_Py_HashSeed basics (3.3) - Pastebin.com (original) (raw)

gpshead

Jan 13th, 2012

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  1. $ hg diff
  2. diff --git a/Include/object.h b/Include/object.h
  3. --- a/Include/object.h
  4. +++ b/Include/object.h
  5. @@ -51,6 +51,14 @@
  6. whose size is determined when the object is allocated.
  7. */
  8. +/* Used to make bytes and unicode hashes unpredictable. */
  9. +#define Py_HASH_SEED_SUPPORTED /* TODO(gregory.p.smith): make this a configure
  10. +#ifdef Py_HASH_SEED_SUPPORTED
  11. +PyAPI_DATA(Py_hash_t) _Py_HashSeed;
  12. +#else
  13. +#define _Py_HashSeed 0
  14. +#endif
  16. /* Py_DEBUG implies Py_TRACE_REFS. */
  17. #if defined(Py_DEBUG) && !defined(Py_TRACE_REFS)
  18. #define Py_TRACE_REFS
  19. diff --git a/Objects/object.c b/Objects/object.c
  20. --- a/Objects/object.c
  21. +++ b/Objects/object.c
  22. @@ -8,6 +8,10 @@
  23. extern "C" {
  24. #endif
  25. +#ifdef Py_HASH_SEED_SUPPORTED
  26. +Py_hash_t _Py_HashSeed;
  27. +#endif
  29. #ifdef Py_REF_DEBUG
  30. Py_ssize_t _Py_RefTotal;
  31. @@ -759,7 +763,7 @@
  32. Py_uhash_t x;
  33. Py_ssize_t i;
  34. - x = (Py_uhash_t) *p << 7;
  35. + x = _Py_HashSeed ^ ((Py_uhash_t) *p << 7);
  36. for (i = 0; i < len; i++)
  37. x = (1000003U * x) ^ (Py_uhash_t) *p++;
  38. x ^= (Py_uhash_t) len;
  39. diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
  40. --- a/Objects/unicodeobject.c
  41. +++ b/Objects/unicodeobject.c
  42. @@ -11162,7 +11162,7 @@
  43. /* The hash function as a macro, gets expanded three times below. */
  44. #define HASH(P) \
  45. - x = (Py_uhash_t)*P << 7; \
  46. + x = _Py_HashSeed ^ ((Py_uhash_t)*P << 7); \
  47. while (--len >= 0) \
  48. x = (1000003*x) ^ (Py_uhash_t)*P++;
  49. diff --git a/Python/pythonrun.c b/Python/pythonrun.c
  50. --- a/Python/pythonrun.c
  51. +++ b/Python/pythonrun.c
  52. @@ -203,6 +203,12 @@
  53. initialized = 1;
  54. _Py_Finalizing = NULL;
  55. +#ifdef Py_HASH_SEED_SUPPORTED
  56. + _Py_HashSeed = 0; /* TODO(gregory.p.smith): Init from a random source. */
  57. + /* pid combined with highest resolution time possible at a minimum if
  58. + * a /dev/urandom or equivalent API is not available. */
  59. +#endif
  61. #if defined(HAVE_LANGINFO_H) && defined(HAVE_SETLOCALE)
  62. /* Set up the LC_CTYPE locale, so we can obtain
  63. the locale's charset without having to switch