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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jiri Pirko <jiri@mellanox.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.15 12/23] rocker: fix possible null pointer dereference in rocker_router_fib_event_work
Date:   Fri,  9 Feb 2018 14:40:10 +0100
Message-Id: <20180209133938.984457121@linuxfoundation.org>
In-Reply-To: <20180209133938.366024920@linuxfoundation.org>
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4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Pirko <jiri@mellanox.com>


[ Upstream commit a83165f00f16c0e0ef5b7cec3cbd0d4788699265 ]

Currently, rocker user may experience following null pointer
derefence bug:

[    3.062141] BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0
[    3.065163] IP: rocker_router_fib_event_work+0x36/0x110 [rocker]

The problem is uninitialized rocker->wops pointer that is initialized
only with the first initialized port. So move the port initialization
before registering the fib events.

Fixes: 936bd486564a ("rocker: use FIB notifications instead of switchdev calls")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/rocker/rocker_main.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/drivers/net/ethernet/rocker/rocker_main.c
+++ b/drivers/net/ethernet/rocker/rocker_main.c
@@ -2902,6 +2902,12 @@ static int rocker_probe(struct pci_dev *
 		goto err_alloc_ordered_workqueue;
 	}
 
+	err = rocker_probe_ports(rocker);
+	if (err) {
+		dev_err(&pdev->dev, "failed to probe ports\n");
+		goto err_probe_ports;
+	}
+
 	/* Only FIBs pointing to our own netdevs are programmed into
 	 * the device, so no need to pass a callback.
 	 */
@@ -2918,22 +2924,16 @@ static int rocker_probe(struct pci_dev *
 
 	rocker->hw.id = rocker_read64(rocker, SWITCH_ID);
 
-	err = rocker_probe_ports(rocker);
-	if (err) {
-		dev_err(&pdev->dev, "failed to probe ports\n");
-		goto err_probe_ports;
-	}
-
 	dev_info(&pdev->dev, "Rocker switch with id %*phN\n",
 		 (int)sizeof(rocker->hw.id), &rocker->hw.id);
 
 	return 0;
 
-err_probe_ports:
-	unregister_switchdev_notifier(&rocker_switchdev_notifier);
 err_register_switchdev_notifier:
 	unregister_fib_notifier(&rocker->fib_nb);
 err_register_fib_notifier:
+	rocker_remove_ports(rocker);
+err_probe_ports:
 	destroy_workqueue(rocker->rocker_owq);
 err_alloc_ordered_workqueue:
 	free_irq(rocker_msix_vector(rocker, ROCKER_MSIX_VEC_EVENT), rocker);
@@ -2961,9 +2961,9 @@ static void rocker_remove(struct pci_dev
 {
 	struct rocker *rocker = pci_get_drvdata(pdev);
 
-	rocker_remove_ports(rocker);
 	unregister_switchdev_notifier(&rocker_switchdev_notifier);
 	unregister_fib_notifier(&rocker->fib_nb);
+	rocker_remove_ports(rocker);
 	rocker_write32(rocker, CONTROL, ROCKER_CONTROL_RESET);
 	destroy_workqueue(rocker->rocker_owq);
 	free_irq(rocker_msix_vector(rocker, ROCKER_MSIX_VEC_EVENT), rocker);