From 146d8fef9da1ba854de7fa28b9cb9eb147535f88 Mon Sep 17 00:00:00 2001 From: David Howells Date: Sat, 4 Mar 2017 00:01:41 +0000 Subject: rxrpc: Call state should be read with READ_ONCE() under some circumstances The call state may be changed at any time by the data-ready routine in response to received packets, so if the call state is to be read and acted upon several times in a function, READ_ONCE() must be used unless the call state lock is held. Signed-off-by: David Howells Signed-off-by: David S. Miller --- net/rxrpc/sendmsg.c | 48 ++++++++++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 18 deletions(-) (limited to 'net/rxrpc/sendmsg.c') diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index bc2d3dcff9de..47ccfeacc1c6 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -488,6 +488,7 @@ rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) __releases(&rx->sk.sk_lock.slock) { + enum rxrpc_call_state state; enum rxrpc_command cmd; struct rxrpc_call *call; unsigned long user_call_ID = 0; @@ -526,13 +527,17 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) return PTR_ERR(call); /* ... and we have the call lock. */ } else { - ret = -EBUSY; - if (call->state == RXRPC_CALL_UNINITIALISED || - call->state == RXRPC_CALL_CLIENT_AWAIT_CONN || - call->state == RXRPC_CALL_SERVER_PREALLOC || - call->state == RXRPC_CALL_SERVER_SECURING || - call->state == RXRPC_CALL_SERVER_ACCEPTING) + switch (READ_ONCE(call->state)) { + case RXRPC_CALL_UNINITIALISED: + case RXRPC_CALL_CLIENT_AWAIT_CONN: + case RXRPC_CALL_SERVER_PREALLOC: + case RXRPC_CALL_SERVER_SECURING: + case RXRPC_CALL_SERVER_ACCEPTING: + ret = -EBUSY; goto error_release_sock; + default: + break; + } ret = mutex_lock_interruptible(&call->user_mutex); release_sock(&rx->sk); @@ -542,10 +547,11 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) } } + state = READ_ONCE(call->state); _debug("CALL %d USR %lx ST %d on CONN %p", - call->debug_id, call->user_call_ID, call->state, call->conn); + call->debug_id, call->user_call_ID, state, call->conn); - if (call->state >= RXRPC_CALL_COMPLETE) { + if (state >= RXRPC_CALL_COMPLETE) { /* it's too late for this call */ ret = -ESHUTDOWN; } else if (cmd == RXRPC_CMD_SEND_ABORT) { @@ -555,12 +561,12 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) } else if (cmd != RXRPC_CMD_SEND_DATA) { ret = -EINVAL; } else if (rxrpc_is_client_call(call) && - call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) { + state != RXRPC_CALL_CLIENT_SEND_REQUEST) { /* request phase complete for this client call */ ret = -EPROTO; } else if (rxrpc_is_service_call(call) && - call->state != RXRPC_CALL_SERVER_ACK_REQUEST && - call->state != RXRPC_CALL_SERVER_SEND_REPLY) { + state != RXRPC_CALL_SERVER_ACK_REQUEST && + state != RXRPC_CALL_SERVER_SEND_REPLY) { /* Reply phase not begun or not complete for service call. */ ret = -EPROTO; } else { @@ -605,14 +611,20 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call, _debug("CALL %d USR %lx ST %d on CONN %p", call->debug_id, call->user_call_ID, call->state, call->conn); - if (call->state >= RXRPC_CALL_COMPLETE) { - ret = -ESHUTDOWN; /* it's too late for this call */ - } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST && - call->state != RXRPC_CALL_SERVER_ACK_REQUEST && - call->state != RXRPC_CALL_SERVER_SEND_REPLY) { - ret = -EPROTO; /* request phase complete for this client call */ - } else { + switch (READ_ONCE(call->state)) { + case RXRPC_CALL_CLIENT_SEND_REQUEST: + case RXRPC_CALL_SERVER_ACK_REQUEST: + case RXRPC_CALL_SERVER_SEND_REPLY: ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len); + break; + case RXRPC_CALL_COMPLETE: + /* It's too late for this call */ + ret = -ESHUTDOWN; + break; + default: + /* Request phase complete for this client call */ + ret = -EPROTO; + break; } mutex_unlock(&call->user_mutex); -- cgit v1.2.3 From 6fc166d62c6f9f6eda5ea300f671d34e89bdd3c8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 9 Mar 2017 08:10:32 +0000 Subject: rxrpc: rxrpc_kernel_send_data() needs to handle failed call better If rxrpc_kernel_send_data() is asked to send data through a call that has already failed (due to a remote abort, received protocol error or network error), then return the associated error code saved in the call rather than ESHUTDOWN. This allows the caller to work out whether to ask for the abort code or not based on this. Signed-off-by: David Howells Signed-off-by: David S. Miller --- net/rxrpc/sendmsg.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/rxrpc/sendmsg.c') diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index 47ccfeacc1c6..97ab214ca411 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -618,8 +618,9 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call, ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len); break; case RXRPC_CALL_COMPLETE: - /* It's too late for this call */ - ret = -ESHUTDOWN; + read_lock_bh(&call->state_lock); + ret = -call->error; + read_unlock_bh(&call->state_lock); break; default: /* Request phase complete for this client call */ -- cgit v1.2.3