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secure_seq: use the 64 bits of the siphash for port offset calculation 

SipHash replaced MD5 in secure_ipv{4,6}_port_ephemeral() via commit
7cd23e5300 ("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 functions return the full 64-bit of siphash_3u32().
We also make sure the port offset calculation in __inet_hash_connect()
remains done on 32-bit to avoid the need for div_u64_rem() and an extra
cost on 32-bit systems.

Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Moshe Kol <moshe.kol@mail.huji.ac.il>
Cc: Yossi Gilad <yossi.gilad@mail.huji.ac.il>
Cc: Amit Klein <aksecurity@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Willy Tarreau 2022-05-02 10:46:08 +02:00 committed by Jakub Kicinski
parent 205557ba99
commit b2d057560b
5 changed files with 13 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/inet_hashtables.h
View File

@ -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 **));

4
include/net/secure_seq.h
View File

@ -4,8 +4,8 @@
#include <linux/types.h>
u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
__be16 dport);
u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
__be16 sport, __be16 dport);

4
net/core/secure_seq.c
View File

@ -94,7 +94,7 @@ u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr,
}
EXPORT_SYMBOL(secure_tcpv6_seq);
u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
__be16 dport)
{
const struct {
@ -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,

10
net/ipv4/inet_hashtables.c
View File

@ -504,7 +504,7 @@ not_unique:
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 **))
{
@ -777,7 +777,9 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
net_get_random_once(table_perturb, sizeof(table_perturb));
index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT);
offset = (READ_ONCE(table_perturb[index]) + port_offset) % remaining;
offset = READ_ONCE(table_perturb[index]) + port_offset;
offset %= remaining;
/* In first pass we try ports of @low parity.
* inet_csk_get_port() does the opposite choice.
*/
@ -859,7 +861,7 @@ ok:
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);

4
net/ipv6/inet6_hashtables.c
View File

@ -308,7 +308,7 @@ not_unique:
return -EADDRNOTAVAIL;
}
static u32 inet6_sk_port_offset(const struct sock *sk)
static u64 inet6_sk_port_offset(const struct sock *sk)
{
const struct inet_sock *inet = inet_sk(sk);
@ -320,7 +320,7 @@ static u32 inet6_sk_port_offset(const struct sock *sk)
int inet6_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 = inet6_sk_port_offset(sk);