IB/cm: Fix rb-tree duplicate free and use-after-free

commit 0ca81a2840f77855bbad1b9f172c545c4dc9e6a4 upstream.

ib_send_cm_sidr_rep could sometimes erase the node from the sidr
(depending on errors in the process). Since ib_send_cm_sidr_rep is
called both from cm_sidr_req_handler and cm_destroy_id, cm_id_priv
could be either erased from the rb_tree twice or not erased at all.
Fixing that by making sure it's erased only once before freeing
cm_id_priv.

Fixes: a977049dacde ('[PATCH] IB: Add the kernel CM implementation')
Signed-off-by: Doron Tsur <doront@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 8b72f39..722a893 100644 (file)
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -856,6 +856,11 @@ retest:
        case IB_CM_SIDR_REQ_RCVD:
                spin_unlock_irq(&cm_id_priv->lock);
                cm_reject_sidr_req(cm_id_priv, IB_SIDR_REJECT);
+               spin_lock_irq(&cm.lock);
+               if (!RB_EMPTY_NODE(&cm_id_priv->sidr_id_node))
+                       rb_erase(&cm_id_priv->sidr_id_node,
+                                &cm.remote_sidr_table);
+               spin_unlock_irq(&cm.lock);
                break;
        case IB_CM_REQ_SENT:
                ib_cancel_mad(cm_id_priv->av.port->mad_agent, cm_id_priv->msg);
@@ -3092,7 +3097,10 @@ int ib_send_cm_sidr_rep(struct ib_cm_id *cm_id,
        spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
        spin_lock_irqsave(&cm.lock, flags);
-       rb_erase(&cm_id_priv->sidr_id_node, &cm.remote_sidr_table);
+       if (!RB_EMPTY_NODE(&cm_id_priv->sidr_id_node)) {
+               rb_erase(&cm_id_priv->sidr_id_node, &cm.remote_sidr_table);
+               RB_CLEAR_NODE(&cm_id_priv->sidr_id_node);
+       }
        spin_unlock_irqrestore(&cm.lock, flags);
        return 0;