Re: [PATCH -next] selinux: fix error return code in policydb_read()

[Ondrej Mosnacek <omosnace@redhat.com>]

On Fri, May 1, 2020 at 9:08 PM Paul Moore <paul@paul-moore.com> wrote:
> On Wed, Apr 29, 2020 at 9:32 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> > On Wed, Apr 29, 2020 at 3:15 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
> > > On Wed, Apr 29, 2020 at 07:30:53AM +0000, Wei Yongjun wrote:
> > > > Fix to return negative error code -ENOMEM from the kvcalloc() error
> > > > handling case instead of 0, as done elsewhere in this function.
> > > >
> > >
> > > Please add a Fixes tag and Cc Kent.
> > >
> > > Fixes: acdf52d97f82 ("selinux: convert to kvmalloc")
> > >
> > >
> > > > Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
> > > > ---
> > > >  security/selinux/ss/policydb.c | 1 +
> > > >  1 file changed, 1 insertion(+)
> > > >
> > > > diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
> > > > index a0b3dc152468..a51e051df2cc 100644
> > > > --- a/security/selinux/ss/policydb.c
> > > > +++ b/security/selinux/ss/policydb.c
> > > > @@ -2638,6 +2638,7 @@ int policydb_read(struct policydb *p, void *fp)
> > > >       if (rc)
> > > >               goto bad;
> > > >
> > > > +     rc = -ENOMEM;
> > > >       p->type_attr_map_array = kvcalloc(p->p_types.nprim,
> > > >                                         sizeof(*p->type_attr_map_array),
> > > >                                         GFP_KERNEL);
> > >
> > > There is another bug earlier in the function as well:
> > >
> > > security/selinux/ss/policydb.c
> > >   2537
> > >   2538          rc = next_entry(buf, fp, sizeof(u32));
> > >   2539          if (rc)
> > >   2540                  goto bad;
> > >   2541          nel = le32_to_cpu(buf[0]);
> > >   2542
> > >   2543          p->role_tr = hashtab_create(role_trans_hash, role_trans_cmp, nel);
> > >   2544          if (!p->role_tr)
> > >   2545                  goto bad;
> > >                         ^^^^^^^^
> > >
> > >   2546          for (i = 0; i < nel; i++) {
> > >   2547                  rc = -ENOMEM;
> > >
> > > This style of setting the error code seems very bug prone.
> > >
> > > The Fixes tag for this one is:
> > > Fixes: e67b2ec9f617 ("selinux: store role transitions in a hash table")
> >
> > FYI, this one is also indirectly fixed by this patch, which is
> > currently pending review:
> > https://patchwork.kernel.org/patch/11514495/
>
> If we know the code is broken, let's fix it independently of a feature
> patch.  Ondrej, I believe the original patch is yours so please send
> me a new patch with just the fix, thank you.

Sure, here you go:
https://lore.kernel.org/selinux/20200501195111.3335258-1-omosnace@redhat.com/T/

-- 
Ondrej Mosnacek <omosnace at redhat dot com>
Software Engineer, Security Technologies
Red Hat, Inc.