[ added dri-devel@lists.freedesktop.org to Cc: ]
On 09/12/2018 09:30 AM, Tomi Valkeinen wrote:
OMAPFB_MEMORY_READ ioctl reads pixels from the LCD's memory and copies them to a userspace buffer. The code has two issues:
- The user provided width and height could be large enough to overflow the calculations
- The copy_to_user() can copy uninitialized memory to the userspace, which might contain sensitive kernel information.
Fix these by limiting the width & height parameters, and only copying the amount of data that we actually received from the LCD.
Signed-off-by: Tomi Valkeinen tomi.valkeinen@ti.com Reported-by: Jann Horn jannh@google.com Cc: stable@vger.kernel.org Cc: security@kernel.org Cc: Will Deacon will.deacon@arm.com Cc: Jann Horn jannh@google.com Cc: Tony Lindgren tony@atomide.com
Patch queued for 4.19, thanks.
drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c b/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c index ef69273074ba..a3edb20ea4c3 100644 --- a/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c +++ b/drivers/video/fbdev/omap2/omapfb/omapfb-ioctl.c @@ -496,6 +496,9 @@ static int omapfb_memory_read(struct fb_info *fbi, if (!access_ok(VERIFY_WRITE, mr->buffer, mr->buffer_size)) return -EFAULT;
- if (mr->w > 4096 || mr->h > 4096)
return -EINVAL;- if (mr->w * mr->h * 3 > mr->buffer_size) return -EINVAL;
@@ -509,7 +512,7 @@ static int omapfb_memory_read(struct fb_info *fbi, mr->x, mr->y, mr->w, mr->h); if (r > 0) {
if (copy_to_user(mr->buffer, buf, mr->buffer_size))
if (copy_to_user(mr->buffer, buf, r)) r = -EFAULT;
Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics