[issue13703] Hash collision security issue

[Marc-Andre Lemburg]

Marc-Andre Lemburg <mal at egenix.com> added the comment:

STINNER Victor wrote:
> 
> Patch version 7:
>  - Make PyOS_URandom() private (renamed to _PyOS_URandom)
>  - os.urandom() releases the GIL for I/O operation for its implementation reading /dev/urandom
>  - move _Py_unicode_hash_secret_t documentation into unicode_hash()
> 
> I moved also fixes for tests in a separated patch: random_fix-tests.patch.

Don't you think that the number of corrections you have to apply in order
to get the tests working again shows how much impact such a change would
have in real-world applications ?

Perhaps we should start to think about a compromise: make both the
collision counting and the hash seeding optional and let the user
decide which option is best.

BTW: The patch still includes the unnecessary _Py_unicode_hash_secret.suffix
which needlessly complicates the code and doesn't any additional
protection against hash value collisions.

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