Commit c972c1c4 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Paolo Abeni
Browse files

ipv4: Switch inet_addr_hash() to less predictable hash. 



Recently, commit 4a0ec2aa ("ipv6: switch inet6_addr_hash()
to less predictable hash") and commit 4daf4dc2 ("ipv6: switch
inet6_acaddr_hash() to less predictable hash") hardened IPv6
address hash functions.

inet_addr_hash() is also highly predictable, and a malicious use
could abuse a specific bucket.

Let's follow the change on IPv4 by using jhash_1word().

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241018014100.93776-1-kuniyu@amazon.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 7213a1c4

include/net/ip.h

+5 −0
Original line number Diff line number Diff line
@@ -690,6 +690,11 @@ static inline unsigned int ipv4_addr_hash(__be32 ip) 
	return (__force unsigned int) ip;

}



static inline u32 __ipv4_addr_hash(const __be32 ip, const u32 initval)

{

	return jhash_1word((__force u32)ip, initval);

}



static inline u32 ipv4_portaddr_hash(const struct net *net,

				     __be32 saddr,

				     unsigned int port)

net/ipv4/devinet.c

+1 −1
Original line number Diff line number Diff line
@@ -121,7 +121,7 @@ struct inet_fill_args { 


static u32 inet_addr_hash(const struct net *net, __be32 addr)

{

	u32 val = (__force u32) addr ^ net_hash_mix(net);

	u32 val = __ipv4_addr_hash(addr, net_hash_mix(net));



	return hash_32(val, IN4_ADDR_HSIZE_SHIFT);

}