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 sa11x0_dma_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: dmaengine@xxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- drivers/dma/sa11x0-dma.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/dma/sa11x0-dma.c b/drivers/dma/sa11x0-dma.c index a29c13cae716..e5849622f198 100644 --- a/drivers/dma/sa11x0-dma.c +++ b/drivers/dma/sa11x0-dma.c @@ -78,7 +78,7 @@ struct sa11x0_dma_desc { bool cyclic; unsigned sglen; - struct sa11x0_dma_sg sg[]; + struct sa11x0_dma_sg sg[] __counted_by(sglen); }; struct sa11x0_dma_phy; @@ -558,6 +558,7 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg( dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc); return NULL; } + txd->sglen = j; j = 0; for_each_sg(sg, sgent, sglen, i) { @@ -593,7 +594,6 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_slave_sg( txd->ddar = c->ddar; txd->size = size; - txd->sglen = j; dev_dbg(chan->device->dev, "vchan %p: txd %p: size %zu nr %u\n", &c->vc, &txd->vd, txd->size, txd->sglen); @@ -628,6 +628,7 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_dma_cyclic( dev_dbg(chan->device->dev, "vchan %p: kzalloc failed\n", &c->vc); return NULL; } + txd->sglen = sglen; for (i = k = 0; i < size / period; i++) { size_t tlen, len = period; @@ -653,7 +654,6 @@ static struct dma_async_tx_descriptor *sa11x0_dma_prep_dma_cyclic( txd->ddar = c->ddar; txd->size = size; - txd->sglen = sglen; txd->cyclic = 1; txd->period = sgperiod; -- 2.34.1
