From 15a7dea750e0162f273c6e61a94f96944b75b31e Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 30 Aug 2019 12:25:47 +0200 Subject: [PATCH] net/tls: use RCU protection on icsk->icsk_ulp_data 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 Signed-off-by: David S. Miller --- 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 | 26 +++++++++++++++++++------- 5 files changed, 29 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 #include #include +#include #include #include @@ -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 a470df7ffcf9..e188139f0464 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 43252a801c3f..f8f2d2c3d627 100644 --- a/net/tls/tls_main.c +++ b/net/tls/tls_main.c @@ -251,14 +251,26 @@ 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) { 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) + kfree_rcu(ctx, rcu); + else + kfree(ctx); } static void tls_sk_proto_cleanup(struct sock *sk, @@ -306,7 +318,7 @@ 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; if (sk->sk_write_space == tls_write_space) sk->sk_write_space = ctx->sk_write_space; @@ -321,7 +333,7 @@ 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, @@ -610,7 +622,7 @@ 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; @@ -651,8 +663,8 @@ static void tls_hw_sk_destruct(struct sock *sk) ctx->sk_destruct(sk); /* Free ctx */ - tls_ctx_free(ctx); - icsk->icsk_ulp_data = NULL; + rcu_assign_pointer(icsk->icsk_ulp_data, NULL); + tls_ctx_free(sk, ctx); } static int tls_hw_prot(struct sock *sk) -- 2.30.2