Re: [PATCH v4 10/13] net/neighbor: use get_random_u32 for 32-bit hash random

[Theodore Ts'o]

On Tue, Jun 06, 2017 at 07:48:01PM +0200, Jason A. Donenfeld wrote:
> Using get_random_u32 here is faster, more fitting of the use case, and
> just as cryptographically secure. It also has the benefit of providing
> better randomness at early boot, which is when many of these structures
> are assigned.
> 
> Signed-off-by: Jason A. Donenfeld 
> Cc: David Miller 

Applied to the random.git dev branch, thanks.

  - Ted

[PATCH v4 10/13] net/neighbor: use get_random_u32 for 32-bit hash random

[Jason A. Donenfeld]

Using get_random_u32 here is faster, more fitting of the use case, and
just as cryptographically secure. It also has the benefit of providing
better randomness at early boot, which is when many of these structures
are assigned.

Signed-off-by: Jason A. Donenfeld 
Cc: David Miller 
---
 net/core/neighbour.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index d274f81fcc2c..9784133b0cdb 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -312,8 +312,7 @@ static struct neighbour *neigh_alloc(struct neigh_table 
*tbl, struct net_device
 
 static void neigh_get_hash_rnd(u32 *x)
 {
-   get_random_bytes(x, sizeof(*x));
-   *x |= 1;
+   *x = get_random_u32() | 1;
 }
 
 static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
-- 
2.13.0