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Message-ID: <20241018014100.93776-1-kuniyu@amazon.com>
Date: Thu, 17 Oct 2024 18:41:00 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>, David Ahern <dsahern@...nel.org>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net-next] ipv4: Switch inet_addr_hash() to less predictable hash.
Recently, commit 4a0ec2aa0704 ("ipv6: switch inet6_addr_hash()
to less predictable hash") and commit 4daf4dc275f1 ("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: Kuniyuki Iwashima <kuniyu@...zon.com>
---
include/net/ip.h | 5 +++++
net/ipv4/devinet.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/net/ip.h b/include/net/ip.h
index 4be0a6a603b2..0e548c1f2a0e 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -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)
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index d81fff93d208..3e5e3b5e78c4 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -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);
}
--
2.39.5 (Apple Git-154)
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