Re: [PATCH-for-5.0] tools/virtiofsd/passthrough_ll: Fix double close()

[Dr. David Alan Gilbert]

* Philippe Mathieu-Daudé (address@hidden) wrote:
> On 3/21/20 1:06 PM, Philippe Mathieu-Daudé wrote:
> > On success, the fdopendir() call closes fd. Later on the error
> > path we try to close an already-closed fd. This can lead to
> > use-after-free. Fix by only closing the fd if the fdopendir()
> > call failed.
> > 
> > Cc: address@hidden
> > Fixes: 7c6b66027 (Import passthrough_ll from libfuse fuse-3.8.0)
> 
> libfuse is correct, the bug was introduced in commit b39bce121b, so:
> 
> Fixes: b39bce121b (add dirp_map to hide lo_dirp pointers)

Queued with that tweak

> > Reported-by: Coverity (CID 1421933 USE_AFTER_FREE)
> > Suggested-by: Peter Maydell <address@hidden>
> > Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> > ---
> >   tools/virtiofsd/passthrough_ll.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/tools/virtiofsd/passthrough_ll.c 
> > b/tools/virtiofsd/passthrough_ll.c
> > index 4f259aac70..4c35c95b25 100644
> > --- a/tools/virtiofsd/passthrough_ll.c
> > +++ b/tools/virtiofsd/passthrough_ll.c
> > @@ -1520,8 +1520,7 @@ out_err:
> >       if (d) {
> >           if (d->dp) {
> >               closedir(d->dp);
> > -        }
> > -        if (fd != -1) {
> > +        } else if (fd != -1) {
> >               close(fd);
> >           }
> >           free(d);
> > 
> 
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK