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Groups > linux.kernel > #1697339
| From | Kees Cook <keescook@chromium.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [v3] mm: Add SLUB free list pointer obfuscation |
| Date | 2017-07-26 18:30 +0200 |
| Message-ID | <u7xma-2CU-21@gated-at.bofh.it> (permalink) |
| References | <u02Qa-5ct-1@gated-at.bofh.it> <u6SVI-227-15@gated-at.bofh.it> <u7in7-1wt-3@gated-at.bofh.it> <u7vNn-1yO-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, Jul 26, 2017 at 7:08 AM, Christopher Lameter <cl@linux.com> wrote:
> On Tue, 25 Jul 2017, Kees Cook wrote:
>
>> > @@ -290,6 +290,10 @@ static inline void set_freepointer(struct kmem_cache *s,
>> > void *object, void *fp)
>> > {
>> > unsigned long freeptr_addr = (unsigned long)object + s->offset;
>> >
>> > +#ifdef CONFIG_SLAB_FREELIST_HARDENED
>> > + BUG_ON(object == fp); /* naive detection of double free or corruption */
>> > +#endif
>> > +
>> > *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
>>
>> What happens if, instead of BUG_ON, we do:
>>
>> if (unlikely(WARN_RATELIMIT(object == fp, "double-free detected"))
>> return;
>
> This may work for the free fastpath but the set_freepointer function is
> use in multiple other locations. Maybe just add this to the fastpath
> instead of to this fucnction?
Do you mean do_slab_free()?
-Kees
--
Kees Cook
Pixel Security
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Re: [v3] mm: Add SLUB free list pointer obfuscation Alexander Popov <alex.popov@linux.com> - 2017-07-24 23:20 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Alexander Popov <alex.popov@linux.com> - 2017-07-25 11:50 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Kees Cook <keescook@chromium.org> - 2017-07-26 02:30 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Christopher Lameter <cl@linux.com> - 2017-07-26 16:50 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Kees Cook <keescook@chromium.org> - 2017-07-26 18:30 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Christopher Lameter <cl@linux.com> - 2017-07-26 19:00 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Kees Cook <keescook@chromium.org> - 2017-07-26 19:20 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Christopher Lameter <cl@linux.com> - 2017-07-27 17:20 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Alexander Popov <alex.popov@linux.com> - 2017-07-28 00:50 +0200
Re: [v3] mm: Add SLUB free list pointer obfuscation Christopher Lameter <cl@linux.com> - 2017-07-28 02:00 +0200
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