[U-Boot] [PATCH 1/1] dm: usb: ehci: avoid possible NULL dereference

[Marek Vasut]

On 11/20/2017 03:39 PM, Heinrich Schuchardt wrote:
> 
> 
> On 11/20/2017 01:47 AM, Marek Vasut wrote:
>> On 11/19/2017 11:42 PM, Heinrich Schuchardt wrote:
>>> It is unwise to first dereference a pointer and
>>> afterwards to check if it was NULL.
>>
>> The check is still incomplete, the hccr is not checked.
> 
> Thanks for reviewing.
> 
> Depending on CONFIG_DM_USB ctrl->hccr is set in ehci_register or in
> usb_lowlevel_init.
> 
> There are other functions (ehci_get_portsc_register, ehci_submit_root,
> ehci_common_init) on ctrl->hccr != NULL too.
> 
> Shouldn't we check(!ctrl || !ctrl->hcor || !ctrl->hccr) in ehci_register
> and usb_lowlevel_init instead of checking it in ehci_shutdown?

Sounds good

> Best regards
> 
> Heinrich
> 
>>
>>> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
>>> ---
>>>   drivers/usb/host/ehci-hcd.c | 4 +++-
>>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
>>> index be3e842dcc..80bc8219af 100644
>>> --- a/drivers/usb/host/ehci-hcd.c
>>> +++ b/drivers/usb/host/ehci-hcd.c
>>> @@ -208,11 +208,13 @@ static int ehci_shutdown(struct ehci_ctrl *ctrl)
>>>   {
>>>       int i, ret = 0;
>>>       uint32_t cmd, reg;
>>> -    int max_ports = HCS_N_PORTS(ehci_readl(&ctrl->hccr->cr_hcsparams));
>>> +    int max_ports;
>>>         if (!ctrl || !ctrl->hcor)
>>>           return -EINVAL;
>>>   +    max_ports = HCS_N_PORTS(ehci_readl(&ctrl->hccr->cr_hcsparams));
>>> +
>>>       cmd = ehci_readl(&ctrl->hcor->or_usbcmd);
>>>       /* If not run, directly return */
>>>       if (!(cmd & CMD_RUN))
>>>
>>
>>


-- 
Best regards,
Marek Vasut