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authorDavid Herrmann <dh.herrmann@gmail.com>2014-08-24 19:23:26 +0200
committerDave Airlie <airlied@redhat.com>2014-08-28 11:38:04 +1000
commit00e7208997d7a42b6f7b22f582523755f43a2f9b (patch)
treef78c53805cf874e597290c8feaa4bb7282e669bb /drivers/gpu/drm
parent4d6923733f158e7f8f0695b43c30c22a59ec0a34 (diff)
downloadlinux-stericsson-00e7208997d7a42b6f7b22f582523755f43a2f9b.tar.gz
drm: fix division-by-zero on dumb_create()
Kinda unexpected, but DIV_ROUND_UP() can overflow if passed an argument bigger than UINT_MAX - DIVISOR. Fix this by testing for "!cpp" before using it in the following division. Note that DIV_ROUND_UP() is defined as: #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) ..this will obviously overflow if (n + d - 1) is bigger than UINT_MAX. Reported-by: Tommi Rantala <tt.rantala@gmail.com> Signed-off-by: David Herrmann <dh.herrmann@gmail.com> Reviewed-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm')
-rw-r--r--drivers/gpu/drm/drm_crtc.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index fa2be249999c..90e773019eac 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -4696,8 +4696,9 @@ int drm_mode_create_dumb_ioctl(struct drm_device *dev,
return -EINVAL;
/* overflow checks for 32bit size calculations */
+ /* NOTE: DIV_ROUND_UP() can overflow */
cpp = DIV_ROUND_UP(args->bpp, 8);
- if (cpp > 0xffffffffU / args->width)
+ if (!cpp || cpp > 0xffffffffU / args->width)
return -EINVAL;
stride = cpp * args->width;
if (args->height > 0xffffffffU / stride)