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SubjectRe: [PATCH 3/5] usb: gadget: f_mass_storage: Prevent NULL pointer dereference
On 04/05/2011 06:56 PM, ext Michal Nazarewicz wrote:
> On Tue, 05 Apr 2011 17:36:40 +0200, Roger Quadros
> <roger.quadros@nokia.com> wrote:
>> Prevent a NULL pointer dereference in fsg_config_from_params() if
>> 'file' parameter is not specified.
>
> Have you observed this behaviour? I don't see how it could happen with
> module parameters and if it appears in some gadget it's a bug in the

It can happen if the gadget that uses f_mass_storage specifies
file_count=1 and doesn't specify a file name.

> gadget. Not that I'm saying checking for null pointer is a bad idea.

OK. let's do that then.

>
>> Signed-off-by: Roger Quadros <roger.quadros@nokia.com>
>> ---
>> drivers/usb/gadget/f_mass_storage.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/usb/gadget/f_mass_storage.c
>> b/drivers/usb/gadget/f_mass_storage.c
>> index 5d7de93..f6bd001 100644
>> --- a/drivers/usb/gadget/f_mass_storage.c
>> +++ b/drivers/usb/gadget/f_mass_storage.c
>> @@ -3177,7 +3177,7 @@ fsg_config_from_params(struct fsg_config *cfg,
>> lun->removable = /* Removable by default */
>> params->removable_count <= i || params->removable[i];
>> lun->filename =
>> - params->file_count > i && params->file[i][0]
>> + params->file_count > i && params->file[i]
>
> You're removing the check if an empty file name has been specified. It
> should read:
>
> + params->file_count > i && params->file[i] &&
> params->file[i][0]

Right.

>
> And since the line is getting pretty long, maybe convert it to a proper
> “if”. I'm sure Greg will like that. ;)
>
>> ? params->file[i]
>> : 0;
>> }
>
ok.

--
regards,
-roger
--
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