| Message ID | 20230817235859.49846-3-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| 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 axi_dmac_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: Lars-Peter Clausen <lars@metafoo.de> > 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/dma-axi-dmac.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c > index fc7cdad37161..b9f85cb20d3e 100644 > --- a/drivers/dma/dma-axi-dmac.c > +++ b/drivers/dma/dma-axi-dmac.c > @@ -117,7 +117,7 @@ struct axi_dmac_desc { > unsigned int num_submitted; > unsigned int num_completed; > unsigned int num_sgs; > - struct axi_dmac_sg sg[]; > + struct axi_dmac_sg sg[] __counted_by(num_sgs); > }; > > struct axi_dmac_chan { > @@ -484,12 +484,11 @@ static struct axi_dmac_desc *axi_dmac_alloc_desc(unsigned int num_sgs) > desc = kzalloc(struct_size(desc, sg, num_sgs), GFP_NOWAIT); > if (!desc) > return NULL; > + desc->num_sgs = num_sgs; > > for (i = 0; i < num_sgs; i++) > desc->sg[i].id = AXI_DMAC_SG_UNUSED; > > - desc->num_sgs = num_sgs; > - > return desc; > } >
diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c index fc7cdad37161..b9f85cb20d3e 100644 --- a/drivers/dma/dma-axi-dmac.c +++ b/drivers/dma/dma-axi-dmac.c @@ -117,7 +117,7 @@ struct axi_dmac_desc { unsigned int num_submitted; unsigned int num_completed; unsigned int num_sgs; - struct axi_dmac_sg sg[]; + struct axi_dmac_sg sg[] __counted_by(num_sgs); }; struct axi_dmac_chan { @@ -484,12 +484,11 @@ static struct axi_dmac_desc *axi_dmac_alloc_desc(unsigned int num_sgs) desc = kzalloc(struct_size(desc, sg, num_sgs), GFP_NOWAIT); if (!desc) return NULL; + desc->num_sgs = num_sgs; for (i = 0; i < num_sgs; i++) desc->sg[i].id = AXI_DMAC_SG_UNUSED; - desc->num_sgs = num_sgs; - return desc; }
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 axi_dmac_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: Lars-Peter Clausen <lars@metafoo.de> Cc: dmaengine@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/dma/dma-axi-dmac.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)