diff options
| author | David Herrmann <dh.herrmann@gmail.com> | 2014-08-24 19:23:26 +0200 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2014-08-28 11:38:04 +1000 |
| commit | 00e7208997d7a42b6f7b22f582523755f43a2f9b (patch) | |
| tree | f78c53805cf874e597290c8feaa4bb7282e669bb /drivers | |
| parent | 4d6923733f158e7f8f0695b43c30c22a59ec0a34 (diff) | |
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')
| -rw-r--r-- | drivers/gpu/drm/drm_crtc.c | 3 |
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) |