From: Willy Tarreau <w@1wt.eu>
To: netdev@vger.kernel.org
Cc: David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Eric Dumazet <edumazet@google.com>,
Moshe Kol <moshe.kol@mail.huji.ac.il>,
Yossi Gilad <yossi.gilad@mail.huji.ac.il>,
Amit Klein <aksecurity@gmail.com>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
linux-kernel@vger.kernel.org, Willy Tarreau <w@1wt.eu>
Subject: [PATCH v2 net 5/7] tcp: dynamically allocate the perturb table used by source ports
Date: Thu, 28 Apr 2022 14:39:59 +0200 [thread overview]
Message-ID: <20220428124001.7428-6-w@1wt.eu> (raw)
In-Reply-To: <20220428124001.7428-1-w@1wt.eu>
We'll need to further increase the size of this table and it's likely
that at some point its size will not be suitable anymore for a static
table. Let's allocate it on boot from inet_hashinfo2_init(), which is
called from tcp_init().
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>
---
net/ipv4/inet_hashtables.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 63bb4902f018..48ca07853068 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -731,7 +731,8 @@ EXPORT_SYMBOL_GPL(inet_unhash);
* privacy, this only consumes 1 KB of kernel memory.
*/
#define INET_TABLE_PERTURB_SHIFT 8
-static u32 table_perturb[1 << INET_TABLE_PERTURB_SHIFT];
+#define INET_TABLE_PERTURB_SIZE (1 << INET_TABLE_PERTURB_SHIFT)
+static u32 *table_perturb;
int __inet_hash_connect(struct inet_timewait_death_row *death_row,
struct sock *sk, u64 port_offset,
@@ -774,7 +775,8 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
if (likely(remaining > 1))
remaining &= ~1U;
- net_get_random_once(table_perturb, sizeof(table_perturb));
+ net_get_random_once(table_perturb,
+ INET_TABLE_PERTURB_SIZE * sizeof(*table_perturb));
index = hash_32(port_offset, INET_TABLE_PERTURB_SHIFT);
offset = READ_ONCE(table_perturb[index]) + (port_offset >> 32);
@@ -912,6 +914,12 @@ void __init inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
low_limit,
high_limit);
init_hashinfo_lhash2(h);
+
+ /* this one is used for source ports of outgoing connections */
+ table_perturb = kmalloc_array(INET_TABLE_PERTURB_SIZE,
+ sizeof(*table_perturb), GFP_KERNEL);
+ if (!table_perturb)
+ panic("TCP: failed to alloc table_perturb");
}
int inet_hashinfo2_init_mod(struct inet_hashinfo *h)
--
2.17.5
next prev parent reply other threads:[~2022-04-28 12:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-28 12:39 [PATCH v2 net 0/7] insufficient TCP source port randomness Willy Tarreau
2022-04-28 12:39 ` [PATCH v2 net 1/7] secure_seq: use the 64 bits of the siphash for port offset calculation Willy Tarreau
2022-04-29 14:38 ` Jason A. Donenfeld
2022-04-28 12:39 ` [PATCH v2 net 2/7] tcp: use different parts of the port_offset for index and offset Willy Tarreau
2022-04-28 12:39 ` [PATCH v2 net 3/7] tcp: resalt the secret every 10 seconds Willy Tarreau
2022-04-29 14:37 ` Jason A. Donenfeld
2022-04-29 15:29 ` Willy Tarreau
2022-04-29 14:48 ` Jason A. Donenfeld
2022-04-29 15:30 ` Willy Tarreau
2022-04-28 12:39 ` [PATCH v2 net 4/7] tcp: add small random increments to the source port Willy Tarreau
2022-04-28 12:39 ` Willy Tarreau [this message]
2022-04-28 12:40 ` [PATCH v2 net 6/7] tcp: increase source port perturb table to 2^16 Willy Tarreau
2022-04-28 12:40 ` [PATCH v2 net 7/7] tcp: drop the hash_32() part from the index calculation Willy Tarreau
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