From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967433AbaFQV6m (ORCPT ); Tue, 17 Jun 2014 17:58:42 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54927 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967177AbaFQVws (ORCPT ); Tue, 17 Jun 2014 17:52:48 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Stephane Grosjean , Marc Kleine-Budde , Kamal Mostafa Subject: [PATCH 3.13 156/212] can: peak_pci: prevent use after free at netdev removal Date: Tue, 17 Jun 2014 14:44:10 -0700 Message-Id: <1403041506-13646-157-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1403041506-13646-1-git-send-email-kamal@canonical.com> References: <1403041506-13646-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.4 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephane Grosjean 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 Signed-off-by: Stephane Grosjean Signed-off-by: Marc Kleine-Budde Signed-off-by: Kamal Mostafa --- 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 065ca49..546a848 100644 --- a/drivers/net/can/sja1000/peak_pci.c +++ b/drivers/net/can/sja1000/peak_pci.c @@ -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 */ -- 1.9.1