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Message-Id: <b7c351a5ad6c756129d036fd87db6b4edcd3cb6a.1565882584.git.dcaratti@redhat.com>
Date: Thu, 15 Aug 2019 18:00:42 +0200
From: Davide Caratti <dcaratti@...hat.com>
To: Boris Pismenny <borisp@...lanox.com>,
Jakub Kicinski <jakub.kicinski@...ronome.com>,
John Fastabend <john.fastabend@...il.com>,
Dave Watson <davejwatson@...com>,
Aviad Yehezkel <aviadye@...lanox.com>,
"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: [PATCH net-next 1/3] net/tls: use RCU protection on icsk->icsk_ulp_data
From: Jakub Kicinski <jakub.kicinski@...ronome.com>
We need to make sure context does not get freed while diag
code is interrogating it. Free struct tls_context with
kfree_rcu().
We add the __rcu annotation directly in icsk, and cast it
away in the datapath accessor. Presumably all ULPs will
do a similar thing.
Signed-off-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
---
include/net/inet_connection_sock.h | 2 +-
include/net/tls.h | 9 +++++++--
net/core/sock_map.c | 2 +-
net/tls/tls_device.c | 2 +-
net/tls/tls_main.c | 31 +++++++++++++++++++++++-------
5 files changed, 34 insertions(+), 12 deletions(-)
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index c57d53e7e02c..895546058a20 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -97,7 +97,7 @@ struct inet_connection_sock {
const struct tcp_congestion_ops *icsk_ca_ops;
const struct inet_connection_sock_af_ops *icsk_af_ops;
const struct tcp_ulp_ops *icsk_ulp_ops;
- void *icsk_ulp_data;
+ void __rcu *icsk_ulp_data;
void (*icsk_clean_acked)(struct sock *sk, u32 acked_seq);
struct hlist_node icsk_listen_portaddr_node;
unsigned int (*icsk_sync_mss)(struct sock *sk, u32 pmtu);
diff --git a/include/net/tls.h b/include/net/tls.h
index 41b2d41bb1b8..4997742475cd 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -41,6 +41,7 @@
#include <linux/tcp.h>
#include <linux/skmsg.h>
#include <linux/netdevice.h>
+#include <linux/rcupdate.h>
#include <net/tcp.h>
#include <net/strparser.h>
@@ -290,6 +291,7 @@ struct tls_context {
struct list_head list;
refcount_t refcount;
+ struct rcu_head rcu;
};
enum tls_offload_ctx_dir {
@@ -348,7 +350,7 @@ struct tls_offload_context_rx {
#define TLS_OFFLOAD_CONTEXT_SIZE_RX \
(sizeof(struct tls_offload_context_rx) + TLS_DRIVER_STATE_SIZE_RX)
-void tls_ctx_free(struct tls_context *ctx);
+void tls_ctx_free(struct sock *sk, struct tls_context *ctx);
int wait_on_pending_writer(struct sock *sk, long *timeo);
int tls_sk_query(struct sock *sk, int optname, char __user *optval,
int __user *optlen);
@@ -467,7 +469,10 @@ static inline struct tls_context *tls_get_ctx(const struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
- return icsk->icsk_ulp_data;
+ /* Use RCU on icsk_ulp_data only for sock diag code,
+ * TLS data path doesn't need rcu_dereference().
+ */
+ return (__force void *)icsk->icsk_ulp_data;
}
static inline void tls_advance_record_sn(struct sock *sk,
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 1330a7442e5b..01998860afaa 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -345,7 +345,7 @@ static int sock_map_update_common(struct bpf_map *map, u32 idx,
return -EINVAL;
if (unlikely(idx >= map->max_entries))
return -E2BIG;
- if (unlikely(icsk->icsk_ulp_data))
+ if (unlikely(rcu_access_pointer(icsk->icsk_ulp_data)))
return -EINVAL;
link = sk_psock_init_link();
diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
index d184230665eb..436df5b4bb60 100644
--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -61,7 +61,7 @@ static void tls_device_free_ctx(struct tls_context *ctx)
if (ctx->rx_conf == TLS_HW)
kfree(tls_offload_ctx_rx(ctx));
- tls_ctx_free(ctx);
+ tls_ctx_free(NULL, ctx);
}
static void tls_device_gc_task(struct work_struct *work)
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 9cbbae606ced..04829bef514c 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -251,14 +251,31 @@ static void tls_write_space(struct sock *sk)
ctx->sk_write_space(sk);
}
-void tls_ctx_free(struct tls_context *ctx)
+/**
+ * tls_ctx_free() - free TLS ULP context
+ * @sk: socket to with @ctx is attached
+ * @ctx: TLS context structure
+ *
+ * Free TLS context. If @sk is %NULL caller guarantees that the socket
+ * to which @ctx was attached has no outstanding references.
+ */
+void tls_ctx_free(struct sock *sk, struct tls_context *ctx)
{
+ struct inet_connection_sock *icsk;
+
if (!ctx)
return;
memzero_explicit(&ctx->crypto_send, sizeof(ctx->crypto_send));
memzero_explicit(&ctx->crypto_recv, sizeof(ctx->crypto_recv));
- kfree(ctx);
+
+ if (sk) {
+ icsk = inet_csk(sk);
+ rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
+ kfree_rcu(ctx, rcu);
+ } else {
+ kfree(ctx);
+ }
}
static void tls_sk_proto_cleanup(struct sock *sk,
@@ -306,7 +323,7 @@ static void tls_sk_proto_close(struct sock *sk, long timeout)
write_lock_bh(&sk->sk_callback_lock);
if (free_ctx)
- icsk->icsk_ulp_data = NULL;
+ rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
sk->sk_prot = ctx->sk_proto;
write_unlock_bh(&sk->sk_callback_lock);
release_sock(sk);
@@ -319,7 +336,7 @@ static void tls_sk_proto_close(struct sock *sk, long timeout)
ctx->sk_proto_close(sk, timeout);
if (free_ctx)
- tls_ctx_free(ctx);
+ tls_ctx_free(sk, ctx);
}
static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
@@ -608,7 +625,7 @@ static struct tls_context *create_ctx(struct sock *sk)
if (!ctx)
return NULL;
- icsk->icsk_ulp_data = ctx;
+ rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
ctx->setsockopt = sk->sk_prot->setsockopt;
ctx->getsockopt = sk->sk_prot->getsockopt;
ctx->sk_proto_close = sk->sk_prot->close;
@@ -649,8 +666,8 @@ static void tls_hw_sk_destruct(struct sock *sk)
ctx->sk_destruct(sk);
/* Free ctx */
- tls_ctx_free(ctx);
- icsk->icsk_ulp_data = NULL;
+ tls_ctx_free(sk, ctx);
+ rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
}
static int tls_hw_prot(struct sock *sk)
--
2.20.1
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