Posted Jan 26, 2007 1:00 UTC (Fri) by PaulMcKenney (subscriber, #9624)
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Certainly malicious kernel modules and drivers could cause arbitrary mischief! But I am curious what added complication you see with non-malicious kernel modules (as opposed to non-malicious kernel drivers.
The rcutorture module is an example of a kernel module that is (more or less) non-malicious, and rcu_barrier() seems to work OK for it.
Please let me know what I am missing!
RCU and Unloadable Modules
Posted Jan 26, 2007 21:47 UTC (Fri) by ortalo (subscriber, #4654)
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IIRC I posted the comment erroneously (I wanted to post it on the previous article: "KHB: Recovering Device Drivers: From Sandboxing to Surviving").
Anyway, my idea was that regular device drivers modules are usually associated with hardware management and loaded according to some hardware-related event (possibly kernel-controlled in the first place). So you can build something where such kernel code could be trusted, even if loaded dynamically.
However, with a security orientation, one usually try to refrain from using admnistrator-loadable modules in order to avoid that a successful attack enables the attacker to install kernel level backdoors (nearly impossible to detect).