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: 782a985d7a ("PCI: Introduce new device binding path using pci_dev.driver_override")
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
CC: stable@vger.kernel.org	# v3.16+
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Alexander Graf <agraf@suse.de>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sasha Levin 2015-02-04 17:38:15 -05:00 committed by Bjorn Helgaas
parent c517d838eb
commit 4efe874aac

View File

@ -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);