Re: [PATCH] HID: Extend report buffer size

[Jiri Kosina]

On Tue, 11 Feb 2020, Alan Stern 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?
> 
> Bring the whole matter to Jiri's attention.  He is the person who will
> take care of it.

I have been a bit swamped during past few days. Johan's patch is in my 
list of things to process either today or tomorrow.

Thanks,

-- 
Jiri Kosina
SUSE Labs