/* {{{ */
static int php_random_bytes(void *bytes, size_t size)
{
#if PHP_WIN32
/* Defer to CryptGenRandom on Windows */
if (php_win32_get_random_bytes(bytes, size) == FAILURE) {
zend_throw_exception(zend_ce_exception, "Could not gather sufficient random data", 0);
return FAILURE;
}
#elif HAVE_DECL_ARC4RANDOM_BUF
arc4random_buf(bytes, size);
#else
int fd = RANDOM_G(fd);
size_t read_bytes = 0;
if (fd < 0) {
#if HAVE_DEV_ARANDOM
fd = open("/dev/arandom", O_RDONLY);
#elif HAVE_DEV_URANDOM
fd = open("/dev/urandom", O_RDONLY);
#endif
if (fd < 0) {
zend_throw_exception(zend_ce_exception, "Cannot open source device", 0);
return FAILURE;
}
RANDOM_G(fd) = fd;
}
while (read_bytes < size) {
ssize_t n = read(fd, bytes + read_bytes, size - read_bytes);
if (n <= 0) {
break;
}
read_bytes += n;
}
if (read_bytes < size) {
zend_throw_exception(zend_ce_exception, "Could not gather sufficient random data", 0);
return FAILURE;
}
#endif
return SUCCESS;
}
static int php_random_bytes(void *bytes, size_t size)
{
#if PHP_WIN32
/* Defer to CryptGenRandom on Windows */
if (php_win32_get_random_bytes(bytes, size) == FAILURE) {
zend_throw_exception(zend_ce_exception, "Could not gather sufficient random data", 0);
return FAILURE;
}
#elif HAVE_DECL_ARC4RANDOM_BUF && ((defined(__OpenBSD__) && OpenBSD >= 201405) || (defined(__NetBSD__) && __NetBSD_Version__ >= 700000001))
arc4random_buf(bytes, size);
#elif HAVE_DECL_GETRANDOM
/* Linux getrandom(2) syscall */
size_t read_bytes = 0;
size_t amount_to_read = 0;
ssize_t n;
/* Keep reading until we get enough entropy */
do {
amount_to_read = size - read_bytes;
/* Below, (bytes + read_bytes) is pointer arithmetic.
bytes read_bytes size
| | |
[#######=============] (we're going to write over the = region)
\\\\\\\\\\\\\
amount_to_read
*/
n = syscall(SYS_getrandom, bytes + read_bytes, amount_to_read, 0);
if (n == -1) {
if (errno == EINTR || errno == EAGAIN) {
/* Try again */
continue;
}
/*
If the syscall fails, we are doomed. The loop that calls
php_random_bytes should be terminated by the exception instead
of proceeding to demand more entropy.
*/
zend_throw_exception(zend_ce_exception, "Could not gather sufficient random data", errno);
return FAILURE;
}
read_bytes += (size_t) n;
} while (read_bytes < size);
#else
int fd = RANDOM_G(fd);
struct stat st;
size_t read_bytes = 0;
ssize_t n;
if (fd < 0) {
#if HAVE_DEV_URANDOM
fd = open("/dev/urandom", O_RDONLY);
#endif
if (fd < 0) {
zend_throw_exception(zend_ce_exception, "Cannot open source device", 0);
return FAILURE;
}
/* Does the file exist and is it a character device? */
if (fstat(fd, &st) != 0 ||
# ifdef S_ISNAM
!(S_ISNAM(st.st_mode) || S_ISCHR(st.st_mode))
# else
!S_ISCHR(st.st_mode)
# endif
) {
close(fd);
zend_throw_exception(zend_ce_exception, "Error reading from source device", 0);
return FAILURE;
}
RANDOM_G(fd) = fd;
}
while (read_bytes < size) {
n = read(fd, bytes + read_bytes, size - read_bytes);
if (n <= 0) {
break;
}
read_bytes += n;
}
if (read_bytes < size) {
zend_throw_exception(zend_ce_exception, "Could not gather sufficient random data", 0);
return FAILURE;
}
#endif
return SUCCESS;
}
/* {{{ */
PHPAPI int php_random_bytes(void *bytes, size_t size, zend_bool should_throw)
{
#ifdef PHP_WIN32
/* Defer to CryptGenRandom on Windows */
if (php_win32_get_random_bytes(bytes, size) == FAILURE) {
if (should_throw) {
zend_throw_exception(zend_ce_exception, "Could not gather sufficient random data", 0);
}
return FAILURE;
}
#elif HAVE_DECL_ARC4RANDOM_BUF && ((defined(__OpenBSD__) && OpenBSD >= 201405) || (defined(__NetBSD__) && __NetBSD_Version__ >= 700000001))
arc4random_buf(bytes, size);
#else
size_t read_bytes = 0;
ssize_t n;
#if defined(__linux__) && defined(SYS_getrandom)
/* Linux getrandom(2) syscall */
/* Keep reading until we get enough entropy */
while (read_bytes < size) {
/* Below, (bytes + read_bytes) is pointer arithmetic.
bytes read_bytes size
| | |
[#######=============] (we're going to write over the = region)
\\\\\\\\\\\\\
amount_to_read
*/
size_t amount_to_read = size - read_bytes;
n = syscall(SYS_getrandom, bytes + read_bytes, amount_to_read, 0);
if (n == -1) {
if (errno == ENOSYS) {
/* This can happen if PHP was compiled against a newer kernel where getrandom()
* is available, but then runs on an older kernel without getrandom(). If this
* happens we simply fall back to reading from /dev/urandom. */
ZEND_ASSERT(read_bytes == 0);
break;
} else if (errno == EINTR || errno == EAGAIN) {
/* Try again */
continue;
} else {
/* If the syscall fails, fall back to reading from /dev/urandom */
break;
}
}
read_bytes += (size_t) n;
}
#endif
if (read_bytes < size) {
int fd = RANDOM_G(fd);
struct stat st;
if (fd < 0) {
#if HAVE_DEV_URANDOM
fd = open("/dev/urandom", O_RDONLY);
#endif
if (fd < 0) {
if (should_throw) {
zend_throw_exception(zend_ce_exception, "Cannot open source device", 0);
}
return FAILURE;
}
/* Does the file exist and is it a character device? */
if (fstat(fd, &st) != 0 ||
# ifdef S_ISNAM
!(S_ISNAM(st.st_mode) || S_ISCHR(st.st_mode))
# else
!S_ISCHR(st.st_mode)
# endif
) {
close(fd);
if (should_throw) {
zend_throw_exception(zend_ce_exception, "Error reading from source device", 0);
}
return FAILURE;
}
RANDOM_G(fd) = fd;
}
for (read_bytes = 0; read_bytes < size; read_bytes += (size_t) n) {
n = read(fd, bytes + read_bytes, size - read_bytes);
if (n <= 0) {
break;
}
}
if (read_bytes < size) {
if (should_throw) {
zend_throw_exception(zend_ce_exception, "Could not gather sufficient random data", 0);
}
return FAILURE;
}
}
#endif
return SUCCESS;
}
