[PATCH 6.12.y] HID: core: Mitigate potential OOB by removing bogus memset()

[PATCH 6.12.y] HID: core: Mitigate potential OOB by removing bogus memset()

[Wenshan Lan]

From: Lee Jones <lee@kernel.org>

[ Upstream commit 0a3fe972a7cb1404f693d6f1711f32bc1d244b1c ]

The memset() in hid_report_raw_event() has the good intention of
clearing out bogus data by zeroing the area from the end of the incoming
data string to the assumed end of the buffer.  However, as we have
previously seen, doing so can easily result in OOB reads and writes in
the subsequent thread of execution.

The current suggestion from one of the HID maintainers is to remove the
memset() and simply return if the incoming event buffer size is not
large enough to fill the associated report.

Suggested-by Benjamin Tissoires <bentiss@kernel.org>

Signed-off-by: Lee Jones <lee@kernel.org>
[bentiss: changed the return value]
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
[ Replace hid_warn_ratelimited() with hid_warn() in v6.12. ]
Signed-off-by: Wenshan Lan <jetlan9@163.com>
---
 drivers/hid/hid-core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 294a25330ed0..6d61bf20ec3f 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2029,9 +2029,10 @@ int hid_report_raw_event(struct hid_device *hid, enum hid_report_type type, u8 *
 		rsize = max_buffer_size;
 
 	if (csize < rsize) {
-		dbg_hid("report %d is too short, (%d < %d)\n", report->id,
-				csize, rsize);
-		memset(cdata + csize, 0, rsize - csize);
+		hid_warn(hid, "Event data for report %d was too short (%d vs %d)\n",
+			 report->id, rsize, csize);
+		ret = -EINVAL;
+		goto out;
 	}
 
 	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
-- 
2.43.0

Re: [PATCH 6.12.y] HID: core: Mitigate potential OOB by removing bogus memset()

[Benjamin Tissoires]

On Jun 03 2026, Wenshan Lan wrote:
> From: Lee Jones <lee@kernel.org>
> 
> [ Upstream commit 0a3fe972a7cb1404f693d6f1711f32bc1d244b1c ]
> 
> The memset() in hid_report_raw_event() has the good intention of
> clearing out bogus data by zeroing the area from the end of the incoming
> data string to the assumed end of the buffer.  However, as we have
> previously seen, doing so can easily result in OOB reads and writes in
> the subsequent thread of execution.
> 
> The current suggestion from one of the HID maintainers is to remove the
> memset() and simply return if the incoming event buffer size is not
> large enough to fill the associated report.
> 
> Suggested-by Benjamin Tissoires <bentiss@kernel.org>
> 
> Signed-off-by: Lee Jones <lee@kernel.org>
> [bentiss: changed the return value]
> Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
> [ Replace hid_warn_ratelimited() with hid_warn() in v6.12. ]
> Signed-off-by: Wenshan Lan <jetlan9@163.com>
> ---

This commit is known for breaking devices. You can't backport this
without the following 3 fixes:
4d3a2a466b8d ("HID: core: Fix size_t specifier in hid_report_raw_event()")
206342541fc8 ("HID: core: introduce hid_safe_input_report()")
2c85c61d1332 ("HID: pass the buffer size to hid_report_raw_event")

Note that this is the same for your 6.6, 6.1 and 5.15 patches.

Cheers,
Benjamin

>  drivers/hid/hid-core.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 294a25330ed0..6d61bf20ec3f 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -2029,9 +2029,10 @@ int hid_report_raw_event(struct hid_device *hid, enum hid_report_type type, u8 *
>  		rsize = max_buffer_size;
>  
>  	if (csize < rsize) {
> -		dbg_hid("report %d is too short, (%d < %d)\n", report->id,
> -				csize, rsize);
> -		memset(cdata + csize, 0, rsize - csize);
> +		hid_warn(hid, "Event data for report %d was too short (%d vs %d)\n",
> +			 report->id, rsize, csize);
> +		ret = -EINVAL;
> +		goto out;
>  	}
>  
>  	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
> -- 
> 2.43.0
> 
> 

Re: [PATCH 6.12.y] HID: core: Mitigate potential OOB by removing bogus memset()

[Wenshan Lan]

On 6/3/2026 3:04 PM, Benjamin Tissoires wrote:
> On Jun 03 2026, Wenshan Lan wrote:
>> From: Lee Jones <lee@kernel.org>
>>
>> [ Upstream commit 0a3fe972a7cb1404f693d6f1711f32bc1d244b1c ]
>>
>> The memset() in hid_report_raw_event() has the good intention of
>> clearing out bogus data by zeroing the area from the end of the incoming
>> data string to the assumed end of the buffer.  However, as we have
>> previously seen, doing so can easily result in OOB reads and writes in
>> the subsequent thread of execution.
>>
>> The current suggestion from one of the HID maintainers is to remove the
>> memset() and simply return if the incoming event buffer size is not
>> large enough to fill the associated report.
>>
>> Suggested-by Benjamin Tissoires <bentiss@kernel.org>
>>
>> Signed-off-by: Lee Jones <lee@kernel.org>
>> [bentiss: changed the return value]
>> Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
>> [ Replace hid_warn_ratelimited() with hid_warn() in v6.12. ]
>> Signed-off-by: Wenshan Lan <jetlan9@163.com>
>> ---
> This commit is known for breaking devices. You can't backport this
> without the following 3 fixes:
> 4d3a2a466b8d ("HID: core: Fix size_t specifier in hid_report_raw_event()")
> 206342541fc8 ("HID: core: introduce hid_safe_input_report()")
> 2c85c61d1332 ("HID: pass the buffer size to hid_report_raw_event")
>
> Note that this is the same for your 6.6, 6.1 and 5.15 patches.

Thanks for your suggestion, I will send a V2 later.

Wenshan

>
> Cheers,
> Benjamin
>
>>   drivers/hid/hid-core.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
>> index 294a25330ed0..6d61bf20ec3f 100644
>> --- a/drivers/hid/hid-core.c
>> +++ b/drivers/hid/hid-core.c
>> @@ -2029,9 +2029,10 @@ int hid_report_raw_event(struct hid_device *hid, enum hid_report_type type, u8 *
>>   		rsize = max_buffer_size;
>>   
>>   	if (csize < rsize) {
>> -		dbg_hid("report %d is too short, (%d < %d)\n", report->id,
>> -				csize, rsize);
>> -		memset(cdata + csize, 0, rsize - csize);
>> +		hid_warn(hid, "Event data for report %d was too short (%d vs %d)\n",
>> +			 report->id, rsize, csize);
>> +		ret = -EINVAL;
>> +		goto out;
>>   	}
>>   
>>   	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
>> -- 
>> 2.43.0
>>
>>

Re: [PATCH 6.12.y] HID: core: Mitigate potential OOB by removing bogus memset()

[Lee Jones]

On Wed, 03 Jun 2026, Wenshan Lan wrote:

> 
> On 6/3/2026 3:04 PM, Benjamin Tissoires wrote:
> > On Jun 03 2026, Wenshan Lan wrote:
> > > From: Lee Jones <lee@kernel.org>
> > > 
> > > [ Upstream commit 0a3fe972a7cb1404f693d6f1711f32bc1d244b1c ]
> > > 
> > > The memset() in hid_report_raw_event() has the good intention of
> > > clearing out bogus data by zeroing the area from the end of the incoming
> > > data string to the assumed end of the buffer.  However, as we have
> > > previously seen, doing so can easily result in OOB reads and writes in
> > > the subsequent thread of execution.
> > > 
> > > The current suggestion from one of the HID maintainers is to remove the
> > > memset() and simply return if the incoming event buffer size is not
> > > large enough to fill the associated report.
> > > 
> > > Suggested-by Benjamin Tissoires <bentiss@kernel.org>
> > > 
> > > Signed-off-by: Lee Jones <lee@kernel.org>
> > > [bentiss: changed the return value]
> > > Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
> > > [ Replace hid_warn_ratelimited() with hid_warn() in v6.12. ]
> > > Signed-off-by: Wenshan Lan <jetlan9@163.com>
> > > ---
> > This commit is known for breaking devices. You can't backport this
> > without the following 3 fixes:
> > 4d3a2a466b8d ("HID: core: Fix size_t specifier in hid_report_raw_event()")
> > 206342541fc8 ("HID: core: introduce hid_safe_input_report()")
> > 2c85c61d1332 ("HID: pass the buffer size to hid_report_raw_event")
> > 
> > Note that this is the same for your 6.6, 6.1 and 5.15 patches.
> 
> Thanks for your suggestion, I will send a V2 later.

https://lore.kernel.org/all/20260601083642.908433-1-lee@kernel.org/

-- 
Lee Jones