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authorKees Cook <keescook@chromium.org>2020-08-06 23:18:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 11:33:22 -0700
commit3404be67bf73515babd74acd8525d09dafe4234d (patch)
treea4d1134a39ba90f9735c18cce0a4e7a9f7329e48 /init/Kconfig
parentfa9ba3aa89f9f1c003b5f5cde893bbbc140c7223 (diff)
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: 598a0717a816 ("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>
Diffstat (limited to 'init/Kconfig')
-rw-r--r--init/Kconfig9
1 files changed, 5 insertions, 4 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 9082ed33a9cd..d6a0b31b13dc 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1913,9 +1913,8 @@ config SLAB_MERGE_DEFAULT
command line.
config SLAB_FREELIST_RANDOM
- default n
+ bool "Randomize slab freelist"
depends on SLAB || SLUB
- bool "SLAB freelist randomization"
help
Randomizes the freelist order used on creating new pages. This
security feature reduces the predictability of the kernel slab
@@ -1923,12 +1922,14 @@ config SLAB_FREELIST_RANDOM
config SLAB_FREELIST_HARDENED
bool "Harden slab freelist metadata"
- depends on SLUB
+ depends on SLAB || SLUB
help
Many kernel heap attacks try to target slab cache metadata and
other infrastructure. This options makes minor performance
sacrifices to harden the kernel slab allocator against common
- freelist exploit methods.
+ freelist exploit methods. Some slab implementations have more
+ sanity-checking than others. This option is most effective with
+ CONFIG_SLUB.
config SHUFFLE_PAGE_ALLOCATOR
bool "Page allocator randomization"