2023-02-06 05:43:51

by sangsup lee

Subject: [PATCH] fpga: dfl-afu-region: Add overflow checks for region size and offset

From: Sangsup Lee <[email protected]>

The size + offset is able to be integer overflow value and it lead to mis-allocate region.

Signed-off-by: Sangsup Lee <[email protected]>
---
drivers/fpga/dfl-afu-region.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/fpga/dfl-afu-region.c b/drivers/fpga/dfl-afu-region.c
index 2e7b41629406..82b530111601 100644
--- a/drivers/fpga/dfl-afu-region.c
+++ b/drivers/fpga/dfl-afu-region.c
@@ -151,12 +151,17 @@ int afu_mmio_region_get_by_offset(struct dfl_feature_platform_data *pdata,
struct dfl_afu_mmio_region *region;
struct dfl_afu *afu;
int ret = 0;
+ u64 region_size = 0;

mutex_lock(&pdata->lock);
+ if (check_add_overflow(offset, size, &region_size)) {
+ ret = -EINVAL;
+ goto exit;
+ }
afu = dfl_fpga_pdata_get_private(pdata);
for_each_region(region, afu)
if (region->offset <= offset &&
- region->offset + region->size >= offset + size) {
+ region->offset + region->size >= region_size) {
*pregion = *region;
goto exit;
}
--
2.25.1

2023-02-06 16:51:37

by Russ Weight

Subject: Re: [PATCH] fpga: dfl-afu-region: Add overflow checks for region size and offset

On 2/5/23 21:43, [email protected] wrote:
> From: Sangsup Lee <[email protected]>
>
> The size + offset is able to be integer overflow value and it lead to mis-allocate region.
Reviewed-by: Russ Weight <[email protected]>
> Signed-off-by: Sangsup Lee <[email protected]>
> ---
> drivers/fpga/dfl-afu-region.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/fpga/dfl-afu-region.c b/drivers/fpga/dfl-afu-region.c
> index 2e7b41629406..82b530111601 100644
> --- a/drivers/fpga/dfl-afu-region.c
> +++ b/drivers/fpga/dfl-afu-region.c
> @@ -151,12 +151,17 @@ int afu_mmio_region_get_by_offset(struct dfl_feature_platform_data *pdata,
> struct dfl_afu_mmio_region *region;
> struct dfl_afu *afu;
> int ret = 0;
> + u64 region_size = 0;
>
> mutex_lock(&pdata->lock);
> + if (check_add_overflow(offset, size, &region_size)) {
> + ret = -EINVAL;
> + goto exit;
> + }
> afu = dfl_fpga_pdata_get_private(pdata);
> for_each_region(region, afu)
> if (region->offset <= offset &&
> - region->offset + region->size >= offset + size) {
> + region->offset + region->size >= region_size) {
> *pregion = *region;
> goto exit;
> }

2023-02-10 08:32:29

by Xu Yilun

Subject: Re: [PATCH] fpga: dfl-afu-region: Add overflow checks for region size and offset

On 2023-02-05 at 21:43:26 -0800, [email protected] wrote:
> From: Sangsup Lee <[email protected]>
>
> The size + offset is able to be integer overflow value and it lead to mis-allocate region.

But I didn't see the memory allocation.

>
> Signed-off-by: Sangsup Lee <[email protected]>
> ---
> drivers/fpga/dfl-afu-region.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/fpga/dfl-afu-region.c b/drivers/fpga/dfl-afu-region.c
> index 2e7b41629406..82b530111601 100644
> --- a/drivers/fpga/dfl-afu-region.c
> +++ b/drivers/fpga/dfl-afu-region.c
> @@ -151,12 +151,17 @@ int afu_mmio_region_get_by_offset(struct dfl_feature_platform_data *pdata,
> struct dfl_afu_mmio_region *region;
> struct dfl_afu *afu;
> int ret = 0;
> + u64 region_size = 0;

Reverse Xmax tree please.

>
> mutex_lock(&pdata->lock);
> + if (check_add_overflow(offset, size, &region_size)) {

I'm not sure if the check is necessary.

The offset comes from: offset = vma->vm_pgoff << PAGE_SHIFT
The size comes from: size = vma->vm_end - vma->vm_start
Is it possible the upper mm layer passes invalid vma?

Thanks,
Yilun

> + ret = -EINVAL;
> + goto exit;
> + }
> afu = dfl_fpga_pdata_get_private(pdata);
> for_each_region(region, afu)
> if (region->offset <= offset &&
> - region->offset + region->size >= offset + size) {
> + region->offset + region->size >= region_size) {
> *pregion = *region;
> goto exit;
> }
> --
> 2.25.1
>

2023-04-09 19:02:35

by Salvatore Bonaccorso

Subject: Re: [PATCH] fpga: dfl-afu-region: Add overflow checks for region size and offset

Hi,

On Fri, Feb 10, 2023 at 04:21:37PM +0800, Xu Yilun wrote:
> On 2023-02-05 at 21:43:26 -0800, [email protected] wrote:
> > From: Sangsup Lee <[email protected]>
> >
> > The size + offset is able to be integer overflow value and it lead to mis-allocate region.
>
> But I didn't see the memory allocation.
>
> >
> > Signed-off-by: Sangsup Lee <[email protected]>
> > ---
> > drivers/fpga/dfl-afu-region.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/fpga/dfl-afu-region.c b/drivers/fpga/dfl-afu-region.c
> > index 2e7b41629406..82b530111601 100644
> > --- a/drivers/fpga/dfl-afu-region.c
> > +++ b/drivers/fpga/dfl-afu-region.c
> > @@ -151,12 +151,17 @@ int afu_mmio_region_get_by_offset(struct dfl_feature_platform_data *pdata,
> > struct dfl_afu_mmio_region *region;
> > struct dfl_afu *afu;
> > int ret = 0;
> > + u64 region_size = 0;
>
> Reverse Xmax tree please.
>
> >
> > mutex_lock(&pdata->lock);
> > + if (check_add_overflow(offset, size, &region_size)) {
>
> I'm not sure if the check is necessary.
>
> The offset comes from: offset = vma->vm_pgoff << PAGE_SHIFT
> The size comes from: size = vma->vm_end - vma->vm_start
> Is it possible the upper mm layer passes invalid vma?
>
> Thanks,
> Yilun

Did you saw the comments on your patch by Yilun? Did it felt trough
the cracks?

Regards,
Salvatore

2023-04-10 02:20:40

by sangsup lee

Subject: Re: [PATCH] fpga: dfl-afu-region: Add overflow checks for region size and offset

Hi,

In my opinion the code has an insecure code pattern.
The size may have integer overflow condition i think.
But, I did not do dynamic analysis but I did static audit fpga code(I
don't have an fpga device).
because of this. I don't make sure about Yilun's comment.
I think the code must have defensive coding rules.

best regards.