fork: make whole stack_canary random

On machines with sizeof(unsigned long)==8, this ensures that the more
significant 32 bits of stack_canary are random, too.
stack_canary is defined as unsigned long, all the architectures with stack
protector support already pick the stack_canary of init as a random
unsigned long, and get_random_long() should be as fast as get_random_int(),
so there seems to be no good reason against this.

This should help if someone tries to guess a stack canary with brute force.

(This change has been made in PaX already, with a different RNG.)

Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Kees Cook <keescook@chromium.org>

0 files changed, 0 insertions, 0 deletions