| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 260/264] tcp: use different parts of the port_offset for index and offset | Date | Thu, 23 Jun 2022 18:44:13 +0200 |
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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 @@ -589,7 +589,7 @@ 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.
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