From: Andrey Konovalov <andreyknvl@google.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>
Cc: Will Deacon <will.deacon@arm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>,
Vlastimil Babka <vbabka@suse.cz>
Subject: [PATCH v3 1/2] kasan, mm: fix conflicts with init_on_alloc/free
Date: Fri, 15 Jan 2021 18:41:52 +0100 [thread overview]
Message-ID: <093428b5d2ca8b507f4a79f92f9929b35f7fada7.1610731872.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1610731872.git.andreyknvl@google.com>
A few places where SLUB accesses object's data or metadata were missed in
a previous patch. This leads to false positives with hardware tag-based
KASAN when bulk allocations are used with init_on_alloc/free.
Fix the false-positives by resetting pointer tags during these accesses.
(The kasan_reset_tag call is removed from slab_alloc_node, as it's added
into maybe_wipe_obj_freeptr.)
Link: https://linux-review.googlesource.com/id/I50dd32838a666e173fe06c3c5c766f2c36aae901
Fixes: aa1ef4d7b3f67 ("kasan, mm: reset tags when accessing metadata")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
mm/slub.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index dc5b42e700b8..75fb097d990d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2791,7 +2791,8 @@ static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
void *obj)
{
if (unlikely(slab_want_init_on_free(s)) && obj)
- memset((void *)((char *)obj + s->offset), 0, sizeof(void *));
+ memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
+ 0, sizeof(void *));
}
/*
@@ -2883,7 +2884,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
stat(s, ALLOC_FASTPATH);
}
- maybe_wipe_obj_freeptr(s, kasan_reset_tag(object));
+ maybe_wipe_obj_freeptr(s, object);
if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object)
memset(kasan_reset_tag(object), 0, s->object_size);
@@ -3329,7 +3330,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
int j;
for (j = 0; j < i; j++)
- memset(p[j], 0, s->object_size);
+ memset(kasan_reset_tag(p[j]), 0, s->object_size);
}
/* memcg and kmem_cache debug support */
--
2.30.0.284.gd98b1dd5eaa7-goog
next prev parent reply other threads:[~2021-01-15 17:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-15 17:41 [PATCH v3 0/2] kasan: fixes for 5.11-rc Andrey Konovalov
2021-01-15 17:41 ` Andrey Konovalov [this message]
2021-01-15 17:41 ` [PATCH v3 2/2] kasan, arm64: fix pointer tags in KASAN reports Andrey Konovalov
2021-01-15 17:59 ` Catalin Marinas
2021-01-15 18:08 ` Andrey Konovalov
2021-01-15 18:03 ` Vincenzo Frascino
2021-01-18 18:31 ` [PATCH v3 0/2] kasan: fixes for 5.11-rc Catalin Marinas
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