Messages in this thread | | | Date | Tue, 06 Aug 2002 11:42:49 +0200 | From | Manfred Spraul <> | Subject | Re: [TRIVIAL] Warn users about machines with non-working WP bit |
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David S. Miller wrote:
> From: Manfred Spraul <manfred@colorfullife.com> > Date: Tue, 06 Aug 2002 11:17:33 +0200 > > > - printk("No.\n"); > > + printk("No (that's security hole).\n"); > > #ifdef CONFIG_X86_WP_WORKS_OK > > Could you explain the hole? > WP works for user space apps, only ring0 (or ring 0-2?) code > ignores the WP bit on i386. > >So copy_to_user() could write to user areas that are write-proteced. > >verify_area() checks aren't enough, consider a threaded application >calling mprotect() while the copy is in progress. > > Then we should either fix copy_to_user(), or mark 80386 unsupported, or disable multi-threading on 80386. It's a random memory corruption, far worse than a security hole.
-- Manfred
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