uas: Add uas_find_endpoints() helper function

This is a preparation patch for adding better descriptor validation.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

1 files changed, 23 insertions, 11 deletions

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index e817e72d8673..1ac66f290fbf 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -898,16 +898,11 @@ static int uas_switch_interface(struct usb_device *udev,
                         intf->altsetting[0].desc.bInterfaceNumber, alt);
 }
 
-static void uas_configure_endpoints(struct uas_dev_info *devinfo)
+static int uas_find_endpoints(struct usb_host_interface *alt,
+                              struct usb_host_endpoint *eps[])
 {
-        struct usb_host_endpoint *eps[4] = { };
-        struct usb_interface *intf = devinfo->intf;
-        struct usb_device *udev = devinfo->udev;
-        struct usb_host_endpoint *endpoint = intf->cur_altsetting->endpoint;
-        unsigned i, n_endpoints = intf->cur_altsetting->desc.bNumEndpoints;
-
-        devinfo->uas_sense_old = 0;
-        devinfo->cmnd = NULL;
+        struct usb_host_endpoint *endpoint = alt->endpoint;
+        unsigned i, n_endpoints = alt->desc.bNumEndpoints;
 
         for (i = 0; i < n_endpoints; i++) {
                 unsigned char *extra = endpoint[i].extra;
@@ -924,12 +919,29 @@ static void uas_configure_endpoints(struct uas_dev_info *devinfo)
                 }
         }
 
+        if (!eps[0] || !eps[1] || !eps[2] || !eps[3])
+                return -ENODEV;
+
+        return 0;
+}
+
+static void uas_configure_endpoints(struct uas_dev_info *devinfo)
+{
+        struct usb_host_endpoint *eps[4] = { };
+        struct usb_device *udev = devinfo->udev;
+        int r;
+
+        devinfo->uas_sense_old = 0;
+        devinfo->cmnd = NULL;
+
+        r = uas_find_endpoints(devinfo->intf->cur_altsetting, eps);
+
         /*
-         * Assume that if we didn't find a control pipe descriptor, we're
+         * Assume that if we didn't find a proper set of descriptors, we're
          * using a device with old firmware that happens to be set up like
          * this.
          */
-        if (!eps[0]) {
+        if (r != 0) {
                 devinfo->cmd_pipe = usb_sndbulkpipe(udev, 1);
                 devinfo->status_pipe = usb_rcvbulkpipe(udev, 1);
                 devinfo->data_in_pipe = usb_rcvbulkpipe(udev, 2);