefully decent if that isn't available. 
	 */

	if (!buf[0])
		if (BUF_strlcpy(buf,"/dev/arandom",size) >= size) {
			return(NULL);
		}	
	if (stat(buf,&sb) == -1)
		if (BUF_strlcpy(buf,"/dev/arandom",size) >= size) {
			return(NULL);
		}	

#endif
	return(buf);
	}