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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, andreyknvl@google.com,
	aryabinin@virtuozzo.com, dvyukov@google.com, glider@google.com,
	linux-mm@kvack.org, mm-commits@vger.kernel.org,
	torvalds@linux-foundation.org, walter-zh.wu@mediatek.com
Subject: [patch 09/16] kasan: fix null pointer dereference in kasan_record_aux_stack
Date: Tue, 29 Dec 2020 15:14:46 -0800	[thread overview]
Message-ID: <20201229231446.l1zpffxO9%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201229151349.3285926ec0d1f65a27ac8534@linux-foundation.org>

From: Walter Wu <walter-zh.wu@mediatek.com>
Subject: kasan: fix null pointer dereference in kasan_record_aux_stack

Syzbot reported the following [1]:

 BUG: kernel NULL pointer dereference, address: 0000000000000008
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 2d993067 P4D 2d993067 PUD 19a3c067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP KASAN
 CPU: 1 PID: 3852 Comm: kworker/1:2 Not tainted 5.10.0-syzkaller #0
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 Workqueue: events free_ipc
 RIP: 0010:kasan_record_aux_stack+0x77/0xb0

Add null checking slab object from kasan_get_alloc_meta()
in order to avoid null pointer dereference.

[1] https://syzkaller.appspot.com/x/log.txt?x=10a82a50d00000

Link: https://lkml.kernel.org/r/20201228080018.23041-1-walter-zh.wu@mediatek.com
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/kasan/generic.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/kasan/generic.c~kasan-fix-null-pointer-dereference-in-kasan_record_aux_stack
+++ a/mm/kasan/generic.c
@@ -337,6 +337,8 @@ void kasan_record_aux_stack(void *addr)
 	cache = page->slab_cache;
 	object = nearest_obj(cache, page, addr);
 	alloc_meta = kasan_get_alloc_meta(cache, object);
+	if (!alloc_meta)
+		return;
 
 	alloc_meta->aux_stack[1] = alloc_meta->aux_stack[0];
 	alloc_meta->aux_stack[0] = kasan_save_stack(GFP_NOWAIT);
_

  parent reply	other threads:[~2020-12-29 23:15 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-29 23:13 incoming Andrew Morton
2020-12-29 23:14 ` [patch 01/16] selftests/vm: fix building protection keys test Andrew Morton
2020-12-29 23:14 ` [patch 02/16] mm/hugetlb: fix deadlock in hugetlb_cow error path Andrew Morton
2020-12-29 23:14 ` [patch 03/16] Revert "kbuild: avoid static_assert for genksyms" Andrew Morton
2020-12-29 23:14 ` [patch 04/16] checkpatch: prefer strscpy to strlcpy Andrew Morton
2020-12-29 23:14 ` [patch 05/16] mm: add prototype for __add_to_page_cache_locked() Andrew Morton
2020-12-29 23:14 ` [patch 06/16] mm: memmap defer init doesn't work as expected Andrew Morton
2020-12-29 23:14 ` [patch 07/16] mm/mremap.c: fix extent calculation Andrew Morton
2020-12-29 23:14 ` [patch 08/16] mm: generalise COW SMC TLB flushing race comment Andrew Morton
2020-12-29 23:14 ` Andrew Morton [this message]
2020-12-29 23:14 ` [patch 10/16] local64.h: make <asm/local64.h> mandatory Andrew Morton
2020-12-29 23:14 ` [patch 11/16] sizes.h: add SZ_8G/SZ_16G/SZ_32G macros Andrew Morton
2020-12-29 23:14 ` [patch 12/16] kdev_t: always inline major/minor helper functions Andrew Morton
2020-12-29 23:14 ` [patch 13/16] lib/genalloc: fix the overflow when size is too big Andrew Morton
2020-12-29 23:15 ` [patch 14/16] lib/zlib: fix inflating zlib streams on s390 Andrew Morton
2020-12-29 23:15 ` [patch 15/16] zlib: move EXPORT_SYMBOL() and MODULE_LICENSE() out of dfltcc_syms.c Andrew Morton
2020-12-29 23:15 ` [patch 16/16] mm: slub: call account_slab_page() after slab page initialization Andrew Morton

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