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authorJason Wang <jasowang@redhat.com>2013-05-07 13:42:49 +0800
committerAnthony Liguori <aliguori@us.ibm.com>2013-05-08 15:54:21 -0500
commit5f5a1318653c08e435cfa52f60b6a712815b659d (patch)
treef0225933089d17dc522c51ab17b71e24c619c4cb
parent62c96360ae7f2c7a8b029277fbb7cb082fdef7fd (diff)
downloadqemu-arm-5f5a1318653c08e435cfa52f60b6a712815b659d.tar.gz
virtio: properly validate address before accessing config
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> Acked-by: Petr Matousek <pmatouse@redhat.com> Message-id: 1367905369-10765-1-git-send-email-jasowang@redhat.com Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
-rw-r--r--hw/virtio/virtio.c30
1 files changed, 18 insertions, 12 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 53a0d90468..8176c147e1 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);