From: Walter Wu <walter-zh.wu@mediatek.com>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"Matthias Brugger" <matthias.bgg@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrey Konovalov <andreyknvl@google.com>
Cc: Walter Wu <walter-zh.wu@mediatek.com>,
wsd_upstream@mediatek.com, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com, linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: kasan: fix phys_to_virt() false positive on tag-based kasan
Date: Mon, 19 Aug 2019 19:44:20 +0800 [thread overview]
Message-ID: <20190819114420.2535-1-walter-zh.wu@mediatek.com> (raw)
__arm_v7s_unmap() call iopte_deref() to translate pyh_to_virt address,
but it will modify pointer tag into 0xff, so there is a false positive.
When enable tag-based kasan, phys_to_virt() function need to rewrite
its original pointer tag in order to avoid kasan report an incorrect
memory corruption.
BUG: KASAN: double-free or invalid-free in __arm_v7s_unmap+0x720/0xda4
Pointer tag: [ff], memory tag: [c1]
Call trace:
dump_backtrace+0x0/0x1d4
show_stack+0x14/0x1c
dump_stack+0xe8/0x140
print_address_description+0x80/0x2f0
kasan_report_invalid_free+0x58/0x74
__kasan_slab_free+0x1e4/0x220
kasan_slab_free+0xc/0x18
kmem_cache_free+0xfc/0x884
__arm_v7s_unmap+0x720/0xda4
__arm_v7s_map+0xc8/0x774
arm_v7s_map+0x80/0x158
mtk_iommu_map+0xb4/0xe0
iommu_map+0x154/0x450
iommu_map_sg+0xe4/0x150
iommu_dma_map_sg+0x214/0x4ec
__iommu_map_sg_attrs+0xf0/0x110
ion_map_dma_buf+0xe8/0x114
dma_buf_map_attachment+0x4c/0x80
disp_sync_prepare_buf+0x378/0x820
_ioctl_prepare_buffer+0x130/0x870
mtk_disp_mgr_ioctl+0x5c4/0xab0
do_vfs_ioctl+0x8e0/0x15a4
__arm64_sys_ioctl+0x8c/0xb4
el0_svc_common+0xe4/0x1e0
el0_svc_handler+0x30/0x3c
el0_svc+0x8/0xc
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
---
arch/arm64/include/asm/kasan.h | 1 -
arch/arm64/include/asm/memory.h | 10 ++++++++++
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/kasan.h b/arch/arm64/include/asm/kasan.h
index b52aacd2c526..59894cafad60 100644
--- a/arch/arm64/include/asm/kasan.h
+++ b/arch/arm64/include/asm/kasan.h
@@ -5,7 +5,6 @@
#ifndef __ASSEMBLY__
#include <linux/linkage.h>
-#include <asm/memory.h>
#include <asm/pgtable-types.h>
#define arch_kasan_set_tag(addr, tag) __tag_set(addr, tag)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 8ffcf5a512bb..75af5ba9ff22 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -171,6 +171,7 @@
#include <linux/bitops.h>
#include <linux/mmdebug.h>
+#include <asm/kasan.h>
extern s64 memstart_addr;
/* PHYS_OFFSET - the physical address of the start of memory. */
@@ -282,7 +283,16 @@ static inline phys_addr_t virt_to_phys(const volatile void *x)
#define phys_to_virt phys_to_virt
static inline void *phys_to_virt(phys_addr_t x)
{
+#ifdef CONFIG_KASAN_SW_TAGS
+ unsigned long addr = __phys_to_virt(x);
+ u8 *tag = (void *)(addr >> KASAN_SHADOW_SCALE_SHIFT)
+ + KASAN_SHADOW_OFFSET;
+
+ addr = __tag_set(addr, *tag);
+ return (void *)addr;
+#else
return (void *)(__phys_to_virt(x));
+#endif
}
/*
--
2.18.0
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next reply other threads:[~2019-08-19 11:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 11:44 Walter Wu [this message]
2019-08-19 12:56 ` [PATCH] arm64: kasan: fix phys_to_virt() false positive on tag-based kasan Will Deacon
2019-08-19 13:23 ` Mark Rutland
2019-08-19 13:34 ` Will Deacon
2019-08-19 14:05 ` Andrey Konovalov
2019-08-19 14:22 ` Will Deacon
2019-08-19 14:35 ` Robin Murphy
2019-08-19 14:43 ` Will Deacon
2019-08-19 15:03 ` Mark Rutland
2019-08-19 15:37 ` Andrey Konovalov
2019-08-19 16:03 ` Mark Rutland
2019-08-19 14:06 ` Andrey Ryabinin
2019-08-19 14:21 ` Walter Wu
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