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 uniphier_xdmac_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: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: dmaengine@xxxxxxxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- drivers/dma/uniphier-xdmac.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/dma/uniphier-xdmac.c b/drivers/dma/uniphier-xdmac.c index 290836b7e1be..dd51522879a7 100644 --- a/drivers/dma/uniphier-xdmac.c +++ b/drivers/dma/uniphier-xdmac.c @@ -80,7 +80,7 @@ struct uniphier_xdmac_desc { unsigned int nr_node; unsigned int cur_node; enum dma_transfer_direction dir; - struct uniphier_xdmac_desc_node nodes[]; + struct uniphier_xdmac_desc_node nodes[] __counted_by(nr_node); }; struct uniphier_xdmac_chan { @@ -295,6 +295,7 @@ uniphier_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst, xd = kzalloc(struct_size(xd, nodes, nr), GFP_NOWAIT); if (!xd) return NULL; + xd->nr_node = nr; for (i = 0; i < nr; i++) { burst_size = min_t(size_t, len, XDMAC_MAX_WORD_SIZE); @@ -309,7 +310,6 @@ uniphier_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst, } xd->dir = DMA_MEM_TO_MEM; - xd->nr_node = nr; xd->cur_node = 0; return vchan_tx_prep(vc, &xd->vd, flags); @@ -351,6 +351,7 @@ uniphier_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, xd = kzalloc(struct_size(xd, nodes, sg_len), GFP_NOWAIT); if (!xd) return NULL; + xd->nr_node = sg_len; for_each_sg(sgl, sg, sg_len, i) { xd->nodes[i].src = (direction == DMA_DEV_TO_MEM) @@ -385,7 +386,6 @@ uniphier_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, } xd->dir = direction; - xd->nr_node = sg_len; xd->cur_node = 0; return vchan_tx_prep(vc, &xd->vd, flags); -- 2.34.1
