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    SubjectRe: [PATCH v8] RO/NX protection for loadable kernel modules
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    On Wed, 3 Feb 2010 09:35:39 am Andi Kleen wrote:
    > Siarhei Liakh <sliakh.lkml@gmail.com> writes:
    >
    > > This patch is a logical extension of the protection provided by
    > > CONFIG_DEBUG_RODATA to LKMs. The protection is provided by splitting
    > > module_core and module_init into three logical parts each and setting
    > > appropriate page access permissions for each individual section:
    >
    > My current kernel has 52 modules loaded, most of them very small.
    > Assuming the additional alignment of the data section cost two more
    > pages on average (I think that's a good assumption), that's roughly
    > 424KB of additional memory, plus associated runtime costs in increased
    > TLB usage.
    >
    > What would I get for that if I applied the patch and enabled the option?

    Strict RO/NX protection. But without the option enabled, the patch gives
    best-effort protection, which is nice (for no additional space).

    Cheers,
    Rusty.


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