From: Andrey Konovalov <andreyknvl@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Marco Elver <elver@google.com>, Ard Biesheuvel <ardb@kernel.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
Walter Wu <walter-zh.wu@mediatek.com>,
Elena Petrova <lenaptr@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v2 1/5] kasan: don't tag stacks allocated with pagealloc
Date: Tue, 4 Aug 2020 14:41:24 +0200 [thread overview]
Message-ID: <12d8c678869268dd0884b01271ab592f30792abf.1596544734.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1596544734.git.andreyknvl@google.com>
This patch prepares Software Tag-Based KASAN for stack tagging support.
With Tag-Based KASAN when kernel stacks are allocated via pagealloc
(which happens when CONFIG_VMAP_STACK is not enabled), they get tagged.
KASAN instrumentation doesn't expect the sp register to be tagged, and
this leads to false-positive reports.
Fix by resetting the tag of kernel stack pointers after allocation.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
kernel/fork.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index efc5493203ae..75415f5e647c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -261,7 +261,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
THREAD_SIZE_ORDER);
if (likely(page)) {
- tsk->stack = page_address(page);
+ tsk->stack = kasan_reset_tag(page_address(page));
return tsk->stack;
}
return NULL;
@@ -307,6 +307,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk,
{
unsigned long *stack;
stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
+ stack = kasan_reset_tag(stack);
tsk->stack = stack;
return stack;
}
--
2.28.0.163.g6104cc2f0b6-goog
next prev parent reply other threads:[~2020-08-04 12:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-04 12:41 [PATCH v2 0/5] kasan: support stack instrumentation for tag-based mode Andrey Konovalov
2020-08-04 12:41 ` Andrey Konovalov [this message]
2020-08-04 12:41 ` [PATCH v2 2/5] efi: provide empty efi_enter_virtual_mode implementation Andrey Konovalov
2020-08-04 12:45 ` Ard Biesheuvel
2020-08-04 12:41 ` [PATCH v2 3/5] kasan, arm64: don't instrument functions that enable kasan Andrey Konovalov
2020-08-04 13:19 ` Catalin Marinas
2020-08-04 13:24 ` Andrey Konovalov
2020-08-04 12:41 ` [PATCH v2 4/5] kasan: allow enabling stack tagging for tag-based mode Andrey Konovalov
2020-08-04 12:41 ` [PATCH v2 5/5] kasan: adjust kasan_stack_oob " Andrey Konovalov
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