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 <m...@redhat.com> Cc: Petr Matousek <pmato...@redhat.com> Signed-off-by: Jason Wang <jasow...@redhat.com> --- hw/virtio/virtio-pci.c | 9 +++++++++ hw/virtio/virtio.c | 18 ------------------ 2 files changed, 9 insertions(+), 18 deletions(-) diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index a1f15a8..7f6c7d1 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -400,6 +400,10 @@ static uint64_t virtio_pci_config_read(void *opaque, hwaddr addr, } addr -= config; + if (addr + size > proxy->vdev->config_len) { + return (uint32_t)-1; + } + switch (size) { case 1: val = virtio_config_readb(proxy->vdev, addr); @@ -430,6 +434,11 @@ static void virtio_pci_config_write(void *opaque, hwaddr addr, return; } addr -= config; + + if (addr + size > proxy->vdev->config_len) { + return; + } + /* * Virtio-PCI is odd. Ioports are LE but config space is target native * endian. diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 1c2282c..3397b5e 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -563,9 +563,6 @@ uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr) vdev->get_config(vdev, vdev->config); - if (addr > (vdev->config_len - sizeof(val))) - return (uint32_t)-1; - val = ldub_p(vdev->config + addr); return val; } @@ -576,9 +573,6 @@ uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr) vdev->get_config(vdev, vdev->config); - if (addr > (vdev->config_len - sizeof(val))) - return (uint32_t)-1; - val = lduw_p(vdev->config + addr); return val; } @@ -589,9 +583,6 @@ uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr) vdev->get_config(vdev, vdev->config); - if (addr > (vdev->config_len - sizeof(val))) - return (uint32_t)-1; - val = ldl_p(vdev->config + addr); return val; } @@ -600,9 +591,6 @@ void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data) { uint8_t val = data; - if (addr > (vdev->config_len - sizeof(val))) - return; - stb_p(vdev->config + addr, val); if (vdev->set_config) @@ -613,9 +601,6 @@ void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data) { uint16_t val = data; - if (addr > (vdev->config_len - sizeof(val))) - return; - stw_p(vdev->config + addr, val); if (vdev->set_config) @@ -626,9 +611,6 @@ void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data) { uint32_t val = data; - if (addr > (vdev->config_len - sizeof(val))) - return; - stl_p(vdev->config + addr, val); if (vdev->set_config) -- 1.7.1