From: Willy Tarreau w@1wt.eu
commit 9e9b70ae923baf2b5e8a0ea4fd0c8451801ac526 upstream.
Amit Klein suggests that we use different parts of port_offset for the table's index and the port offset so that there is no direct relation between them.
Cc: Jason A. Donenfeld Jason@zx2c4.com Cc: Moshe Kol moshe.kol@mail.huji.ac.il Cc: Yossi Gilad yossi.gilad@mail.huji.ac.il Cc: Amit Klein aksecurity@gmail.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: Willy Tarreau w@1wt.eu Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/inet_hashtables.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -639,7 +639,7 @@ int __inet_hash_connect(struct inet_time net_get_random_once(table_perturb, sizeof(table_perturb)); index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT);
- offset = READ_ONCE(table_perturb[index]) + port_offset; + offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32); offset %= remaining;
/* In first pass we try ports of @low parity.