Re: [PATCH] HID: Extend report buffer size

[peter enderborg]

On 2/10/20 4:01 PM, Alan Stern wrote:
> On Mon, 10 Feb 2020, Peter Enderborg wrote:
>
>> In the patch "HID: Fix slab-out-of-bounds read in hid_field_extract"
>> there added a check for buffer overruns. This made Elgato StreamDeck
>> to fail. This patch extend the buffer to 8192 to solve this. It also
>> adds a print of the requested length if it fails on this test.
>>
>> Signed-off-by: Peter Enderborg <peter.enderborg@xxxxxxxx>
>> ---
>>  drivers/hid/hid-core.c | 2 +-
>>  include/linux/hid.h    | 2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
>> index 851fe54ea59e..28841219b3d2 100644
>> --- a/drivers/hid/hid-core.c
>> +++ b/drivers/hid/hid-core.c
>> @@ -290,7 +290,7 @@ static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsign
>>  
>>  	/* Total size check: Allow for possible report index byte */
>>  	if (report->size > (HID_MAX_BUFFER_SIZE - 1) << 3) {
>> -		hid_err(parser->device, "report is too long\n");
>> +		hid_err(parser->device, "report is too long (%d)\n", report->size);
>>  		return -1;
>>  	}
>>  
>> diff --git a/include/linux/hid.h b/include/linux/hid.h
>> index cd41f209043f..875f71132b14 100644
>> --- a/include/linux/hid.h
>> +++ b/include/linux/hid.h
>> @@ -492,7 +492,7 @@ struct hid_report_enum {
>>  };
>>  
>>  #define HID_MIN_BUFFER_SIZE	64		/* make sure there is at least a packet size of space */
>> -#define HID_MAX_BUFFER_SIZE	4096		/* 4kb */
>> +#define HID_MAX_BUFFER_SIZE	8192		/* 8kb */
>>  #define HID_CONTROL_FIFO_SIZE	256		/* to init devices with >100 reports */
>>  #define HID_OUTPUT_FIFO_SIZE	64
> The second part of this patch is identical to the "HID: core: increase
> HID report buffer size to 8KiB" patch submitted by Johan Korsnes a few
> weeks ago.  You might want to submit just the first part of your patch,
> or not submit anything at all.
>
> Alan Stern
>
>
Korsnes patch is not in Torvalds tree nor is it requested for stable. How do we get it there?