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Changes between Version 2 and Version 3 of Howitworks

v2	v3
77	77	their segment. If a driver tries to access such memory, it will get a general
78	78	protection fault and the kernel will kill the offending thread and proceed to
79		unload the module (cleanly if possible). Why is this good? Here is an
80		example of how the Ring Cycle acts better than the current linux kernel:
	79	unload the module (cleanly if possible).
81	80
82		Imagine you have a driver which although normally works well, has a bug
83		(perhaps due to a buffer overflow) which when given malformed data will let
84		the user write 1 byte anywhere in memory. In a regular (linux or windows)
85		kernel, a malicious user could use this to clobber important kernel data
86		structures (such as the IDT) and crash the system, or even worse, use it to
87		gain more privilege than they should have and read or corrupt sensitive data.
88
89		In the Ring Cycle kernel, all the above data structures live in the ring 0
90		portion of the address space and cannot be touched by the driver. When the
91		user tries to clobber these structures, the processor will issue a general
92		protection fault and the user is stopped in his tracks.
93
	81	For more details, please see the following:
	82	* [wiki:IOModel Asynchronous I/O model]
	83	* [wiki:ProtectionModel Protection model]
	84	* [wiki:CallGates Call gates/Driver API]