The rule change will require merchants to gain cardholder approval at the conclusion of the trial before they start billing. To help cardholders with that decision, merchants will be required to send the cardholder – either by email or text – the transaction amount, payment date, merchant name along with explicit instructions on how to cancel a trial.
原因是 Linux 與 OS X 上有 direct-physical map 的機制,會把整塊 physical memory 對應到 virtual memory 的固定位置上,這些位置不會再發給 user space 使用,所以是通的:
On Linux and OS X, this is done via a direct-physical map, i.e., the entire physical memory is directly mapped to a pre-defined virtual address (cf. Figure 2).
而在 Windows 上則是比較複雜,但大部分的 physical memory 都有對應到 kernel address space,而每個 process 裡面也都還是有完整的 kernel address space (只是受到權限控制),所以 Meltdown 的攻擊仍然有效:
Instead of a direct-physical map, Windows maintains a multiple so-called paged pools, non-paged pools, and the system cache. These pools are virtual memory regions in the kernel address space mapping physical pages to virtual addresses which are either required to remain in the memory (non-paged pool) or can be removed from the memory because a copy is already stored on the disk (paged pool). The system cache further contains mappings of all file-backed pages. Combined, these memory pools will typically map a large fraction of the physical memory into the kernel address space of every process.
Update (June 28): After twice confirming it used location to suggest new friends, Facebook now says it doesn’t currently use “location data, such as device location and location information you add to your profile, to suggest people you may know.” The company says it ran a brief test using location last year. New story here.
“People You May Know are people on Facebook that you might know,” a Facebook spokesperson said. “We show you people based on mutual friends, work and education information, networks you’re part of, contacts you’ve imported and many other factors.”
One of those factors is smartphone location. A Facebook spokesperson said though that shared location alone would not result in a friend suggestion, saying that the two parents must have had something else in common, such as overlapping networks.
“Location information by itself doesn’t indicate that two people might be friends,” said the Facebook spokesperson. “That’s why location is only one of the factors we use to suggest people you may know.”