| Message ID | 20230817235859.49846-6-keescook@chromium.org |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | dmaengine: Annotate with __counted_by | expand |
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@kernel.org> > Cc: dmaengine@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> 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);
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);
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@kernel.org> Cc: dmaengine@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/dma/moxart-dma.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)