[PATCH] mtd: cfi: Annotate struct cfi_private with __counted_by

[PATCH] mtd: cfi: Annotate struct cfi_private with __counted_by

[Kees Cook]

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 cfi_private.

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

Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/mtd/cfi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mtd/cfi.h b/include/linux/mtd/cfi.h
index d88bb56c18e2..947410faf9e2 100644
--- a/include/linux/mtd/cfi.h
+++ b/include/linux/mtd/cfi.h
@@ -287,7 +287,7 @@ struct cfi_private {
 	unsigned long chipshift; /* Because they're of the same type */
 	const char *im_name;	 /* inter_module name for cmdset_setup */
 	unsigned long quirks;
-	struct flchip chips[];  /* per-chip data structure for each chip */
+	struct flchip chips[] __counted_by(numchips);  /* per-chip data structure for each chip */
 };
 
 uint32_t cfi_build_cmd_addr(uint32_t cmd_ofs,
-- 
2.34.1


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Re: [PATCH] mtd: cfi: Annotate struct cfi_private with __counted_by

[Gustavo A. R. Silva]

On 9/15/23 14:12, 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 cfi_private.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Vignesh Raghavendra <vigneshr@ti.com>
> Cc: linux-mtd@lists.infradead.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   include/linux/mtd/cfi.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/mtd/cfi.h b/include/linux/mtd/cfi.h
> index d88bb56c18e2..947410faf9e2 100644
> --- a/include/linux/mtd/cfi.h
> +++ b/include/linux/mtd/cfi.h
> @@ -287,7 +287,7 @@ struct cfi_private {
>   	unsigned long chipshift; /* Because they're of the same type */
>   	const char *im_name;	 /* inter_module name for cmdset_setup */
>   	unsigned long quirks;
> -	struct flchip chips[];  /* per-chip data structure for each chip */
> +	struct flchip chips[] __counted_by(numchips);  /* per-chip data structure for each chip */
>   };
>   
>   uint32_t cfi_build_cmd_addr(uint32_t cmd_ofs,

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Re: [PATCH] mtd: cfi: Annotate struct cfi_private with __counted_by

[Miquel Raynal]

On Fri, 2023-09-15 at 20:12:06 UTC, 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 cfi_private.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Vignesh Raghavendra <vigneshr@ti.com>
> Cc: linux-mtd@lists.infradead.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.

Miquel

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