#define CP210x_PART_CP2102 0x02
#define CP210x_PART_CP2103 0x03
-/* Return the size of the buffer needed to hold a string of len x formatted
- * for send to CP210X, and its reverse.
- */
-#define USBSTRLEN(strlen) (strlen * 2 + 2)
+/* Taken from drivers/usb/gadget/usbstring.c */
+static int utf8_to_utf16le(const char *s, __le16 *cp, unsigned len)
+{
+ int count = 0;
+ u8 c;
+ u16 uchar;
+
+ /* this insists on correct encodings, though not minimal ones.
+ * BUT it currently rejects legit 4-byte UTF-8 code points,
+ * which need surrogate pairs. (Unicode 3.1 can use them.)
+ */
+ while (len != 0 && (c = (u8) *s++) != 0) {
+ if (unlikely(c & 0x80)) {
+ // 2-byte sequence:
+ // 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
+ if ((c & 0xe0) == 0xc0) {
+ uchar = (c & 0x1f) << 6;
+
+ c = (u8) *s++;
+ if ((c & 0xc0) != 0x80)
+ goto fail;
+ c &= 0x3f;
+ uchar |= c;
+
+ // 3-byte sequence (most CJKV characters):
+ // zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
+ } else if ((c & 0xf0) == 0xe0) {
+ uchar = (c & 0x0f) << 12;
+
+ c = (u8) *s++;
+ if ((c & 0xc0) != 0x80)
+ goto fail;
+ c &= 0x3f;
+ uchar |= c << 6;
+
+ c = (u8) *s++;
+ if ((c & 0xc0) != 0x80)
+ goto fail;
+ c &= 0x3f;
+ uchar |= c;
+
+ /* no bogus surrogates */
+ if (0xd800 <= uchar && uchar <= 0xdfff)
+ goto fail;
+
+ // 4-byte sequence (surrogate pairs, currently rare):
+ // 11101110wwwwzzzzyy + 110111yyyyxxxxxx
+ // = 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx
+ // (uuuuu = wwww + 1)
+ // FIXME accept the surrogate code points (only)
+
+ } else
+ goto fail;
+ } else
+ uchar = c;
+ *cp++ = uchar;
+ count++;
+ len--;
+ }
+ return count;
+fail:
+ return -1;
+}
-/* Populates usbstr with: (len) + (0x03) + unicode(str). Each char in str
- * takes two bytes in unicode format.
- * Returns the resulting length of the string in usbstr.
+
+/*
+ * make_usb_string
+ * Populates usbstr with: (len) + (USB_DT_STRING) + unicode(str). Each char in
+ * usbstr consumes two bytes in unicode (__le16) format.
+ * Returns the resulting length of usbstr in bytes.
* This function can accept overlapping usbstr and str as long as the overlap
* does not cause data written to usbstr to overwrite data not yet read from
* str.
*/
-static int make_usb_string(char *usbstr, size_t usblen, char *src,
+static int make_usb_string(__le16* usbstr, size_t usblen, const char *src,
size_t srclen)
{
- int len = 0;
-
- if (usbstr && usblen >= 2 && src && *src && srclen) {
- char *p;
-
- if (usblen > 255)
- usblen = 255;
-
- p = usbstr + 1;
- *p++ = 0x03;
- len = 2;
- while (srclen && len < usblen) {
- *p++ = *src++;
- *p++ = 0;
- len += 2;
- srclen--;
- }
- *usbstr = (char)len;
+ int len;
+
+ /* string descriptors have length, type, then UTF16-LE text */
+ if (usblen > 254)
+ usblen = 254;
+ len = min(usblen / 2 - 1, srclen);
+ len = utf8_to_utf16le(src, usbstr + 1, len);
+ if (len >= 0) {
+ len = (len + 1) * 2;
+ ((u8 *)usbstr)[0] = len;
+ ((u8 *)usbstr)[1] = USB_DT_STRING;
}
return len;
}
* is the size of the buffer at kbuf.
* Returns the number of bytes used in kbuf.
*/
-static size_t cp210x_usbstr_from_user(char *kbuf,
+static size_t cp210x_usbstr_from_user(__le16 *kbuf,
struct cp210x_buffer __user *ubuf, size_t klen)
{
struct cp210x_buffer t;
size_t slen;
if (copy_from_user(&t, ubuf, sizeof(t)))
- return 0;
- slen = (klen - 2) / 2;
+ return -EINVAL;
+ slen = klen / 2 - 1;
if (!t.buf || !t.len || t.len > slen)
- return 0;
+ return -EINVAL;
if (t.len < slen)
slen = t.len;
- str = kbuf + klen - slen;
+ str = (char *)kbuf + klen - slen;
if (copy_from_user(str, (__u8 __user *)t.buf, slen))
- return 0;
+ return -EINVAL;
return make_usb_string(kbuf, klen, str, slen);
}
* Set a USB string descriptor using proprietary cp210x control messages.
* Return the number of characters actually written.
*/
-static int cp210x_setstr(struct usb_serial_port *port, int cmd, char *usbstr)
+static int cp210x_setstr(struct usb_serial_port *port, int cmd, __le16 *usbstr)
{
- unsigned len = usbstr[0];
+ int len = ((u8 *)usbstr)[0];
int ret = cp210x_ctlmsg(port, 0xff, USB_TYPE_VENDOR,
0x3700 | (cmd & 0xff), 0, usbstr, len);
dbg("%s - cmd 0x%02x len %d ret %d", __FUNCTION__, cmd, len, ret);
if (cp210x_get_partnum(port) == CP210x_PART_CP2103) {
u8 gpio = 0;
if (!cp210x_gpioget(port, &gpio) && !copy_to_user(
- (u8 __user *)arg, &gpio, sizeof(gpio)))
+ (__u8 __user *)arg, &gpio,
+ sizeof(gpio)))
return 0;
}
return -EFAULT;
case CP210x_IOCTL_SETPRODUCT:
{
- char usbstr[USBSTRLEN(CP210x_MAX_PRODUCT_STRLEN)];
+ __le16 usbstr[CP210x_MAX_PRODUCT_STRLEN + 1];
size_t len = cp210x_usbstr_from_user(usbstr,
(struct cp210x_buffer __user *)arg,
sizeof(usbstr));
- if (len && cp210x_setstr(port, 0x03, usbstr) == len)
+ if (len > 0 && cp210x_setstr(port, 0x03, usbstr) == len)
return 0;
return -EFAULT;
}
case CP210x_IOCTL_SETSERIAL:
{
- char usbstr[USBSTRLEN(CP210x_MAX_SERIAL_STRLEN)];
+ __le16 usbstr[CP210x_MAX_SERIAL_STRLEN + 1];
size_t len = cp210x_usbstr_from_user(usbstr,
(struct cp210x_buffer __user *)arg,
sizeof(usbstr));
- if (len && cp210x_setstr(port, 0x04, usbstr) == len)
+ if (len > 0 && cp210x_setstr(port, 0x04, usbstr) == len)
return 0;
return -EFAULT;
}