secure_seq: use the 64 bits of the siphash for port offset calculation

mainline inclusion
from mainline-v5.18-rc6
commit b2d05756
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I57M5L
CVE: CVE-2022-1012

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b2d057560b8107c633b39aabe517ff9d93f285e3



--------------------------------

SipHash replaced MD5 in secure_ipv{4,6}_port_ephemeral() via commit
7cd23e53 ("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>

Conflicts:
	net/ipv4/inet_hashtables.c

Signed-off-by: Baisong Zhong <zhongbaisong@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>