2022-03-21 22:48:14

by Keir Fraser

Subject: [PATCH] virtio: pci: Sanity check the bar index in find_shm_cap

The bar index is used as an index into the device's resource list
and should be checked as within range for a standard bar.

Signed-off-by: Keir Fraser <[email protected]>
---
drivers/virtio/virtio_pci_modern.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 5455bc041fb6..84bace98dff5 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -293,7 +293,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,

for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR); pos > 0;
pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
- u8 type, cap_len, id;
+ u8 type, cap_len, id, res_bar;
u32 tmp32;
u64 res_offset, res_length;

@@ -317,7 +317,12 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,

/* Type, and ID match, looks good */
pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
- bar), bar);
+ bar), &res_bar);
+ if (res_bar >= PCI_STD_NUM_BARS) {
+ dev_err(&dev->dev, "%s: shm cap with bad bar: %d\n",
+ __func__, res_bar);
+ continue;
+ }

/* Read the lower 32bit of length and offset */
pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
@@ -337,6 +342,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
length_hi), &tmp32);
res_length |= ((u64)tmp32) << 32;

+ *bar = res_bar;
*offset = res_offset;
*len = res_length;

--
2.35.1.894.gb6a874cedc-goog

2022-03-22 04:12:31

by Jason Wang

Subject: Re: [PATCH] virtio: pci: Sanity check the bar index in find_shm_cap

On Mon, Mar 21, 2022 at 11:49 PM Keir Fraser <[email protected]> wrote:
>
> The bar index is used as an index into the device's resource list
> and should be checked as within range for a standard bar.
>
> Signed-off-by: Keir Fraser <[email protected]>

Patch looks good, do we need a similar check in vp_modern_map_capability()?

Thanks

> ---
> drivers/virtio/virtio_pci_modern.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 5455bc041fb6..84bace98dff5 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -293,7 +293,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
>
> for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR); pos > 0;
> pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> - u8 type, cap_len, id;
> + u8 type, cap_len, id, res_bar;
> u32 tmp32;
> u64 res_offset, res_length;
>
> @@ -317,7 +317,12 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
>
> /* Type, and ID match, looks good */
> pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> - bar), bar);
> + bar), &res_bar);
> + if (res_bar >= PCI_STD_NUM_BARS) {
> + dev_err(&dev->dev, "%s: shm cap with bad bar: %d\n",
> + __func__, res_bar);
> + continue;
> + }
>
> /* Read the lower 32bit of length and offset */
> pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
> @@ -337,6 +342,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
> length_hi), &tmp32);
> res_length |= ((u64)tmp32) << 32;
>
> + *bar = res_bar;
> *offset = res_offset;
> *len = res_length;
>
> --
> 2.35.1.894.gb6a874cedc-goog
>

2022-03-22 10:54:28

by Keir Fraser

Subject: Re: [PATCH] virtio: pci: Sanity check the bar index in find_shm_cap

On Tue, Mar 22, 2022 at 11:36:23AM +0800, Jason Wang wrote:
> On Mon, Mar 21, 2022 at 11:49 PM Keir Fraser <[email protected]> wrote:
> >
> > The bar index is used as an index into the device's resource list
> > and should be checked as within range for a standard bar.
> >
> > Signed-off-by: Keir Fraser <[email protected]>
>
> Patch looks good, do we need a similar check in vp_modern_map_capability()?

Yes it looks like we do. Would you like me to fix that also? If so: separate patch, or
revised version of this patch?

> Thanks
>
> > ---
> > drivers/virtio/virtio_pci_modern.c | 10 ++++++++--
> > 1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > index 5455bc041fb6..84bace98dff5 100644
> > --- a/drivers/virtio/virtio_pci_modern.c
> > +++ b/drivers/virtio/virtio_pci_modern.c
> > @@ -293,7 +293,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
> >
> > for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR); pos > 0;
> > pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> > - u8 type, cap_len, id;
> > + u8 type, cap_len, id, res_bar;
> > u32 tmp32;
> > u64 res_offset, res_length;
> >
> > @@ -317,7 +317,12 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
> >
> > /* Type, and ID match, looks good */
> > pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > - bar), bar);
> > + bar), &res_bar);
> > + if (res_bar >= PCI_STD_NUM_BARS) {
> > + dev_err(&dev->dev, "%s: shm cap with bad bar: %d\n",
> > + __func__, res_bar);
> > + continue;
> > + }
> >
> > /* Read the lower 32bit of length and offset */
> > pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
> > @@ -337,6 +342,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
> > length_hi), &tmp32);
> > res_length |= ((u64)tmp32) << 32;
> >
> > + *bar = res_bar;
> > *offset = res_offset;
> > *len = res_length;
> >
> > --
> > 2.35.1.894.gb6a874cedc-goog
> >
>

2022-03-22 14:41:33

by Michael S. Tsirkin

Subject: Re: [PATCH] virtio: pci: Sanity check the bar index in find_shm_cap

On Tue, Mar 22, 2022 at 09:20:27AM +0000, Keir Fraser wrote:
> On Tue, Mar 22, 2022 at 11:36:23AM +0800, Jason Wang wrote:
> > On Mon, Mar 21, 2022 at 11:49 PM Keir Fraser <[email protected]> wrote:
> > >
> > > The bar index is used as an index into the device's resource list
> > > and should be checked as within range for a standard bar.
> > >
> > > Signed-off-by: Keir Fraser <[email protected]>
> >
> > Patch looks good, do we need a similar check in vp_modern_map_capability()?
>
> Yes it looks like we do. Would you like me to fix that also? If so: separate patch, or
> revised version of this patch?

Yes pls. A fixed version is better, less work for everyone.

> > Thanks
> >
> > > ---
> > > drivers/virtio/virtio_pci_modern.c | 10 ++++++++--
> > > 1 file changed, 8 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > > index 5455bc041fb6..84bace98dff5 100644
> > > --- a/drivers/virtio/virtio_pci_modern.c
> > > +++ b/drivers/virtio/virtio_pci_modern.c
> > > @@ -293,7 +293,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
> > >
> > > for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR); pos > 0;
> > > pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
> > > - u8 type, cap_len, id;
> > > + u8 type, cap_len, id, res_bar;
> > > u32 tmp32;
> > > u64 res_offset, res_length;
> > >
> > > @@ -317,7 +317,12 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
> > >
> > > /* Type, and ID match, looks good */
> > > pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
> > > - bar), bar);
> > > + bar), &res_bar);
> > > + if (res_bar >= PCI_STD_NUM_BARS) {
> > > + dev_err(&dev->dev, "%s: shm cap with bad bar: %d\n",
> > > + __func__, res_bar);
> > > + continue;
> > > + }
> > >
> > > /* Read the lower 32bit of length and offset */
> > > pci_read_config_dword(dev, pos + offsetof(struct virtio_pci_cap,
> > > @@ -337,6 +342,7 @@ static int virtio_pci_find_shm_cap(struct pci_dev *dev, u8 required_id,
> > > length_hi), &tmp32);
> > > res_length |= ((u64)tmp32) << 32;
> > >
> > > + *bar = res_bar;
> > > *offset = res_offset;
> > > *len = res_length;
> > >
> > > --
> > > 2.35.1.894.gb6a874cedc-goog
> > >
> >