Re: [PATCH 1/2] x86/events/amd/iommu: Fix sysfs type mismatch

[Nathan Chancellor]

On Thu, Apr 15, 2021 at 08:53:35AM +0100, Christoph Hellwig wrote:
> On Wed, Apr 14, 2021 at 05:11:11PM -0700, Nathan Chancellor wrote:
> > dev_attr_show() calls _iommu_event_show() via an indirect call but
> > _iommu_event_show()'s type does not currently match the type of the
> > show() member in 'struct device_attribute', resulting in a Control Flow
> > Integrity violation.
> 
> While the fix looks fine I think we need to solve this kind of problem
> by better type checking.  The fact that we can use the wong type here
> without a compiler warning is the real issue.

I agree. Unfortunately, it seems that is going to be a much longer tail
project because of how pervasive this is (using container_of() +
attributes to get callbacks).

https://lore.kernel.org/r/202006112217.2E6CE093@keescook/
https://lore.kernel.org/r/202104021823.64FA6119@keescook/

Cheers,
Nathan