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

…uffer 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 4efe874 ("PCI: Don't read past the end of sysfs "driver_override" buffer") from Sasha Levin. Fixes: 3d713e0 ("driver core: platform: add device binding path 'driver_override'") Cc: [email protected] # v3.17+ Signed-off-by: Nicolai Stange <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
mrcsosa · Sep 18, 2017 · bf563b0 · bf563b0
1 parent 452562a
commit bf563b0
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
@@ -868,7 +868,8 @@ 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);