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authorAlon Levy <alevy@redhat.com>2012-02-26 17:09:21 +0100
committerGerd Hoffmann <kraxel@redhat.com>2012-02-27 13:37:36 +0100
commit8db36e9dddb1b6fab3554a8c00d92268b33a487b (patch)
tree303227f25d7569061e9636bdcb5e4f007cb2e0fb /hw
parentaa0568ff2559d7717f4684af6a83d0bd1a125f56 (diff)
usb-desc: fix user trigerrable segfaults (!config)
Check for dev->config being NULL in two places: USB_REQ_GET_CONFIGURATION and USB_REQ_GET_STATUS. The behavior of USB_REQ_GET_STATUS is unspecified in the Default state, that corresponds to dev->config being NULL (it defaults to NULL and is reset whenever a SET_CONFIGURATION with value 0, or attachment). I implemented it to correspond with the state before ed5a83ddd8c1d8ec7b1015315530cf29949e7c48, the commit moving SET_STATUS to usb-desc; if dev->config is not set we return whatever is in the first configuration. The behavior of USB_REQ_GET_CONFIGURATION is also undefined before any SET_CONFIGURATION, but here we just return 0 (same as specified for the Address state). A win7 guest failed to initialize the device before this patch, segfaulting when GET_STATUS was called with dev->config == NULL. With this patch the passthrough device still doesn't work but the failure is unrelated. Signed-off-by: Alon Levy <alevy@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/usb-desc.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/hw/usb-desc.c b/hw/usb-desc.c
index 3c3ed6a80..ccf85ade9 100644
--- a/hw/usb-desc.c
+++ b/hw/usb-desc.c
@@ -536,7 +536,11 @@ int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
break;
case DeviceRequest | USB_REQ_GET_CONFIGURATION:
- data[0] = dev->config->bConfigurationValue;
+ /*
+ * 9.4.2: 0 should be returned if the device is unconfigured, otherwise
+ * the non zero value of bConfigurationValue.
+ */
+ data[0] = dev->config ? dev->config->bConfigurationValue : 0;
ret = 1;
break;
case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
@@ -544,9 +548,18 @@ int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
trace_usb_set_config(dev->addr, value, ret);
break;
- case DeviceRequest | USB_REQ_GET_STATUS:
+ case DeviceRequest | USB_REQ_GET_STATUS: {
+ const USBDescConfig *config = dev->config ?
+ dev->config : &dev->device->confs[0];
+
data[0] = 0;
- if (dev->config->bmAttributes & 0x40) {
+ /*
+ * Default state: Device behavior when this request is received while
+ * the device is in the Default state is not specified.
+ * We return the same value that a configured device would return if
+ * it used the first configuration.
+ */
+ if (config->bmAttributes & 0x40) {
data[0] |= 1 << USB_DEVICE_SELF_POWERED;
}
if (dev->remote_wakeup) {
@@ -555,6 +568,7 @@ int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
data[1] = 0x00;
ret = 2;
break;
+ }
case DeviceOutRequest | USB_REQ_CLEAR_FEATURE:
if (value == USB_DEVICE_REMOTE_WAKEUP) {
dev->remote_wakeup = 0;