| Message ID | 1409233801-11928-1-git-send-email-dh.herrmann@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index f09b752..61b6978 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -4720,8 +4720,8 @@ int drm_mode_create_dumb_ioctl(struct drm_device *dev, return -EINVAL; /* overflow checks for 32bit size calculations */ - cpp = DIV_ROUND_UP(args->bpp, 8); - if (cpp > 0xffffffffU / args->width) + cpp = DIV_ROUND_UP(args->bpp, 8); /* might overflow! */ + if (!cpp || cpp > 0xffffffffU / args->width) return -EINVAL; stride = cpp * args->width; if (args->height > 0xffffffffU / stride)
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> --- v2: add comment that DIV_ROUND_UP() might overflow add Rob's r-b drivers/gpu/drm/drm_crtc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)