| Message ID | 1367905369-10765-1-git-send-email-jasowang@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Tue, May 07, 2013 at 01:42:49PM +0800, Jason Wang wrote: > There are several several issues in the current checking: > > - The check was based on the minus of unsigned values which can overflow > - It was done after .{set|get}_config() which can lead crash when config_len > is zero since vdev->config is NULL > > Fix this by: > > - Validate the address in virtio_pci_config_{read|write}() before > .{set|get}_config > - Use addition instead minus to do the validation > > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Petr Matousek <pmatouse@redhat.com> > Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> > --- > Changes from V1: > - Doing check in virtio.c instead of virtio-pci.c > - Drop the patch of virtio-ccw and s390-virtio-bus > --- > hw/virtio/virtio.c | 30 ++++++++++++++++++------------ > 1 files changed, 18 insertions(+), 12 deletions(-) > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index 53a0d90..8176c14 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -568,10 +568,11 @@ uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint8_t val; > > - k->get_config(vdev, vdev->config); > - > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return (uint32_t)-1; > + } > + > + k->get_config(vdev, vdev->config); > > val = ldub_p(vdev->config + addr); > return val; > @@ -582,10 +583,11 @@ uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint16_t val; > > - k->get_config(vdev, vdev->config); > - > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return (uint32_t)-1; > + } > + > + k->get_config(vdev, vdev->config); > > val = lduw_p(vdev->config + addr); > return val; > @@ -596,10 +598,11 @@ uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint32_t val; > > - k->get_config(vdev, vdev->config); > - > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return (uint32_t)-1; > + } > + > + k->get_config(vdev, vdev->config); > > val = ldl_p(vdev->config + addr); > return val; > @@ -610,8 +613,9 @@ void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint8_t val = data; > > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return; > + } > > stb_p(vdev->config + addr, val); > > @@ -625,8 +629,9 @@ void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint16_t val = data; > > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return; > + } > > stw_p(vdev->config + addr, val); > > @@ -640,8 +645,9 @@ void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint32_t val = data; > > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return; > + } > > stl_p(vdev->config + addr, val); > > -- > 1.7.1
On Tue, May 07, 2013 at 01:42:49PM +0800, Jason Wang wrote: > There are several several issues in the current checking: > > - The check was based on the minus of unsigned values which can overflow > - It was done after .{set|get}_config() which can lead crash when config_len > is zero since vdev->config is NULL > > Fix this by: > > - Validate the address in virtio_pci_config_{read|write}() before > .{set|get}_config > - Use addition instead minus to do the validation > > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Petr Matousek <pmatouse@redhat.com> > Signed-off-by: Jason Wang <jasowang@redhat.com> I would rather see explicit check for (addr + sizeof(val)) overflow, but I was able to convince myself that it cannot happen due to the addr properties. Acked-by: Petr Matousek <pmatouse@redhat.com> > > --- > Changes from V1: > - Doing check in virtio.c instead of virtio-pci.c > - Drop the patch of virtio-ccw and s390-virtio-bus > --- > hw/virtio/virtio.c | 30 ++++++++++++++++++------------ > 1 files changed, 18 insertions(+), 12 deletions(-) > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index 53a0d90..8176c14 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -568,10 +568,11 @@ uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint8_t val; > > - k->get_config(vdev, vdev->config); > - > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return (uint32_t)-1; > + } > + > + k->get_config(vdev, vdev->config); > > val = ldub_p(vdev->config + addr); > return val; > @@ -582,10 +583,11 @@ uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint16_t val; > > - k->get_config(vdev, vdev->config); > - > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return (uint32_t)-1; > + } > + > + k->get_config(vdev, vdev->config); > > val = lduw_p(vdev->config + addr); > return val; > @@ -596,10 +598,11 @@ uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint32_t val; > > - k->get_config(vdev, vdev->config); > - > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return (uint32_t)-1; > + } > + > + k->get_config(vdev, vdev->config); > > val = ldl_p(vdev->config + addr); > return val; > @@ -610,8 +613,9 @@ void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint8_t val = data; > > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return; > + } > > stb_p(vdev->config + addr, val); > > @@ -625,8 +629,9 @@ void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint16_t val = data; > > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return; > + } > > stw_p(vdev->config + addr, val); > > @@ -640,8 +645,9 @@ void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data) > VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); > uint32_t val = data; > > - if (addr > (vdev->config_len - sizeof(val))) > + if (addr + sizeof(val) > vdev->config_len) { > return; > + } > > stl_p(vdev->config + addr, val); > > -- > 1.7.1 >
Applied. Thanks. Regards, Anthony Liguori
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 53a0d90..8176c14 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -568,10 +568,11 @@ uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr) VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); uint8_t val; - k->get_config(vdev, vdev->config); - - if (addr > (vdev->config_len - sizeof(val))) + if (addr + sizeof(val) > vdev->config_len) { return (uint32_t)-1; + } + + k->get_config(vdev, vdev->config); val = ldub_p(vdev->config + addr); return val; @@ -582,10 +583,11 @@ uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr) VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); uint16_t val; - k->get_config(vdev, vdev->config); - - if (addr > (vdev->config_len - sizeof(val))) + if (addr + sizeof(val) > vdev->config_len) { return (uint32_t)-1; + } + + k->get_config(vdev, vdev->config); val = lduw_p(vdev->config + addr); return val; @@ -596,10 +598,11 @@ uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr) VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); uint32_t val; - k->get_config(vdev, vdev->config); - - if (addr > (vdev->config_len - sizeof(val))) + if (addr + sizeof(val) > vdev->config_len) { return (uint32_t)-1; + } + + k->get_config(vdev, vdev->config); val = ldl_p(vdev->config + addr); return val; @@ -610,8 +613,9 @@ void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data) VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); uint8_t val = data; - if (addr > (vdev->config_len - sizeof(val))) + if (addr + sizeof(val) > vdev->config_len) { return; + } stb_p(vdev->config + addr, val); @@ -625,8 +629,9 @@ void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data) VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); uint16_t val = data; - if (addr > (vdev->config_len - sizeof(val))) + if (addr + sizeof(val) > vdev->config_len) { return; + } stw_p(vdev->config + addr, val); @@ -640,8 +645,9 @@ void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data) VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); uint32_t val = data; - if (addr > (vdev->config_len - sizeof(val))) + if (addr + sizeof(val) > vdev->config_len) { return; + } stl_p(vdev->config + addr, val);
There are several several issues in the current checking: - The check was based on the minus of unsigned values which can overflow - It was done after .{set|get}_config() which can lead crash when config_len is zero since vdev->config is NULL Fix this by: - Validate the address in virtio_pci_config_{read|write}() before .{set|get}_config - Use addition instead minus to do the validation Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Petr Matousek <pmatouse@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com> --- Changes from V1: - Doing check in virtio.c instead of virtio-pci.c - Drop the patch of virtio-ccw and s390-virtio-bus --- hw/virtio/virtio.c | 30 ++++++++++++++++++------------ 1 files changed, 18 insertions(+), 12 deletions(-)