genwqe: Prevent an integer overflow in the ioctl
commit 110080cea0d0e4dfdb0b536e7f8a5633ead6a781 upstream. There are a couple potential integer overflows here. round_up(m->size + (m->addr & ~PAGE_MASK), PAGE_SIZE); The first thing is that the "m->size + (...)" addition could overflow, and the second is that round_up() overflows to zero if the result is within PAGE_SIZE of the type max. In this code, the "m->size" variable is an u64 but we're saving the result in "map_size" which is an unsigned long and genwqe_user_vmap() takes an unsigned long as well. So I have used ULONG_MAX as the upper bound. From a practical perspective unsigned long is fine/better than trying to change all the types to u64. Fixes: eaf4722d ("GenWQE Character device and DDCB queue") Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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