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From: Dmitry Safonov <dima@arista.com>
To: linux-kernel@vger.kernel.org, David Ahern <dsahern@kernel.org>,
	Eric Dumazet <edumazet@google.com>
Cc: Dmitry Safonov <dima@arista.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Ard Biesheuvel <ardb@kernel.org>,
	Bob Gilligan <gilligan@arista.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	"David S. Miller" <davem@davemloft.net>,
	Dmitry Safonov <0x7f454c46@gmail.com>,
	Eric Biggers <ebiggers@kernel.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Francesco Ruggeri <fruggeri@arista.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Ivan Delalande <colona@arista.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Leonard Crestez <cdleonard@gmail.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Salam Noureddine <noureddine@arista.com>,
	Shuah Khan <shuah@kernel.org>,
	netdev@vger.kernel.org, linux-crypto@vger.kernel.org
Subject: [PATCH v3 04/36] net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction
Date: Thu, 27 Oct 2022 21:43:15 +0100	[thread overview]
Message-ID: <20221027204347.529913-5-dima@arista.com> (raw)
In-Reply-To: <20221027204347.529913-1-dima@arista.com>

To do that, separate two scenarios:
- where it's the first MD5 key on the system, which means that enabling
  of the static key may need to sleep;
- copying of an existing key from a listening socket to the request
  socket upon receiving a signed TCP segment, where static key was
  already enabled (when the key was added to the listening socket).

Now the life-time of the static branch for TCP-MD5 is until:
- last tcp_md5sig_info is destroyed
- last socket in time-wait state with MD5 key is closed.

Which means that after all sockets with TCP-MD5 keys are gone, the
system gets back the performance of disabled md5-key static branch.

Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 include/net/tcp.h        | 10 ++++---
 net/ipv4/tcp.c           |  5 +---
 net/ipv4/tcp_ipv4.c      | 56 ++++++++++++++++++++++++++++++----------
 net/ipv4/tcp_minisocks.c |  9 ++++---
 net/ipv4/tcp_output.c    |  4 +--
 net/ipv6/tcp_ipv6.c      | 10 +++----
 6 files changed, 63 insertions(+), 31 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 14d45661a84d..a0cdf013782a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1675,7 +1675,11 @@ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
 			const struct sock *sk, const struct sk_buff *skb);
 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 		   int family, u8 prefixlen, int l3index, u8 flags,
-		   const u8 *newkey, u8 newkeylen, gfp_t gfp);
+		   const u8 *newkey, u8 newkeylen);
+int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
+		     int family, u8 prefixlen, int l3index,
+		     struct tcp_md5sig_key *key);
+
 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
 		   int family, u8 prefixlen, int l3index, u8 flags);
 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
@@ -1683,7 +1687,7 @@ struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
 
 #ifdef CONFIG_TCP_MD5SIG
 #include <linux/jump_label.h>
-extern struct static_key_false tcp_md5_needed;
+extern struct static_key_false_deferred tcp_md5_needed;
 struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
 					   const union tcp_md5_addr *addr,
 					   int family);
@@ -1691,7 +1695,7 @@ static inline struct tcp_md5sig_key *
 tcp_md5_do_lookup(const struct sock *sk, int l3index,
 		  const union tcp_md5_addr *addr, int family)
 {
-	if (!static_branch_unlikely(&tcp_md5_needed))
+	if (!static_branch_unlikely(&tcp_md5_needed.key))
 		return NULL;
 	return __tcp_md5_do_lookup(sk, l3index, addr, family);
 }
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ef14efa1fb70..936ed566cc89 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -4460,11 +4460,8 @@ bool tcp_alloc_md5sig_pool(void)
 	if (unlikely(!READ_ONCE(tcp_md5sig_pool_populated))) {
 		mutex_lock(&tcp_md5sig_mutex);
 
-		if (!tcp_md5sig_pool_populated) {
+		if (!tcp_md5sig_pool_populated)
 			__tcp_alloc_md5sig_pool();
-			if (tcp_md5sig_pool_populated)
-				static_branch_inc(&tcp_md5_needed);
-		}
 
 		mutex_unlock(&tcp_md5sig_mutex);
 	}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index fae80b1a1796..f812d507fc9a 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1064,7 +1064,7 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req)
  * We need to maintain these in the sk structure.
  */
 
-DEFINE_STATIC_KEY_FALSE(tcp_md5_needed);
+DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ);
 EXPORT_SYMBOL(tcp_md5_needed);
 
 static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new)
@@ -1177,9 +1177,6 @@ static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_md5sig_info *md5sig;
 
-	if (rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)))
-		return 0;
-
 	md5sig = kmalloc(sizeof(*md5sig), gfp);
 	if (!md5sig)
 		return -ENOMEM;
@@ -1191,9 +1188,9 @@ static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp)
 }
 
 /* This can be called on a newly created socket, from other files */
-int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
-		   int family, u8 prefixlen, int l3index, u8 flags,
-		   const u8 *newkey, u8 newkeylen, gfp_t gfp)
+static int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
+			    int family, u8 prefixlen, int l3index, u8 flags,
+			    const u8 *newkey, u8 newkeylen, gfp_t gfp)
 {
 	/* Add Key to the list */
 	struct tcp_md5sig_key *key;
@@ -1220,9 +1217,6 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 		return 0;
 	}
 
-	if (tcp_md5sig_info_add(sk, gfp))
-		return -ENOMEM;
-
 	md5sig = rcu_dereference_protected(tp->md5sig_info,
 					   lockdep_sock_is_held(sk));
 
@@ -1246,8 +1240,44 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
 	hlist_add_head_rcu(&key->node, &md5sig->head);
 	return 0;
 }
+
+int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
+		   int family, u8 prefixlen, int l3index, u8 flags,
+		   const u8 *newkey, u8 newkeylen)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
+		if (tcp_md5sig_info_add(sk, GFP_KERNEL))
+			return -ENOMEM;
+
+		static_branch_inc(&tcp_md5_needed.key);
+	}
+
+	return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags,
+				newkey, newkeylen, GFP_KERNEL);
+}
 EXPORT_SYMBOL(tcp_md5_do_add);
 
+int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr,
+		     int family, u8 prefixlen, int l3index,
+		     struct tcp_md5sig_key *key)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) {
+		if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC)))
+			return -ENOMEM;
+
+		atomic_inc(&tcp_md5_needed.key.key.enabled);
+	}
+
+	return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index,
+				key->flags, key->key, key->keylen,
+				sk_gfp_mask(sk, GFP_ATOMIC));
+}
+EXPORT_SYMBOL(tcp_md5_key_copy);
+
 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
 		   u8 prefixlen, int l3index, u8 flags)
 {
@@ -1334,7 +1364,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, int optname,
 		return -EINVAL;
 
 	return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags,
-			      cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
+			      cmd.tcpm_key, cmd.tcpm_keylen);
 }
 
 static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp,
@@ -1591,8 +1621,7 @@ struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
 		 * memory, then we end up not copying the key
 		 * across. Shucks.
 		 */
-		tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index, key->flags,
-			       key->key, key->keylen, GFP_ATOMIC);
+		tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key);
 		sk_gso_disable(newsk);
 	}
 #endif
@@ -2284,6 +2313,7 @@ void tcp_v4_destroy_sock(struct sock *sk)
 		tcp_clear_md5_list(sk);
 		kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
 		tp->md5sig_info = NULL;
+		static_branch_slow_dec_deferred(&tcp_md5_needed);
 	}
 #endif
 
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index c375f603a16c..fb500160b8d2 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -291,13 +291,14 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 		 */
 		do {
 			tcptw->tw_md5_key = NULL;
-			if (static_branch_unlikely(&tcp_md5_needed)) {
+			if (static_branch_unlikely(&tcp_md5_needed.key)) {
 				struct tcp_md5sig_key *key;
 
 				key = tp->af_specific->md5_lookup(sk, sk);
 				if (key) {
 					tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
 					BUG_ON(tcptw->tw_md5_key && !tcp_alloc_md5sig_pool());
+					atomic_inc(&tcp_md5_needed.key.key.enabled);
 				}
 			}
 		} while (0);
@@ -337,11 +338,13 @@ EXPORT_SYMBOL(tcp_time_wait);
 void tcp_twsk_destructor(struct sock *sk)
 {
 #ifdef CONFIG_TCP_MD5SIG
-	if (static_branch_unlikely(&tcp_md5_needed)) {
+	if (static_branch_unlikely(&tcp_md5_needed.key)) {
 		struct tcp_timewait_sock *twsk = tcp_twsk(sk);
 
-		if (twsk->tw_md5_key)
+		if (twsk->tw_md5_key) {
 			kfree_rcu(twsk->tw_md5_key, rcu);
+			static_branch_slow_dec_deferred(&tcp_md5_needed);
+		}
 	}
 #endif
 }
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index c69f4d966024..86e71c8c76bc 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -766,7 +766,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 
 	*md5 = NULL;
 #ifdef CONFIG_TCP_MD5SIG
-	if (static_branch_unlikely(&tcp_md5_needed) &&
+	if (static_branch_unlikely(&tcp_md5_needed.key) &&
 	    rcu_access_pointer(tp->md5sig_info)) {
 		*md5 = tp->af_specific->md5_lookup(sk, sk);
 		if (*md5) {
@@ -922,7 +922,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 
 	*md5 = NULL;
 #ifdef CONFIG_TCP_MD5SIG
-	if (static_branch_unlikely(&tcp_md5_needed) &&
+	if (static_branch_unlikely(&tcp_md5_needed.key) &&
 	    rcu_access_pointer(tp->md5sig_info)) {
 		*md5 = tp->af_specific->md5_lookup(sk, sk);
 		if (*md5) {
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 2a3f9296df1e..f528702185c4 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -677,12 +677,11 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, int optname,
 	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 		return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
 				      AF_INET, prefixlen, l3index, flags,
-				      cmd.tcpm_key, cmd.tcpm_keylen,
-				      GFP_KERNEL);
+				      cmd.tcpm_key, cmd.tcpm_keylen);
 
 	return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
 			      AF_INET6, prefixlen, l3index, flags,
-			      cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
+			      cmd.tcpm_key, cmd.tcpm_keylen);
 }
 
 static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
@@ -1382,9 +1381,8 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
 		 * memory, then we end up not copying the key
 		 * across. Shucks.
 		 */
-		tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
-			       AF_INET6, 128, l3index, key->flags, key->key, key->keylen,
-			       sk_gfp_mask(sk, GFP_ATOMIC));
+		tcp_md5_key_copy(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
+			         AF_INET6, 128, l3index, key);
 	}
 #endif
 
-- 
2.38.1


  parent reply	other threads:[~2022-10-27 20:44 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-27 20:43 [PATCH v3 00/36] net/tcp: Add TCP-AO support Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 01/36] crypto: Introduce crypto_pool Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 02/36] crypto_pool: Add crypto_pool_reserve_scratch() Dmitry Safonov
2022-10-28  7:06   ` kernel test robot
2022-10-27 20:43 ` [PATCH v3 03/36] net/tcp: Separate tcp_md5sig_info allocation into tcp_md5sig_info_add() Dmitry Safonov
2022-10-27 20:43 ` Dmitry Safonov [this message]
2022-10-27 20:43 ` [PATCH v3 05/36] net/tcp: Use crypto_pool for TCP-MD5 Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 06/36] net/ipv6: sr: Switch to using crypto_pool Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 07/36] tcp: Add TCP-AO config and structures Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 08/36] net/tcp: Introduce TCP_AO setsockopt()s Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 09/36] net/tcp: Prevent TCP-MD5 with TCP-AO being set Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 10/36] net/tcp: Calculate TCP-AO traffic keys Dmitry Safonov
2022-10-28  8:07   ` kernel test robot
2022-10-27 20:43 ` [PATCH v3 11/36] net/tcp: Add TCP-AO sign to outgoing packets Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 12/36] net/tcp: Add tcp_parse_auth_options() Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 13/36] net/tcp: Add AO sign to RST packets Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 14/36] net/tcp: Add TCP-AO sign to twsk Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 15/36] net/tcp: Wire TCP-AO to request sockets Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 16/36] net/tcp: Sign SYN-ACK segments with TCP-AO Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 17/36] net/tcp: Verify inbound TCP-AO signed segments Dmitry Safonov
2022-10-28  5:15   ` kernel test robot
2022-10-27 20:43 ` [PATCH v3 18/36] net/tcp: Add TCP-AO segments counters Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 19/36] net/tcp: Add TCP-AO SNE support Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 20/36] net/tcp: Add tcp_hash_fail() ratelimited logs Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 21/36] net/tcp: Ignore specific ICMPs for TCP-AO connections Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 22/36] net/tcp: Add option for TCP-AO to (not) hash header Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 23/36] net/tcp: Add getsockopt(TCP_AO_GET) Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 24/36] net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs) Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 25/36] net/tcp-ao: Add static_key for TCP-AO Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 26/36] selftests/net: Add TCP-AO library Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 27/36] selftests/net: Verify that TCP-AO complies with ignoring ICMPs Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 28/36] selftest/net: Add TCP-AO ICMPs accept test Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 29/36] selftest/tcp-ao: Add a test for MKT matching Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 30/36] selftest/tcp-ao: Add test for TCP-AO add setsockopt() command Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 31/36] selftests/tcp-ao: Add TCP-AO + TCP-MD5 + no sign listen socket tests Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 32/36] selftests/aolib: Add test/benchmark for removing MKTs Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 33/36] selftests/nettest: Remove client_pw Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 34/36] selftest/nettest: Rename md5_prefix* => auth_prefix* Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 35/36] selftests/nettest: Add TCP-AO support Dmitry Safonov
2022-10-27 20:43 ` [PATCH v3 36/36] selftests/fcnal-test.sh: Add TCP-AO tests Dmitry Safonov
2022-11-01  2:22 ` [PATCH v3 00/36] net/tcp: Add TCP-AO support David Ahern
2022-11-01 17:35   ` Dmitry Safonov

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