Re: nfc: nci: fix potential NULL pointer dereference

Hi Guenter,

Please, see my comments below

Quoting Guenter Roeck [off-list ref]:

On Mon, Jun 12, 2017 at 05:02:23PM -0500, Gustavo A. R. Silva wrote:

quoted

NULL check at line 76: if (conn_info) {, implies that pointer conn_info
might be NULL, but this pointer is being previously dereferenced,
which might cause a NULL pointer dereference.

Add NULL check before dereferencing pointer conn_info in order to
avoid a potential NULL pointer dereference.

Addresses-Coverity-ID: 1362349
Signed-off-by: Gustavo A. R. Silva <redacted>
---
 net/nfc/nci/core.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 61fff42..d2198ce 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c

@@ -70,14 +70,13 @@ int nci_get_conn_info_by_dest_type_params(struct nci_dev *ndev, u8 dest_type,
 	struct nci_conn_info *conn_info;

 	list_for_each_entry(conn_info, &ndev->conn_info_list, list) {

conn_info is set in list_for_each_entry() using container_of(),
which is never NULL. Plus, it is dereferenced there as well.
The check is unnecessary.

Thanks for clarifying.

Guenter

quoted

-		if (conn_info->dest_type == dest_type) {
+		if (conn_info && conn_info->dest_type == dest_type) {
 			if (!params)
 				return conn_info->conn_id;
-			if (conn_info) {

So, this NULL check could be removed as it seems it is not useful at all ?

quoted

-				if (params->id == conn_info->dest_params->id &&
-				    params->protocol == conn_info->dest_params->protocol)
-					return conn_info->conn_id;
-			}
+
+			if (params->id == conn_info->dest_params->id &&
+			    params->protocol == conn_info->dest_params->protocol)
+				return conn_info->conn_id;
 		}
 	}

Thank you