diff options
| author | Kees Cook <[email protected]> | 2020-08-06 23:18:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2020-08-07 11:33:22 -0700 |
| commit | 3404be67bf73515babd74acd8525d09dafe4234d (patch) | |
| tree | a4d1134a39ba90f9735c18cce0a4e7a9f7329e48 | |
| parent | fa9ba3aa89f9f1c003b5f5cde893bbbc140c7223 (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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Alexander Popov <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Matthew Garrett <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Vijayanand Jitta <[email protected]>
Cc: Vinayak Menon <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | init/Kconfig | 9 |
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" |