Commit 2c401236 authored by Eric Dumazet's avatar Eric Dumazet Committed by Yang Yingliang
Browse files

ipv4: use siphash instead of Jenkins in fnhe_hashfun() 



mainline inclusion
from mainline-v5.14
commit 6457378f
category: bugfix
bugzilla: NA
CVE: CVE-2021-20322

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

A group of security researchers brought to our attention
the weakness of hash function used in fnhe_hashfun().

Lets use siphash instead of Jenkins Hash, to considerably
reduce security risks.

Also remove the inline keyword, this really is distracting.

Fixes: d546c621 ("ipv4: harden fnhe_hashfun()")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarKeyu Man <kman001@ucr.edu>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarXu Jia <xujia39@huawei.com>
Reviewed-by: default avatarYue Haibing <yuehaibing@huawei.com>
Reviewed-by: default avatarXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
parent 3dd66e0b

net/ipv4/route.c

+6 −6
Original line number Diff line number Diff line
@@ -614,14 +614,14 @@ static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash) 
	return oldest;

}



static inline u32 fnhe_hashfun(__be32 daddr)

static u32 fnhe_hashfun(__be32 daddr)

{

	static u32 fnhe_hashrnd __read_mostly;

	u32 hval;

	static siphash_key_t fnhe_hash_key __read_mostly;

	u64 hval;



	net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));

	hval = jhash_1word((__force u32) daddr, fnhe_hashrnd);

	return hash_32(hval, FNHE_HASH_SHIFT);

	net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));

	hval = siphash_1u32((__force u32) daddr, &fnhe_hash_key);

	return hash_64(hval, FNHE_HASH_SHIFT);

}



static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)