On Mon, Mar 1, 2021 at 3:55 PM James Carter <jwcart2@xxxxxxxxx> wrote:
>
> On Sun, Feb 28, 2021 at 3:51 AM Nicolas Iooss <nicolas.iooss@xxxxxxx> wrote:
> >
> > Facebook's Infer static analyzer warns about a use-after-free issue in
> > libsemanage:
> >
> > int semanage_direct_mls_enabled(semanage_handle_t * sh)
> > {
> > sepol_policydb_t *p = NULL;
> > int retval;
> >
> > retval = sepol_policydb_create(&p);
> > if (retval < 0)
> > goto cleanup;
> >
> > /* ... */
> > cleanup:
> > sepol_policydb_free(p);
> > return retval;
> > }
> >
> > When sepol_policydb_create() is called, p is allocated and
> > policydb_init() is called. If this second call fails, p is freed
> > andsepol_policydb_create() returns -1, but p still stores a pointer to
> > freed memory. This pointer is then freed again in the cleanup part of
> > semanage_direct_mls_enabled().
> >
> > Fix this by setting p to NULL in sepol_policydb_create() after freeing
> > it.
> >
> > Signed-off-by: Nicolas Iooss <nicolas.iooss@xxxxxxx>
>
> Acked-by: James Carter <jwcart2@xxxxxxxxx>
Merged.
Nicolas
> > ---
> > libsepol/src/policydb_public.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/libsepol/src/policydb_public.c b/libsepol/src/policydb_public.c
> > index e5def7078eb0..0218c9403856 100644
> > --- a/libsepol/src/policydb_public.c
> > +++ b/libsepol/src/policydb_public.c
> > @@ -68,6 +68,7 @@ int sepol_policydb_create(sepol_policydb_t ** sp)
> > p = &(*sp)->p;
> > if (policydb_init(p)) {
> > free(*sp);
> > + *sp = NULL;
> > return -1;
> > }
> > return 0;
> > --
> > 2.30.0
> >
