UPSTREAM: xfrm/compat: prevent potential spectre v1 gadget in xfrm_xlate32_attr()

  int type = nla_type(nla);

  if (type > XFRMA_MAX) {
            return -EOPNOTSUPP;
  }

@type is then used as an array index and can be used
as a Spectre v1 gadget.

  if (nla_len(nla) < compat_policy[type].len) {

array_index_nospec() can be used to prevent leaking
content of kernel memory to malicious users.

Bug: 254441685
Fixes: 5106f4a8acff ("xfrm/compat: Add 32=>64-bit messages translator")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dmitry Safonov <dima@arista.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
(cherry picked from commit b6ee896385380aa621102e8ea402ba12db1cabff)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Iac8d61100685ad513e04d2623fe0b79ba331167a