[PATCH 2/2] AppArmor: Fix lsm_get_self_attr()

[Paul Moore]

On Fri, Feb 23, 2024 at 4:07 PM Paul Moore <paul at paul-moore.com> wrote:
> On Fri, Feb 23, 2024 at 2:06 PM Mickaël Salaün <mic at digikod.net> wrote:
> >
> > aa_getprocattr() may not initialize the value's pointer in some case.
> > As for proc_pid_attr_read(), initialize this pointer to NULL in
> > apparmor_getselfattr() to avoid an UAF in the kfree() call.
> >
> > Cc: Casey Schaufler <casey at schaufler-ca.com>
> > Cc: John Johansen <john.johansen at canonical.com>
> > Cc: Paul Moore <paul at paul-moore.com>
> > Cc: stable at vger.kernel.org
> > Fixes: 223981db9baf ("AppArmor: Add selfattr hooks")
> > Signed-off-by: Mickaël Salaün <mic at digikod.net>
> > ---
> >  security/apparmor/lsm.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> If you like John, I can send this up to Linus with the related SELinux
> fix, I would just need an ACK from you.

Reviewed-by: Paul Moore <paul at paul-moore.com>

This patch looks good to me, and while we've still got at least two
(maybe three?) more weeks before v6.8 is tagged, I think it would be
good to get this up to Linus ASAP.  I'll hold off for another day, but
if we don't see any comment from John I'll go ahead and merge this and
send it up to Linus with the SELinux fix; I'm sure John wouldn't be
happy if v6.8 went out the door without this fix.

> > diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> > index 98e1150bee9d..9a3dcaafb5b1 100644
> > --- a/security/apparmor/lsm.c
> > +++ b/security/apparmor/lsm.c
> > @@ -784,7 +784,7 @@ static int apparmor_getselfattr(unsigned int attr, struct lsm_ctx __user *lx,
> >         int error = -ENOENT;
> >         struct aa_task_ctx *ctx = task_ctx(current);
> >         struct aa_label *label = NULL;
> > -       char *value;
> > +       char *value = NULL;
> >
> >         switch (attr) {
> >         case LSM_ATTR_CURRENT:
> > --
> > 2.43.0

-- 
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