Quoting Chris Wilson (2019-03-14 09:58:29)
> We assumed that vm_mmap() would reject an attempt to mmap past the end of
> the filp (our object), but we were wrong.
>
> Reported-by: Antonio Argenziano <antonio.argenziano@xxxxxxxxx>
> Testcase: igt/gem_mmap/bad-size
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Antonio Argenziano <antonio.argenziano@xxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
With the SIGBUS => EINVAL difference documented this is:
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Regards, Joonas
> ---
> drivers/gpu/drm/i915/i915_gem.c | 15 +++++++++------
> 1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index b38c9531b5e8..b7086c8d4726 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1639,8 +1639,13 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> * pages from.
> */
> if (!obj->base.filp) {
> - i915_gem_object_put(obj);
> - return -ENXIO;
> + addr = -ENXIO;
> + goto err;
> + }
> +
> + if (range_overflows(args->offset, args->size, (u64)obj->base.size)) {
> + addr = -EINVAL;
> + goto err;
> }
>
> addr = vm_mmap(obj->base.filp, 0, args->size,
> @@ -1654,8 +1659,8 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> struct vm_area_struct *vma;
>
> if (down_write_killable(&mm->mmap_sem)) {
> - i915_gem_object_put(obj);
> - return -EINTR;
> + addr = -EINTR;
> + goto err;
> }
> vma = find_vma(mm, addr);
> if (vma && __vma_matches(vma, obj->base.filp, addr, args->size))
> @@ -1673,12 +1678,10 @@ i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
> i915_gem_object_put(obj);
>
> args->addr_ptr = (u64)addr;
> -
> return 0;
>
> err:
> i915_gem_object_put(obj);
> -
> return addr;
> }
>
> --
> 2.20.1
>
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