/**
* If the libsodium PHP extension is loaded, we'll use it above any other
* solution.
*
* libsodium-php project:
* @ref https://github.com/jedisct1/libsodium-php
*
* @param int $bytes
*
* @throws Exception
*
* @return string
*/
function random_bytes($bytes)
{
try {
$bytes = RandomCompat_intval($bytes);
} catch (TypeError $ex) {
throw new TypeError('random_bytes(): $bytes must be an integer');
}
if ($bytes < 1) {
throw new Error('Length must be greater than 0');
}
/**
* \Sodium\randombytes_buf() doesn't allow more than 2147483647 bytes to be
* generated in one invocation.
*/
if ($bytes > 2147483647) {
$buf = '';
for ($i = 0; $i < $bytes; $i += 1073741824) {
$n = $bytes - $i > 1073741824 ? 1073741824 : $bytes - $i;
$buf .= \Sodium\randombytes_buf($n);
}
} else {
$buf = \Sodium\randombytes_buf($bytes);
}
if ($buf !== false) {
if (RandomCompat_strlen($buf) === $bytes) {
return $buf;
}
}
/**
* If we reach here, PHP has failed us.
*/
throw new Exception('Could not gather sufficient random data');
}
public function testIntval()
{
if (!function_exists('RandomCompat_intval')) {
return $this->markTestSkipped('We don\' need to test this in PHP 7.');
}
// Equals
$this->assertEquals(abs(RandomCompat_intval(-4.5)), abs(RandomCompat_intval(4.5)));
// True
$this->assertTrue(is_int(RandomCompat_intval(PHP_INT_MAX, true)));
$this->assertTrue(is_int(RandomCompat_intval(~PHP_INT_MAX, true)));
$this->assertTrue(is_int(RandomCompat_intval(~PHP_INT_MAX + 1, true)));
$this->assertTrue(is_int(RandomCompat_intval("1337e3", true)));
$this->assertTrue(is_int(RandomCompat_intval("1.", true)));
// False
$this->assertFalse(is_int(RandomCompat_intval((double) PHP_INT_MAX, true)));
$this->assertFalse(is_int(RandomCompat_intval((double) ~PHP_INT_MAX, true)));
$this->assertFalse(is_int(RandomCompat_intval(PHP_INT_MAX + 1, true)));
$this->assertFalse(is_int(RandomCompat_intval(~PHP_INT_MAX - 1, true)));
$this->assertFalse(is_int(RandomCompat_intval(~PHP_INT_MAX - 0.1, true)));
$this->assertFalse(is_int(RandomCompat_intval(PHP_INT_MAX + 0.1, true)));
$this->assertFalse(is_int(RandomCompat_intval("hello", true)));
if (PHP_INT_SIZE === 8) {
$this->assertFalse(is_int(RandomCompat_intval("-9223372036854775809", true)));
$this->assertTrue(is_int(RandomCompat_intval("-9223372036854775808", true)));
$this->assertFalse(is_int(RandomCompat_intval("9223372036854775808", true)));
$this->assertTrue(is_int(RandomCompat_intval("9223372036854775807", true)));
} else {
$this->assertFalse(is_int(RandomCompat_intval("2147483648", true)));
$this->assertTrue(is_int(RandomCompat_intval("2147483647", true)));
$this->assertFalse(is_int(RandomCompat_intval("-2147483649", true)));
$this->assertTrue(is_int(RandomCompat_intval("-2147483648", true)));
}
}
/**
* Windows with PHP < 5.3.0 will not have the function
* openssl_random_pseudo_bytes() available, so let's use
* CAPICOM to work around this deficiency.
*
* @param int $bytes
*
* @throws Exception
*
* @return string
*/
function random_bytes($bytes)
{
try {
$bytes = RandomCompat_intval($bytes);
} catch (TypeError $ex) {
throw new TypeError('random_bytes(): $bytes must be an integer');
}
if ($bytes < 1) {
throw new Error('Length must be greater than 0');
}
$buf = '';
$util = new COM('CAPICOM.Utilities.1');
$execCount = 0;
/**
* Let's not let it loop forever. If we run N times and fail to
* get N bytes of random data, then CAPICOM has failed us.
*/
do {
$buf .= base64_decode($util->GetRandom($bytes, 0));
if (RandomCompat_strlen($buf) >= $bytes) {
/**
* Return our random entropy buffer here:
*/
return RandomCompat_substr($buf, 0, $bytes);
}
++$execCount;
} while ($execCount < $bytes);
/**
* If we reach here, PHP has failed us.
*/
throw new Exception('Could not gather sufficient random data');
}
/**
* Since openssl_random_pseudo_bytes() uses openssl's
* RAND_pseudo_bytes() API, which has been marked as deprecated by the
* OpenSSL team, this is our last resort before failure.
*
* @ref https://www.openssl.org/docs/crypto/RAND_bytes.html
*
* @param int $bytes
*
* @throws Exception
*
* @return string
*/
function random_bytes($bytes)
{
try {
$bytes = RandomCompat_intval($bytes);
} catch (TypeError $ex) {
throw new TypeError('random_bytes(): $bytes must be an integer');
}
if ($bytes < 1) {
throw new Error('Length must be greater than 0');
}
$secure = true;
/**
* $secure is passed by reference. If it's set to false, fail. Note
* that this will only return false if this function fails to return
* any data.
*
* @ref https://github.com/paragonie/random_compat/issues/6#issuecomment-119564973
*/
$buf = openssl_random_pseudo_bytes($bytes, $secure);
if ($buf !== false && $secure) {
if (RandomCompat_strlen($buf) === $bytes) {
return $buf;
}
}
/**
* If we reach here, PHP has failed us.
*/
throw new Exception('Could not gather sufficient random data');
}
public function testIntval()
{
if (!function_exists('RandomCompat_intval')) {
return $this->markTestSkipped('We don\' need to test this in PHP 7.');
}
// Equals
$this->assertEquals(abs(RandomCompat_intval(-4.5)), abs(RandomCompat_intval(4.5)));
// True
$this->assertTrue(is_int(RandomCompat_intval(PHP_INT_MAX, true)));
$this->assertTrue(is_int(RandomCompat_intval(~PHP_INT_MAX, true)));
$this->assertTrue(is_int(RandomCompat_intval(~PHP_INT_MAX + 1, true)));
// False
$this->assertFalse(is_int(RandomCompat_intval((double) PHP_INT_MAX, true)));
$this->assertFalse(is_int(RandomCompat_intval((double) ~PHP_INT_MAX, true)));
$this->assertFalse(is_int(RandomCompat_intval(PHP_INT_MAX + 1, true)));
$this->assertFalse(is_int(RandomCompat_intval(~PHP_INT_MAX - 1, true)));
$this->assertFalse(is_int(RandomCompat_intval(PHP_INT_MAX - 0.01, true)));
$this->assertFalse(is_int(RandomCompat_intval(~PHP_INT_MAX + 0.01, true)));
}
/**
* Powered by ext/mcrypt (and thankfully NOT libmcrypt)
*
* @ref https://bugs.php.net/bug.php?id=55169
* @ref https://github.com/php/php-src/blob/c568ffe5171d942161fc8dda066bce844bdef676/ext/mcrypt/mcrypt.c#L1321-L1386
*
* @param int $bytes
*
* @throws Exception
*
* @return string
*/
function random_bytes($bytes)
{
try {
$bytes = RandomCompat_intval($bytes);
} catch (TypeError $ex) {
throw new TypeError('random_bytes(): $bytes must be an integer');
}
if ($bytes < 1) {
throw new Error('Length must be greater than 0');
}
$buf = @mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM);
if ($buf !== false && RandomCompat_strlen($buf) === $bytes) {
/**
* Return our random entropy buffer here:
*/
return $buf;
}
/**
* If we reach here, PHP has failed us.
*/
throw new Exception('Could not gather sufficient random data');
}
/**
* Unless open_basedir is enabled, use /dev/urandom for
* random numbers in accordance with best practices
*
* Why we use /dev/urandom and not /dev/random
* @ref http://sockpuppet.org/blog/2014/02/25/safely-generate-random-numbers
*
* @param int $bytes
*
* @throws Exception
*
* @return string
*/
function random_bytes($bytes)
{
static $fp = null;
/**
* This block should only be run once
*/
if (empty($fp)) {
/**
* We use /dev/urandom if it is a char device.
* We never fall back to /dev/random
*/
$fp = fopen('/dev/urandom', 'rb');
if (!empty($fp)) {
$st = fstat($fp);
if (($st['mode'] & 0170000) !== 020000) {
fclose($fp);
$fp = false;
}
}
if (!empty($fp)) {
/**
* stream_set_read_buffer() does not exist in HHVM
*
* If we don't set the stream's read buffer to 0, PHP will
* internally buffer 8192 bytes, which can waste entropy
*
* stream_set_read_buffer returns 0 on success
*/
if (function_exists('stream_set_read_buffer')) {
stream_set_read_buffer($fp, RANDOM_COMPAT_READ_BUFFER);
}
if (function_exists('stream_set_chunk_size')) {
stream_set_chunk_size($fp, RANDOM_COMPAT_READ_BUFFER);
}
}
}
try {
$bytes = RandomCompat_intval($bytes);
} catch (TypeError $ex) {
throw new TypeError('random_bytes(): $bytes must be an integer');
}
if ($bytes < 1) {
throw new Error('Length must be greater than 0');
}
/**
* This if() block only runs if we managed to open a file handle
*
* It does not belong in an else {} block, because the above
* if (empty($fp)) line is logic that should only be run once per
* page load.
*/
if (!empty($fp)) {
$remaining = $bytes;
$buf = '';
/**
* We use fread() in a loop to protect against partial reads
*/
do {
$read = fread($fp, $remaining);
if ($read === false) {
/**
* We cannot safely read from the file. Exit the
* do-while loop and trigger the exception condition
*/
$buf = false;
break;
}
/**
* Decrease the number of bytes returned from remaining
*/
$remaining -= RandomCompat_strlen($read);
$buf .= $read;
} while ($remaining > 0);
/**
* Is our result valid?
*/
if ($buf !== false) {
if (RandomCompat_strlen($buf) === $bytes) {
/**
* Return our random entropy buffer here:
*/
return $buf;
}
}
}
/**
* If we reach here, PHP has failed us.
*/
throw new Exception('Error reading from source device');
}
/**
* Fetch a random integer between $min and $max inclusive
*
* @param int $min
* @param int $max
*
* @throws Exception
*
* @return int
*/
function random_int($min, $max)
{
/**
* Type and input logic checks
*
* If you pass it a float in the range (~PHP_INT_MAX, PHP_INT_MAX)
* (non-inclusive), it will sanely cast it to an int. If you it's equal to
* ~PHP_INT_MAX or PHP_INT_MAX, we let it fail as not an integer. Floats
* lose precision, so the <= and => operators might accidentally let a float
* through.
*/
try {
$min = RandomCompat_intval($min);
} catch (TypeError $ex) {
throw new TypeError('random_int(): $min must be an integer');
}
try {
$max = RandomCompat_intval($max);
} catch (TypeError $ex) {
throw new TypeError('random_int(): $max must be an integer');
}
/**
* Now that we've verified our weak typing system has given us an integer,
* let's validate the logic then we can move forward with generating random
* integers along a given range.
*/
if ($min > $max) {
throw new Error('Minimum value must be less than or equal to the maximum value');
}
if ($max === $min) {
return $min;
}
/**
* Initialize variables to 0
*
* We want to store:
* $bytes => the number of random bytes we need
* $mask => an integer bitmask (for use with the &) operator
* so we can minimize the number of discards
*/
$attempts = $bits = $bytes = $mask = $valueShift = 0;
/**
* At this point, $range is a positive number greater than 0. It might
* overflow, however, if $max - $min > PHP_INT_MAX. PHP will cast it to
* a float and we will lose some precision.
*/
$range = $max - $min;
/**
* Test for integer overflow:
*/
if (!is_int($range)) {
/**
* Still safely calculate wider ranges.
* Provided by @CodesInChaos, @oittaa
*
* @ref https://gist.github.com/CodesInChaos/03f9ea0b58e8b2b8d435
*
* We use ~0 as a mask in this case because it generates all 1s
*
* @ref https://eval.in/400356 (32-bit)
* @ref http://3v4l.org/XX9r5 (64-bit)
*/
$bytes = PHP_INT_SIZE;
$mask = ~0;
} else {
/**
* $bits is effectively ceil(log($range, 2)) without dealing with
* type juggling
*/
while ($range > 0) {
if ($bits % 8 === 0) {
++$bytes;
}
++$bits;
$range >>= 1;
$mask = $mask << 1 | 1;
}
$valueShift = $min;
}
/**
* Now that we have our parameters set up, let's begin generating
* random integers until one falls between $min and $max
*/
do {
/**
* The rejection probability is at most 0.5, so this corresponds
* to a failure probability of 2^-128 for a working RNG
*/
if ($attempts > 128) {
throw new Exception('random_int: RNG is broken - too many rejections');
}
/**
* Let's grab the necessary number of random bytes
*/
$randomByteString = random_bytes($bytes);
if ($randomByteString === false) {
throw new Exception('Random number generator failure');
}
/**
* Let's turn $randomByteString into an integer
*
* This uses bitwise operators (<< and |) to build an integer
* out of the values extracted from ord()
*
* Example: [9F] | [6D] | [32] | [0C] =>
* 159 + 27904 + 3276800 + 201326592 =>
* 204631455
*/
$val = 0;
for ($i = 0; $i < $bytes; ++$i) {
$val |= ord($randomByteString[$i]) << $i * 8;
}
/**
* Apply mask
*/
$val &= $mask;
$val += $valueShift;
++$attempts;
/**
* If $val overflows to a floating point number,
* ... or is larger than $max,
* ... or smaller than $min,
* then try again.
*/
} while (!is_int($val) || $val > $max || $val < $min);
return (int) $val;
}
