mm/slab: expand CONFIG_SLAB_FREELIST_HARDENED to include SLAB
Patch series "mm: Expand CONFIG_SLAB_FREELIST_HARDENED to include SLAB"
In reviewing Vlastimil Babka's latest slub debug series, I realized[1]
that several checks under CONFIG_SLAB_FREELIST_HARDENED weren't being
applied to SLAB. Fix this by expanding the Kconfig coverage, and adding a
simple double-free test for SLAB.
This patch (of 2):
Include SLAB caches when performing kmem_cache pointer verification. A
defense against such corruption[1] should be applied to all the
allocators. With this added, the "SLAB_FREE_CROSS" and "SLAB_FREE_PAGE"
LKDTM tests now pass on SLAB:
lkdtm: Performing direct entry SLAB_FREE_CROSS
lkdtm: Attempting cross-cache slab free ...
------------[ cut here ]------------
cache_from_obj: Wrong slab cache. lkdtm-heap-b but object is from lkdtm-heap-a
WARNING: CPU: 2 PID: 2195 at mm/slab.h:530 kmem_cache_free+0x8d/0x1d0
...
lkdtm: Performing direct entry SLAB_FREE_PAGE
lkdtm: Attempting non-Slab slab free ...
------------[ cut here ]------------
virt_to_cache: Object is not a Slab page!
WARNING: CPU: 1 PID: 2202 at mm/slab.h:489 kmem_cache_free+0x196/0x1d0
Additionally clean up neighboring Kconfig entries for clarity,
readability, and redundant option removal.
[1] https://github.com/ThomasKing2014/slides/raw/master/Building%20universal%20Android%20rooting%20with%20a%20type%20confusion%20vulnerability.pdf
Fixes: 598a0717a8
("mm/slab: validate cache membership under freelist hardening")
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Garrett <mjg59@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Link: http://lkml.kernel.org/r/20200625215548.389774-1-keescook@chromium.org
Link: http://lkml.kernel.org/r/20200625215548.389774-2-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
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@ -1913,9 +1913,8 @@ config SLAB_MERGE_DEFAULT
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command line.
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config SLAB_FREELIST_RANDOM
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default n
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bool "Randomize slab freelist"
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depends on SLAB || SLUB
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bool "SLAB freelist randomization"
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help
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Randomizes the freelist order used on creating new pages. This
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security feature reduces the predictability of the kernel slab
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@ -1923,12 +1922,14 @@ config SLAB_FREELIST_RANDOM
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config SLAB_FREELIST_HARDENED
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bool "Harden slab freelist metadata"
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depends on SLUB
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depends on SLAB || SLUB
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help
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Many kernel heap attacks try to target slab cache metadata and
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other infrastructure. This options makes minor performance
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sacrifices to harden the kernel slab allocator against common
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freelist exploit methods.
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freelist exploit methods. Some slab implementations have more
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sanity-checking than others. This option is most effective with
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CONFIG_SLUB.
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config SHUFFLE_PAGE_ALLOCATOR
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bool "Page allocator randomization"
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