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@xxxxxx>
Reported-by: Jann Horn <jannh@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Cc: security@xxxxxxxxxx
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Tony Lindgren <tony@xxxxxxxxxxx>
---
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;
}
--
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