Re: [PATCH 1/1] hid: fix I2C read buffer overflow in raw_event() for mcp2221

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Oct 07, 2025 at 05:23:17PM +0200, Lecomte, Arnaud wrote:
> 
> On 07/10/2025 15:16, Greg KH wrote:
> > On Tue, Oct 07, 2025 at 03:08:11PM +0200, Romain Sioen wrote:
> > > From: Arnaud Lecomte <contact@arnaud-lcm.com>
> > > 
> > > [ Upstream commit b56cc41a3ae7323aa3c6165f93c32e020538b6d2 ]
> > > 
> > > As reported by syzbot, mcp2221_raw_event lacked
> > > validation of incoming I2C read data sizes, risking buffer
> > > overflows in mcp->rxbuf during multi-part transfers.
> > > As highlighted in the DS20005565B spec, p44, we have:
> > > "The number of read-back data bytes to follow in this packet:
> > > from 0 to a maximum of 60 bytes of read-back bytes."
> > > This patch enforces we don't exceed this limit.
> > > 
> > > Reported-by: syzbot+52c1a7d3e5b361ccd346@syzkaller.appspotmail.com
> > > Closes: https://syzkaller.appspot.com/bug?extid=52c1a7d3e5b361ccd346
> > > Tested-by: syzbot+52c1a7d3e5b361ccd346@syzkaller.appspotmail.com
> > > Signed-off-by: Arnaud Lecomte <contact@arnaud-lcm.com>
> > > Link: https://patch.msgid.link/20250726220931.7126-1-contact@arnaud-lcm.com
> > > Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
> > > [romain.sioen@microchip.com: backport to stable, up to 6.12. Add "Fixes" tag]
> > I don't see a fixes tag :(
> Hey, I am the author of the patch. I can find the fixes tag if this looks
> good to you.

There's no need for a fixes tag, just let us know where you want this
backported to.

thanks,

greg k-h