From 17309a6a43561bd7f4d4b51d7987225eb2b13d05 Mon Sep 17 00:00:00 2001
From: Tao Ren <rentao.bupt@gmail.com>
Date: Sun, 15 Mar 2020 12:16:28 -0700
Subject: [PATCH] usb: gadget: add "usb_validate_langid" function
The USB LANGID validation code in "check_user_usb_string" function is
moved to "usb_validate_langid" function which can be used by other usb
gadget drivers.
Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
---
drivers/usb/gadget/configfs.c | 14 +-------------
drivers/usb/gadget/usbstring.c | 24 ++++++++++++++++++++++++
include/linux/usb/gadget.h | 3 +++
3 files changed, 28 insertions(+), 13 deletions(-)
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 32b637e3e1fa2..822ef0470c5ff 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -13,8 +13,6 @@
int check_user_usb_string(const char *name,
struct usb_gadget_strings *stringtab_dev)
{
- unsigned primary_lang;
- unsigned sub_lang;
u16 num;
int ret;
@@ -22,17 +20,7 @@ int check_user_usb_string(const char *name,
if (ret)
return ret;
- primary_lang = num & 0x3ff;
- sub_lang = num >> 10;
-
- /* simple sanity check for valid langid */
- switch (primary_lang) {
- case 0:
- case 0x62 ... 0xfe:
- case 0x100 ... 0x3ff:
- return -EINVAL;
- }
- if (!sub_lang)
+ if (!usb_validate_langid(num))
return -EINVAL;
stringtab_dev->language = num;
diff --git a/drivers/usb/gadget/usbstring.c b/drivers/usb/gadget/usbstring.c
index 7c24d1ce10889..58a4d33250902 100644
--- a/drivers/usb/gadget/usbstring.c
+++ b/drivers/usb/gadget/usbstring.c
@@ -65,3 +65,27 @@ usb_gadget_get_string (const struct usb_gadget_strings *table, int id, u8 *buf)
return buf [0];
}
EXPORT_SYMBOL_GPL(usb_gadget_get_string);
+
+/**
+ * usb_validate_langid - validate usb language identifiers
+ * @lang: usb language identifier
+ *
+ * Returns true for valid language identifier, otherwise false.
+ */
+bool usb_validate_langid(u16 langid)
+{
+ u16 primary_lang = langid & 0x3ff; /* bit [9:0] */
+ u16 sub_lang = langid >> 10; /* bit [15:10] */
+
+ switch (primary_lang) {
+ case 0:
+ case 0x62 ... 0xfe:
+ case 0x100 ... 0x3ff:
+ return false;
+ }
+ if (!sub_lang)
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(usb_validate_langid);
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 9411c08a5c7e1..e959c09a97c93 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -773,6 +773,9 @@ struct usb_gadget_string_container {
/* put descriptor for string with that id into buf (buflen >= 256) */
int usb_gadget_get_string(const struct usb_gadget_strings *table, int id, u8 *buf);
+/* check if the given language identifier is valid */
+bool usb_validate_langid(u16 langid);
+
/*-------------------------------------------------------------------------*/
/* utility to simplify managing config descriptors */
--
2.30.2