Patch "net/mlx4_core: Use-after-free causes a resource leak in flow-steering detach" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    net/mlx4_core: Use-after-free causes a resource leak in flow-steering detach

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-mlx4_core-use-after-free-causes-a-resource-leak-in-flow-steering-detach.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri Aug  4 13:32:40 PDT 2017
From: Jack Morgenstein <jackm@dev.mellanox.co.il>
Date: Thu, 29 Dec 2016 18:37:09 +0200
Subject: net/mlx4_core: Use-after-free causes a resource leak in flow-steering detach

From: Jack Morgenstein <jackm@dev.mellanox.co.il>


[ Upstream commit 3b01fe7f91c8e4f9afc4fae3c5af72c14958d2d8 ]

mlx4_QP_FLOW_STEERING_DETACH_wrapper first removes the steering
rule (which results in freeing the rule structure), and then
references a field in this struct (the qp number) when releasing the
busy-status on the rule's qp.

Since this memory was freed, it could reallocated and changed.
Therefore, the qp number in the struct may be incorrect,
so that we are releasing the incorrect qp. This leaves the rule's qp
in the busy state (and could possibly release an incorrect qp as well).

Fix this by saving the qp number in a local variable, for use after
removing the steering rule.

Fixes: 2c473ae7e582 ("net/mlx4_core: Disallow releasing VF QPs which have steering rules")
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx4/resource_tracker.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
+++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
@@ -4474,6 +4474,7 @@ int mlx4_QP_FLOW_STEERING_DETACH_wrapper
 	struct res_qp *rqp;
 	struct res_fs_rule *rrule;
 	u64 mirr_reg_id;
+	int qpn;
 
 	if (dev->caps.steering_mode !=
 	    MLX4_STEERING_MODE_DEVICE_MANAGED)
@@ -4490,10 +4491,11 @@ int mlx4_QP_FLOW_STEERING_DETACH_wrapper
 	}
 	mirr_reg_id = rrule->mirr_rule_id;
 	kfree(rrule->mirr_mbox);
+	qpn = rrule->qpn;
 
 	/* Release the rule form busy state before removal */
 	put_res(dev, slave, vhcr->in_param, RES_FS_RULE);
-	err = get_res(dev, slave, rrule->qpn, RES_QP, &rqp);
+	err = get_res(dev, slave, qpn, RES_QP, &rqp);
 	if (err)
 		return err;
 
@@ -4518,7 +4520,7 @@ int mlx4_QP_FLOW_STEERING_DETACH_wrapper
 	if (!err)
 		atomic_dec(&rqp->ref_count);
 out:
-	put_res(dev, slave, rrule->qpn, RES_QP);
+	put_res(dev, slave, qpn, RES_QP);
 	return err;
 }
 


Patches currently in stable-queue which might be from jackm@dev.mellanox.co.il are

queue-4.9/net-mlx4_core-fix-raw-qp-flow-steering-rules-under-sriov.patch
queue-4.9/net-mlx4_core-use-after-free-causes-a-resource-leak-in-flow-steering-detach.patch