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@xxxxxxxxxx> Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx> Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx> Cc: dmaengine@xxxxxxxxxxxxxxx Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- drivers/dma/stm32-mdma.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c index 0de234022c6d..926d6ecf1274 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -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: -- 2.34.1
