mirror of https://gitee.com/openkylin/linux.git
USB: Clean up root hub string descriptors
The previous code had a bug that would add a trailing null byte to the returned descriptor. Signed-off-by: George Spelvin <linux@horizon.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
George Spelvin
Greg Kroah-Hartman
parent
48d316770b
commit
392ca68b40
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@ -337,72 +337,89 @@ static const u8 ss_rh_config_descriptor[] = {
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/*-------------------------------------------------------------------------*/
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/*
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* helper routine for returning string descriptors in UTF-16LE
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* input can actually be ISO-8859-1; ASCII is its 7-bit subset
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/**
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* ascii2desc() - Helper routine for producing UTF-16LE string descriptors
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* @s: Null-terminated ASCII (actually ISO-8859-1) string
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* @buf: Buffer for USB string descriptor (header + UTF-16LE)
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* @len: Length (in bytes; may be odd) of descriptor buffer.
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*
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* The return value is the number of bytes filled in: 2 + 2*strlen(s) or
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* buflen, whichever is less.
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*
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* USB String descriptors can contain at most 126 characters; input
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* strings longer than that are truncated.
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*/
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static unsigned ascii2utf(char *s, u8 *utf, int utfmax)
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static unsigned
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ascii2desc(char const *s, u8 *buf, unsigned len)
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{
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unsigned retval;
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unsigned n, t = 2 + 2*strlen(s);
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for (retval = 0; *s && utfmax > 1; utfmax -= 2, retval += 2) {
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*utf++ = *s++;
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*utf++ = 0;
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if (t > 254)
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t = 254; /* Longest possible UTF string descriptor */
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if (len > t)
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len = t;
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t += USB_DT_STRING << 8; /* Now t is first 16 bits to store */
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n = len;
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while (n--) {
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*buf++ = t;
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if (!n--)
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break;
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*buf++ = t >> 8;
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t = (unsigned char)*s++;
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}
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if (utfmax > 0) {
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*utf = *s;
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++retval;
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}
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return retval;
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return len;
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}
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/*
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* rh_string - provides manufacturer, product and serial strings for root hub
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* @id: the string ID number (1: serial number, 2: product, 3: vendor)
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/**
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* rh_string() - provides string descriptors for root hub
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* @id: the string ID number (0: langids, 1: serial #, 2: product, 3: vendor)
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* @hcd: the host controller for this root hub
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* @data: return packet in UTF-16 LE
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* @len: length of the return packet
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* @data: buffer for output packet
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* @len: length of the provided buffer
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*
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* Produces either a manufacturer, product or serial number string for the
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* virtual root hub device.
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* Returns the number of bytes filled in: the length of the descriptor or
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* of the provided buffer, whichever is less.
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*/
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static unsigned rh_string(int id, struct usb_hcd *hcd, u8 *data, unsigned len)
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static unsigned
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rh_string(int id, struct usb_hcd const *hcd, u8 *data, unsigned len)
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{
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char buf [100];
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char buf[100];
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char const *s;
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static char const langids[4] = {4, USB_DT_STRING, 0x09, 0x04};
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// language ids
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if (id == 0) {
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buf[0] = 4; buf[1] = 3; /* 4 bytes string data */
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buf[2] = 0x09; buf[3] = 0x04; /* MSFT-speak for "en-us" */
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len = min_t(unsigned, len, 4);
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memcpy (data, buf, len);
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switch (id) {
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case 0:
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/* Array of LANGID codes (0x0409 is MSFT-speak for "en-us") */
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/* See http://www.usb.org/developers/docs/USB_LANGIDs.pdf */
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if (len > 4)
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len = 4;
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memcpy(data, langids, len);
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return len;
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// serial number
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} else if (id == 1) {
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strlcpy (buf, hcd->self.bus_name, sizeof buf);
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// product description
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} else if (id == 2) {
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strlcpy (buf, hcd->product_desc, sizeof buf);
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// id 3 == vendor description
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} else if (id == 3) {
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case 1:
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/* Serial number */
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s = hcd->self.bus_name;
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break;
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case 2:
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/* Product name */
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s = hcd->product_desc;
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break;
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case 3:
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/* Manufacturer */
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snprintf (buf, sizeof buf, "%s %s %s", init_utsname()->sysname,
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init_utsname()->release, hcd->driver->description);
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s = buf;
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break;
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default:
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/* Can't happen; caller guarantees it */
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return 0;
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}
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switch (len) { /* All cases fall through */
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default:
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len = 2 + ascii2utf (buf, data + 2, len - 2);
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case 2:
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data [1] = 3; /* type == string */
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case 1:
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data [0] = 2 * (strlen (buf) + 1);
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case 0:
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; /* Compiler wants a statement here */
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}
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return len;
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return ascii2desc(s, data, len);
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}
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