diff options
| author | Willy Tarreau <w@1wt.eu> | 2022-05-02 11:46:08 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-05-05 05:22:20 +0300 |
| commit | b2d057560b8107c633b39aabe517ff9d93f285e3 (patch) | |
| tree | cb66d5f31162d4a88c8814a5ecba085492ef98be /net/ipv4 | |
| parent | 205557ba9904eec0a8e9ca28ec32e567f5027338 (diff) | |
| download | linux-b2d057560b8107c633b39aabe517ff9d93f285e3.tar.xz | |
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
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 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>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/inet_hashtables.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 17440840a791..9d24d9319f3d 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -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); |