On 14/03/2019 07:58, Chris Wilson wrote:
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
---
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;
}
Patch is good, and certainly for our use cases we can afford to check at
this level.
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
I am only wondering what happens to reads/write to the trailing area?
Does shmemfs expands the backing store for this mmap and we just end up
with otherwise unused chunk at the end?
Regards,
Tvrtko
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
