| Message ID | 20200116192809.843138-1-matthew.auld@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] drm/i915/userptr: add user_size limit check | expand |
Quoting Matthew Auld (2020-01-16 19:28:08) > Don't allow a mismatch between obj->base.size/vma->size and the actual > number of pages for the backing store, which is limited to INT_MAX > pages. > > Signed-off-by: Matthew Auld <matthew.auld@intel.com> > Cc: Chris Wilson <chris@chris-wilson.co.uk> > --- > drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c > index e5558af111e2..fef96a303d9d 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c > @@ -768,6 +768,18 @@ i915_gem_userptr_ioctl(struct drm_device *dev, > if (args->flags & ~(I915_USERPTR_READ_ONLY | > I915_USERPTR_UNSYNCHRONIZED)) > return -EINVAL; > + /* > + * XXX: There is a prevalence of the assumption that we fit the > + * object's page count inside a 32bit _signed_ variable. Let's document > + * this and catch if we ever need to fix it. In the meantime, if you do > + * spot such a local variable, please consider fixing! > + */ > + > + if (args->user_size >> PAGE_SHIFT > INT_MAX) > + return -E2BIG; Are we not safe yet? > + > + if (overflows_type(args->user_size, obj->base.size)) > + return -E2BIG; Ok. -Chris
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c index e5558af111e2..fef96a303d9d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -768,6 +768,18 @@ i915_gem_userptr_ioctl(struct drm_device *dev, if (args->flags & ~(I915_USERPTR_READ_ONLY | I915_USERPTR_UNSYNCHRONIZED)) return -EINVAL; + /* + * XXX: There is a prevalence of the assumption that we fit the + * object's page count inside a 32bit _signed_ variable. Let's document + * this and catch if we ever need to fix it. In the meantime, if you do + * spot such a local variable, please consider fixing! + */ + + if (args->user_size >> PAGE_SHIFT > INT_MAX) + return -E2BIG; + + if (overflows_type(args->user_size, obj->base.size)) + return -E2BIG; if (!args->user_size) return -EINVAL;
Don't allow a mismatch between obj->base.size/vma->size and the actual number of pages for the backing store, which is limited to INT_MAX pages. Signed-off-by: Matthew Auld <matthew.auld@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)