Re: [PATCH v2] RDMA: Directly cast the sockaddr union to sockaddr

Jason Gunthorpe
2019-05-16T15:21:48Z

On Thu, May 16, 2019 at 02:44:28PM +0200, Simon Horman wrote:
> On Mon, May 13, 2019 at 09:55:21PM -0300, Jason Gunthorpe wrote:
> > gcc 9 now does allocation size tracking and thinks that passing the member
> > of a union and then accessing beyond that member's bounds is an overflow.
> >
> > Instead of using the union member, use the entire union with a cast to
> > get to the sockaddr. gcc will now know that the memory extends the full
> > size of the union.
> >
> > Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
> > drivers/infiniband/core/addr.c | 16 ++++++++--------
> > drivers/infiniband/hw/ocrdma/ocrdma_ah.c | 5 ++---
> > drivers/infiniband/hw/ocrdma/ocrdma_hw.c | 5 ++---
> > 3 files changed, 12 insertions(+), 14 deletions(-)
> >
> > I missed the ocrdma files in the v1
> >
> > We can revisit what to do with that repetitive union after the merge
> > window, but this simple patch will eliminate the warnings for now.
> >
> > Linus, I'll send this as a PR tomorrow - there is also a bug fix for
> > the rdma-netlink changes posted that should go too.
>
> <2c>
> I would be very happy to see this revisited in such a way
> that some use is made of the C type system (instead of casts).
> </2c>

Well, I was thinking of swapping the union to sockaddr_storage ..

Do you propose to add a union to the kernel's sockaddr storage?

Jason