From 951f2f960e5bbce20309de44626cf11d17847712 Mon Sep 17 00:00:00 2001 From: Julia Lawall Date: Mon, 8 Aug 2011 06:28:50 +0000 Subject: [PATCH] drivers/net/can/sja1000/plx_pci.c: eliminate double free In this code, the failure_cleanup label calls the function plx_pci_del_card, which frees everything in the card->net_dev array. dev is placed in this array immediately after allocation, so the two subsequent jumps to failure_cleanup should not also call free_sja1000dev, but the second one does. If plx_pci_check_sja1000 fails, then free_sja1000dev is also called on dev. Because dev is already in the card->net_dev array, this implies that when plx_pci_del_card is later called, it may get freed again. So that entry is reset to NULL after the free. Finally, if there is a problem with one channel, there will be a hole in the array. card->channels counts the number of channels that have succeeded, and does not keep track of the index of the largest element in the array that is valid. So the loop in plx_pci_del_card is changed to go up to PLX_PCI_MAX_CHAN, which is only 2. Signed-off-by: Julia Lawall Signed-off-by: David S. Miller --- drivers/net/can/sja1000/plx_pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/sja1000/plx_pci.c b/drivers/net/can/sja1000/plx_pci.c index 231385b8e08f..c7f3d4ea1167 100644 --- a/drivers/net/can/sja1000/plx_pci.c +++ b/drivers/net/can/sja1000/plx_pci.c @@ -408,7 +408,7 @@ static void plx_pci_del_card(struct pci_dev *pdev) struct sja1000_priv *priv; int i = 0; - for (i = 0; i < card->channels; i++) { + for (i = 0; i < PLX_PCI_MAX_CHAN; i++) { dev = card->net_dev[i]; if (!dev) continue; @@ -536,7 +536,6 @@ static int __devinit plx_pci_add_card(struct pci_dev *pdev, if (err) { dev_err(&pdev->dev, "Registering device failed " "(err=%d)\n", err); - free_sja1000dev(dev); goto failure_cleanup; } @@ -549,6 +548,7 @@ static int __devinit plx_pci_add_card(struct pci_dev *pdev, dev_err(&pdev->dev, "Channel #%d not detected\n", i + 1); free_sja1000dev(dev); + card->net_dev[i] = NULL; } } -- 2.39.5