IB/qib: Protect from buffer overflow in struct qib_user_sdma_pkt fields

IB/qib: Protect from buffer overflow in struct qib_user_sdma_pkt fields

Overflowing either addrlimit or bytes_togo can allow userspace to trigger
a buffer overflow of kernel memory. Check for overflows in all the places
doing math on user controlled buffers.

Fixes: f931551bafe1 ("IB/qib: Add new qib driver for QLogic PCIe InfiniBand adapters")
Link: https://lore.kernel.org/r/20211012175519.7298.77738.stgit@awfm-01.cornelisnetworks.com
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>