TEST(sys_random, getentropy) {
#if defined(HAVE_SYS_RANDOM)
char buf1[64];
char buf2[64];
ASSERT_EQ(0, getentropy(buf1, sizeof(buf1)));
ASSERT_EQ(0, getentropy(buf2, sizeof(buf2)));
ASSERT_TRUE(memcmp(buf1, buf2, sizeof(buf1)) != 0);
#else
GTEST_SKIP() << "<sys/random.h> not available";
#endif
}
TEST(sys_random, getentropy) {
#if defined(HAVE_SYS_RANDOM)
char buf1[64];
char buf2[64];
ASSERT_EQ(0, getentropy(buf1, sizeof(buf1)));
ASSERT_EQ(0, getentropy(buf2, sizeof(buf2)));
ASSERT_TRUE(memcmp(buf1, buf2, sizeof(buf1)) != 0);
#else
GTEST_LOG_(INFO) << "This test requires a C library with <sys/random.h>.\n";
#endif
}
static int osrandom_rand_bytes(unsigned char *buffer, int size) {
int len;
int res;
switch(getentropy_works) {
#if defined(__APPLE__)
case CRYPTOGRAPHY_OSRANDOM_GETENTROPY_FALLBACK:
return dev_urandom_read(buffer, size);
#endif
case CRYPTOGRAPHY_OSRANDOM_GETENTROPY_WORKS:
while (size > 0) {
/* OpenBSD and macOS restrict maximum buffer size to 256. */
len = size > 256 ? 256 : size;
res = getentropy(buffer, (size_t)len);
if (res < 0) {
ERR_Cryptography_OSRandom_error(
CRYPTOGRAPHY_OSRANDOM_F_RAND_BYTES,
CRYPTOGRAPHY_OSRANDOM_R_GETENTROPY_FAILED,
__FILE__, __LINE__
);
return 0;
}
buffer += len;
size -= len;
}
return 1;
}
__builtin_unreachable();
}
static int li_getentropy (void *buf, size_t buflen)
{
#ifdef HAVE_GETENTROPY
return getentropy(buf, buflen);
#else
/*(see NOTES section in 'man getrandom' on Linux)*/
#if defined(HAVE_GETRANDOM) || defined(SYS_getrandom)
if (buflen <= 256) {
#ifdef HAVE_GETRANDOM /*(not implemented in glibc yet)*/
int num = getrandom(buf, buflen, 0);
#elif defined(SYS_getrandom)
/* https://lwn.net/Articles/605828/ */
/* https://bbs.archlinux.org/viewtopic.php?id=200039 */
int num = (int)syscall(SYS_getrandom, buf, buflen, 0);
#endif
if (num == (int)buflen) return 0;
if (num < 0) return num; /* -1 */
}
#else
UNUSED(buf);
UNUSED(buflen);
#endif
errno = EIO;
return -1;
#endif
}
static void
_rs_stir(void)
{
u_char rnd[KEYSZ + IVSZ];
if (getentropy(rnd, sizeof rnd) == -1) {
#ifdef SIGKILL
raise(SIGKILL);
#else
exit(9); /* windows */
#endif
}
if (!rs)
_rs_init(rnd, sizeof(rnd));
else
_rs_rekey(rnd, sizeof(rnd));
explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */
/* invalidate rs_buf */
rs->rs_have = 0;
memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
rs->rs_count = 1600000;
}
static int get(struct RandomSeed* randomSeed, uint64_t output[8])
{
if (getentropy(output, 64) < 0) {
return -1;
} else {
return 0;
}
}
TEST(sys_random, getentropy_EFAULT) {
#if defined(HAVE_SYS_RANDOM)
errno = 0;
ASSERT_EQ(-1, getentropy(nullptr, 1));
ASSERT_EQ(EFAULT, errno);
#else
GTEST_SKIP() << "<sys/random.h> not available";
#endif
}
TEST(sys_random, getentropy_EFAULT) {
#if defined(HAVE_SYS_RANDOM)
errno = 0;
ASSERT_EQ(-1, getentropy(nullptr, 1));
ASSERT_EQ(EFAULT, errno);
#else
GTEST_LOG_(INFO) << "This test requires a C library with <sys/random.h>.\n";
#endif
}
/*
* syscall_random(): Try to get random data using a system call
* returns the number of bytes returned in buf, or < 0 on error.
*/
static ssize_t syscall_random(void *buf, size_t buflen)
{
/*
* Note: 'buflen' equals the size of the buffer which is used by the
* get_entropy() callback of the RAND_DRBG. It is roughly bounded by
*
* 2 * RAND_POOL_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^14
*
* which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
* between size_t and ssize_t is safe even without a range check.
*/
/*
* Do runtime detection to find getentropy().
*
* Known OSs that should support this:
* - Darwin since 16 (OSX 10.12, IOS 10.0).
* - Solaris since 11.3
* - OpenBSD since 5.6
* - Linux since 3.17 with glibc 2.25
* - FreeBSD since 12.0 (1200061)
*/
# if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__) && !defined(__hpux)
extern int getentropy(void *buffer, size_t length) __attribute__((weak));
if (getentropy != NULL)
return getentropy(buf, buflen) == 0 ? (ssize_t)buflen : -1;
# else
union {
void *p;
int (*f)(void *buffer, size_t length);
} p_getentropy;
/*
* We could cache the result of the lookup, but we normally don't
* call this function often.
*/
ERR_set_mark();
p_getentropy.p = DSO_global_lookup("getentropy");
ERR_pop_to_mark();
if (p_getentropy.p != NULL)
return p_getentropy.f(buf, buflen) == 0 ? (ssize_t)buflen : -1;
# endif
/* Linux supports this since version 3.17 */
# if defined(__linux) && defined(SYS_getrandom)
return syscall(SYS_getrandom, buf, buflen, 0);
# elif (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
return sysctl_random(buf, buflen);
# else
errno = ENOSYS;
return -1;
# endif
}
TEST(sys_random, getentropy_EIO) {
#if defined(HAVE_SYS_RANDOM)
char buf[BUFSIZ];
static_assert(BUFSIZ > 256, "BUFSIZ <= 256!");
errno = 0;
ASSERT_EQ(-1, getentropy(buf, sizeof(buf)));
ASSERT_EQ(EIO, errno);
#else
GTEST_SKIP() << "<sys/random.h> not available";
#endif
}
TEST(sys_random, getentropy_EIO) {
#if defined(HAVE_SYS_RANDOM)
char buf[BUFSIZ];
static_assert(BUFSIZ > 256, "BUFSIZ <= 256!");
errno = 0;
ASSERT_EQ(-1, getentropy(buf, sizeof(buf)));
ASSERT_EQ(EIO, errno);
#else
GTEST_LOG_(INFO) << "This test requires a C library with <sys/random.h>.\n";
#endif
}
/** Generates a random vector of AUTH_VECTOR_LEN octets
*
* @param vector a buffer with at least %AUTH_VECTOR_LEN bytes.
*/
static void rc_random_vector (unsigned char *vector)
{
int randno;
int i;
#if defined(HAVE_GETENTROPY)
if (getentropy(vector, AUTH_VECTOR_LEN) >= 0) {
return;
} /* else fall through */
#elif defined(HAVE_DEV_URANDOM)
int fd;
/* well, I added this to increase the security for user passwords.
we use /dev/urandom here, as /dev/random might block and we don't
need that much randomness. BTW, great idea, Ted! -lf, 03/18/95 */
if ((fd = open(_PATH_DEV_URANDOM, O_RDONLY)) >= 0)
{
unsigned char *pos;
int readcount;
i = AUTH_VECTOR_LEN;
pos = vector;
while (i > 0)
{
readcount = read(fd, (char *)pos, i);
if (readcount >= 0) {
pos += readcount;
i -= readcount;
} else {
if (errno != EINTR && errno != EAGAIN)
goto fallback;
}
}
close(fd);
return;
} /* else fall through */
#endif
fallback:
for (i = 0; i < AUTH_VECTOR_LEN;)
{
randno = random ();
memcpy ((char *) vector, (char *) &randno, sizeof (int));
vector += sizeof (int);
i += sizeof (int);
}
return;
}
/*
* syscall_random(): Try to get random data using a system call
* returns the number of bytes returned in buf, or <= 0 on error.
*/
int syscall_random(void *buf, size_t buflen)
{
/*
* Do runtime detection to find getentropy().
*
* Known OSs that should support this:
* - Darwin since 16 (OSX 10.12, IOS 10.0).
* - Solaris since 11.3
* - OpenBSD since 5.6
* - Linux since 3.17 with glibc 2.25
* - FreeBSD since 12.0 (1200061)
*/
# if defined(__GNUC__) && __GNUC__>=2 && defined(__ELF__) && !defined(__hpux)
extern int getentropy(void *bufer, size_t length) __attribute__((weak));
if (getentropy != NULL)
return getentropy(buf, buflen) == 0 ? buflen : 0;
# else
union {
void *p;
int (*f)(void *buffer, size_t length);
} p_getentropy;
/*
* We could cache the result of the lookup, but we normally don't
* call this function often.
*/
ERR_set_mark();
p_getentropy.p = DSO_global_lookup("getentropy");
ERR_pop_to_mark();
if (p_getentropy.p != NULL)
return p_getentropy.f(buf, buflen) == 0 ? buflen : 0;
# endif
/* Linux supports this since version 3.17 */
# if defined(__linux) && defined(SYS_getrandom)
return (int)syscall(SYS_getrandom, buf, buflen, 0);
# endif
# if (defined(__FreeBSD__) || defined(__NetBSD__)) && defined(KERN_ARND)
return (int)sysctl_random(buf, buflen);
# endif
return -1;
}
/* Fill buffer with size pseudo-random bytes generated by getentropy().
Return 0 on success, or raise an exception and return -1 on error.
If fatal is nonzero, call Py_FatalError() instead of raising an exception
on error. */
static int
py_getentropy(unsigned char *buffer, Py_ssize_t size, int fatal)
{
while (size > 0) {
Py_ssize_t len = Py_MIN(size, 256);
int res;
if (!fatal) {
Py_BEGIN_ALLOW_THREADS
res = getentropy(buffer, len);
Py_END_ALLOW_THREADS
if (res < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
}
else {
static void
_rs_stir(void)
{
u_char rnd[KEYSZ + IVSZ];
if (getentropy(rnd, sizeof rnd) == -1)
_getentropy_fail();
if (!rs)
_rs_init(rnd, sizeof(rnd));
else
_rs_rekey(rnd, sizeof(rnd));
explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */
/* invalidate rs_buf */
rs->rs_have = 0;
memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
rs->rs_count = 1600000;
}
/* Generate pseudorandom data to stdout. Long parameter is kilobytes */
int prandom (long quantity)
{
char entropy[1024];
char pdata[1024];
int x,y;
int xlim = 1024;
long kb_rem = quantity;
while(kb_rem > 0) {
getentropy(entropy);
if (kb_rem < 1024) {
xlim = kb_rem;
}
for(x=0; x<xlim; x++) {
for(y=0; y<1024; y++) {
pdata[y] = entropy[x] ^ entropy[y];
}
write(1, pdata, 1024);
}
kb_rem = kb_rem - 1024;
}
return 0;
}
while (size > 0) {
Py_ssize_t len = Py_MIN(size, 256);
int res;
if (!fatal) {
Py_BEGIN_ALLOW_THREADS
res = getentropy(buffer, len);
Py_END_ALLOW_THREADS
if (res < 0) {
PyErr_SetFromErrno(PyExc_OSError);
return -1;
}
}
else {
res = getentropy(buffer, len);
if (res < 0)
Py_FatalError("getentropy() failed");
}
buffer += len;
size -= len;
}
return 0;
}
#else
/* Issue #25003: Don' use getentropy() on Solaris (available since
* Solaris 11.3), it is blocking whereas os.urandom() should not block. */
#if defined(HAVE_GETRANDOM) || defined(HAVE_GETRANDOM_SYSCALL)
int my_getentropy(void *buf, size_t buflen){
return getentropy(buf, buflen);
}
/** Generate 128 bits of random noise for seeding RNGs. Attempts to
* use various OS-specific sources of random bits, with a fallback
* based on time and pid. */
void
generate_seed(uint64_t seeds[])
{
bool seed_generated = false;
static int stream_count = 0;
int len = sizeof(uint64_t) * 2;
#ifdef HAVE_GETENTROPY
/* On OpenBSD and up to date Linux, use getentropy() to avoid the
open/read/close sequence with /dev/urandom */
if (!seed_generated && getentropy(seeds, len) == 0) {
fprintf(stderr, "Seeded RNG with getentropy()\n");
seed_generated = true;
}
#endif
#ifdef HAVE_ARC4RANDOM_BUF
/* Most (all?) of the BSDs have this seeder. Use it for the reasons
above. Also available on Linux with libbsd, but we don't check
for that. */
if (!seed_generated) {
arc4random_buf(seeds, len);
fprintf(stderr, "Seeded RNG with arc4random\n");
seed_generated = true;
}
#endif
#ifdef WIN32
if (!seed_generated) {
/* Use the Win32 bcrypto RNG interface */
if (BCryptGenRandom(NULL, (PUCHAR) seeds, len,
BCRYPT_USE_SYSTEM_PREFERRED_RNG) == STATUS_SUCCESS) {
fprintf(stderr, "Seeding RNG with BCryptGenRandom()\n");
seed_generated = true;
}
}
#endif
#ifdef HAVE_DEV_URANDOM
if (!seed_generated) {
/* Seed from /dev/urandom if available */
int fd;
fd = open("/dev/urandom", O_RDONLY);
if (fd >= 0) {
int r = read(fd, (void *) seeds, len);
close(fd);
if (r != len) {
fprintf(stderr, "Couldn't read from /dev/urandom! Resorting to normal "
"seeding method.\n");
} else {
fprintf(stderr, "Seeding RNG with /dev/urandom\n");
seed_generated = true;
}
} else {
fprintf(stderr, "Couldn't open /dev/urandom to seed random number "
"generator. Resorting to normal seeding method.\n");
}
}
#endif
if (!seed_generated) {
/* Default seeder. Pick a seed that's slightly random */
#ifdef WIN32
seeds[0] = (uint64_t) time(NULL);
seeds[1] = (uint64_t) GetCurrentProcessId() + stream_count;
#else
seeds[0] = (uint64_t) time(NULL);
seeds[1] = (uint64_t) getpid() + stream_count;
#endif
stream_count += 1;
}
}