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can: peak_pci: prevent use after free at netdev removal 

commit 0b5a958cf4 upstream.

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.

Reported-by: Christopher R. Baker <cbaker@rec.ri.cmu.edu>
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stephane Grosjean 2014-05-20 11:38:56 +02:00 committed by Greg Kroah-Hartman
parent acdad30d78
commit 8a478b1a7f
1 changed files with 9 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/net/can/sja1000/peak_pci.c
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@ -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;
@ -687,11 +687,13 @@ failure_remove_channels:
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 */
@ -725,10 +727,12 @@ 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 */