2023-09-23 02:06:02

by Kees Cook

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

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 <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
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

2023-09-23 20:22:22

by Gustavo A. R. Silva

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

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 <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

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

2023-09-28 04:46:50

by Dipen Patel

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

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 <[email protected]>
>> Cc: [email protected]
>> Signed-off-by: Kees Cook <[email protected]>
>
> Reviewed-by: Gustavo A. R. Silva <[email protected]>
>
> Thanks
Reviewed-by: Dipen Patel <[email protected]>

2023-09-28 10:53:17

by Justin Stitt

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

On Sat, Sep 23, 2023 at 2:54 AM Kees Cook <[email protected]> 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 <[email protected]>
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>

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 <[email protected]>

> ---
> 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
>
>