On 8/17/23 17:58, 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 moxart_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>
Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Thanks
--
Gustavo
---
drivers/dma/moxart-dma.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/moxart-dma.c b/drivers/dma/moxart-dma.c
index 7565ad98ba66..c1dd5716a46d 100644
--- a/drivers/dma/moxart-dma.c
+++ b/drivers/dma/moxart-dma.c
@@ -124,7 +124,7 @@ struct moxart_desc {
unsigned int dma_cycles;
struct virt_dma_desc vd;
uint8_t es;
- struct moxart_sg sg[];
+ struct moxart_sg sg[] __counted_by(sglen);
};
struct moxart_chan {
@@ -309,6 +309,7 @@ static struct dma_async_tx_descriptor *moxart_prep_slave_sg(
d = kzalloc(struct_size(d, sg, sg_len), GFP_ATOMIC);
if (!d)
return NULL;
+ d->sglen = sg_len;
d->dma_dir = dir;
d->dev_addr = dev_addr;
@@ -319,8 +320,6 @@ static struct dma_async_tx_descriptor *moxart_prep_slave_sg(
d->sg[i].len = sg_dma_len(sgent);
}
- d->sglen = sg_len;
-
ch->error = 0;
return vchan_tx_prep(&ch->vc, &d->vd, tx_flags);
