From 4efe874aace57dba967624ce1c48322da2447b75 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Wed, 4 Feb 2015 17:38:15 -0500 Subject: [PATCH] PCI: Don't read past the end of sysfs "driver_override" buffer When printing the driver_override parameter when it is 4095 and 4094 bytes long, the printing code would access invalid memory because we need count+1 bytes for printing. Fixes: 782a985d7af2 ("PCI: Introduce new device binding path using pci_dev.driver_override") Signed-off-by: Sasha Levin Signed-off-by: Bjorn Helgaas Acked-by: Alex Williamson CC: stable@vger.kernel.org # v3.16+ CC: Konrad Rzeszutek Wilk CC: Alexander Graf CC: Greg Kroah-Hartman --- drivers/pci/pci-sysfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index aa012fb3834b..312f23a8429c 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -521,7 +521,8 @@ static ssize_t driver_override_store(struct device *dev, struct pci_dev *pdev = to_pci_dev(dev); char *driver_override, *old = pdev->driver_override, *cp; - if (count > PATH_MAX) + /* We need to keep extra room for a newline */ + if (count >= (PAGE_SIZE - 1)) return -EINVAL; driver_override = kstrndup(buf, count, GFP_KERNEL); @@ -549,7 +550,7 @@ static ssize_t driver_override_show(struct device *dev, { struct pci_dev *pdev = to_pci_dev(dev); - return sprintf(buf, "%s\n", pdev->driver_override); + return snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override); } static DEVICE_ATTR_RW(driver_override);