diff options
| author | David Herrmann <dh.herrmann@gmail.com> | 2014-08-24 19:23:26 +0200 |
|---|---|---|
| committer | David Herrmann <dh.herrmann@gmail.com> | 2014-08-28 15:45:43 +0200 |
| commit | 171e7ac302f6992ba9fce64903611c2435de1dd3 (patch) | |
| tree | 839357bf5c7b0b49df58fca820cee46aaeb43bac | |
| parent | 04cd214516d8a6f0f8c0116185d6e360df0860d2 (diff) | |
drm: fix division-by-zero on dumb_create()drm-next
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>
| -rw-r--r-- | drivers/gpu/drm/drm_crtc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index f09b75212081..61b6978e1581 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) |