> On Aug 22, 2015, at 17:05, Borislav Petkov <b...@suse.de> wrote: > > On Fri, Aug 21, 2015 at 02:06:16PM -0700, H. Peter Anvin wrote: >> What I'm saying is that we do do STAC, which *disables* SMAP. We have >> to do that because one pointer is known to be a user space pointer. >> >> However, we currently don't verify that the *other* pointer is kernel >> space, which it is supposed to be (if not, we should be using >> copy_in_user). We have to do this manually since we have to STAC which >> means SMAP doesn't do anything at all. I believe it would be a good >> idea to add such checks (and they would even benefit non-SMAP hardware.) > > Ah, ok, so we're on the same page. > > And yep, Linus gave the probe_kernel_read() suggestion in another mail. > i am not clear about what is STAC / SMAP ? could you give me a link for understanding ?
Linus suggest to use probe_kernel_read() , but also said it is not efficient to use it, because we need copy the data 2 times by this method. my patch suggests to use copy_in_user() , but seems not a generic(portable) function on all architectures. Thanks-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
