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path: root/src/lib/libcrypto/crypto/getentropy_osx.c
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Diffstat (limited to 'src/lib/libcrypto/crypto/getentropy_osx.c')
-rw-r--r--src/lib/libcrypto/crypto/getentropy_osx.c429
1 files changed, 0 insertions, 429 deletions
diff --git a/src/lib/libcrypto/crypto/getentropy_osx.c b/src/lib/libcrypto/crypto/getentropy_osx.c
deleted file mode 100644
index c5bbb7e338..0000000000
--- a/src/lib/libcrypto/crypto/getentropy_osx.c
+++ /dev/null
@@ -1,429 +0,0 @@
1/* $OpenBSD: getentropy_osx.c,v 1.10 2016/08/07 03:27:21 tb Exp $ */
2
3/*
4 * Copyright (c) 2014 Theo de Raadt <deraadt@openbsd.org>
5 * Copyright (c) 2014 Bob Beck <beck@obtuse.com>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 *
19 * Emulation of getentropy(2) as documented at:
20 * http://man.openbsd.org/getentropy.2
21 */
22
23#include <sys/types.h>
24#include <sys/param.h>
25#include <sys/ioctl.h>
26#include <sys/resource.h>
27#include <sys/syscall.h>
28#include <sys/sysctl.h>
29#include <sys/statvfs.h>
30#include <sys/socket.h>
31#include <sys/mount.h>
32#include <sys/mman.h>
33#include <sys/stat.h>
34#include <sys/time.h>
35#include <stdlib.h>
36#include <stdint.h>
37#include <stdio.h>
38#include <termios.h>
39#include <fcntl.h>
40#include <signal.h>
41#include <string.h>
42#include <errno.h>
43#include <unistd.h>
44#include <time.h>
45#include <mach/mach_time.h>
46#include <mach/mach_host.h>
47#include <mach/host_info.h>
48#include <sys/socketvar.h>
49#include <sys/vmmeter.h>
50#include <netinet/in.h>
51#include <netinet/tcp.h>
52#include <netinet/udp.h>
53#include <netinet/ip_var.h>
54#include <netinet/tcp_var.h>
55#include <netinet/udp_var.h>
56#include <CommonCrypto/CommonDigest.h>
57#define SHA512_Update(a, b, c) (CC_SHA512_Update((a), (b), (c)))
58#define SHA512_Init(xxx) (CC_SHA512_Init((xxx)))
59#define SHA512_Final(xxx, yyy) (CC_SHA512_Final((xxx), (yyy)))
60#define SHA512_CTX CC_SHA512_CTX
61#define SHA512_DIGEST_LENGTH CC_SHA512_DIGEST_LENGTH
62
63#define REPEAT 5
64#define min(a, b) (((a) < (b)) ? (a) : (b))
65
66#define HX(a, b) \
67 do { \
68 if ((a)) \
69 HD(errno); \
70 else \
71 HD(b); \
72 } while (0)
73
74#define HR(x, l) (SHA512_Update(&ctx, (char *)(x), (l)))
75#define HD(x) (SHA512_Update(&ctx, (char *)&(x), sizeof (x)))
76#define HF(x) (SHA512_Update(&ctx, (char *)&(x), sizeof (void*)))
77
78int getentropy(void *buf, size_t len);
79
80static int gotdata(char *buf, size_t len);
81static int getentropy_urandom(void *buf, size_t len);
82static int getentropy_fallback(void *buf, size_t len);
83
84int
85getentropy(void *buf, size_t len)
86{
87 int ret = -1;
88
89 if (len > 256) {
90 errno = EIO;
91 return (-1);
92 }
93
94 /*
95 * Try to get entropy with /dev/urandom
96 *
97 * This can fail if the process is inside a chroot or if file
98 * descriptors are exhausted.
99 */
100 ret = getentropy_urandom(buf, len);
101 if (ret != -1)
102 return (ret);
103
104 /*
105 * Entropy collection via /dev/urandom and sysctl have failed.
106 *
107 * No other API exists for collecting entropy, and we have
108 * no failsafe way to get it on OSX that is not sensitive
109 * to resource exhaustion.
110 *
111 * We have very few options:
112 * - Even syslog_r is unsafe to call at this low level, so
113 * there is no way to alert the user or program.
114 * - Cannot call abort() because some systems have unsafe
115 * corefiles.
116 * - Could raise(SIGKILL) resulting in silent program termination.
117 * - Return EIO, to hint that arc4random's stir function
118 * should raise(SIGKILL)
119 * - Do the best under the circumstances....
120 *
121 * This code path exists to bring light to the issue that OSX
122 * does not provide a failsafe API for entropy collection.
123 *
124 * We hope this demonstrates that OSX should consider
125 * providing a new failsafe API which works in a chroot or
126 * when file descriptors are exhausted.
127 */
128#undef FAIL_INSTEAD_OF_TRYING_FALLBACK
129#ifdef FAIL_INSTEAD_OF_TRYING_FALLBACK
130 raise(SIGKILL);
131#endif
132 ret = getentropy_fallback(buf, len);
133 if (ret != -1)
134 return (ret);
135
136 errno = EIO;
137 return (ret);
138}
139
140/*
141 * Basic sanity checking; wish we could do better.
142 */
143static int
144gotdata(char *buf, size_t len)
145{
146 char any_set = 0;
147 size_t i;
148
149 for (i = 0; i < len; ++i)
150 any_set |= buf[i];
151 if (any_set == 0)
152 return (-1);
153 return (0);
154}
155
156static int
157getentropy_urandom(void *buf, size_t len)
158{
159 struct stat st;
160 size_t i;
161 int fd, flags;
162 int save_errno = errno;
163
164start:
165
166 flags = O_RDONLY;
167#ifdef O_NOFOLLOW
168 flags |= O_NOFOLLOW;
169#endif
170#ifdef O_CLOEXEC
171 flags |= O_CLOEXEC;
172#endif
173 fd = open("/dev/urandom", flags, 0);
174 if (fd == -1) {
175 if (errno == EINTR)
176 goto start;
177 goto nodevrandom;
178 }
179#ifndef O_CLOEXEC
180 fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
181#endif
182
183 /* Lightly verify that the device node looks sane */
184 if (fstat(fd, &st) == -1 || !S_ISCHR(st.st_mode)) {
185 close(fd);
186 goto nodevrandom;
187 }
188 for (i = 0; i < len; ) {
189 size_t wanted = len - i;
190 ssize_t ret = read(fd, (char *)buf + i, wanted);
191
192 if (ret == -1) {
193 if (errno == EAGAIN || errno == EINTR)
194 continue;
195 close(fd);
196 goto nodevrandom;
197 }
198 i += ret;
199 }
200 close(fd);
201 if (gotdata(buf, len) == 0) {
202 errno = save_errno;
203 return (0); /* satisfied */
204 }
205nodevrandom:
206 errno = EIO;
207 return (-1);
208}
209
210static int tcpmib[] = { CTL_NET, AF_INET, IPPROTO_TCP, TCPCTL_STATS };
211static int udpmib[] = { CTL_NET, AF_INET, IPPROTO_UDP, UDPCTL_STATS };
212static int ipmib[] = { CTL_NET, AF_INET, IPPROTO_IP, IPCTL_STATS };
213static int kmib[] = { CTL_KERN, KERN_USRSTACK };
214static int hwmib[] = { CTL_HW, HW_USERMEM };
215
216static int
217getentropy_fallback(void *buf, size_t len)
218{
219 uint8_t results[SHA512_DIGEST_LENGTH];
220 int save_errno = errno, e, pgs = getpagesize(), faster = 0, repeat;
221 static int cnt;
222 struct timespec ts;
223 struct timeval tv;
224 struct rusage ru;
225 sigset_t sigset;
226 struct stat st;
227 SHA512_CTX ctx;
228 static pid_t lastpid;
229 pid_t pid;
230 size_t i, ii, m;
231 char *p;
232 struct tcpstat tcpstat;
233 struct udpstat udpstat;
234 struct ipstat ipstat;
235 u_int64_t mach_time;
236 unsigned int idata;
237 void *addr;
238
239 pid = getpid();
240 if (lastpid == pid) {
241 faster = 1;
242 repeat = 2;
243 } else {
244 faster = 0;
245 lastpid = pid;
246 repeat = REPEAT;
247 }
248 for (i = 0; i < len; ) {
249 int j;
250 SHA512_Init(&ctx);
251 for (j = 0; j < repeat; j++) {
252 HX((e = gettimeofday(&tv, NULL)) == -1, tv);
253 if (e != -1) {
254 cnt += (int)tv.tv_sec;
255 cnt += (int)tv.tv_usec;
256 }
257
258 mach_time = mach_absolute_time();
259 HD(mach_time);
260
261 ii = sizeof(addr);
262 HX(sysctl(kmib, sizeof(kmib) / sizeof(kmib[0]),
263 &addr, &ii, NULL, 0) == -1, addr);
264
265 ii = sizeof(idata);
266 HX(sysctl(hwmib, sizeof(hwmib) / sizeof(hwmib[0]),
267 &idata, &ii, NULL, 0) == -1, idata);
268
269 ii = sizeof(tcpstat);
270 HX(sysctl(tcpmib, sizeof(tcpmib) / sizeof(tcpmib[0]),
271 &tcpstat, &ii, NULL, 0) == -1, tcpstat);
272
273 ii = sizeof(udpstat);
274 HX(sysctl(udpmib, sizeof(udpmib) / sizeof(udpmib[0]),
275 &udpstat, &ii, NULL, 0) == -1, udpstat);
276
277 ii = sizeof(ipstat);
278 HX(sysctl(ipmib, sizeof(ipmib) / sizeof(ipmib[0]),
279 &ipstat, &ii, NULL, 0) == -1, ipstat);
280
281 HX((pid = getpid()) == -1, pid);
282 HX((pid = getsid(pid)) == -1, pid);
283 HX((pid = getppid()) == -1, pid);
284 HX((pid = getpgid(0)) == -1, pid);
285 HX((e = getpriority(0, 0)) == -1, e);
286
287 if (!faster) {
288 ts.tv_sec = 0;
289 ts.tv_nsec = 1;
290 (void) nanosleep(&ts, NULL);
291 }
292
293 HX(sigpending(&sigset) == -1, sigset);
294 HX(sigprocmask(SIG_BLOCK, NULL, &sigset) == -1,
295 sigset);
296
297 HF(getentropy); /* an addr in this library */
298 HF(printf); /* an addr in libc */
299 p = (char *)&p;
300 HD(p); /* an addr on stack */
301 p = (char *)&errno;
302 HD(p); /* the addr of errno */
303
304 if (i == 0) {
305 struct sockaddr_storage ss;
306 struct statvfs stvfs;
307 struct termios tios;
308 struct statfs stfs;
309 socklen_t ssl;
310 off_t off;
311
312 /*
313 * Prime-sized mappings encourage fragmentation;
314 * thus exposing some address entropy.
315 */
316 struct mm {
317 size_t npg;
318 void *p;
319 } mm[] = {
320 { 17, MAP_FAILED }, { 3, MAP_FAILED },
321 { 11, MAP_FAILED }, { 2, MAP_FAILED },
322 { 5, MAP_FAILED }, { 3, MAP_FAILED },
323 { 7, MAP_FAILED }, { 1, MAP_FAILED },
324 { 57, MAP_FAILED }, { 3, MAP_FAILED },
325 { 131, MAP_FAILED }, { 1, MAP_FAILED },
326 };
327
328 for (m = 0; m < sizeof mm/sizeof(mm[0]); m++) {
329 HX(mm[m].p = mmap(NULL,
330 mm[m].npg * pgs,
331 PROT_READ|PROT_WRITE,
332 MAP_PRIVATE|MAP_ANON, -1,
333 (off_t)0), mm[m].p);
334 if (mm[m].p != MAP_FAILED) {
335 size_t mo;
336
337 /* Touch some memory... */
338 p = mm[m].p;
339 mo = cnt %
340 (mm[m].npg * pgs - 1);
341 p[mo] = 1;
342 cnt += (int)((long)(mm[m].p)
343 / pgs);
344 }
345
346 /* Check cnts and times... */
347 mach_time = mach_absolute_time();
348 HD(mach_time);
349 cnt += (int)mach_time;
350
351 HX((e = getrusage(RUSAGE_SELF,
352 &ru)) == -1, ru);
353 if (e != -1) {
354 cnt += (int)ru.ru_utime.tv_sec;
355 cnt += (int)ru.ru_utime.tv_usec;
356 }
357 }
358
359 for (m = 0; m < sizeof mm/sizeof(mm[0]); m++) {
360 if (mm[m].p != MAP_FAILED)
361 munmap(mm[m].p, mm[m].npg * pgs);
362 mm[m].p = MAP_FAILED;
363 }
364
365 HX(stat(".", &st) == -1, st);
366 HX(statvfs(".", &stvfs) == -1, stvfs);
367 HX(statfs(".", &stfs) == -1, stfs);
368
369 HX(stat("/", &st) == -1, st);
370 HX(statvfs("/", &stvfs) == -1, stvfs);
371 HX(statfs("/", &stfs) == -1, stfs);
372
373 HX((e = fstat(0, &st)) == -1, st);
374 if (e == -1) {
375 if (S_ISREG(st.st_mode) ||
376 S_ISFIFO(st.st_mode) ||
377 S_ISSOCK(st.st_mode)) {
378 HX(fstatvfs(0, &stvfs) == -1,
379 stvfs);
380 HX(fstatfs(0, &stfs) == -1,
381 stfs);
382 HX((off = lseek(0, (off_t)0,
383 SEEK_CUR)) < 0, off);
384 }
385 if (S_ISCHR(st.st_mode)) {
386 HX(tcgetattr(0, &tios) == -1,
387 tios);
388 } else if (S_ISSOCK(st.st_mode)) {
389 memset(&ss, 0, sizeof ss);
390 ssl = sizeof(ss);
391 HX(getpeername(0,
392 (void *)&ss, &ssl) == -1,
393 ss);
394 }
395 }
396
397 HX((e = getrusage(RUSAGE_CHILDREN,
398 &ru)) == -1, ru);
399 if (e != -1) {
400 cnt += (int)ru.ru_utime.tv_sec;
401 cnt += (int)ru.ru_utime.tv_usec;
402 }
403 } else {
404 /* Subsequent hashes absorb previous result */
405 HD(results);
406 }
407
408 HX((e = gettimeofday(&tv, NULL)) == -1, tv);
409 if (e != -1) {
410 cnt += (int)tv.tv_sec;
411 cnt += (int)tv.tv_usec;
412 }
413
414 HD(cnt);
415 }
416
417 SHA512_Final(results, &ctx);
418 memcpy((char *)buf + i, results, min(sizeof(results), len - i));
419 i += min(sizeof(results), len - i);
420 }
421 explicit_bzero(&ctx, sizeof ctx);
422 explicit_bzero(results, sizeof results);
423 if (gotdata(buf, len) == 0) {
424 errno = save_errno;
425 return (0); /* satisfied */
426 }
427 errno = EIO;
428 return (-1);
429}
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