[PATCH 3.8 35/65] can: peak_pci: prevent use after free at netdev removal
From: Kamal Mostafa
Date: Tue Jun 24 2014 - 16:33:38 EST
3.8.13.25 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Stephane Grosjean <s.grosjean@xxxxxxxxxxxxxxx>
commit 0b5a958cf4df3a5cd578b861471e62138f55c85e 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@xxxxxxxxxxxxxx>
Signed-off-by: Stephane Grosjean <s.grosjean@xxxxxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/net/can/sja1000/peak_pci.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/can/sja1000/peak_pci.c b/drivers/net/can/sja1000/peak_pci.c
index d84888f..1a18a0c 100644
--- a/drivers/net/can/sja1000/peak_pci.c
+++ b/drivers/net/can/sja1000/peak_pci.c
@@ -555,7 +555,7 @@ 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;
@@ -691,11 +691,13 @@ 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 */
@@ -729,10 +731,12 @@ 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 */
--
1.9.1
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