[PATCH net 1/7] secure_seq: return the full 64-bit of the siphash

From: Willy Tarreau
Date: Wed Apr 27 2022 - 02:53:23 EST


SipHash replaced MD5 in secure_ipv4_port_ephemeral() via commit
7cd23e5300c1 ("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 function return the full 64-bit
of siphash_3u32().

Cc: Jason A. Donenfeld <Jason@xxxxxxxxx>
Cc: Moshe Kol <moshe.kol@xxxxxxxxxxxxxxx>
Cc: Yossi Gilad <yossi.gilad@xxxxxxxxxxxxxxx>
Cc: Amit Klein <aksecurity@xxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
include/net/inet_hashtables.h | 2 +-
include/net/secure_seq.h | 2 +-
net/core/secure_seq.c | 2 +-
net/ipv4/inet_hashtables.c | 6 +++---
4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index f72ec113ae56..98e1ec1a14f0 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -425,7 +425,7 @@ static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
}

int __inet_hash_connect(struct inet_timewait_death_row *death_row,
- struct sock *sk, u32 port_offset,
+ struct sock *sk, u64 port_offset,
int (*check_established)(struct inet_timewait_death_row *,
struct sock *, __u16,
struct inet_timewait_sock **));
diff --git a/include/net/secure_seq.h b/include/net/secure_seq.h
index d7d2495f83c2..5cea9ed9c773 100644
--- a/include/net/secure_seq.h
+++ b/include/net/secure_seq.h
@@ -4,7 +4,7 @@

#include <linux/types.h>

-u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
+u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
__be16 dport);
u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
index 9b8443774449..2cdd43a63f64 100644
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
@@ -142,7 +142,7 @@ u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
}
EXPORT_SYMBOL_GPL(secure_tcp_seq);

-u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
+u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
{
net_secret_init();
return siphash_3u32((__force u32)saddr, (__force u32)daddr,
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 17440840a791..09cbad0488ca 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -504,7 +504,7 @@ static int __inet_check_established(struct inet_timewait_death_row *death_row,
return -EADDRNOTAVAIL;
}

-static u32 inet_sk_port_offset(const struct sock *sk)
+static u64 inet_sk_port_offset(const struct sock *sk)
{
const struct inet_sock *inet = inet_sk(sk);

@@ -734,7 +734,7 @@ EXPORT_SYMBOL_GPL(inet_unhash);
static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT];

int __inet_hash_connect(struct inet_timewait_death_row *death_row,
- struct sock *sk, u32 port_offset,
+ struct sock *sk, u64 port_offset,
int (*check_established)(struct inet_timewait_death_row *,
struct sock *, __u16, struct inet_timewait_sock **))
{
@@ -859,7 +859,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
int inet_hash_connect(struct inet_timewait_death_row *death_row,
struct sock *sk)
{
- u32 port_offset = 0;
+ u64 port_offset = 0;

if (!inet_sk(sk)->inet_num)
port_offset = inet_sk_port_offset(sk);
--
2.17.5