Obvious bug in 5.0 USB stack, in file usb_cdc.c

johnstrohm — Wed, 01 Oct 2014 20:19:14 GMT

Routines USB_Cdc_Allocate_Handle() and USB_Cdc_Free_Handle both walk through cdc_device_array.

cdc_device_struct_t cdc_device_array[MAX_CDC_DEVICE];

static usb_status USB_Cdc_Allocate_Handle(cdc_handle_t* handle)

{

uint32_t cnt = 0;

for (;cnt< MAX_CDC_DEVICE;cnt++)

{

if (cdc_device_array[cnt].controller_handle == NULL)

{

*handle = (cdc_handle_t)&cdc_device_array[cnt];

return USB_OK;

}

return USBERR_DEVICE_BUSY;

}

static usb_status USB_Cdc_Free_Handle(cdc_handle_t handle)

{

int32_t cnt = 0;

for (;cnt< USBCFG_DEV_MAX_CLASS_OBJECT;cnt++)

{

if (((cdc_handle_t)&cdc_device_array[cnt]) == handle)

{

OS_Mem_zero((void *)handle, sizeof(cdc_device_struct_t));

return USB_OK;

}

return USBERR_INVALID_PARAM;

}

If some poor maintenance guy changes USBCFG_DEV_MAX_CLASS_OBJECT, and forgets to update MAX_CDC_DEVICE, he will break USB_Cdc_Free_Handle().

The for-statement in USB_Cdc_Free_Handle()

for (;cnt< USBCFG_DEV_MAX_CLASS_OBJECT;cnt++)

should be identical to the for-statement in USB_Cdc_Allocate_Handle().

for (;cnt< MAX_CDC_DEVICE;cnt++)

Re: Obvious bug in 5.0 USB stack, in file usb_cdc.c

jeremyzhou — Fri, 10 Oct 2014 07:56:53 GMT

Hi John,

I'll report this issue to AE team for checking and thank you very much for your focus on Freescale product.
Have a great day,
Ping

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