4 ms·
> It's not W^X. W^X implies read-only pages are not possible, and they are. What? W^X implies that Write and Execute or mutually exclusive, can't have both ac
by admax88q 8y ago
> It's not W^X. W^X implies read-only pages are not possible, and they are.
What? W^X implies that Write and Execute or mutually exclusive, can't have both active at the same time.
> They "invented" that, what 5-10 years after Linux?
It's not so much that they "invented" it, but that they're much more diligent about making sure all the base system and ports use it. It's enforced that unless your file-system is mounted with "wxallowed" then any process that tries to mark a page both writeable and executable will fail.
- knorker 8y ago> What? W^X implies that Write and Execute or mutually exclusive, The truth table for XOR also says that "neither write nor execute" is impossible. > It's not so much that they "invented" it, but that they're much more diligent about making sure all the base system and ports use They've definitely taken it further, and turned on by default and all that, which is great. However they did at the time say that they both invented it, and that it couldn't be done on x86. Of course grsec had been doing it, including on x86, for many years. Theo's defense of why they've not done things Linux has done is that they're not interested in Linux, and don't look at it. Which is an interesting way to assure you're "state of the art"; don't look at what others are doing. So both at the time and now they say they "invented" it. Later of course they "invented" how to do it on x86, too.