From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pan Bian Subject: [PATCH] sis5513: fix potential use after free Date: Wed, 28 Nov 2018 08:55:26 +0800 Message-ID: <1543366526-46767-1-git-send-email-bianpan2016@163.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: "David S. Miller" Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, Pan Bian List-Id: linux-ide@vger.kernel.org The function sis_find_family drops lpc_bridge reference via pci_dev_put, however, after that, field lpc_bridge->revision is read. This may result in a use after free bug. The patch moves the put operation after the condition check. Signed-off-by: Pan Bian --- drivers/ide/sis5513.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/ide/sis5513.c b/drivers/ide/sis5513.c index 024bc7b..69f9889 100644 --- a/drivers/ide/sis5513.c +++ b/drivers/ide/sis5513.c @@ -434,7 +434,6 @@ static int sis_find_family(struct pci_dev *dev) lpc_bridge = pci_get_slot(dev->bus, 0x10); /* Bus 0, Dev 2, Fn 0 */ pci_read_config_byte(dev, 0x49, &prefctl); - pci_dev_put(lpc_bridge); if (lpc_bridge->revision == 0x10 && (prefctl & 0x80)) { printk(KERN_INFO DRV_NAME " %s: SiS 961B MuTIOL IDE UDMA133 controller\n", @@ -445,6 +444,8 @@ static int sis_find_family(struct pci_dev *dev) pci_name(dev)); chipset_family = ATA_100; } + + pci_dev_put(lpc_bridge); } } -- 2.7.4