QDnsLookup/Unix: rework the buffer-size check code

This is neater with a simple offset and avoids the potential UB code this
was carrying in:
  p += size;
  (p < response + responseLength)

It's UB to add to a pointer a size that moves it past the end of its
array. In practice we don't expect this to happen because of
construction (p is always pointing to a heap or auxiliary-thread stack
buffer), but in theory it could happen that said buffer is too close to
the end of the virtual address space and adding `size` causes it to
overflow back to small values.

Change-Id: I5f7f427ded124479baa6fffd175f59939c15c666
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

0 files changed, 0 insertions, 0 deletions