* frm crispinat_private "09/05/01 16:10:35 -0700" | sed '1,$s/^/* /' * * Casey Schaufler wrote: * *> The capable()+restrictive scheme fails if the existing kernel *> code short circuits out on failure, and there's no reason it *> shouldn't if hooks are documented as restrictive. Any performance *> optimizer (and the Linux community is full of 'em) will look *> at code which calls a restrictive hook after a failure case and *> "fix" it, in what for our nefarious purposes would be the *> veterinary sense. *> * However, the "authoritative" change that is being proposed ALSO * short-circuits on DAC failure. That is a BIG part of the question of "is * this good enough for SGI's purposes?" Most of the people messing with * the code believe that it is infeasible to insert an authoritative hook on * every short-circuit case. * * So, in no event are we going to get "no short circuiting". With that in * mind, does the "kinda authoritative" approach embodied in Stephen's patch * -> Lachlan's patch -> Chris Wright's patch present a substantial * improvement in LSM usefulness to SGI? Yes. The principle is "always call a hook". The implementation of that principle can be either post-DAC logic authoritative hook or pre-DAC logic hook. Our ideal solution is #2, but that collides with Wirex's requirements, so a post-DAC authoritaive hook where it works for both Wirex and SGI and a pre-DAC where Wirex doesn't care works best for both sides of the argument of DAC before MAC vs MAC before DAC. The case of short circuiting can be addressed by pre-DAC hooks which can be either authortative or restrictive (we don't care at that point). * * Crispin richard. ----------------------------------------------------------------------- Richard Offer Technical Lead, Trust Technology, SGI "Specialization is for insects" _______________________________________________________________________ _______________________________________________ linux-security-module mailing list linux-security-moduleat_private http://mail.wirex.com/mailman/listinfo/linux-security-module
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