| Message ID | 20230817235859.49846-13-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 stm32_mdma_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: Maxime Coquelin <mcoquelin.stm32@gmail.com> > Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> > Cc: dmaengine@vger.kernel.org > Cc: linux-stm32@st-md-mailman.stormreply.com > Cc: linux-arm-kernel@lists.infradead.org > Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks -- Gustavo > --- > drivers/dma/stm32-mdma.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c > index 0de234022c6d..926d6ecf1274 100644 > --- a/drivers/dma/stm32-mdma.c > +++ b/drivers/dma/stm32-mdma.c > @@ -224,7 +224,7 @@ struct stm32_mdma_desc { > u32 ccr; > bool cyclic; > u32 count; > - struct stm32_mdma_desc_node node[]; > + struct stm32_mdma_desc_node node[] __counted_by(count); > }; > > struct stm32_mdma_dma_config { > @@ -321,6 +321,7 @@ static struct stm32_mdma_desc *stm32_mdma_alloc_desc( > desc = kzalloc(struct_size(desc, node, count), GFP_NOWAIT); > if (!desc) > return NULL; > + desc->count = count; > > for (i = 0; i < count; i++) { > desc->node[i].hwdesc = > @@ -330,8 +331,6 @@ static struct stm32_mdma_desc *stm32_mdma_alloc_desc( > goto err; > } > > - desc->count = count; > - > return desc; > > err:
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c index 0de234022c6d..926d6ecf1274 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -224,7 +224,7 @@ struct stm32_mdma_desc { u32 ccr; bool cyclic; u32 count; - struct stm32_mdma_desc_node node[]; + struct stm32_mdma_desc_node node[] __counted_by(count); }; struct stm32_mdma_dma_config { @@ -321,6 +321,7 @@ static struct stm32_mdma_desc *stm32_mdma_alloc_desc( desc = kzalloc(struct_size(desc, node, count), GFP_NOWAIT); if (!desc) return NULL; + desc->count = count; for (i = 0; i < count; i++) { desc->node[i].hwdesc = @@ -330,8 +331,6 @@ static struct stm32_mdma_desc *stm32_mdma_alloc_desc( goto err; } - desc->count = count; - return desc; err:
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 stm32_mdma_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: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: dmaengine@vger.kernel.org Cc: linux-stm32@st-md-mailman.stormreply.com Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/dma/stm32-mdma.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)