lkml.org 
[lkml]   [2019]   [Oct]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] drm/i810: Prevent underflow in ioctl
The "used" variables here come from the user in the ioctl and it can be
negative. It could result in an out of bounds write.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
drivers/gpu/drm/i810/i810_dma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i810/i810_dma.c b/drivers/gpu/drm/i810/i810_dma.c
index 2a77823b8e9a..e66c38332df4 100644
--- a/drivers/gpu/drm/i810/i810_dma.c
+++ b/drivers/gpu/drm/i810/i810_dma.c
@@ -728,7 +728,7 @@ static void i810_dma_dispatch_vertex(struct drm_device *dev,
if (nbox > I810_NR_SAREA_CLIPRECTS)
nbox = I810_NR_SAREA_CLIPRECTS;

- if (used > 4 * 1024)
+ if (used < 0 || used > 4 * 1024)
used = 0;

if (sarea_priv->dirty)
@@ -1048,7 +1048,7 @@ static void i810_dma_dispatch_mc(struct drm_device *dev, struct drm_buf *buf, in
if (u != I810_BUF_CLIENT)
DRM_DEBUG("MC found buffer that isn't mine!\n");

- if (used > 4 * 1024)
+ if (used < 0 || used > 4 * 1024)
used = 0;

sarea_priv->dirty = 0x7f;
--
2.20.1
\
 
 \ /
  Last update: 2019-10-04 12:23    [W:0.085 / U:1.400 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site