Re: [PATCH v5] drm/fbdev-generic: prohibit potential out-of-bounds access

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Thomas,

On Thu, Apr 20, 2023 at 1:10 PM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
> Am 20.04.23 um 12:04 schrieb Sui Jingfeng:
> > What will happen if the 'screen_size' is not page_size aligned and mmap
> > will mapping in the granularity of pages ?
>
> You need to map at page granularity. If screen_size is not page-size
> aligned, there's this trailing buffer that is accessible, but cannot be
> displayed. But userspace has no direct way of knowing that, so let's
> ignore that problem for now.

Userspace can know, if fb_fix_screeninfo.smem_{start,len} match
the actual offset and size.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds




[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux