[PATCH] HID: logitech-dj: fix unintentional integer overflow on left shift

From: Colin Ian King <redacted>

Shifting the integer value 1 is evaluated using 32-bit rithmetic
and then used in an expression that expects a 64-bit value, so
there is potentially an integer overflow. Fix this by using th
BIT_ULL macro to perform the shift and avoid the overflow.

Addresses-Coverity: ("Uninitentional integer overflow")
Fixes: 534a7b8e10ec ("HID: Add full support for Logitech Unifying receivers")
Signed-off-by: Colin Ian King <redacted>
---
 drivers/hid/hid-logitech-dj.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 45e7e0bdd382..747f41be0603 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c

@@ -1035,7 +1035,7 @@ static void logi_dj_recv_forward_null_report(struct dj_receiver_dev *djrcv_dev,
 	memset(reportbuffer, 0, sizeof(reportbuffer));
 
 	for (i = 0; i < NUMBER_OF_HID_REPORTS; i++) {
-		if (djdev->reports_supported & (1 << i)) {
+		if (djdev->reports_supported & BIT_ULL(i)) {
 			reportbuffer[0] = i;
 			if (hid_input_report(djdev->hdev,
 					     HID_INPUT_REPORT,

-- 
2.29.2

On Sun, Feb 07, 2021 at 11:21:20PM +0000, Colin King wrote:

                        ^^^^^^^^^^^^^^^^^^^^^
This is 32, so it can't be undefined.

-		if (djdev->reports_supported & (1 << i)) {
+		if (djdev->reports_supported & BIT_ULL(i)) {
 			reportbuffer[0] = i;
 			if (hid_input_report(djdev->hdev,
 					     HID_INPUT_REPORT,

regards,
dan carpenter

On 08/02/2021 15:06, Dan Carpenter wrote:

On Sun, Feb 07, 2021 at 11:21:20PM +0000, Colin King wrote:

quoted

From: Colin Ian King <redacted>

Shifting the integer value 1 is evaluated using 32-bit rithmetic
and then used in an expression that expects a 64-bit value, so
there is potentially an integer overflow. Fix this by using th
BIT_ULL macro to perform the shift and avoid the overflow.

Addresses-Coverity: ("Uninitentional integer overflow")
Fixes: 534a7b8e10ec ("HID: Add full support for Logitech Unifying receivers")
Signed-off-by: Colin Ian King <redacted>
---
 drivers/hid/hid-logitech-dj.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 45e7e0bdd382..747f41be0603 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c

@@ -1035,7 +1035,7 @@ static void logi_dj_recv_forward_null_report(struct dj_receiver_dev *djrcv_dev,
 	memset(reportbuffer, 0, sizeof(reportbuffer));
 
 	for (i = 0; i < NUMBER_OF_HID_REPORTS; i++) {

                        ^^^^^^^^^^^^^^^^^^^^^
This is 32, so it can't be undefined.

Urgh, looks like coverity is being overly pedantic here. :-(

quoted

-		if (djdev->reports_supported & (1 << i)) {
+		if (djdev->reports_supported & BIT_ULL(i)) {
 			reportbuffer[0] = i;
 			if (hid_input_report(djdev->hdev,
 					     HID_INPUT_REPORT,

regards,
dan carpenter