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0 pointstliltocatl4mo ago0 comments

But that wouldn't protect against out-of boundary access (which is the whole point of segments), would it?

0 comments

thats enforced by the VM hardware - we just shuffle the PTEs around to match the appropriate segment view

As long as it's a linear address space, adding/subtracting a large enough value to a pointer (array, stack) could still cross into another "segment".

convolvatron4mo ago

but those wouldn't be mapped unless you have crossed a call gate that enabled them. the kernel call gate implementation changes the VM map (region visibility) accordingly

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convolvatron4mo ago

thats enforced by the VM hardware - we just shuffle the PTEs around to match the appropriate segment view

rep_lodsb4mo ago

As long as it's a linear address space, adding/subtracting a large enough value to a pointer (array, stack) could still cross into another "segment".

convolvatron4mo ago

but those wouldn't be mapped unless you have crossed a call gate that enabled them. the kernel call gate implementation changes the VM map (region visibility) accordingly

j / k navigate · click thread line to collapse