[Crash-utility] [PATCH] Fixed the segment fault when ikconfig passed nonstandard values

[HAGIO KAZUHITO(萩尾 一仁)]

Hi Jakie,

I replied only to the list but you look not subscribed?
so sending you this again just in case..

Thanks,
Kazu

-----Original Message-----
> -----Original Message-----
> > From: Jackie Liu <liuyun01 at kylinos.cn>
> >
> > Some strange reasons may cause kcore to collect some strange
> > entries of ikconfig, such as CONFIG_SECU+[some hex data] causes
> > the 'val' to be NULL, and then crashes when strdup.
> >
> > Signed-off-by: Jackie Liu <liuyun01 at kylinos.cn>
> > ---
> >  kernel.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/kernel.c b/kernel.c
> > index 9871637..aa86f0d 100644
> > --- a/kernel.c
> > +++ b/kernel.c
> > @@ -10244,6 +10244,9 @@ static void add_ikconfig_entry(char *line, struct ikconfig_list *ent)
> >  	sscanf(name, "CONFIG_%s", name);
> >  	val = strtok_r(NULL, "", &tokptr);
> >
> > +	if (!val)
> > +		return;
> > +
> 
> This looks harmless, but kt->ikconfig_ents is incremented unconditionally
> in setup_ikconfig() and inconsistent with the following debug message
> 
>                         if (setup_ikconfig(pos)) {
>                                 kt->ikconfig_flags |= IKCONFIG_LOADED;
>                                 if (CRASHDEBUG(1))
>                                         fprintf(fp,
>                                         "ikconfig: %d valid configs.\n",
>                                                 kt->ikconfig_ents);
> 
> and it consumes an element of the ikconfig_all array needlessly, so
> how about something like this?:
> 
>   if (!val) {
>     if (CRASHDEBUG(2))
>        error(WARNING, "invalid ikconfig entry: %s\n", line);
>     return FALSE;
>   }
>   ...
>   return TRUE;
> 
> and in setup_ikconfig():
> 
>   if (add_ikconfig_entry(ent, &ikconfig_all[kt->ikconfig_ents])
>       kt->ikconfig_ents++;
> 
> Thanks,
> Kazu
> 
> >  	ent->name = strdup(name);
> >  	ent->val = strdup(val);
> >  }
> > --
> > 2.17.1
> >
> >