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| author | Andrey Konovalov <andreyknvl@google.com> | 2020-12-22 12:00:46 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-22 12:55:07 -0800 |
| commit | 2cdbed63490d0d2bcbae60abcc5639caa5aba49b (patch) | |
| tree | 8eb9b73b331c54dd6f5d359ccf9acc5acdbb408d /mm/kasan/generic.c | |
| parent | ffcc5cea46c0c3dde4eeb101fdf3a37da43863de (diff) | |
| download | linux-2cdbed63490d0d2bcbae60abcc5639caa5aba49b.tar.bz2 | |
kasan: hide invalid free check implementation
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
For software KASAN modes the check is based on the value in the shadow
memory. Hardware tag-based KASAN won't be using shadow, so hide the
implementation of the check in check_invalid_free().
Also simplify the code for software tag-based mode.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/d01534a4b977f97d87515dc590e6348e1406de81.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan/generic.c')
| -rw-r--r-- | mm/kasan/generic.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index 71ae070b80c6..662212d103b5 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -187,6 +187,13 @@ bool check_memory_region(unsigned long addr, size_t size, bool write, return check_memory_region_inline(addr, size, write, ret_ip); } +bool check_invalid_free(void *addr) +{ + s8 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(addr)); + + return shadow_byte < 0 || shadow_byte >= KASAN_GRANULE_SIZE; +} + void kasan_cache_shrink(struct kmem_cache *cache) { quarantine_remove_cache(cache); |