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 <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>
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index aa012fb..312f23a 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -521,7 +521,8 @@
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 @@
{
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);