random: always fill buffer in get_random_bytes_wait

In the unfortunate event that a developer fails to check the return
value of get_random_bytes_wait, or simply wants to make a "best effort"
attempt, for whatever that's worth, it's much better to still fill the
buffer with _something_ rather than catastrophically failing in the case
of an interruption. This is both a defense in depth measure against
inevitable programming bugs, as well as a means of making the API a bit
more useful.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Jason A. Donenfeld 2018-02-04 23:07:46 +01:00 committed by Theodore Ts'o
parent 9f886f4d1d
commit 25e3fca492

View file

@ -85,10 +85,8 @@ static inline unsigned long get_random_canary(void)
static inline int get_random_bytes_wait(void *buf, int nbytes)
{
int ret = wait_for_random_bytes();
if (unlikely(ret))
return ret;
get_random_bytes(buf, nbytes);
return 0;
return ret;
}
#define declare_get_random_var_wait(var) \