mmc: ushc: fix NULL-deref at probe

commit 181302dc7239add8ab1449c23ecab193f52ee6ab upstream.

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer should a malicious device lack endpoints.

Fixes: 53f3a9e26ed5 ("mmc: USB SD Host Controller (USHC) driver")
Cc: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/mmc/host/ushc.c b/drivers/mmc/host/ushc.c
index f08f944..82f5726 100644 (file)
--- a/drivers/mmc/host/ushc.c
+++ b/drivers/mmc/host/ushc.c
@@ -426,6 +426,9 @@ static int ushc_probe(struct usb_interface *intf, const struct usb_device_id *id
        struct ushc_data *ushc;
        int ret;
 
+       if (intf->cur_altsetting->desc.bNumEndpoints < 1)
+               return -ENODEV;
+
        mmc = mmc_alloc_host(sizeof(struct ushc_data), &intf->dev);
        if (mmc == NULL)
                return -ENOMEM;