[PATCH] net: rds: Fix possible null-pointer dereferences in rds_rdma_cm_event_handler_cmn()

[PATCH] net: rds: Fix possible null-pointer dereferences in rds_rdma_cm_event_handler_cmn()

[Jia-Ju Bai]

In rds_rdma_cm_event_handler_cmn(), there are some if statements to
check whether conn is NULL, such as on lines 65, 96 and 112.
But conn is not checked before being used on line 108:
    trans->cm_connect_complete(conn, event);
and on lines 140-143:
    rdsdebug("DISCONNECT event - dropping connection "
            "%pI6c->%pI6c\n", &conn->c_laddr,
            &conn->c_faddr);
    rds_conn_drop(conn);

Thus, possible null-pointer dereferences may occur.

To fix these bugs, conn is checked before being used.

These bugs are found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 net/rds/rdma_transport.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/rds/rdma_transport.c b/net/rds/rdma_transport.c
index ff74c4bbb9fc..9986d6065c4d 100644
--- a/net/rds/rdma_transport.c
+++ b/net/rds/rdma_transport.c
@@ -105,7 +105,8 @@ static int rds_rdma_cm_event_handler_cmn(struct rdma_cm_id *cm_id,
 		break;
 
 	case RDMA_CM_EVENT_ESTABLISHED:
-		trans->cm_connect_complete(conn, event);
+		if (conn)
+			trans->cm_connect_complete(conn, event);
 		break;
 
 	case RDMA_CM_EVENT_REJECTED:
@@ -137,6 +138,8 @@ static int rds_rdma_cm_event_handler_cmn(struct rdma_cm_id *cm_id,
 		break;
 
 	case RDMA_CM_EVENT_DISCONNECTED:
+		if (!conn)
+			break;
 		rdsdebug("DISCONNECT event - dropping connection "
 			 "%pI6c->%pI6c\n", &conn->c_laddr,
 			 &conn->c_faddr);
-- 
2.17.0

Re: [PATCH] net: rds: Fix possible null-pointer dereferences in rds_rdma_cm_event_handler_cmn()

[santosh.shilimkar]

On 7/26/19 7:17 AM, Jia-Ju Bai wrote:
> In rds_rdma_cm_event_handler_cmn(), there are some if statements to
> check whether conn is NULL, such as on lines 65, 96 and 112.
> But conn is not checked before being used on line 108:
>      trans->cm_connect_complete(conn, event);
> and on lines 140-143:
>      rdsdebug("DISCONNECT event - dropping connection "
>              "%pI6c->%pI6c\n", &conn->c_laddr,
>              &conn->c_faddr);
>      rds_conn_drop(conn);
> 
> Thus, possible null-pointer dereferences may occur.
> 
> To fix these bugs, conn is checked before being used.
> 
> These bugs are found by a static analysis tool STCheck written by us.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
That's possible. Looks good.

Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

Re: [PATCH] net: rds: Fix possible null-pointer dereferences in rds_rdma_cm_event_handler_cmn()

[David Miller]

From: Jia-Ju Bai <baijiaju1990@gmail.com>
Date: Fri, 26 Jul 2019 22:17:05 +0800

> In rds_rdma_cm_event_handler_cmn(), there are some if statements to
> check whether conn is NULL, such as on lines 65, 96 and 112.
> But conn is not checked before being used on line 108:
>     trans->cm_connect_complete(conn, event);
> and on lines 140-143:
>     rdsdebug("DISCONNECT event - dropping connection "
>             "%pI6c->%pI6c\n", &conn->c_laddr,
>             &conn->c_faddr);
>     rds_conn_drop(conn);
> 
> Thus, possible null-pointer dereferences may occur.
> 
> To fix these bugs, conn is checked before being used.
> 
> These bugs are found by a static analysis tool STCheck written by us.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>

Applied.