Re: [dpdk-dev] [PATCH] power: fix use-after-free in pstate code

[Liang Ma <liangma@liangbit.com>]

On Wed, Apr 07, 2021 at 05:53:48PM +0100, Burakov, Anatoly wrote:
> On 07-Apr-21 5:31 PM, Burakov, Anatoly wrote:
> > On 07-Apr-21 4:56 PM, Anatoly Burakov wrote:
> > > Previous fix has addressed the incorrect handling of `base_frequency`
> > > file, but has added a use-after-free error due to the fact that all
> > > further code paths will lead to an `fclose()` call at the end, so the
> > > additional `fclose()` call right after processing the file was
> > > unnecessary.
> > > 
> > > Coverity issue: 369901
> > > 
> > > Fixes: 8a5febaac4f7 ("power: fix P-state base frequency handling")
> > > 
> > > Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> > > ---
> > 
> > Actually, self-nack, because this:
> > 
> >      snprintf(fullpath_min, sizeof(fullpath_min), POWER_SYSFILE_MIN_FREQ,
> >              pi->lcore_id);
> >      f_min = fopen(fullpath_min, "rw+");
> >      FOPEN_OR_ERR_RET(f_min, -1);
> > 
> >      snprintf(fullpath_max, sizeof(fullpath_max), POWER_SYSFILE_MAX_FREQ,
> >              pi->lcore_id);
> >      f_max = fopen(fullpath_max, "rw+");
> >      if (f_max == NULL)
> >          fclose(f_min);
> >      FOPEN_OR_ERR_RET(f_max, -1);
> > 
> > comes after, and will leak the f_base descriptor. Closing it and setting
> > it to NULL seems like a better solution.
> > 
> 
> Actually no, scratch that, it doesn't :) that's before. So, patch should be
> OK.
A Cup Coffee will help ;-) 
> 
> -- 
> Thanks,
> Anatoly