[PATCH 6.12 205/242] usb: gadget: f_rndis: Protect RNDIS options with mutex

Greg Kroah-Hartman
2026-04-08T18:49:55Z

From: Kuen-Han Tsai <khtsai@google.com>

commit 8d8c68b1fc06ece60cf43e1306ff0f4ac121547e upstream.

The class/subclass/protocol options are suspectible to race conditions
as they can be accessed concurrently through configfs.

Use existing mutex to protect these options. This issue was identified
during code inspection.

Fixes: 73517cf49bd4 ("usb: gadget: add RNDIS configfs options for class/subclass/protocol")
Cc: stable@vger.kernel.org
Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Link: https://patch.msgid.link/20260320-usb-net-lifecycle-v1-2-4886b578161b@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/gadget/function/f_rndis.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/usb/gadget/function/f_rndis.c
+++ b/drivers/usb/gadget/function/f_rndis.c
@@ -11,6 +11,7 @@

/* #define VERBOSE_DEBUG */

+#include <linux/cleanup.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
@@ -678,9 +679,11 @@ rndis_bind(struct usb_configuration *c,
return -ENOMEM;
}

- rndis_iad_descriptor.bFunctionClass = rndis_opts->class;
- rndis_iad_descriptor.bFunctionSubClass = rndis_opts->subclass;
- rndis_iad_descriptor.bFunctionProtocol = rndis_opts->protocol;
+ scoped_guard(mutex, &rndis_opts->lock) {
+ rndis_iad_descriptor.bFunctionClass = rndis_opts->class;
+ rndis_iad_descriptor.bFunctionSubClass = rndis_opts->subclass;
+ rndis_iad_descriptor.bFunctionProtocol = rndis_opts->protocol;
+ }

/*
* in drivers/usb/gadget/configfs.c:configfs_composite_bind()