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When they say "map the zero page" in the article, it appears they are talking about the page with index zero, not the page with all zeros in it. Does anyone kno
by Vecr 4y ago
When they say "map the zero page" in the article, it appears they are talking about the page with index zero, not the page with all zeros in it. Does anyone know if this is correct?
- bennettnate5 4y agoYes, you have that right. By mapping memory to the page at index zero (the page a 'null' pointer would point to), an attacker can leverage a null dereference to achieve much more interesting/dangerous outcomes than just a crash.
- pjmlp 4y agoYep, that is common OS speak.
- seba_dos1 4y agoI don't know any context where "the zero page" means "the page with all zeros in it". It's a rather commonly used term.
- Dylan16807 4y agoGoogle linux zero page. The results about the page at address zero and the results about the page of all zeros are about equally common. The page full of zeros is used constantly when processes allocate memory, and is set to copy-on-write.
- roguebantha 4y agoYes I had considered it rather apparent I was referring to the page at the virtual address zero, but I've definitely referred to the CoW page used for private anonymous mappings as the "zero page" too, so I understand the confusion. I probably should have made it more clear! Sorry about that.