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Prefer hardcoded PN533 descriptors to the real ones

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PN533 easily corrupts its USB descriptors. We know that and we
already try to detect and even repair them.

However there are situations where lower software layers get
confused before libnfc can help. On Windows, libusb may set
dev->config to NULL, but we can also have a non NULL dev->config
referencing corrupted data.

In order to get more robust, let us replace the Windows libusb
specific (dev->config == NULL) test by an inconditionnal use of
hardcoded descriptors when they are available.
This commit is contained in:
Emmanuel Dreyfus 2018-11-12 15:26:43 +00:00 committed by Romuald Conty
parent ddfe2e648a
commit 85100c0aae
1 changed files with 13 additions and 16 deletions
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29
libnfc/drivers/pn53x_usb.c
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@ -236,7 +236,7 @@ pn53x_usb_get_device_model(uint16_t vendor_id, uint16_t product_id)
return UNKNOWN;
}
static void
static bool
pn53x_usb_get_end_points_default(struct usb_device *dev, struct pn53x_usb_data *data)
{
for (size_t n = 0; n < sizeof(pn53x_usb_supported_devices) / sizeof(struct pn53x_usb_supported_device); n++) {
@ -246,13 +246,13 @@ pn53x_usb_get_end_points_default(struct usb_device *dev, struct pn53x_usb_data *
data->uiEndPointIn = pn53x_usb_supported_devices[n].uiEndPointIn;
data->uiEndPointOut = pn53x_usb_supported_devices[n].uiEndPointOut;
data->uiMaxPacketSize = pn53x_usb_supported_devices[n].uiMaxPacketSize;
}
return;
return true;
}
}
}
return;
return false;
}
int pn53x_usb_ack(nfc_device *pnd);
@ -305,13 +305,12 @@ pn53x_usb_scan(const nfc_context *context, nfc_connstring connstrings[], const s
if ((pn53x_usb_supported_devices[n].vendor_id == dev->descriptor.idVendor) &&
(pn53x_usb_supported_devices[n].product_id == dev->descriptor.idProduct)) {
// Make sure there are 2 endpoints available
// with libusb-win32 we got some null pointers so be robust before looking at endpoints:
if (dev->config == NULL) {
// We tolerate null config if we have defaults
if (pn53x_usb_supported_devices[n].uiMaxPacketSize == 0)
// Nope, we maybe want the next one, let's try to find another
continue;
} else {
// libusb-win32 may return a NULL dev->config,
// or the descriptoes may be corrupted, hence
// let us assume we will use hardcoded defaults
// from n53x_usb_supported_devices if available.
// otherwise get data from the descriptors.
if (pn53x_usb_supported_devices[n].uiMaxPacketSize == 0) {
if (dev->config->interface == NULL || dev->config->interface->altsetting == NULL) {
// Nope, we maybe want the next one, let's try to find another
continue;
@ -422,11 +421,9 @@ pn53x_usb_open(const nfc_context *context, const nfc_connstring connstring)
// Open the USB device
if ((data.pudh = usb_open(dev)) == NULL)
continue;
// Retrieve end points, using default if dev->config is broken
if (dev->config == NULL) {
pn53x_usb_get_end_points_default(dev, &data);
data.possibly_corrupted_usbdesc = true;
} else {
// Retrieve end points, using hardcoded defaults if available
// or using the descriptors otherwise.
if (pn53x_usb_get_end_points_default(dev, &data) == false) {
pn53x_usb_get_end_points(dev, &data);
}
// Set configuration