[PATCH AUTOSEL 5.19 54/64] ARM: 9202/1: kasan: support CONFIG_KASAN_VMALLOC

[Sasha Levin]

From: Lecopzer Chen <lecopz...@mediatek.com>

[ Upstream commit 565cbaad83d83e288927b96565211109bc984007 ]

Simply make shadow of vmalloc area mapped on demand.

Since the virtual address of vmalloc for Arm is also between
MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
address has already included between KASAN_SHADOW_START and
KASAN_SHADOW_END.
Thus we need to change nothing for memory map of Arm.

This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
and support CONFIG_VMAP_STACK with KASan.

Signed-off-by: Lecopzer Chen <lecopz...@mediatek.com>
Tested-by: Linus Walleij <linus....@linaro.org>
Reviewed-by: Linus Walleij <linus....@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+k...@armlinux.org.uk>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
arch/arm/Kconfig | 1 +
arch/arm/mm/kasan_init.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7630ba9cb6cc..545d2d4a492b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -75,6 +75,7 @@ config ARM
select HAVE_ARCH_KFENCE if MMU && !XIP_KERNEL
select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
+ select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_PFN_VALID
select HAVE_ARCH_SECCOMP
diff --git a/arch/arm/mm/kasan_init.c b/arch/arm/mm/kasan_init.c
index 5ad0d6c56d56..29caee9c79ce 100644
--- a/arch/arm/mm/kasan_init.c
+++ b/arch/arm/mm/kasan_init.c
@@ -236,7 +236,11 @@ void __init kasan_init(void)

clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);

- kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
+ if (!IS_ENABLED(CONFIG_KASAN_VMALLOC))
+ kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
+ kasan_mem_to_shadow((void *)VMALLOC_END));
+
+ kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_END),
kasan_mem_to_shadow((void *)-1UL) + 1);

for_each_mem_range(i, &pa_start, &pa_end) {
--
2.35.1

[Sasha Levin]

From: Lecopzer Chen <lecopz...@mediatek.com>

[ Upstream commit 565cbaad83d83e288927b96565211109bc984007 ]

Simply make shadow of vmalloc area mapped on demand.

Since the virtual address of vmalloc for Arm is also between
MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
address has already included between KASAN_SHADOW_START and
KASAN_SHADOW_END.
Thus we need to change nothing for memory map of Arm.

This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
and support CONFIG_VMAP_STACK with KASan.

Signed-off-by: Lecopzer Chen <lecopz...@mediatek.com>
Tested-by: Linus Walleij <linus....@linaro.org>
Reviewed-by: Linus Walleij <linus....@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+k...@armlinux.org.uk>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
arch/arm/Kconfig | 1 +
arch/arm/mm/kasan_init.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig

index 2e8091e2d8a8..f440cf59cea1 100644

[Sasha Levin]

From: Lecopzer Chen <lecopz...@mediatek.com>

[ Upstream commit 565cbaad83d83e288927b96565211109bc984007 ]

Simply make shadow of vmalloc area mapped on demand.

Since the virtual address of vmalloc for Arm is also between
MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
address has already included between KASAN_SHADOW_START and
KASAN_SHADOW_END.
Thus we need to change nothing for memory map of Arm.

This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
and support CONFIG_VMAP_STACK with KASan.

Signed-off-by: Lecopzer Chen <lecopz...@mediatek.com>
Tested-by: Linus Walleij <linus....@linaro.org>
Reviewed-by: Linus Walleij <linus....@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+k...@armlinux.org.uk>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
arch/arm/Kconfig | 1 +
arch/arm/mm/kasan_init.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig

index 4ebd512043be..44f328fa5996 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -71,6 +71,7 @@ config ARM
select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU

select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
+ select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_PFN_VALID
select HAVE_ARCH_SECCOMP
diff --git a/arch/arm/mm/kasan_init.c b/arch/arm/mm/kasan_init.c

index 4b1619584b23..040346cc4a3a 100644

[Ard Biesheuvel]

On Sun, 14 Aug 2022 at 17:30, Sasha Levin <sas...@kernel.org> wrote:
>
> From: Lecopzer Chen <lecopz...@mediatek.com>
>
> [ Upstream commit 565cbaad83d83e288927b96565211109bc984007 ]
>
> Simply make shadow of vmalloc area mapped on demand.
>
> Since the virtual address of vmalloc for Arm is also between
> MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
> address has already included between KASAN_SHADOW_START and
> KASAN_SHADOW_END.
> Thus we need to change nothing for memory map of Arm.
>
> This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
> and support CONFIG_VMAP_STACK with KASan.
>
> Signed-off-by: Lecopzer Chen <lecopz...@mediatek.com>
> Tested-by: Linus Walleij <linus....@linaro.org>
> Reviewed-by: Linus Walleij <linus....@linaro.org>
> Signed-off-by: Russell King (Oracle) <rmk+k...@armlinux.org.uk>
> Signed-off-by: Sasha Levin <sas...@kernel.org>

This patch does not belong in -stable. It has no fixes: or cc:stable
tags, and the contents are completely inappropriate for backporting
anywhere. In general, I think that no patch that touches arch/arm
(with the exception of DTS updates, perhaps) should ever be backported
unless proposed or acked by the maintainer.

I know I shouldn't ask, but how were these patches build/boot tested?
KAsan is very tricky to get right, especially on 32-bit ARM ...

[Sasha Levin]

On Tue, Aug 16, 2022 at 04:45:14PM +0200, Ard Biesheuvel wrote:
>On Sun, 14 Aug 2022 at 17:30, Sasha Levin <sas...@kernel.org> wrote:
>>
>> From: Lecopzer Chen <lecopz...@mediatek.com>
>>
>> [ Upstream commit 565cbaad83d83e288927b96565211109bc984007 ]
>>
>> Simply make shadow of vmalloc area mapped on demand.
>>
>> Since the virtual address of vmalloc for Arm is also between
>> MODULE_VADDR and 0x100000000 (ZONE_HIGHMEM), which means the shadow
>> address has already included between KASAN_SHADOW_START and
>> KASAN_SHADOW_END.
>> Thus we need to change nothing for memory map of Arm.
>>
>> This can fix ARM_MODULE_PLTS with KASan, support KASan for higmem
>> and support CONFIG_VMAP_STACK with KASan.
>>
>> Signed-off-by: Lecopzer Chen <lecopz...@mediatek.com>
>> Tested-by: Linus Walleij <linus....@linaro.org>
>> Reviewed-by: Linus Walleij <linus....@linaro.org>
>> Signed-off-by: Russell King (Oracle) <rmk+k...@armlinux.org.uk>
>> Signed-off-by: Sasha Levin <sas...@kernel.org>
>
>This patch does not belong in -stable. It has no fixes: or cc:stable
>tags, and the contents are completely inappropriate for backporting
>anywhere. In general, I think that no patch that touches arch/arm
>(with the exception of DTS updates, perhaps) should ever be backported
>unless proposed or acked by the maintainer.

I'll drop it.

>I know I shouldn't ask, but how were these patches build/boot tested?
>KAsan is very tricky to get right, especially on 32-bit ARM ...

They were only build tested at this stage. They go through
boot/functional test only after they are actually queued up for the
various trees.

--
Thanks,
Sasha