From af28e59271e9087267b9ca7ac08779af9167383d Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 2 Mar 2017 23:48:52 +0000 Subject: [PATCH] rxrpc: Fix potential NULL-pointer exception Fix a potential NULL-pointer exception in rxrpc_do_sendmsg(). The call state check that I added should have gone into the else-body of the if-statement where we actually have a call to check. Found by CoverityScan CID#1414316 ("Dereference after null check"). Fixes: 8c55767f55a4 ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg") Reported-by: Colin Ian King Signed-off-by: David Howells Signed-off-by: David S. Miller --- net/rxrpc/sendmsg.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index 31c1538c1a8de..27685d8cba1ae 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -517,13 +517,6 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len) ret = -EBADSLT; if (cmd != RXRPC_CMD_SEND_DATA) goto error_release_sock; - 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) - goto error_release_sock; call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID, exclusive); /* The socket is now unlocked... */ @@ -531,6 +524,14 @@ 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) + goto error_release_sock; + ret = mutex_lock_interruptible(&call->user_mutex); release_sock(&rx->sk); if (ret < 0) { -- 2.39.5