Commit a97ca4f7 authored Sep 11, 2017 by Nicolai Stange Committed by Greg Kroah-Hartman Oct 12, 2017

driver core: platform: Don't read past the end of "driver_override" buffer

commit bf563b01c2895a4bfd1a29cc5abc67fe706ecffd upstream.

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.

Reject driver_override values of these lengths in driver_override_store().

This is in close analogy to commit 4efe874a ("PCI: Don't read past the
end of sysfs "driver_override" buffer") from Sasha Levin.

Fixes: 3d713e0e ("driver core: platform: add device binding path 'driver_override'")
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent fc3c6722

drivers/base/platform.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -858,7 +858,8 @@ static ssize_t driver_override_store(struct device *dev,
		struct platform_device *pdev = to_platform_device(dev);
		char driver_override, old, *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);