Re: [PATCH] tipc: stop tipc crypto on failure in tipc_node_create

[Fedor Pchelkin]

On 23/07/25 03:46PM, Xin Long wrote:
> On Tue, Jul 25, 2023 at 2:37 PM Fedor Pchelkin <pchelkin@xxxxxxxxx> wrote:
> >
> > If tipc_link_bc_create() fails inside tipc_node_create() for a newly
> > allocated tipc node then we should stop its tipc crypto and free the
> > resources allocated with a call to tipc_crypto_start().
> >
> > Call tipc_crypto_stop() in that case. Also extract the similar error exit
> > paths into a goto statement.
> >
> > Found by Linux Verification Center (linuxtesting.org).
> >
> > Fixes: cb8092d70a6f ("tipc: move bc link creation back to tipc_node_create")
> > Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
> > ---
> >  net/tipc/node.c | 17 +++++++++++------
> >  1 file changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/net/tipc/node.c b/net/tipc/node.c
> > index 5e000fde8067..0d64005a803b 100644
> > --- a/net/tipc/node.c
> > +++ b/net/tipc/node.c
> > @@ -546,9 +546,7 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr, u8 *peer_id,
> >  #ifdef CONFIG_TIPC_CRYPTO
> >         if (unlikely(tipc_crypto_start(&n->crypto_rx, net, n))) {
> >                 pr_warn("Failed to start crypto RX(%s)!\n", n->peer_id_string);
> > -               kfree(n);
> > -               n = NULL;
> > -               goto exit;
> > +               goto free_node;
> >         }
> >  #endif
> >         n->addr = addr;
> > @@ -583,9 +581,7 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr, u8 *peer_id,
> >                                  n->capabilities, &n->bc_entry.inputq1,
> >                                  &n->bc_entry.namedq, snd_l, &n->bc_entry.link)) {
> >                 pr_warn("Broadcast rcv link creation failed, no memory\n");
> > -               kfree(n);
> > -               n = NULL;
> > -               goto exit;
> > +               goto stop_crypto;
> >         }
> >         tipc_node_get(n);
> Can you please try moving up tipc_node_get(n) ahead tipc_link_bc_create()
> and use tipc_node_put(n) to replace kfree(n) to avoid the extra
> tipc_crypto_stop() call below?
> 
> Thanks.
> 

Guess moving tipc_node_get() before tipc_link_bc_create() would not solve
the problem as ref is already initialized to 1 at that point. So just
replacing direct kfree() with tipc_node_put() will fix it.

Thank you for advice! I'll resend the v2 shortly.

> >         timer_setup(&n->timer, tipc_node_timeout, 0);
> > @@ -610,6 +606,15 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr, u8 *peer_id,
> >  exit:
> >         spin_unlock_bh(&tn->node_list_lock);
> >         return n;
> > +stop_crypto:
> > +
> > +#ifdef CONFIG_TIPC_CRYPTO
> > +       tipc_crypto_stop(&n->crypto_rx);
> > +free_node:
> > +#endif
> > +       kfree(n);
> > +       spin_unlock_bh(&tn->node_list_lock);
> > +       return NULL;
> >  }
> >
> >  static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
> > --
> > 2.41.0
> >