From e87fd0f4acecace717916dd204ff4ebf067e783b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 25 Aug 2021 16:17:29 -0700 Subject: [PATCH] ipv4: use siphash instead of Jenkins in fnhe_hashfun() ANBZ: #535 commit 6457378fe796 ("ipv4: use siphash instead of Jenkins in fnhe_hashfun()") 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: d546c621542d ("ipv4: harden fnhe_hashfun()") Signed-off-by: Eric Dumazet Reported-by: Keyu Man Cc: Willy Tarreau Signed-off-by: David S. Miller Signed-off-by: Xuan Zhuo Acked-by: Dust Li --- net/ipv4/route.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 850938e00a5ee1..aa6e9ffa514c1d 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -612,14 +612,14 @@ 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)