Commit 03547217 authored by Kees Cook's avatar Kees Cook Committed by Vinod Koul
Browse files

dmaengine: stm32-mdma: Annotate struct stm32_mdma_desc 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 stm32_mdma_desc.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

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



Cc: Vinod Koul <vkoul@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: dmaengine@vger.kernel.org
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatar"Gustavo A. R. Silva" <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230817235859.49846-13-keescook@chromium.org


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 195e46df

drivers/dma/stm32-mdma.c

+2 −3
Original line number Diff line number Diff line
@@ -224,7 +224,7 @@ struct stm32_mdma_desc { 
	u32 ccr;

	bool cyclic;

	u32 count;

	struct stm32_mdma_desc_node node[];

	struct stm32_mdma_desc_node node[] __counted_by(count);

};



struct stm32_mdma_dma_config {
@@ -321,6 +321,7 @@ static struct stm32_mdma_desc *stm32_mdma_alloc_desc( 
	desc = kzalloc(struct_size(desc, node, count), GFP_NOWAIT);

	if (!desc)

		return NULL;

	desc->count = count;



	for (i = 0; i < count; i++) {

		desc->node[i].hwdesc =
@@ -330,8 +331,6 @@ static struct stm32_mdma_desc *stm32_mdma_alloc_desc( 
			goto err;

	}



	desc->count = count;



	return desc;



err: