2021-01-29 17:36:20

by Alexandre Ghiti

Subject: [PATCH] riscv: virt_addr_valid must check the address belongs to linear mapping

virt_addr_valid macro checks that a virtual address is valid, ie that
the address belongs to the linear mapping and that the corresponding
physical page exists.

Add the missing check that ensures the virtual address belongs to the
linear mapping, otherwise __virt_to_phys, when compiled with
CONFIG_DEBUG_VIRTUAL enabled, raises a WARN that is interpreted as a
kernel bug by syzbot.

Signed-off-by: Alexandre Ghiti <[email protected]>
---
arch/riscv/include/asm/page.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index 2d50f76efe48..64a675c5c30a 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -135,7 +135,10 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);

#endif /* __ASSEMBLY__ */

-#define virt_addr_valid(vaddr) (pfn_valid(virt_to_pfn(vaddr)))
+#define virt_addr_valid(vaddr) ({ \
+ unsigned long _addr = (unsigned long)vaddr; \
+ (unsigned long)(_addr) >= PAGE_OFFSET && pfn_valid(virt_to_pfn(_addr)); \
+})

#define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_NON_EXEC

--
2.20.1

2021-01-29 19:08:25

by Atish Patra

Subject: Re: [PATCH] riscv: virt_addr_valid must check the address belongs to linear mapping

On Fri, Jan 29, 2021 at 9:31 AM Alexandre Ghiti <[email protected]> wrote:
>
> virt_addr_valid macro checks that a virtual address is valid, ie that
> the address belongs to the linear mapping and that the corresponding
> physical page exists.
>
> Add the missing check that ensures the virtual address belongs to the
> linear mapping, otherwise __virt_to_phys, when compiled with
> CONFIG_DEBUG_VIRTUAL enabled, raises a WARN that is interpreted as a
> kernel bug by syzbot.
>
> Signed-off-by: Alexandre Ghiti <[email protected]>
> ---
> arch/riscv/include/asm/page.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> index 2d50f76efe48..64a675c5c30a 100644
> --- a/arch/riscv/include/asm/page.h
> +++ b/arch/riscv/include/asm/page.h
> @@ -135,7 +135,10 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);
>
> #endif /* __ASSEMBLY__ */
>
> -#define virt_addr_valid(vaddr) (pfn_valid(virt_to_pfn(vaddr)))
> +#define virt_addr_valid(vaddr) ({ \
> + unsigned long _addr = (unsigned long)vaddr; \
> + (unsigned long)(_addr) >= PAGE_OFFSET && pfn_valid(virt_to_pfn(_addr)); \
> +})
>
> #define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_NON_EXEC
>
> --
> 2.20.1
>
>
> _______________________________________________
> linux-riscv mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-riscv


Reviewed-by: Atish Patra <[email protected]>

--
Regards,
Atish

2021-01-31 12:43:22

by Dmitry Vyukov

Subject: Re: [PATCH] riscv: virt_addr_valid must check the address belongs to linear mapping

On Fri, Jan 29, 2021 at 6:31 PM Alexandre Ghiti <[email protected]> wrote:
>
> virt_addr_valid macro checks that a virtual address is valid, ie that
> the address belongs to the linear mapping and that the corresponding
> physical page exists.
>
> Add the missing check that ensures the virtual address belongs to the
> linear mapping, otherwise __virt_to_phys, when compiled with
> CONFIG_DEBUG_VIRTUAL enabled, raises a WARN that is interpreted as a
> kernel bug by syzbot.

Thanks, Alexandre. Much appreciated.

> Signed-off-by: Alexandre Ghiti <[email protected]>
> ---
> arch/riscv/include/asm/page.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> index 2d50f76efe48..64a675c5c30a 100644
> --- a/arch/riscv/include/asm/page.h
> +++ b/arch/riscv/include/asm/page.h
> @@ -135,7 +135,10 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);
>
> #endif /* __ASSEMBLY__ */
>
> -#define virt_addr_valid(vaddr) (pfn_valid(virt_to_pfn(vaddr)))
> +#define virt_addr_valid(vaddr) ({ \
> + unsigned long _addr = (unsigned long)vaddr; \
> + (unsigned long)(_addr) >= PAGE_OFFSET && pfn_valid(virt_to_pfn(_addr)); \
> +})
>
> #define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_NON_EXEC
>
> --
> 2.20.1
>

2021-02-03 02:38:08

by Palmer Dabbelt

Subject: Re: [PATCH] riscv: virt_addr_valid must check the address belongs to linear mapping

On Fri, 29 Jan 2021 09:31:05 PST (-0800), [email protected] wrote:
> virt_addr_valid macro checks that a virtual address is valid, ie that
> the address belongs to the linear mapping and that the corresponding
> physical page exists.
>
> Add the missing check that ensures the virtual address belongs to the
> linear mapping, otherwise __virt_to_phys, when compiled with
> CONFIG_DEBUG_VIRTUAL enabled, raises a WARN that is interpreted as a
> kernel bug by syzbot.
>
> Signed-off-by: Alexandre Ghiti <[email protected]>
> ---
> arch/riscv/include/asm/page.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> index 2d50f76efe48..64a675c5c30a 100644
> --- a/arch/riscv/include/asm/page.h
> +++ b/arch/riscv/include/asm/page.h
> @@ -135,7 +135,10 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x);
>
> #endif /* __ASSEMBLY__ */
>
> -#define virt_addr_valid(vaddr) (pfn_valid(virt_to_pfn(vaddr)))
> +#define virt_addr_valid(vaddr) ({ \
> + unsigned long _addr = (unsigned long)vaddr; \
> + (unsigned long)(_addr) >= PAGE_OFFSET && pfn_valid(virt_to_pfn(_addr)); \
> +})
>
> #define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_NON_EXEC

Thanks, this is on fixes.