From 37411cad633f5e41f8a13007654909d21b19363a Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
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: 540b1c48c37a ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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) {
--
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