[PATCH] usb: gadget: uvc: configfs: ensure guid to be valid before set

[Michael Grzeschik]

When setting the guid via configfs it is possible to test if
its value is one of the kernel supported ones by calling
uvc_format_by_guid on it. If the result is NULL, we know the
guid is unsupported and can be ignored.

Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
---
 drivers/usb/gadget/function/uvc_configfs.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c
index 7e704b2bcfd1c..6535e5948b2ef 100644
--- a/drivers/usb/gadget/function/uvc_configfs.c
+++ b/drivers/usb/gadget/function/uvc_configfs.c
@@ -13,6 +13,7 @@
 #include "uvc_configfs.h"
 
 #include <linux/sort.h>
+#include <linux/usb/uvc.h>
 #include <linux/usb/video.h>
 
 /* -----------------------------------------------------------------------------
@@ -2260,6 +2261,8 @@ static ssize_t uvcg_uncompressed_guid_format_store(struct config_item *item,
 	struct f_uvc_opts *opts;
 	struct config_item *opts_item;
 	struct mutex *su_mutex = &ch->fmt.group.cg_subsys->su_mutex;
+	const struct uvc_format_desc *format;
+	u8 tmpguidFormat[sizeof(ch->desc.guidFormat)];
 	int ret;
 
 	mutex_lock(su_mutex); /* for navigating configfs hierarchy */
@@ -2273,7 +2276,16 @@ static ssize_t uvcg_uncompressed_guid_format_store(struct config_item *item,
 		goto end;
 	}
 
-	memcpy(ch->desc.guidFormat, page,
+	memcpy(tmpguidFormat, page,
+	       min(sizeof(tmpguidFormat), len));
+
+	format = uvc_format_by_guid(tmpguidFormat);
+	if (!format) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	memcpy(ch->desc.guidFormat, tmpguidFormat,
 	       min(sizeof(ch->desc.guidFormat), len));
 	ret = sizeof(ch->desc.guidFormat);
 

---
base-commit: 3bf0514dc6f36f81ee11b1becd977cb87b4c90c6
change-id: 20240221-uvc-gadget-configfs-guid-fe09965b42e6

Best regards,
-- 
Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>