[PATCH 8/9] USB usbfs: missing lock in proc_getdriver

[Duncan Sands]

Protect against driver binding changes while reading the driver name.

 devio.c |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)


diff -Nru a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
--- a/drivers/usb/core/devio.c	Wed Apr 14 12:18:30 2004
+++ b/drivers/usb/core/devio.c	Wed Apr 14 12:18:30 2004
@@ -709,12 +709,14 @@
 	if ((ret = findintfif(ps->dev, gd.interface)) < 0)
 		return ret;
 	interface = ps->dev->actconfig->interface[ret];
-	if (!interface->dev.driver)
-		return -ENODATA;
-	strncpy(gd.driver, interface->dev.driver->name, sizeof(gd.driver));
-	if (copy_to_user(arg, &gd, sizeof(gd)))
-		return -EFAULT;
-	return 0;
+	ret = -ENODATA;
+	down_read(&usb_bus_type.subsys.rwsem);
+	if (interface && interface->dev.driver) {
+		strncpy(gd.driver, interface->dev.driver->name, sizeof(gd.driver));
+		ret = copy_to_user(arg, &gd, sizeof(gd)) ? -EFAULT : 0;
+	}
+	up_read(&usb_bus_type.subsys.rwsem);
+	return ret;
 }
 
 static int proc_connectinfo(struct dev_state *ps, void __user *arg)
-
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