4 ms·
It could also just access the physical memory via the direct map (the 1:1 mapping of physical to kernel virtual address space). In fact, this is kind of easier
by drewg123 7y ago
It could also just access the physical memory via the direct map (the 1:1 mapping of physical to kernel virtual address space). In fact, this is kind of easier now, since you're guaranteed to find all the interesting stuff in physical memory since MAP_EXCLUSIVE memory cannot be paged out.
- bzbarsky 7y agoThis is why the article says MAP_EXCLUSIVE would exclude the relevant pages from the direct map.
- drewg123 7y agoUgh, I missed that. But there is still nothing preventing a malicious (nvidia) driver from re-adding the pages back. In fact, since they are missing from the direct map, it points anything malicious right at the interesting physical addresses..