From 15cc10453398c22f78f6c2b897119ecce5e5dd89 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 11 Feb 2021 15:30:37 -0800 Subject: mptcp: deliver ssk errors to msk Currently all errors received on msk subflows are ignored. We need to catch at least the errors on connect() and on fallback sockets. Use a custom sk_error_report callback at subflow level, and do the real action under the msk socket lock - via the usual sock_owned_by_user()/release_callback() schema. Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks") Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- net/mptcp/subflow.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'net/mptcp/subflow.c') diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 278cbe3e539e..0ec3ccac6bb4 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1043,6 +1043,46 @@ static void subflow_write_space(struct sock *ssk) /* we take action in __mptcp_clean_una() */ } +void __mptcp_error_report(struct sock *sk) +{ + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + int err = sock_error(ssk); + + if (!err) + continue; + + /* only propagate errors on fallen-back sockets or + * on MPC connect + */ + if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk)) + continue; + + inet_sk_state_store(sk, inet_sk_state_load(ssk)); + sk->sk_err = -err; + + /* This barrier is coupled with smp_rmb() in mptcp_poll() */ + smp_wmb(); + sk->sk_error_report(sk); + break; + } +} + +static void subflow_error_report(struct sock *ssk) +{ + struct sock *sk = mptcp_subflow_ctx(ssk)->conn; + + mptcp_data_lock(sk); + if (!sock_owned_by_user(sk)) + __mptcp_error_report(sk); + else + set_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags); + mptcp_data_unlock(sk); +} + static struct inet_connection_sock_af_ops * subflow_default_af_ops(struct sock *sk) { @@ -1352,9 +1392,11 @@ static int subflow_ulp_init(struct sock *sk) ctx->tcp_data_ready = sk->sk_data_ready; ctx->tcp_state_change = sk->sk_state_change; ctx->tcp_write_space = sk->sk_write_space; + ctx->tcp_error_report = sk->sk_error_report; sk->sk_data_ready = subflow_data_ready; sk->sk_write_space = subflow_write_space; sk->sk_state_change = subflow_state_change; + sk->sk_error_report = subflow_error_report; out: return err; } @@ -1407,6 +1449,7 @@ static void subflow_ulp_clone(const struct request_sock *req, new_ctx->tcp_data_ready = old_ctx->tcp_data_ready; new_ctx->tcp_state_change = old_ctx->tcp_state_change; new_ctx->tcp_write_space = old_ctx->tcp_write_space; + new_ctx->tcp_error_report = old_ctx->tcp_error_report; new_ctx->rel_write_seq = 1; new_ctx->tcp_sock = newsk; -- cgit v1.2.3 From d8b59efa64060d17b7b61f97d891de2d9f2bd9f0 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 11 Feb 2021 15:30:40 -0800 Subject: mptcp: init mptcp request socket earlier The mptcp subflow route_req() callback performs the subflow req initialization after the route_req() check. If the latter fails, mptcp-specific bits of the current request sockets are left uninitialized. The above causes bad things at req socket disposal time, when the mptcp resources are cleared. This change addresses the issue by splitting subflow_init_req() into the actual initialization and the mptcp-specific checks. The initialization is moved before any possibly failing check. Reported-by: Christoph Paasch Fixes: 7ea851d19b23 ("tcp: merge 'init_req' and 'route_req' functions") Signed-off-by: Paolo Abeni Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- net/mptcp/subflow.c | 40 ++++++++++++++++------------------------ 1 file changed, 16 insertions(+), 24 deletions(-) (limited to 'net/mptcp/subflow.c') diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 0ec3ccac6bb4..8b2338dfdc80 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -92,7 +92,7 @@ static struct mptcp_sock *subflow_token_join_request(struct request_sock *req, return msk; } -static int __subflow_init_req(struct request_sock *req, const struct sock *sk_listener) +static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener) { struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); @@ -100,16 +100,6 @@ static int __subflow_init_req(struct request_sock *req, const struct sock *sk_li subflow_req->mp_join = 0; subflow_req->msk = NULL; mptcp_token_init_request(req); - -#ifdef CONFIG_TCP_MD5SIG - /* no MPTCP if MD5SIG is enabled on this socket or we may run out of - * TCP option space. - */ - if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) - return -EINVAL; -#endif - - return 0; } /* Init mptcp request socket. @@ -117,20 +107,23 @@ static int __subflow_init_req(struct request_sock *req, const struct sock *sk_li * Returns an error code if a JOIN has failed and a TCP reset * should be sent. */ -static int subflow_init_req(struct request_sock *req, - const struct sock *sk_listener, - struct sk_buff *skb) +static int subflow_check_req(struct request_sock *req, + const struct sock *sk_listener, + struct sk_buff *skb) { struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); struct mptcp_options_received mp_opt; - int ret; pr_debug("subflow_req=%p, listener=%p", subflow_req, listener); - ret = __subflow_init_req(req, sk_listener); - if (ret) - return 0; +#ifdef CONFIG_TCP_MD5SIG + /* no MPTCP if MD5SIG is enabled on this socket or we may run out of + * TCP option space. + */ + if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) + return -EINVAL; +#endif mptcp_get_options(skb, &mp_opt); @@ -205,10 +198,7 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req, struct mptcp_options_received mp_opt; int err; - err = __subflow_init_req(req, sk_listener); - if (err) - return err; - + subflow_init_req(req, sk_listener); mptcp_get_options(skb, &mp_opt); if (mp_opt.mp_capable && mp_opt.mp_join) @@ -248,12 +238,13 @@ static struct dst_entry *subflow_v4_route_req(const struct sock *sk, int err; tcp_rsk(req)->is_mptcp = 1; + subflow_init_req(req, sk); dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req); if (!dst) return NULL; - err = subflow_init_req(req, sk, skb); + err = subflow_check_req(req, sk, skb); if (err == 0) return dst; @@ -273,12 +264,13 @@ static struct dst_entry *subflow_v6_route_req(const struct sock *sk, int err; tcp_rsk(req)->is_mptcp = 1; + subflow_init_req(req, sk); dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req); if (!dst) return NULL; - err = subflow_init_req(req, sk, skb); + err = subflow_check_req(req, sk, skb); if (err == 0) return dst; -- cgit v1.2.3