* [PATCH] riscv: Fix W+X mapping warning
@ 2020-11-12 6:48 Kefeng Wang
2020-11-12 7:10 ` Atish Patra
0 siblings, 1 reply; 3+ messages in thread
From: Kefeng Wang @ 2020-11-12 6:48 UTC (permalink / raw)
To: Paul Walmsley, Palmer Dabbelt, Albert Ou, linux-riscv
Cc: Kefeng Wang, Zong Li
When boot with DEBUG_WX triggers the WX warning,
riscv/mm: Found insecure W+X mapping at address ffffffe000000000/0xffffffe000000000
WARNING: CPU: 1 PID: 1 at arch/riscv/mm/ptdump.c:236 note_page+0x248/0x25a
...
Checked W+X mappings: failed, 512 W+X pages found
The kernel_page_tables shows first 2M(kernel image) is with W attribute,
Use _start instead of text_start in mark_rodata_ro().
Before,
0xffffffe000000000-0xffffffe000200000 0x0000000080200000 2M PMD D A . . X W R V
0xffffffe000200000-0xffffffe000a00000 0x0000000080400000 8M PMD D A . . X . R V
0xffffffe000a00000-0xffffffe001000000 0x0000000080c00000 6M PMD D A . . . . R V
0xffffffe001000000-0xffffffe17fe00000 0x0000000081200000 6126M PMD D A . . . W R V
After,
0xffffffe000000000-0xffffffe000a00000 0x0000000080200000 10M PMD D A . . X . R V
0xffffffe000a00000-0xffffffe001000000 0x0000000080c00000 6M PMD D A . . . . R V
0xffffffe001000000-0xffffffe17fe00000 0x0000000081200000 6126M PMD D A . . . W R V
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
arch/riscv/mm/init.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 1d330bde9cf1..d739a46d9fc4 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -624,13 +624,13 @@ static inline void setup_vm_final(void)
#ifdef CONFIG_STRICT_KERNEL_RWX
void mark_rodata_ro(void)
{
- unsigned long text_start = (unsigned long)_text;
+ unsigned long start = (unsigned long)_start;
unsigned long text_end = (unsigned long)_etext;
unsigned long rodata_start = (unsigned long)__start_rodata;
unsigned long data_start = (unsigned long)_data;
unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
- set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
+ set_memory_ro(start, (text_end - start) >> PAGE_SHIFT);
set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
--
2.26.2
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] riscv: Fix W+X mapping warning
2020-11-12 6:48 [PATCH] riscv: Fix W+X mapping warning Kefeng Wang
@ 2020-11-12 7:10 ` Atish Patra
2020-11-12 7:29 ` Kefeng Wang
0 siblings, 1 reply; 3+ messages in thread
From: Atish Patra @ 2020-11-12 7:10 UTC (permalink / raw)
To: Kefeng Wang
Cc: linux-riscv, Albert Ou, Palmer Dabbelt, Zong Li, Paul Walmsley
On Wed, Nov 11, 2020 at 10:44 PM Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>
> When boot with DEBUG_WX triggers the WX warning,
> riscv/mm: Found insecure W+X mapping at address ffffffe000000000/0xffffffe000000000
> WARNING: CPU: 1 PID: 1 at arch/riscv/mm/ptdump.c:236 note_page+0x248/0x25a
> ...
> Checked W+X mappings: failed, 512 W+X pages found
>
> The kernel_page_tables shows first 2M(kernel image) is with W attribute,
> Use _start instead of text_start in mark_rodata_ro().
>
> Before,
> 0xffffffe000000000-0xffffffe000200000 0x0000000080200000 2M PMD D A . . X W R V
> 0xffffffe000200000-0xffffffe000a00000 0x0000000080400000 8M PMD D A . . X . R V
> 0xffffffe000a00000-0xffffffe001000000 0x0000000080c00000 6M PMD D A . . . . R V
> 0xffffffe001000000-0xffffffe17fe00000 0x0000000081200000 6126M PMD D A . . . W R V
>
> After,
> 0xffffffe000000000-0xffffffe000a00000 0x0000000080200000 10M PMD D A . . X . R V
> 0xffffffe000a00000-0xffffffe001000000 0x0000000080c00000 6M PMD D A . . . . R V
> 0xffffffe001000000-0xffffffe17fe00000 0x0000000081200000 6126M PMD D A . . . W R V
>
This is already fixed by the following series.
https://patchwork.kernel.org/project/linux-riscv/list/?series=377843
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
> arch/riscv/mm/init.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 1d330bde9cf1..d739a46d9fc4 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -624,13 +624,13 @@ static inline void setup_vm_final(void)
> #ifdef CONFIG_STRICT_KERNEL_RWX
> void mark_rodata_ro(void)
> {
> - unsigned long text_start = (unsigned long)_text;
> + unsigned long start = (unsigned long)_start;
> unsigned long text_end = (unsigned long)_etext;
> unsigned long rodata_start = (unsigned long)__start_rodata;
> unsigned long data_start = (unsigned long)_data;
> unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
>
> - set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
> + set_memory_ro(start, (text_end - start) >> PAGE_SHIFT);
> set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
> set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
> set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
> --
> 2.26.2
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
--
Regards,
Atish
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] riscv: Fix W+X mapping warning
2020-11-12 7:10 ` Atish Patra
@ 2020-11-12 7:29 ` Kefeng Wang
0 siblings, 0 replies; 3+ messages in thread
From: Kefeng Wang @ 2020-11-12 7:29 UTC (permalink / raw)
To: Atish Patra
Cc: linux-riscv, Albert Ou, Palmer Dabbelt, Zong Li, Paul Walmsley
On 2020/11/12 15:10, Atish Patra wrote:
> On Wed, Nov 11, 2020 at 10:44 PM Kefeng Wang <wangkefeng.wang@huawei.com> wrote:
>> When boot with DEBUG_WX triggers the WX warning,
>> riscv/mm: Found insecure W+X mapping at address ffffffe000000000/0xffffffe000000000
>> WARNING: CPU: 1 PID: 1 at arch/riscv/mm/ptdump.c:236 note_page+0x248/0x25a
>> ...
>> Checked W+X mappings: failed, 512 W+X pages found
>>
>> The kernel_page_tables shows first 2M(kernel image) is with W attribute,
>> Use _start instead of text_start in mark_rodata_ro().
>>
>> Before,
>> 0xffffffe000000000-0xffffffe000200000 0x0000000080200000 2M PMD D A . . X W R V
>> 0xffffffe000200000-0xffffffe000a00000 0x0000000080400000 8M PMD D A . . X . R V
>> 0xffffffe000a00000-0xffffffe001000000 0x0000000080c00000 6M PMD D A . . . . R V
>> 0xffffffe001000000-0xffffffe17fe00000 0x0000000081200000 6126M PMD D A . . . W R V
>>
>> After,
>> 0xffffffe000000000-0xffffffe000a00000 0x0000000080200000 10M PMD D A . . X . R V
>> 0xffffffe000a00000-0xffffffe001000000 0x0000000080c00000 6M PMD D A . . . . R V
>> 0xffffffe001000000-0xffffffe17fe00000 0x0000000081200000 6126M PMD D A . . . W R V
>>
> This is already fixed by the following series.
> https://patchwork.kernel.org/project/linux-riscv/list/?series=377843
Got it.
>
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