* [PATCH v2] virtio: pci: sanity check bar indexes @ 2022-03-22 15:19 Keir Fraser 2022-03-23 7:57 ` Jason Wang 0 siblings, 1 reply; 7+ messages in thread From: Keir Fraser @ 2022-03-22 15:19 UTC (permalink / raw) To: Michael S. Tsirkin, Jason Wang Cc: kernel-team, Keir Fraser, virtualization, linux-kernel 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. Also clean up an existing check to consistently use PCI_STD_NUM_BARS. Signed-off-by: Keir Fraser <keirf@google.com> --- drivers/virtio/virtio_pci_modern.c | 10 ++++++++-- drivers/virtio/virtio_pci_modern_dev.c | 8 +++++++- 2 files changed, 15 insertions(+), 3 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; diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c index e8b3ff2b9fbc..a6911d1e212a 100644 --- a/drivers/virtio/virtio_pci_modern_dev.c +++ b/drivers/virtio/virtio_pci_modern_dev.c @@ -35,6 +35,12 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), &length); + if (bar >= PCI_STD_NUM_BARS) { + dev_err(&dev->dev, + "virtio_pci: bad capability bar %u\n", bar); + return NULL; + } + if (length <= start) { dev_err(&dev->dev, "virtio_pci: bad capability len %u (>%u expected)\n", @@ -120,7 +126,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type, &bar); /* Ignore structures with reserved BAR values */ - if (bar > 0x5) + if (bar >= PCI_STD_NUM_BARS) continue; if (type == cfg_type) { -- 2.35.1.894.gb6a874cedc-goog ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2] virtio: pci: sanity check bar indexes 2022-03-22 15:19 [PATCH v2] virtio: pci: sanity check bar indexes Keir Fraser @ 2022-03-23 7:57 ` Jason Wang 2022-03-23 9:13 ` Keir Fraser 2022-03-23 12:01 ` Michael S. Tsirkin 0 siblings, 2 replies; 7+ messages in thread From: Jason Wang @ 2022-03-23 7:57 UTC (permalink / raw) To: Keir Fraser; +Cc: Michael S. Tsirkin, kernel-team, virtualization, linux-kernel On Tue, Mar 22, 2022 at 11:20 PM Keir Fraser <keirf@google.com> 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. > > Also clean up an existing check to consistently use PCI_STD_NUM_BARS. > > Signed-off-by: Keir Fraser <keirf@google.com> > --- > drivers/virtio/virtio_pci_modern.c | 10 ++++++++-- > drivers/virtio/virtio_pci_modern_dev.c | 8 +++++++- > 2 files changed, 15 insertions(+), 3 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; > > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c > index e8b3ff2b9fbc..a6911d1e212a 100644 > --- a/drivers/virtio/virtio_pci_modern_dev.c > +++ b/drivers/virtio/virtio_pci_modern_dev.c > @@ -35,6 +35,12 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, > pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), > &length); > > + if (bar >= PCI_STD_NUM_BARS) { > + dev_err(&dev->dev, > + "virtio_pci: bad capability bar %u\n", bar); > + return NULL; > + } > + > if (length <= start) { > dev_err(&dev->dev, > "virtio_pci: bad capability len %u (>%u expected)\n", > @@ -120,7 +126,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type, > &bar); > > /* Ignore structures with reserved BAR values */ > - if (bar > 0x5) > + if (bar >= PCI_STD_NUM_BARS) > continue; Just notice that the spec said: " values 0x0 to 0x5 specify a Base Address register (BAR) belonging to the function located beginning at 10h in PCI Configuration Space and used to map the structure into Memory or I/O Space. The BAR is permitted to be either 32-bit or 64-bit, it can map Memory Space or I/O Space. Any other value is reserved for future use. " So we probably need to stick 0x5 instead of 0x6 (PCI_STD_NUM_BARS) for this and other places. Thanks > > if (type == cfg_type) { > -- > 2.35.1.894.gb6a874cedc-goog > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] virtio: pci: sanity check bar indexes 2022-03-23 7:57 ` Jason Wang @ 2022-03-23 9:13 ` Keir Fraser 2022-03-23 9:21 ` Jason Wang 2022-03-23 12:01 ` Michael S. Tsirkin 1 sibling, 1 reply; 7+ messages in thread From: Keir Fraser @ 2022-03-23 9:13 UTC (permalink / raw) To: Jason Wang; +Cc: Michael S. Tsirkin, kernel-team, virtualization, linux-kernel On Wed, Mar 23, 2022 at 03:57:59PM +0800, Jason Wang wrote: > On Tue, Mar 22, 2022 at 11:20 PM Keir Fraser <keirf@google.com> 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. > > > > Also clean up an existing check to consistently use PCI_STD_NUM_BARS. > > > > Signed-off-by: Keir Fraser <keirf@google.com> > > --- > > drivers/virtio/virtio_pci_modern.c | 10 ++++++++-- > > drivers/virtio/virtio_pci_modern_dev.c | 8 +++++++- > > 2 files changed, 15 insertions(+), 3 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; > > > > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c > > index e8b3ff2b9fbc..a6911d1e212a 100644 > > --- a/drivers/virtio/virtio_pci_modern_dev.c > > +++ b/drivers/virtio/virtio_pci_modern_dev.c > > @@ -35,6 +35,12 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, > > pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), > > &length); > > > > + if (bar >= PCI_STD_NUM_BARS) { > > + dev_err(&dev->dev, > > + "virtio_pci: bad capability bar %u\n", bar); > > + return NULL; > > + } > > + > > if (length <= start) { > > dev_err(&dev->dev, > > "virtio_pci: bad capability len %u (>%u expected)\n", > > @@ -120,7 +126,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type, > > &bar); > > > > /* Ignore structures with reserved BAR values */ > > - if (bar > 0x5) > > + if (bar >= PCI_STD_NUM_BARS) > > continue; > > Just notice that the spec said: > > " > values 0x0 to 0x5 specify a Base Address register (BAR) belonging to > the function located beginning at 10h in PCI Configuration Space and > used to map the structure into Memory or I/O Space. The BAR is > permitted to be either 32-bit or 64-bit, it can map Memory Space or > I/O Space. > > Any other value is reserved for future use. > " > > So we probably need to stick 0x5 instead of 0x6 (PCI_STD_NUM_BARS) for > this and other places. The comparison(s) are changed to greater-or-equal, so they are logically equivalent to the old check against naked 0x5 while documenting the intent better. > Thanks > > > > > if (type == cfg_type) { > > -- > > 2.35.1.894.gb6a874cedc-goog > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] virtio: pci: sanity check bar indexes 2022-03-23 9:13 ` Keir Fraser @ 2022-03-23 9:21 ` Jason Wang 0 siblings, 0 replies; 7+ messages in thread From: Jason Wang @ 2022-03-23 9:21 UTC (permalink / raw) To: Keir Fraser; +Cc: Michael S. Tsirkin, kernel-team, virtualization, linux-kernel On Wed, Mar 23, 2022 at 5:13 PM Keir Fraser <keirf@google.com> wrote: > > On Wed, Mar 23, 2022 at 03:57:59PM +0800, Jason Wang wrote: > > On Tue, Mar 22, 2022 at 11:20 PM Keir Fraser <keirf@google.com> 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. > > > > > > Also clean up an existing check to consistently use PCI_STD_NUM_BARS. > > > > > > Signed-off-by: Keir Fraser <keirf@google.com> > > > --- > > > drivers/virtio/virtio_pci_modern.c | 10 ++++++++-- > > > drivers/virtio/virtio_pci_modern_dev.c | 8 +++++++- > > > 2 files changed, 15 insertions(+), 3 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; > > > > > > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c > > > index e8b3ff2b9fbc..a6911d1e212a 100644 > > > --- a/drivers/virtio/virtio_pci_modern_dev.c > > > +++ b/drivers/virtio/virtio_pci_modern_dev.c > > > @@ -35,6 +35,12 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, > > > pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), > > > &length); > > > > > > + if (bar >= PCI_STD_NUM_BARS) { > > > + dev_err(&dev->dev, > > > + "virtio_pci: bad capability bar %u\n", bar); > > > + return NULL; > > > + } > > > + > > > if (length <= start) { > > > dev_err(&dev->dev, > > > "virtio_pci: bad capability len %u (>%u expected)\n", > > > @@ -120,7 +126,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type, > > > &bar); > > > > > > /* Ignore structures with reserved BAR values */ > > > - if (bar > 0x5) > > > + if (bar >= PCI_STD_NUM_BARS) > > > continue; > > > > Just notice that the spec said: > > > > " > > values 0x0 to 0x5 specify a Base Address register (BAR) belonging to > > the function located beginning at 10h in PCI Configuration Space and > > used to map the structure into Memory or I/O Space. The BAR is > > permitted to be either 32-bit or 64-bit, it can map Memory Space or > > I/O Space. > > > > Any other value is reserved for future use. > > " > > > > So we probably need to stick 0x5 instead of 0x6 (PCI_STD_NUM_BARS) for > > this and other places. > > The comparison(s) are changed to greater-or-equal, so they are logically > equivalent to the old check against naked 0x5 while documenting the intent > better. You're right, So: Acked-by: Jason Wang <jasowang@redhat.com> > > > Thanks > > > > > > > > if (type == cfg_type) { > > > -- > > > 2.35.1.894.gb6a874cedc-goog > > > > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] virtio: pci: sanity check bar indexes 2022-03-23 7:57 ` Jason Wang 2022-03-23 9:13 ` Keir Fraser @ 2022-03-23 12:01 ` Michael S. Tsirkin 2022-03-23 13:21 ` Keir Fraser 1 sibling, 1 reply; 7+ messages in thread From: Michael S. Tsirkin @ 2022-03-23 12:01 UTC (permalink / raw) To: Jason Wang; +Cc: Keir Fraser, kernel-team, virtualization, linux-kernel On Wed, Mar 23, 2022 at 03:57:59PM +0800, Jason Wang wrote: > On Tue, Mar 22, 2022 at 11:20 PM Keir Fraser <keirf@google.com> 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. > > > > Also clean up an existing check to consistently use PCI_STD_NUM_BARS. > > > > Signed-off-by: Keir Fraser <keirf@google.com> > > --- > > drivers/virtio/virtio_pci_modern.c | 10 ++++++++-- > > drivers/virtio/virtio_pci_modern_dev.c | 8 +++++++- > > 2 files changed, 15 insertions(+), 3 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, In fact, the spec says such BAR values are reserved, not bad, so the capabiluty should be ignored, they should not cause the driver to error out or print errors. > > @@ -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; > > > > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c > > index e8b3ff2b9fbc..a6911d1e212a 100644 > > --- a/drivers/virtio/virtio_pci_modern_dev.c > > +++ b/drivers/virtio/virtio_pci_modern_dev.c > > @@ -35,6 +35,12 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, > > pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), > > &length); > > > > + if (bar >= PCI_STD_NUM_BARS) { > > + dev_err(&dev->dev, > > + "virtio_pci: bad capability bar %u\n", bar); In fact, I would say the issue is less that bar is reserved. The real issue is that the value apparently changed since we read it the first time. I think it's a good idea to reflect that in the message. Maybe find_capability should return the capability structure so we don't need to re-read it from the device? > > + return NULL; > > + } > > + > > if (length <= start) { > > dev_err(&dev->dev, > > "virtio_pci: bad capability len %u (>%u expected)\n", > > @@ -120,7 +126,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type, > > &bar); > > > > /* Ignore structures with reserved BAR values */ > > - if (bar > 0x5) > > + if (bar >= PCI_STD_NUM_BARS) > > continue; > > Just notice that the spec said: > > " > values 0x0 to 0x5 specify a Base Address register (BAR) belonging to > the function located beginning at 10h in PCI Configuration Space and > used to map the structure into Memory or I/O Space. The BAR is > permitted to be either 32-bit or 64-bit, it can map Memory Space or > I/O Space. > > Any other value is reserved for future use. > " > So we probably need to stick 0x5 instead of 0x6 (PCI_STD_NUM_BARS) for > this and other places. > > Thanks It does not matter much IMHO, the reason spec uses 0 to 0x5 is precisely because that's the standard number of BARs. Both ways work as long as we are consistent, and I guess PCI_STD_NUM_BARS might be preferable since people tend to copy paste values. > > > > if (type == cfg_type) { > > -- > > 2.35.1.894.gb6a874cedc-goog > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] virtio: pci: sanity check bar indexes 2022-03-23 12:01 ` Michael S. Tsirkin @ 2022-03-23 13:21 ` Keir Fraser 2022-03-23 13:23 ` Michael S. Tsirkin 0 siblings, 1 reply; 7+ messages in thread From: Keir Fraser @ 2022-03-23 13:21 UTC (permalink / raw) To: Michael S. Tsirkin; +Cc: Jason Wang, kernel-team, virtualization, linux-kernel On Wed, Mar 23, 2022 at 08:01:42AM -0400, Michael S. Tsirkin wrote: > On Wed, Mar 23, 2022 at 03:57:59PM +0800, Jason Wang wrote: > > On Tue, Mar 22, 2022 at 11:20 PM Keir Fraser <keirf@google.com> 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. > > > > > > Also clean up an existing check to consistently use PCI_STD_NUM_BARS. > > > > > > Signed-off-by: Keir Fraser <keirf@google.com> > > > --- > > > drivers/virtio/virtio_pci_modern.c | 10 ++++++++-- > > > drivers/virtio/virtio_pci_modern_dev.c | 8 +++++++- > > > 2 files changed, 15 insertions(+), 3 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, > > In fact, the spec says such BAR values are reserved, not bad, so > the capabiluty should be ignored, they should not cause the driver to error out > or print errors. Ah yes, so I see. It makes sense then to silently ignore the capability and print nothing. I will fix it. > > > @@ -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; > > > > > > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c > > > index e8b3ff2b9fbc..a6911d1e212a 100644 > > > --- a/drivers/virtio/virtio_pci_modern_dev.c > > > +++ b/drivers/virtio/virtio_pci_modern_dev.c > > > @@ -35,6 +35,12 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, > > > pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), > > > &length); > > > > > > + if (bar >= PCI_STD_NUM_BARS) { > > > + dev_err(&dev->dev, > > > + "virtio_pci: bad capability bar %u\n", bar); > > In fact, I would say the issue is less that bar is reserved. > The real issue is that the value apparently changed since > we read it the first time. I think it's a good idea to > reflect that in the message. Maybe find_capability should return > the capability structure so we don't need to re-read it from > the device? I will have a look and fix it up one way or the other, and respin this patch. Thanks, Keir > > > + return NULL; > > > + } > > > + > > > if (length <= start) { > > > dev_err(&dev->dev, > > > "virtio_pci: bad capability len %u (>%u expected)\n", > > > @@ -120,7 +126,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type, > > > &bar); > > > > > > /* Ignore structures with reserved BAR values */ > > > - if (bar > 0x5) > > > + if (bar >= PCI_STD_NUM_BARS) > > > continue; > > > > Just notice that the spec said: > > > > " > > values 0x0 to 0x5 specify a Base Address register (BAR) belonging to > > the function located beginning at 10h in PCI Configuration Space and > > used to map the structure into Memory or I/O Space. The BAR is > > permitted to be either 32-bit or 64-bit, it can map Memory Space or > > I/O Space. > > > > Any other value is reserved for future use. > > " > > So we probably need to stick 0x5 instead of 0x6 (PCI_STD_NUM_BARS) for > > this and other places. > > > > Thanks > > It does not matter much IMHO, the reason spec uses 0 to 0x5 is precisely > because that's the standard number of BARs. Both ways work as long as we > are consistent, and I guess PCI_STD_NUM_BARS might be preferable since > people tend to copy paste values. > > > > > > > if (type == cfg_type) { > > > -- > > > 2.35.1.894.gb6a874cedc-goog > > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2] virtio: pci: sanity check bar indexes 2022-03-23 13:21 ` Keir Fraser @ 2022-03-23 13:23 ` Michael S. Tsirkin 0 siblings, 0 replies; 7+ messages in thread From: Michael S. Tsirkin @ 2022-03-23 13:23 UTC (permalink / raw) To: Keir Fraser; +Cc: Jason Wang, kernel-team, virtualization, linux-kernel On Wed, Mar 23, 2022 at 01:21:55PM +0000, Keir Fraser wrote: > On Wed, Mar 23, 2022 at 08:01:42AM -0400, Michael S. Tsirkin wrote: > > On Wed, Mar 23, 2022 at 03:57:59PM +0800, Jason Wang wrote: > > > On Tue, Mar 22, 2022 at 11:20 PM Keir Fraser <keirf@google.com> 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. > > > > > > > > Also clean up an existing check to consistently use PCI_STD_NUM_BARS. > > > > > > > > Signed-off-by: Keir Fraser <keirf@google.com> > > > > --- > > > > drivers/virtio/virtio_pci_modern.c | 10 ++++++++-- > > > > drivers/virtio/virtio_pci_modern_dev.c | 8 +++++++- > > > > 2 files changed, 15 insertions(+), 3 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, > > > > In fact, the spec says such BAR values are reserved, not bad, so > > the capabiluty should be ignored, they should not cause the driver to error out > > or print errors. > > Ah yes, so I see. It makes sense then to silently ignore the capability and print nothing. > I will fix it. > > > > > @@ -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; > > > > > > > > diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c > > > > index e8b3ff2b9fbc..a6911d1e212a 100644 > > > > --- a/drivers/virtio/virtio_pci_modern_dev.c > > > > +++ b/drivers/virtio/virtio_pci_modern_dev.c > > > > @@ -35,6 +35,12 @@ vp_modern_map_capability(struct virtio_pci_modern_device *mdev, int off, > > > > pci_read_config_dword(dev, off + offsetof(struct virtio_pci_cap, length), > > > > &length); > > > > > > > > + if (bar >= PCI_STD_NUM_BARS) { > > > > + dev_err(&dev->dev, > > > > + "virtio_pci: bad capability bar %u\n", bar); > > > > In fact, I would say the issue is less that bar is reserved. > > The real issue is that the value apparently changed since > > we read it the first time. I think it's a good idea to > > reflect that in the message. Maybe find_capability should return > > the capability structure so we don't need to re-read it from > > the device? > > I will have a look and fix it up one way or the other, and respin > this patch. > > Thanks, > Keir BTW avoiding extra reads is good for start up speed. This is slow path, but still. > > > > + return NULL; > > > > + } > > > > + > > > > if (length <= start) { > > > > dev_err(&dev->dev, > > > > "virtio_pci: bad capability len %u (>%u expected)\n", > > > > @@ -120,7 +126,7 @@ static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type, > > > > &bar); > > > > > > > > /* Ignore structures with reserved BAR values */ > > > > - if (bar > 0x5) > > > > + if (bar >= PCI_STD_NUM_BARS) > > > > continue; > > > > > > Just notice that the spec said: > > > > > > " > > > values 0x0 to 0x5 specify a Base Address register (BAR) belonging to > > > the function located beginning at 10h in PCI Configuration Space and > > > used to map the structure into Memory or I/O Space. The BAR is > > > permitted to be either 32-bit or 64-bit, it can map Memory Space or > > > I/O Space. > > > > > > Any other value is reserved for future use. > > > " > > > So we probably need to stick 0x5 instead of 0x6 (PCI_STD_NUM_BARS) for > > > this and other places. > > > > > > Thanks > > > > It does not matter much IMHO, the reason spec uses 0 to 0x5 is precisely > > because that's the standard number of BARs. Both ways work as long as we > > are consistent, and I guess PCI_STD_NUM_BARS might be preferable since > > people tend to copy paste values. > > > > > > > > > > if (type == cfg_type) { > > > > -- > > > > 2.35.1.894.gb6a874cedc-goog > > > > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-03-23 13:23 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-03-22 15:19 [PATCH v2] virtio: pci: sanity check bar indexes Keir Fraser 2022-03-23 7:57 ` Jason Wang 2022-03-23 9:13 ` Keir Fraser 2022-03-23 9:21 ` Jason Wang 2022-03-23 12:01 ` Michael S. Tsirkin 2022-03-23 13:21 ` Keir Fraser 2022-03-23 13:23 ` Michael S. Tsirkin
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