2013/3/14 Chris Wilson <ch...@chris-wilson.co.uk>:
> In order to prevent a potential NULL deference with hostile userspace,
> we need to check whether the ioctl was passed an invalid args pointer.
>
> Reported-by: Tommi Rantala <tt.rant...@gmail.com>
> Link:
> http://lkml.kernel.org/r/ca+ydwtpubvbwxbt-tdgpuvj1eu7itmcho_2b3w13hkd5+jw...@mail.gmail.com
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Thanks, looks good. I still see a flood of oopses from the other
ioctls, so it's a bit difficult to test this patch properly.
> ---
> drivers/gpu/drm/i915/i915_gem_execbuffer.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> index 365e41a..9f5602e 100644
> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
> @@ -1103,7 +1103,11 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
> struct drm_i915_gem_exec_object2 *exec2_list = NULL;
> int ret, i;
>
> - if (args->buffer_count < 1) {
> + if (args == NULL)
> + return -EINVAL;
> +
> + if (args->buffer_count < 1 ||
> + args->buffer_count > INT_MAX / sizeof(*exec2_list)) {
> DRM_DEBUG("execbuf with %d buffers\n", args->buffer_count);
> return -EINVAL;
> }
> @@ -1182,8 +1186,11 @@ i915_gem_execbuffer2(struct drm_device *dev, void
> *data,
> struct drm_i915_gem_exec_object2 *exec2_list = NULL;
> int ret;
>
> + if (args == NULL)
> + return -EINVAL;
> +
> if (args->buffer_count < 1 ||
> - args->buffer_count > UINT_MAX / sizeof(*exec2_list)) {
> + args->buffer_count > INT_MAX / sizeof(*exec2_list)) {
> DRM_DEBUG("execbuf2 with %d buffers\n", args->buffer_count);
> return -EINVAL;
> }
> --
> 1.7.10.4
>
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