On Tue, Feb 1, 2022 at 12:38 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote:
> On Fri, Jan 28, 2022 at 3:29 PM <vbendel@xxxxxxxxxx> wrote:
> > From: Vratislav Bendel <vbendel@xxxxxxxxxx>
> >
> > Currently there are two users of policydb->cond_list: cond_read_list()
> > and duplicate_policydb_cond_list(). On their error path one clears
> > ->cond_list to NULL, but the other doesn't.
> > Make the behavior consistent by resetting ->cond_list to NULL in
> > cond_list_destroy(), which is called by both on the error path.
>
> It's also important to see if there are any callers of
> cond_list_destroy() which incorrectly might be making use of
> policydb::cond_list after it has been freed; thankfully that does not
> appear to be the case in any of the call paths I looked at just now.
> As this is more a a style/Right-Thing-To-Do patch and not an immediate
> bugfix I'm going to go and merge this into selinux/next.
After looking at patches 2/3 and 3/3, ignore the last sentence above
and see my comments below :)
> Thanks Vratislav.
>
> > Signed-off-by: Vratislav Bendel <vbendel@xxxxxxxxxx>
> > ---
> > security/selinux/ss/conditional.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
> > index 2ec6e5cd25d9..1d0e5f326b62 100644
> > --- a/security/selinux/ss/conditional.c
> > +++ b/security/selinux/ss/conditional.c
> > @@ -152,6 +152,7 @@ static void cond_list_destroy(struct policydb *p)
> > for (i = 0; i < p->cond_list_len; i++)
> > cond_node_destroy(&p->cond_list[i]);
> > kfree(p->cond_list);
> > + p->cond_list = NULL;
While patch 1/3 may not be a candidate for selinux/stable-5.17 by
itself, patch 2/3 definitely qualifies. Considering that both patches
are small, easily understood, and the likelihood of a merge conflict
between the two is high, why don't you squash 1/3 and 2/3 together so
we can submit this for selinux/stable-5.17? In addition, put the two
lines which reset cond_list and cond_list_len together in v2, it's
cleaner that way, example below. If you don't have time to do that
let me know and I can squash them together and move the
"p->cond_list_len = 0" line (don't worry, I'll preserve your
name/email as the patch author).
static void cond_list_destroy(...)
{
/* ... */
kfree(p->cond_list);
p->cond_list = NULL;
p->cond_list_len = 0;
}
> > }
> >
> > void cond_policydb_destroy(struct policydb *p)
> > @@ -441,7 +442,6 @@ int cond_read_list(struct policydb *p, void *fp)
> > return 0;
> > err:
> > cond_list_destroy(p);
> > - p->cond_list = NULL;
> > return rc;
> > }
--
paul-moore.com
