| Message ID | 20230817235859.49846-12-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 stm32_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@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-dma.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c > index 5c36811aa134..a732b3807b11 100644 > --- a/drivers/dma/stm32-dma.c > +++ b/drivers/dma/stm32-dma.c > @@ -191,7 +191,7 @@ struct stm32_dma_desc { > struct virt_dma_desc vdesc; > bool cyclic; > u32 num_sgs; > - struct stm32_dma_sg_req sg_req[]; > + struct stm32_dma_sg_req sg_req[] __counted_by(num_sgs); > }; > > /** > @@ -1105,6 +1105,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg( > desc = kzalloc(struct_size(desc, sg_req, sg_len), GFP_NOWAIT); > if (!desc) > return NULL; > + desc->num_sgs = sg_len; > > /* Set peripheral flow controller */ > if (chan->dma_sconfig.device_fc) > @@ -1141,8 +1142,6 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg( > desc->sg_req[i].chan_reg.dma_sm1ar += sg_dma_len(sg); > desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items; > } > - > - desc->num_sgs = sg_len; > desc->cyclic = false; > > return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); > @@ -1216,6 +1215,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic( > desc = kzalloc(struct_size(desc, sg_req, num_periods), GFP_NOWAIT); > if (!desc) > return NULL; > + desc->num_sgs = num_periods; > > for (i = 0; i < num_periods; i++) { > desc->sg_req[i].len = period_len; > @@ -1232,8 +1232,6 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic( > if (!chan->trig_mdma) > buf_addr += period_len; > } > - > - desc->num_sgs = num_periods; > desc->cyclic = true; > > return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); > @@ -1254,6 +1252,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy( > desc = kzalloc(struct_size(desc, sg_req, num_sgs), GFP_NOWAIT); > if (!desc) > return NULL; > + desc->num_sgs = num_sgs; > > threshold = chan->threshold; > > @@ -1283,8 +1282,6 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy( > desc->sg_req[i].chan_reg.dma_sndtr = xfer_count; > desc->sg_req[i].len = xfer_count; > } > - > - desc->num_sgs = num_sgs; > desc->cyclic = false; > > return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index 5c36811aa134..a732b3807b11 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -191,7 +191,7 @@ struct stm32_dma_desc { struct virt_dma_desc vdesc; bool cyclic; u32 num_sgs; - struct stm32_dma_sg_req sg_req[]; + struct stm32_dma_sg_req sg_req[] __counted_by(num_sgs); }; /** @@ -1105,6 +1105,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg( desc = kzalloc(struct_size(desc, sg_req, sg_len), GFP_NOWAIT); if (!desc) return NULL; + desc->num_sgs = sg_len; /* Set peripheral flow controller */ if (chan->dma_sconfig.device_fc) @@ -1141,8 +1142,6 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_slave_sg( desc->sg_req[i].chan_reg.dma_sm1ar += sg_dma_len(sg); desc->sg_req[i].chan_reg.dma_sndtr = nb_data_items; } - - desc->num_sgs = sg_len; desc->cyclic = false; return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); @@ -1216,6 +1215,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic( desc = kzalloc(struct_size(desc, sg_req, num_periods), GFP_NOWAIT); if (!desc) return NULL; + desc->num_sgs = num_periods; for (i = 0; i < num_periods; i++) { desc->sg_req[i].len = period_len; @@ -1232,8 +1232,6 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_cyclic( if (!chan->trig_mdma) buf_addr += period_len; } - - desc->num_sgs = num_periods; desc->cyclic = true; return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); @@ -1254,6 +1252,7 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy( desc = kzalloc(struct_size(desc, sg_req, num_sgs), GFP_NOWAIT); if (!desc) return NULL; + desc->num_sgs = num_sgs; threshold = chan->threshold; @@ -1283,8 +1282,6 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy( desc->sg_req[i].chan_reg.dma_sndtr = xfer_count; desc->sg_req[i].len = xfer_count; } - - desc->num_sgs = num_sgs; desc->cyclic = false; return vchan_tx_prep(&chan->vchan, &desc->vdesc, 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 stm32_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@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-dma.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)