Re: [Xen-devel] [PATCH V2] libxc: Prevent NULL pointer dereference in stdiostream_vmessage()

[Jennifer Herbert <Jennifer.Herbert@xxxxxxxxxx>]

I guess I didn't build what I thought I built.
V3 coming up

On 07/07/15 16:51, Andrew Cooper wrote:
> On 07/07/15 16:48, Jennifer Herbert wrote:
> > Unlikely that it may seem localtime_r could fail, which would result in a
> > null pointer dereference.  In this case, it shoud log the errno, (instead of
> > the date/time), and and continue its logging, as this is still useful.
> >
> > Signed-off-by: Jennifer Herbert <jennifer.herbert@xxxxxxxxxx>
> > ---
> >   tools/libxc/xtl_logger_stdio.c |   11 +++++++----
> >   1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/libxc/xtl_logger_stdio.c b/tools/libxc/xtl_logger_stdio.c
> > index d8646e0..5569c50 100644
> > --- a/tools/libxc/xtl_logger_stdio.c
> > +++ b/tools/libxc/xtl_logger_stdio.c
> > @@ -61,10 +61,13 @@ static void stdiostream_vmessage(xentoollog_logger 
> > *logger_in,
> >           struct tm lt_buf;
> >           time_t now = time(0);
> >           struct tm *lt= localtime_r(&now, &lt_buf);
> > -        fprintf(lg->f, "%04d-%02d-%02d %02d:%02d:%02d %s ",
> > -                lt->tm_year+1900, lt->tm_mon+1, lt->tm_mday,
> > -                lt->tm_hour, lt->tm_min, lt->tm_sec,
> > -                tzname[!!lt->tm_isdst]);
> > +        if (lt != NULL)
> > +            fprintf(lg->f, "%04d-%02d-%02d %02d:%02d:%02d %s ",
> > +                    lt->tm_year+1900, lt->tm_mon+1, lt->tm_mday,
> > +                    lt->tm_hour, lt->tm_min, lt->tm_sec,
> > +                    tzname[!!lt->tm_isdst]);
> > +        else
> > +            fprintf(lg-f, "[localtime_r failed: %d] ", errno);
> lg->f ?
>
> ~Andrew
>
> >       }
> >       if (lg->flags & XTL_STDIOSTREAM_SHOW_PID)
> >           fprintf(lg->f, "[%lu] ", (unsigned long)getpid());

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