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Commit 0b5a958c authored by Stephane Grosjean's avatar Stephane Grosjean Committed by Marc Kleine-Budde
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can: peak_pci: prevent use after free at netdev removal 

As remarked by Christopher R. Baker in his post at

http://marc.info/?l=linux-can&m=139707295706465&w=2



there's a possibility for an use after free condition at device removal.

This simplified patch introduces an additional variable to prevent the issue.
Thanks for catching this.

Cc: linux-stable <stable@vger.kernel.org>
Reported-by: default avatarChristopher R. Baker <cbaker@rec.ri.cmu.edu>
Signed-off-by: default avatarStephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 78ff4be4

drivers/net/can/sja1000/peak_pci.c

+9 −5
Original line number Diff line number Diff line
@@ -551,7 +551,7 @@ static int peak_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) 
{

	struct sja1000_priv *priv;

	struct peak_pci_chan *chan;

	struct net_device *dev;

	struct net_device *dev, *prev_dev;

	void __iomem *cfg_base, *reg_base;

	u16 sub_sys_id, icr;

	int i, err, channels;
@@ -688,11 +688,13 @@ static int peak_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent) 
	writew(0x0, cfg_base + PITA_ICR + 2);



	chan = NULL;

	for (dev = pci_get_drvdata(pdev); dev; dev = chan->prev_dev) {

		unregister_sja1000dev(dev);

		free_sja1000dev(dev);

	for (dev = pci_get_drvdata(pdev); dev; dev = prev_dev) {

		priv = netdev_priv(dev);

		chan = priv->priv;

		prev_dev = chan->prev_dev;



		unregister_sja1000dev(dev);

		free_sja1000dev(dev);

	}



	/* free any PCIeC resources too */
@@ -726,10 +728,12 @@ static void peak_pci_remove(struct pci_dev *pdev) 


	/* Loop over all registered devices */

	while (1) {

		struct net_device *prev_dev = chan->prev_dev;



		dev_info(&pdev->dev, "removing device %s\n", dev->name);

		unregister_sja1000dev(dev);

		free_sja1000dev(dev);

		dev = chan->prev_dev;

		dev = prev_dev;



		if (!dev) {

			/* do that only for first channel */