| Message ID | 20210926104757.2021540-1-william.xuanziyang@huawei.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] can: j1939: fix UAF for rx_kref of j1939_priv | expand |
Hi, On Sun, Sep 26, 2021 at 06:47:57PM +0800, Ziyang Xuan wrote: > It will trigger UAF for rx_kref of j1939_priv as following. > > cpu0 cpu1 > j1939_sk_bind(socket0, ndev0, ...) > j1939_netdev_start > j1939_sk_bind(socket1, ndev0, ...) > j1939_netdev_start > j1939_priv_set > j1939_priv_get_by_ndev_locked > j1939_jsk_add > ..... > j1939_netdev_stop > kref_put_lock(&priv->rx_kref, ...) > kref_get(&priv->rx_kref, ...) > REFCOUNT_WARN("addition on 0;...") > > ==================================================== > refcount_t: addition on 0; use-after-free. > WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 > RIP: 0010:refcount_warn_saturate+0x169/0x1e0 > Call Trace: > j1939_netdev_start+0x68b/0x920 > j1939_sk_bind+0x426/0xeb0 > ? security_socket_bind+0x83/0xb0 > > The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to > protect. > > Fixes: 9d71dd0c70099 ("can: add support of SAE J1939 protocol") > Reported-by: syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com > Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> Thank you! Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> > --- > net/can/j1939/main.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c > index 08c8606cfd9c..9bc55ecb37f9 100644 > --- a/net/can/j1939/main.c > +++ b/net/can/j1939/main.c > @@ -249,11 +249,14 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) > struct j1939_priv *priv, *priv_new; > int ret; > > - priv = j1939_priv_get_by_ndev(ndev); > + spin_lock(&j1939_netdev_lock); > + priv = j1939_priv_get_by_ndev_locked(ndev); > if (priv) { > kref_get(&priv->rx_kref); > + spin_unlock(&j1939_netdev_lock); > return priv; > } > + spin_unlock(&j1939_netdev_lock); > > priv = j1939_priv_create(ndev); > if (!priv) > @@ -269,10 +272,10 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) > /* Someone was faster than us, use their priv and roll > * back our's. > */ > + kref_get(&priv_new->rx_kref); > spin_unlock(&j1939_netdev_lock); > dev_put(ndev); > kfree(priv); > - kref_get(&priv_new->rx_kref); > return priv_new; > } > j1939_priv_set(ndev, priv); > -- > 2.25.1 > >
On 26.09.2021 18:47:57, Ziyang Xuan wrote: > It will trigger UAF for rx_kref of j1939_priv as following. > > cpu0 cpu1 > j1939_sk_bind(socket0, ndev0, ...) > j1939_netdev_start > j1939_sk_bind(socket1, ndev0, ...) > j1939_netdev_start > j1939_priv_set > j1939_priv_get_by_ndev_locked > j1939_jsk_add > ..... > j1939_netdev_stop > kref_put_lock(&priv->rx_kref, ...) > kref_get(&priv->rx_kref, ...) > REFCOUNT_WARN("addition on 0;...") > > ==================================================== > refcount_t: addition on 0; use-after-free. > WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 > RIP: 0010:refcount_warn_saturate+0x169/0x1e0 > Call Trace: > j1939_netdev_start+0x68b/0x920 > j1939_sk_bind+0x426/0xeb0 > ? security_socket_bind+0x83/0xb0 > > The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to > protect. > > Fixes: 9d71dd0c70099 ("can: add support of SAE J1939 protocol") > Reported-by: syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com > Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> Added to linux-can/testing, added stable on Cc. Thanks, Marc
diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index 08c8606cfd9c..9bc55ecb37f9 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -249,11 +249,14 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) struct j1939_priv *priv, *priv_new; int ret; - priv = j1939_priv_get_by_ndev(ndev); + spin_lock(&j1939_netdev_lock); + priv = j1939_priv_get_by_ndev_locked(ndev); if (priv) { kref_get(&priv->rx_kref); + spin_unlock(&j1939_netdev_lock); return priv; } + spin_unlock(&j1939_netdev_lock); priv = j1939_priv_create(ndev); if (!priv) @@ -269,10 +272,10 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) /* Someone was faster than us, use their priv and roll * back our's. */ + kref_get(&priv_new->rx_kref); spin_unlock(&j1939_netdev_lock); dev_put(ndev); kfree(priv); - kref_get(&priv_new->rx_kref); return priv_new; } j1939_priv_set(ndev, priv);
It will trigger UAF for rx_kref of j1939_priv as following. cpu0 cpu1 j1939_sk_bind(socket0, ndev0, ...) j1939_netdev_start j1939_sk_bind(socket1, ndev0, ...) j1939_netdev_start j1939_priv_set j1939_priv_get_by_ndev_locked j1939_jsk_add ..... j1939_netdev_stop kref_put_lock(&priv->rx_kref, ...) kref_get(&priv->rx_kref, ...) REFCOUNT_WARN("addition on 0;...") ==================================================== refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 Call Trace: j1939_netdev_start+0x68b/0x920 j1939_sk_bind+0x426/0xeb0 ? security_socket_bind+0x83/0xb0 The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to protect. Fixes: 9d71dd0c70099 ("can: add support of SAE J1939 protocol") Reported-by: syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> --- net/can/j1939/main.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)