random_bytes_openssl.php 2.5 KB

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  1. <?php
  2. /**
  3. * Random_* Compatibility Library
  4. * for using the new PHP 7 random_* API in PHP 5 projects
  5. *
  6. * The MIT License (MIT)
  7. *
  8. * Copyright (c) 2015 Paragon Initiative Enterprises
  9. *
  10. * Permission is hereby granted, free of charge, to any person obtaining a copy
  11. * of this software and associated documentation files (the "Software"), to deal
  12. * in the Software without restriction, including without limitation the rights
  13. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14. * copies of the Software, and to permit persons to whom the Software is
  15. * furnished to do so, subject to the following conditions:
  16. *
  17. * The above copyright notice and this permission notice shall be included in
  18. * all copies or substantial portions of the Software.
  19. *
  20. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26. * SOFTWARE.
  27. */
  28. /**
  29. * Since openssl_random_pseudo_bytes() uses openssl's
  30. * RAND_pseudo_bytes() API, which has been marked as deprecated by the
  31. * OpenSSL team, this is our last resort before failure.
  32. *
  33. * @ref https://www.openssl.org/docs/crypto/RAND_bytes.html
  34. *
  35. * @param int $bytes
  36. *
  37. * @throws Exception
  38. *
  39. * @return string
  40. */
  41. function random_bytes($bytes)
  42. {
  43. try {
  44. $bytes = RandomCompat_intval($bytes);
  45. } catch (TypeError $ex) {
  46. throw new TypeError(
  47. 'random_bytes(): $bytes must be an integer'
  48. );
  49. }
  50. if ($bytes < 1) {
  51. throw new Error(
  52. 'Length must be greater than 0'
  53. );
  54. }
  55. /**
  56. * $secure is passed by reference. If it's set to false, fail. Note
  57. * that this will only return false if this function fails to return
  58. * any data.
  59. *
  60. * @ref https://github.com/paragonie/random_compat/issues/6#issuecomment-119564973
  61. */
  62. $secure = true;
  63. /**
  64. * @var string
  65. */
  66. $buf = openssl_random_pseudo_bytes($bytes, $secure);
  67. if (
  68. is_string($buf)
  69. &&
  70. $secure
  71. &&
  72. RandomCompat_strlen($buf) === $bytes
  73. ) {
  74. return $buf;
  75. }
  76. /**
  77. * If we reach here, PHP has failed us.
  78. */
  79. throw new Exception(
  80. 'Could not gather sufficient random data'
  81. );
  82. }