Re: [PATCH] wimax/i2400m: fix a memory leak bug

[Wenwen Wang]

On Thu, Aug 15, 2019 at 2:45 PM Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> wrote:
>
> * Wenwen Wang <wenwen@xxxxxxxxxx> [190815 14:05]:
> > In i2400m_barker_db_init(), 'options_orig' is allocated through kstrdup()
> > to hold the original command line options. Then, the options are parsed.
> > However, if an error occurs during the parsing process, 'options_orig' is
> > not deallocated, leading to a memory leak bug. To fix this issue, free
> > 'options_orig' before returning the error.
> >
> > Signed-off-by: Wenwen Wang <wenwen@xxxxxxxxxx>
> > ---
> >  drivers/net/wimax/i2400m/fw.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/wimax/i2400m/fw.c b/drivers/net/wimax/i2400m/fw.c
> > index e9fc168..6b36f6d 100644
> > --- a/drivers/net/wimax/i2400m/fw.c
> > +++ b/drivers/net/wimax/i2400m/fw.c
> > @@ -342,6 +342,7 @@ int i2400m_barker_db_init(const char *_options)
> >                                      "a 32-bit number\n",
> >                                      __func__, token);
> >                               result = -EINVAL;
> > +                             kfree(options_orig);
> >                               goto error_parse;
> >                       }
> >                       if (barker == 0) {
> > @@ -350,8 +351,10 @@ int i2400m_barker_db_init(const char *_options)
> >                               continue;
> >                       }
> >                       result = i2400m_barker_db_add(barker);
> > -                     if (result < 0)
> > +                     if (result < 0) {
> > +                             kfree(options_orig);
> >                               goto error_add;
>
> I know that you didn't add this error_add label, but it seems like the
> incorrect goto label.  Although looking at the caller indicates an add
> failed, this label is used prior to and after the memory leak you are
> trying to fix.  It might be better to change this label to something
> like error_parse_add and move the kfree to the unwinding.  If a new
> label is used, it becomes more clear as to what is being undone and
> there aren't two jumps into an unwind from two very different stages of
> the function.  Adding a new label also has the benefit of moving the
> kfree to the unwind of error_parse.

Thanks for your suggestion! I will rework the patch.

Wenwen