[PATCH 3.10 23/24] IB/cm: Fix rb-tree duplicate free and use-after-free

From: Greg Kroah-Hartman
Date: Fri Nov 06 2015 - 14:46:02 EST

3.10-stable review patch. If anyone has any objections, please let me know.


From: Doron Tsur <doront@xxxxxxxxxxxx>

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

Fixes: a977049dacde ('[PATCH] IB: Add the kernel CM implementation')
Signed-off-by: Doron Tsur <doront@xxxxxxxxxxxx>
Signed-off-by: Matan Barak <matanb@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/infiniband/core/cm.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -857,6 +857,11 @@ retest:
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);
ib_cancel_mad(cm_id_priv->av.port->mad_agent, cm_id_priv->msg);
@@ -3093,7 +3098,10 @@ int ib_send_cm_sidr_rep(struct ib_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;

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