* http://man.openbsd.org/getentropy.2
*/
-#include <TargetConditionals.h>
-#include <sys/types.h>
-#include <sys/param.h>
-#include <sys/ioctl.h>
-#include <sys/resource.h>
-#include <sys/syscall.h>
-#include <sys/sysctl.h>
-#include <sys/statvfs.h>
-#include <sys/socket.h>
-#include <sys/mount.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <sys/time.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <termios.h>
-#include <fcntl.h>
-#include <signal.h>
-#include <string.h>
#include <errno.h>
-#include <unistd.h>
-#include <time.h>
-#include <mach/mach_time.h>
-#include <mach/mach_host.h>
-#include <mach/host_info.h>
-#if TARGET_OS_OSX
-#include <sys/socketvar.h>
-#include <sys/vmmeter.h>
-#endif
-#include <netinet/in.h>
-#include <netinet/tcp.h>
-#if TARGET_OS_OSX
-#include <netinet/udp.h>
-#include <netinet/ip_var.h>
-#include <netinet/tcp_var.h>
-#include <netinet/udp_var.h>
-#endif
-#include <CommonCrypto/CommonDigest.h>
-#define SHA512_Update(a, b, c) (CC_SHA512_Update((a), (b), (c)))
-#define SHA512_Init(xxx) (CC_SHA512_Init((xxx)))
-#define SHA512_Final(xxx, yyy) (CC_SHA512_Final((xxx), (yyy)))
-#define SHA512_CTX CC_SHA512_CTX
-#define SHA512_DIGEST_LENGTH CC_SHA512_DIGEST_LENGTH
-
-#define REPEAT 5
-#define min(a, b) (((a) < (b)) ? (a) : (b))
-
-#define HX(a, b) \
- do { \
- if ((a)) \
- HD(errno); \
- else \
- HD(b); \
- } while (0)
-
-#define HR(x, l) (SHA512_Update(&ctx, (char *)(x), (l)))
-#define HD(x) (SHA512_Update(&ctx, (char *)&(x), sizeof (x)))
-#define HF(x) (SHA512_Update(&ctx, (char *)&(x), sizeof (void*)))
+#include <Security/SecRandom.h>
int getentropy(void *buf, size_t len);
-static int getentropy_urandom(void *buf, size_t len);
-static int getentropy_fallback(void *buf, size_t len);
-
int
getentropy(void *buf, size_t len)
{
- int ret = -1;
-
if (len > 256) {
- errno = EIO;
- return (-1);
- }
-
- /*
- * Try to get entropy with /dev/urandom
- *
- * This can fail if the process is inside a chroot or if file
- * descriptors are exhausted.
- */
- ret = getentropy_urandom(buf, len);
- if (ret != -1)
- return (ret);
-
- /*
- * Entropy collection via /dev/urandom and sysctl have failed.
- *
- * No other API exists for collecting entropy, and we have
- * no failsafe way to get it on OSX that is not sensitive
- * to resource exhaustion.
- *
- * We have very few options:
- * - Even syslog_r is unsafe to call at this low level, so
- * there is no way to alert the user or program.
- * - Cannot call abort() because some systems have unsafe
- * corefiles.
- * - Could raise(SIGKILL) resulting in silent program termination.
- * - Return EIO, to hint that arc4random's stir function
- * should raise(SIGKILL)
- * - Do the best under the circumstances....
- *
- * This code path exists to bring light to the issue that OSX
- * does not provide a failsafe API for entropy collection.
- *
- * We hope this demonstrates that OSX should consider
- * providing a new failsafe API which works in a chroot or
- * when file descriptors are exhausted.
- */
-#undef FAIL_INSTEAD_OF_TRYING_FALLBACK
-#ifdef FAIL_INSTEAD_OF_TRYING_FALLBACK
- raise(SIGKILL);
-#endif
- ret = getentropy_fallback(buf, len);
- if (ret != -1)
- return (ret);
-
- errno = EIO;
- return (ret);
-}
-
-static int
-getentropy_urandom(void *buf, size_t len)
-{
- struct stat st;
- size_t i;
- int fd, flags;
- int save_errno = errno;
-
-start:
-
- flags = O_RDONLY;
-#ifdef O_NOFOLLOW
- flags |= O_NOFOLLOW;
-#endif
-#ifdef O_CLOEXEC
- flags |= O_CLOEXEC;
-#endif
- fd = open("/dev/urandom", flags, 0);
- if (fd == -1) {
- if (errno == EINTR)
- goto start;
- goto nodevrandom;
+ goto error;
}
-#ifndef O_CLOEXEC
- fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
-#endif
- /* Lightly verify that the device node looks sane */
- if (fstat(fd, &st) == -1 || !S_ISCHR(st.st_mode)) {
- close(fd);
- goto nodevrandom;
+ if (SecRandomCopyBytes(kSecRandomDefault, len, buf) == errSecSuccess) {
+ return 0;
}
- for (i = 0; i < len; ) {
- size_t wanted = len - i;
- ssize_t ret = read(fd, (char *)buf + i, wanted);
- if (ret == -1) {
- if (errno == EAGAIN || errno == EINTR)
- continue;
- close(fd);
- goto nodevrandom;
- }
- i += ret;
- }
- close(fd);
- errno = save_errno;
- return (0); /* satisfied */
-nodevrandom:
+error:
errno = EIO;
- return (-1);
-}
-
-#if TARGET_OS_OSX
-static int tcpmib[] = { CTL_NET, AF_INET, IPPROTO_TCP, TCPCTL_STATS };
-static int udpmib[] = { CTL_NET, AF_INET, IPPROTO_UDP, UDPCTL_STATS };
-static int ipmib[] = { CTL_NET, AF_INET, IPPROTO_IP, IPCTL_STATS };
-#endif
-static int kmib[] = { CTL_KERN, KERN_USRSTACK };
-static int hwmib[] = { CTL_HW, HW_USERMEM };
-
-static int
-getentropy_fallback(void *buf, size_t len)
-{
- uint8_t results[SHA512_DIGEST_LENGTH];
- int save_errno = errno, e, pgs = getpagesize(), faster = 0, repeat;
- static int cnt;
- struct timespec ts;
- struct timeval tv;
- struct rusage ru;
- sigset_t sigset;
- struct stat st;
- SHA512_CTX ctx;
- static pid_t lastpid;
- pid_t pid;
- size_t i, ii, m;
- char *p;
-#if TARGET_OS_OSX
- struct tcpstat tcpstat;
- struct udpstat udpstat;
- struct ipstat ipstat;
-#endif
- u_int64_t mach_time;
- unsigned int idata;
- void *addr;
-
- pid = getpid();
- if (lastpid == pid) {
- faster = 1;
- repeat = 2;
- } else {
- faster = 0;
- lastpid = pid;
- repeat = REPEAT;
- }
- for (i = 0; i < len; ) {
- int j;
- SHA512_Init(&ctx);
- for (j = 0; j < repeat; j++) {
- HX((e = gettimeofday(&tv, NULL)) == -1, tv);
- if (e != -1) {
- cnt += (int)tv.tv_sec;
- cnt += (int)tv.tv_usec;
- }
-
- mach_time = mach_absolute_time();
- HD(mach_time);
-
- ii = sizeof(addr);
- HX(sysctl(kmib, sizeof(kmib) / sizeof(kmib[0]),
- &addr, &ii, NULL, 0) == -1, addr);
-
- ii = sizeof(idata);
- HX(sysctl(hwmib, sizeof(hwmib) / sizeof(hwmib[0]),
- &idata, &ii, NULL, 0) == -1, idata);
-
-#if TARGET_OS_OSX
- ii = sizeof(tcpstat);
- HX(sysctl(tcpmib, sizeof(tcpmib) / sizeof(tcpmib[0]),
- &tcpstat, &ii, NULL, 0) == -1, tcpstat);
-
- ii = sizeof(udpstat);
- HX(sysctl(udpmib, sizeof(udpmib) / sizeof(udpmib[0]),
- &udpstat, &ii, NULL, 0) == -1, udpstat);
-
- ii = sizeof(ipstat);
- HX(sysctl(ipmib, sizeof(ipmib) / sizeof(ipmib[0]),
- &ipstat, &ii, NULL, 0) == -1, ipstat);
-#endif
-
- HX((pid = getpid()) == -1, pid);
- HX((pid = getsid(pid)) == -1, pid);
- HX((pid = getppid()) == -1, pid);
- HX((pid = getpgid(0)) == -1, pid);
- HX((e = getpriority(0, 0)) == -1, e);
-
- if (!faster) {
- ts.tv_sec = 0;
- ts.tv_nsec = 1;
- (void) nanosleep(&ts, NULL);
- }
-
- HX(sigpending(&sigset) == -1, sigset);
- HX(sigprocmask(SIG_BLOCK, NULL, &sigset) == -1,
- sigset);
-
- HF(getentropy); /* an addr in this library */
- HF(printf); /* an addr in libc */
- p = (char *)&p;
- HD(p); /* an addr on stack */
- p = (char *)&errno;
- HD(p); /* the addr of errno */
-
- if (i == 0) {
- struct sockaddr_storage ss;
- struct statvfs stvfs;
- struct termios tios;
- struct statfs stfs;
- socklen_t ssl;
- off_t off;
-
- /*
- * Prime-sized mappings encourage fragmentation;
- * thus exposing some address entropy.
- */
- struct mm {
- size_t npg;
- void *p;
- } mm[] = {
- { 17, MAP_FAILED }, { 3, MAP_FAILED },
- { 11, MAP_FAILED }, { 2, MAP_FAILED },
- { 5, MAP_FAILED }, { 3, MAP_FAILED },
- { 7, MAP_FAILED }, { 1, MAP_FAILED },
- { 57, MAP_FAILED }, { 3, MAP_FAILED },
- { 131, MAP_FAILED }, { 1, MAP_FAILED },
- };
-
- for (m = 0; m < sizeof mm/sizeof(mm[0]); m++) {
- HX(mm[m].p = mmap(NULL,
- mm[m].npg * pgs,
- PROT_READ|PROT_WRITE,
- MAP_PRIVATE|MAP_ANON, -1,
- (off_t)0), mm[m].p);
- if (mm[m].p != MAP_FAILED) {
- size_t mo;
-
- /* Touch some memory... */
- p = mm[m].p;
- mo = cnt %
- (mm[m].npg * pgs - 1);
- p[mo] = 1;
- cnt += (int)((long)(mm[m].p)
- / pgs);
- }
-
- /* Check cnts and times... */
- mach_time = mach_absolute_time();
- HD(mach_time);
- cnt += (int)mach_time;
-
- HX((e = getrusage(RUSAGE_SELF,
- &ru)) == -1, ru);
- if (e != -1) {
- cnt += (int)ru.ru_utime.tv_sec;
- cnt += (int)ru.ru_utime.tv_usec;
- }
- }
-
- for (m = 0; m < sizeof mm/sizeof(mm[0]); m++) {
- if (mm[m].p != MAP_FAILED)
- munmap(mm[m].p, mm[m].npg * pgs);
- mm[m].p = MAP_FAILED;
- }
-
- HX(stat(".", &st) == -1, st);
- HX(statvfs(".", &stvfs) == -1, stvfs);
- HX(statfs(".", &stfs) == -1, stfs);
-
- HX(stat("/", &st) == -1, st);
- HX(statvfs("/", &stvfs) == -1, stvfs);
- HX(statfs("/", &stfs) == -1, stfs);
-
- HX((e = fstat(0, &st)) == -1, st);
- if (e == -1) {
- if (S_ISREG(st.st_mode) ||
- S_ISFIFO(st.st_mode) ||
- S_ISSOCK(st.st_mode)) {
- HX(fstatvfs(0, &stvfs) == -1,
- stvfs);
- HX(fstatfs(0, &stfs) == -1,
- stfs);
- HX((off = lseek(0, (off_t)0,
- SEEK_CUR)) < 0, off);
- }
- if (S_ISCHR(st.st_mode)) {
- HX(tcgetattr(0, &tios) == -1,
- tios);
- } else if (S_ISSOCK(st.st_mode)) {
- memset(&ss, 0, sizeof ss);
- ssl = sizeof(ss);
- HX(getpeername(0,
- (void *)&ss, &ssl) == -1,
- ss);
- }
- }
-
- HX((e = getrusage(RUSAGE_CHILDREN,
- &ru)) == -1, ru);
- if (e != -1) {
- cnt += (int)ru.ru_utime.tv_sec;
- cnt += (int)ru.ru_utime.tv_usec;
- }
- } else {
- /* Subsequent hashes absorb previous result */
- HD(results);
- }
-
- HX((e = gettimeofday(&tv, NULL)) == -1, tv);
- if (e != -1) {
- cnt += (int)tv.tv_sec;
- cnt += (int)tv.tv_usec;
- }
-
- HD(cnt);
- }
-
- SHA512_Final(results, &ctx);
- memcpy((char *)buf + i, results, min(sizeof(results), len - i));
- i += min(sizeof(results), len - i);
- }
- explicit_bzero(&ctx, sizeof ctx);
- explicit_bzero(results, sizeof results);
- errno = save_errno;
- return (0); /* satisfied */
+ return -1;
}
projects / thirdparty / unbound.git / commitdiff
