* Re: [PATCH] iommu/dma: Fix iova map result check bug
2022-05-07 8:52 [PATCH] iommu/dma: Fix iova map result check bug yf.wang
@ 2022-05-08 16:01 ` Miles Chen
2022-05-09 9:22 ` Robin Murphy
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Miles Chen @ 2022-05-08 16:01 UTC (permalink / raw)
To: yf.wang
Cc: Libo.Kang, Ning.Li, iommu, joro, linux-arm-kernel, linux-kernel,
linux-mediatek, logang, matthias.bgg, stable, will, wsd_upstream,
yong.wu
> The data type of the return value of the iommu_map_sg_atomic
> is ssize_t, but the data type of iova size is size_t,
> e.g. one is int while the other is unsigned int.
>
> When iommu_map_sg_atomic return value is compared with iova size,
> it will force the signed int to be converted to unsigned int, if
> iova map fails and iommu_map_sg_atomic return error code is less
> than 0, then (ret < iova_len) is false, which will to cause not
> do free iova, and the master can still successfully get the iova
> of map fail, which is not expected.
>
> Therefore, we need to check the return value of iommu_map_sg_atomic
> in two cases according to whether it is less than 0.
>
> Fixes: ad8f36e4b6b1 ("iommu: return full error code from iommu_map_sg[_atomic]()")
> Signed-off-by: Yunfei Wang <yf.wang@mediatek.com>
Yes, we have to make sure ssize_t >= 0 before comparing ssize_t and size_t.
Reviewed-by: Miles Chen <miles.chen@mediatek.com>
>
> Cc: <stable@vger.kernel.org> # 5.15.*
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] iommu/dma: Fix iova map result check bug
2022-05-07 8:52 [PATCH] iommu/dma: Fix iova map result check bug yf.wang
2022-05-08 16:01 ` Miles Chen
@ 2022-05-09 9:22 ` Robin Murphy
2022-05-12 5:51 ` Yong Wu
2022-05-13 13:01 ` Joerg Roedel
3 siblings, 0 replies; 5+ messages in thread
From: Robin Murphy @ 2022-05-09 9:22 UTC (permalink / raw)
To: yf.wang, Joerg Roedel, Will Deacon, Matthias Brugger,
Logan Gunthorpe, open list:IOMMU DRIVERS, open list,
moderated list:ARM/Mediatek SoC support,
moderated list:ARM/Mediatek SoC support
Cc: wsd_upstream, Libo Kang, Yong Wu, Ning Li, stable
On 2022-05-07 09:52, yf.wang@mediatek.com wrote:
> From: Yunfei Wang <yf.wang@mediatek.com>
>
> The data type of the return value of the iommu_map_sg_atomic
> is ssize_t, but the data type of iova size is size_t,
> e.g. one is int while the other is unsigned int.
>
> When iommu_map_sg_atomic return value is compared with iova size,
> it will force the signed int to be converted to unsigned int, if
> iova map fails and iommu_map_sg_atomic return error code is less
> than 0, then (ret < iova_len) is false, which will to cause not
> do free iova, and the master can still successfully get the iova
> of map fail, which is not expected.
>
> Therefore, we need to check the return value of iommu_map_sg_atomic
> in two cases according to whether it is less than 0.
Heh, it's always a fun day when I have to go back to the C standard to
remind myself of the usual arithmetic conversions. But indeed this seems
correct, and even though the double comparisons look a little
non-obvious on their own I can't think of an objectively better
alternative, so:
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> Fixes: ad8f36e4b6b1 ("iommu: return full error code from iommu_map_sg[_atomic]()")
> Signed-off-by: Yunfei Wang <yf.wang@mediatek.com>
> Cc: <stable@vger.kernel.org> # 5.15.*
> ---
> drivers/iommu/dma-iommu.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 09f6e1c0f9c0..2932281e93fc 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -776,6 +776,7 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
> unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap;
> struct page **pages;
> dma_addr_t iova;
> + ssize_t ret;
>
> if (static_branch_unlikely(&iommu_deferred_attach_enabled) &&
> iommu_deferred_attach(dev, domain))
> @@ -813,8 +814,8 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
> arch_dma_prep_coherent(sg_page(sg), sg->length);
> }
>
> - if (iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents, ioprot)
> - < size)
> + ret = iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents, ioprot);
> + if (ret < 0 || ret < size)
> goto out_free_sg;
>
> sgt->sgl->dma_address = iova;
> @@ -1209,7 +1210,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
> * implementation - it knows better than we do.
> */
> ret = iommu_map_sg_atomic(domain, iova, sg, nents, prot);
> - if (ret < iova_len)
> + if (ret < 0 || ret < iova_len)
> goto out_free_iova;
>
> return __finalise_sg(dev, sg, nents, iova);
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] iommu/dma: Fix iova map result check bug
2022-05-07 8:52 [PATCH] iommu/dma: Fix iova map result check bug yf.wang
2022-05-08 16:01 ` Miles Chen
2022-05-09 9:22 ` Robin Murphy
@ 2022-05-12 5:51 ` Yong Wu
2022-05-13 13:01 ` Joerg Roedel
3 siblings, 0 replies; 5+ messages in thread
From: Yong Wu @ 2022-05-12 5:51 UTC (permalink / raw)
To: yf.wang, Joerg Roedel, Will Deacon, Matthias Brugger,
Logan Gunthorpe, open list:IOMMU DRIVERS, open list,
moderated list:ARM/Mediatek SoC support,
moderated list:ARM/Mediatek SoC support
Cc: wsd_upstream, Libo Kang, Ning Li, stable
On Sat, 2022-05-07 at 16:52 +0800, yf.wang@mediatek.com wrote:
> From: Yunfei Wang <yf.wang@mediatek.com>
>
> The data type of the return value of the iommu_map_sg_atomic
> is ssize_t, but the data type of iova size is size_t,
> e.g. one is int while the other is unsigned int.
>
> When iommu_map_sg_atomic return value is compared with iova size,
> it will force the signed int to be converted to unsigned int, if
> iova map fails and iommu_map_sg_atomic return error code is less
> than 0, then (ret < iova_len) is false, which will to cause not
> do free iova, and the master can still successfully get the iova
> of map fail, which is not expected.
>
> Therefore, we need to check the return value of iommu_map_sg_atomic
> in two cases according to whether it is less than 0.
>
> Fixes: ad8f36e4b6b1 ("iommu: return full error code from
> iommu_map_sg[_atomic]()")
> Signed-off-by: Yunfei Wang <yf.wang@mediatek.com>
> Cc: <stable@vger.kernel.org> # 5.15.*
> ---
> drivers/iommu/dma-iommu.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 09f6e1c0f9c0..2932281e93fc 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -776,6 +776,7 @@ static struct page
> **__iommu_dma_alloc_noncontiguous(struct device *dev,
> unsigned int count, min_size, alloc_sizes = domain-
> >pgsize_bitmap;
> struct page **pages;
> dma_addr_t iova;
> + ssize_t ret;
>
> if (static_branch_unlikely(&iommu_deferred_attach_enabled) &&
> iommu_deferred_attach(dev, domain))
> @@ -813,8 +814,8 @@ static struct page
> **__iommu_dma_alloc_noncontiguous(struct device *dev,
> arch_dma_prep_coherent(sg_page(sg), sg-
> >length);
> }
>
> - if (iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt-
> >orig_nents, ioprot)
> - < size)
> + ret = iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt-
> >orig_nents, ioprot);
> + if (ret < 0 || ret < size)
if (IS_ERR_VALUE(ret) || ret < size) for readable?
> goto out_free_sg;
>
> sgt->sgl->dma_address = iova;
> @@ -1209,7 +1210,7 @@ static int iommu_dma_map_sg(struct device *dev,
> struct scatterlist *sg,
> * implementation - it knows better than we do.
> */
> ret = iommu_map_sg_atomic(domain, iova, sg, nents, prot);
> - if (ret < iova_len)
> + if (ret < 0 || ret < iova_len)
> goto out_free_iova;
>
> return __finalise_sg(dev, sg, nents, iova);
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^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] iommu/dma: Fix iova map result check bug
2022-05-07 8:52 [PATCH] iommu/dma: Fix iova map result check bug yf.wang
` (2 preceding siblings ...)
2022-05-12 5:51 ` Yong Wu
@ 2022-05-13 13:01 ` Joerg Roedel
3 siblings, 0 replies; 5+ messages in thread
From: Joerg Roedel @ 2022-05-13 13:01 UTC (permalink / raw)
To: yf.wang
Cc: Will Deacon, Matthias Brugger, Logan Gunthorpe,
open list:IOMMU DRIVERS, open list,
moderated list:ARM/Mediatek SoC support,
moderated list:ARM/Mediatek SoC support, wsd_upstream, Libo Kang,
Yong Wu, Ning Li, stable
On Sat, May 07, 2022 at 04:52:03PM +0800, yf.wang@mediatek.com wrote:
> drivers/iommu/dma-iommu.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
Applied, thanks.
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^ permalink raw reply [flat|nested] 5+ messages in thread