2021-02-07 23:23:54

by Colin King

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

From: Colin Ian King <[email protected]>

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 <[email protected]>
---
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


2021-02-08 15:56:16

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH] HID: logitech-dj: fix unintentional integer overflow on left shift

On Sun, Feb 07, 2021 at 11:21:20PM +0000, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> 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 <[email protected]>
> ---
> 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.

> - 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

2021-02-08 15:58:57

by Colin King

[permalink] [raw]
Subject: Re: [PATCH] HID: logitech-dj: fix unintentional integer overflow on left shift

On 08/02/2021 15:06, Dan Carpenter wrote:
> On Sun, Feb 07, 2021 at 11:21:20PM +0000, Colin King wrote:
>> From: Colin Ian King <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>> 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. :-(

>
>> - 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
>