On 22.12.2015 4:40, Laura Abbott wrote: > Each of the different allocators (SLAB/SLUB/SLOB) handles > clearing of objects differently depending on configuration. > Add common infrastructure for selecting sanitization levels > (off, slow path only, partial, full) and marking caches as > appropriate. > > All credit for the original work should be given to Brad Spengler and > the PaX Team. > > Signed-off-by: Laura Abbott <[email protected]> > > +#ifdef CONFIG_SLAB_MEMORY_SANITIZE > +#ifdef CONFIG_X86_64 > +#define SLAB_MEMORY_SANITIZE_VALUE '\xfe' > +#else > +#define SLAB_MEMORY_SANITIZE_VALUE '\xff' > +#endif > +enum slab_sanitize_mode { > + /* No sanitization */ > + SLAB_SANITIZE_OFF = 0, > + > + /* Partial sanitization happens only on the slow path */ > + SLAB_SANITIZE_PARTIAL_SLOWPATH = 1,
Can you explain more about this variant? I wonder who might find it useful except someone getting a false sense of security, but cheaper. It sounds like wanting the cake and eat it too :) I would be surprised if such IMHO half-solution existed in the original PAX_MEMORY_SANITIZE too? Or is there something that guarantees that the objects freed on hotpath won't stay there for long so the danger of leak is low? (And what about use-after-free?) It depends on further slab activity, no? (I'm not that familiar with SLUB, but I would expect the hotpath there being similar to SLAB freeing the object on per-cpu array_cache. But, it seems the PARTIAL_SLOWPATH is not implemented for SLAB, so there might be some fundamental difference I'm missing.) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
