lkml.org 
[lkml]   [2017]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/1] staging: rtl8723bs: make memcmp() calls consistent
On Wed, Dec 13, 2017 at 03:49:12PM +0100, Hans de Goede wrote:
> Hi,
>
> On 13-12-17 12:47, Greg Kroah-Hartman wrote:
> > On Sun, Dec 10, 2017 at 08:35:12PM +0100, Nicolas Iooss wrote:
> > > rtw_pm_set() uses memcmp() with 5-chars strings and a length of 4 when
> > > parsing extra, and then parses extra+4 as an int:
> > >
> > > if (!memcmp(extra, "lps =", 4)) {
> > > sscanf(extra+4, "%u", &mode);
> > > /* ... */
> > > } else if (!memcmp(extra, "ips =", 4)) {
> > > sscanf(extra+4, "%u", &mode);
> > >
> > > The space between the key ("lps" and "ips") and the equal sign seems
> > > suspicious. Remove it in order to make the calls to memcmp() consistent.
> >
> > But you now just changing the parsing logic. What broke because of
> > this? Did you test this codepath with your patch?
> >
> > I'm not disagreeing that this code seems really odd, but it must be
> > working as-is for someone, to change this logic will break their system
> > :(
>
> I don't think this code can work actually, for the memcmp to
> match the extra argument must start with e.g. : "lps =" but then mode
> gets read as: sscanf(extra+4, "%u", &mode);, with extra + 4
> pointing at the "=" in the extra arg, so sscanf will stop right
> away and store 0 in mode.
>
> The rtw_pm_set function is only used in the rtw_private_handler[]
> function pointer array, which itself is used here:
>
> struct iw_handler_def rtw_handlers_def = {
> .standard = rtw_handlers,
> .num_standard = ARRAY_SIZE(rtw_handlers),
> #if defined(CONFIG_WEXT_PRIV)
> .private = rtw_private_handler,
> .private_args = (struct iw_priv_args *)rtw_private_args,
> .num_private = ARRAY_SIZE(rtw_private_handler),
> .num_private_args = ARRAY_SIZE(rtw_private_args),
> #endif
> .get_wireless_stats = rtw_get_wireless_stats,
> };
>
> So this is for a private extension to the iw interface. I think that
> as part of the cleanup of this driver in staging we should just
> remove all private extensions, which will nicely fix the broken
> function by simply removing it :)

Yes, any private extensions should just be deleted.

thanks,

greg k-h

\
 
 \ /
  Last update: 2017-12-13 17:10    [W:0.050 / U:4.288 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site