1/*
2 * Copyright 1995-2020 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/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# if defined(_WIN32) && !defined(_WIN32_WCE)
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 */
64static __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 */
76int 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
174int 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
251const 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}
315