secure_seq: use the 64 bits of the siphash for port offset calculation
authorWilly Tarreau <w@1wt.eu>
Mon, 2 May 2022 08:46:08 +0000 (10:46 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 18 May 2022 08:26:53 +0000 (10:26 +0200)
commit1a8ee547da2b64d6a2aedbd38a691578eff14718
tree17d15bec94b1d8717ccd24661d8060fdd0a06b0b
parent99858114a3b2c8f5f8707d9bbd46c50f547c87c0
secure_seq: use the 64 bits of the siphash for port offset calculation

[ Upstream commit b2d057560b8107c633b39aabe517ff9d93f285e3 ]

SipHash replaced MD5 in secure_ipv{4,6}_port_ephemeral() via commit
7cd23e5300c1 ("secure_seq: use SipHash in place of MD5"), but the output
remained truncated to 32-bit only. In order to exploit more bits from the
hash, let's make the functions return the full 64-bit of siphash_3u32().
We also make sure the port offset calculation in __inet_hash_connect()
remains done on 32-bit to avoid the need for div_u64_rem() and an extra
cost on 32-bit systems.

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: Sasha Levin <sashal@kernel.org>
include/net/inet_hashtables.h
include/net/secure_seq.h
net/core/secure_seq.c
net/ipv4/inet_hashtables.c
net/ipv6/inet6_hashtables.c