hte: Annotate struct hte_device with __counted_by

[PATCH] hte: Annotate struct hte_device with __counted_by

Posted by Kees Cook 2 years, 2 months ago

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct hte_device.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Dipen Patel <dipenp@nvidia.com>
Cc: timestamp@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/hte/hte.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hte/hte.c b/drivers/hte/hte.c
index 598a716b7364..1fd8d2d4528b 100644
--- a/drivers/hte/hte.c
+++ b/drivers/hte/hte.c
@@ -88,7 +88,7 @@ struct hte_device {
 	struct list_head list;
 	struct hte_chip *chip;
 	struct module *owner;
-	struct hte_ts_info ei[];
+	struct hte_ts_info ei[] __counted_by(nlines);
 };
 
 #ifdef CONFIG_DEBUG_FS
-- 
2.34.1

Re: [PATCH] hte: Annotate struct hte_device with __counted_by

Posted by Justin Stitt 2 years, 2 months ago

On Sat, Sep 23, 2023 at 2:54 AM Kees Cook <keescook@chromium.org> wrote:
>
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct hte_device.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Dipen Patel <dipenp@nvidia.com>
> Cc: timestamp@lists.linux.dev
> Signed-off-by: Kees Cook <keescook@chromium.org>

Yep, this flexible array member is counted by @nlines which
is evident throughout hte.c:

        gdev = kzalloc(struct_size(gdev, ei, chip->nlines), GFP_KERNEL);
        ...
        gdev->nlines = chip->nlines;
        ...
        for (i = 0; i < chip->nlines; i++) {
          gdev->ei[i].gdev = gdev;
        ...


Reviewed-by: Justin Stitt <justinstitt@google.com>

> ---
>  drivers/hte/hte.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hte/hte.c b/drivers/hte/hte.c
> index 598a716b7364..1fd8d2d4528b 100644
> --- a/drivers/hte/hte.c
> +++ b/drivers/hte/hte.c
> @@ -88,7 +88,7 @@ struct hte_device {
>         struct list_head list;
>         struct hte_chip *chip;
>         struct module *owner;
> -       struct hte_ts_info ei[];
> +       struct hte_ts_info ei[] __counted_by(nlines);
>  };
>
>  #ifdef CONFIG_DEBUG_FS
> --
> 2.34.1
>
>

Re: [PATCH] hte: Annotate struct hte_device with __counted_by

Posted by Gustavo A. R. Silva 2 years, 2 months ago


On 9/22/23 11:53, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct hte_device.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Dipen Patel <dipenp@nvidia.com>
> Cc: timestamp@lists.linux.dev
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
-- 
Gustavo

> ---
>   drivers/hte/hte.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hte/hte.c b/drivers/hte/hte.c
> index 598a716b7364..1fd8d2d4528b 100644
> --- a/drivers/hte/hte.c
> +++ b/drivers/hte/hte.c
> @@ -88,7 +88,7 @@ struct hte_device {
>   	struct list_head list;
>   	struct hte_chip *chip;
>   	struct module *owner;
> -	struct hte_ts_info ei[];
> +	struct hte_ts_info ei[] __counted_by(nlines);
>   };
>   
>   #ifdef CONFIG_DEBUG_FS

Re: [PATCH] hte: Annotate struct hte_device with __counted_by

Posted by Dipen Patel 2 years, 2 months ago

On 9/23/23 9:37 AM, Gustavo A. R. Silva wrote:
> 
> 
> On 9/22/23 11:53, Kees Cook wrote:
>> Prepare for the coming implementation by GCC and Clang of the __counted_by
>> attribute. Flexible array members annotated with __counted_by can have
>> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
>> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
>> functions).
>>
>> As found with Coccinelle[1], add __counted_by for struct hte_device.
>>
>> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>>
>> Cc: Dipen Patel <dipenp@nvidia.com>
>> Cc: timestamp@lists.linux.dev
>> Signed-off-by: Kees Cook <keescook@chromium.org>
> 
> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> 
> Thanks
Reviewed-by: Dipen Patel <dipenp@nvidia.com>