linux-kernel - [PATCH] rndis_wlan: tighten check of rndis_query

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Message-Id: <20200811140219.8412-1-trix@redhat.com>
Date:   Tue, 11 Aug 2020 07:02:19 -0700
From:   trix@...hat.com
To:     jussi.kivilinna@....fi, kvalo@...eaurora.org, davem@...emloft.net,
        kuba@...nel.org
Cc:     linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Tom Rix <trix@...hat.com>
Subject: [PATCH] rndis_wlan: tighten check of rndis_query_oid return

From: Tom Rix <trix@...hat.com>

clang static analysis reports this problem

rndis_wlan.c:3147:25: warning: Assigned value is garbage or undefined
                wiphy->max_num_pmkids = le32_to_cpu(caps.num_pmkids);
                                      ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The setting of caps happens here, with a call to rndis_query_oid()

	retval = rndis_query_oid(usbdev,
	if (retval >= 0) {

Reviewing rndis_query_oid() shows that on success 0 is returned,
failure is otherwise.  So the retval check is not tight enough.
So tighten the retval check.  Similar problem in
rndis_wlan_get_caps().

Signed-off-by: Tom Rix <trix@...hat.com>
---
 drivers/net/wireless/rndis_wlan.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c
index 8852a1832951..75b5d545b49e 100644
--- a/drivers/net/wireless/rndis_wlan.c
+++ b/drivers/net/wireless/rndis_wlan.c
@@ -3112,7 +3112,7 @@ static int rndis_wlan_get_caps(struct usbnet *usbdev, struct wiphy *wiphy)
 	retval = rndis_query_oid(usbdev,
 				 RNDIS_OID_802_11_NETWORK_TYPES_SUPPORTED,
 				 &networks_supported, &len);
-	if (retval >= 0) {
+	if (!retval) {
 		n = le32_to_cpu(networks_supported.num_items);
 		if (n > 8)
 			n = 8;
@@ -3137,7 +3137,7 @@ static int rndis_wlan_get_caps(struct usbnet *usbdev, struct wiphy *wiphy)
 	retval = rndis_query_oid(usbdev,
 				 RNDIS_OID_802_11_CAPABILITY,
 				 &caps, &len);
-	if (retval >= 0) {
+	if (!retval) {
 		netdev_dbg(usbdev->net, "RNDIS_OID_802_11_CAPABILITY -> len %d, "
 				"ver %d, pmkids %d, auth-encr-pairs %d\n",
 				le32_to_cpu(caps.length),
-- 
2.18.1