[PATCH] USB: Buffer overflow patch for Yealink driver

Just a small patch that fixes a small parameter validation bug.

drivers/usb/input/map_to_7segment.h:
This patch fixes the broken parameter validation in the char to seg7
conversion. This could cause out-of-bounds memory references.

MAINTAINERS:
Yealink maintainer info now in sorted order.

Documentation/input/yealink.txt:
Added a Q&A section that answers some common questions.

Signed-off-by: Henk <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

006491df1a13f85ad245d1039dfdf20e49c394fd

Documentation/input/yealink.txt

···
 
 0. Status
 ~~~~~~~~~
-
 The p1k is a relatively cheap usb 1.1 phone with:
   - keyboard		full support, yealink.ko / input event API
   - LCD			full support, yealink.ko / sysfs API
···
 
 1. Compilation (stand alone version)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
 Currently only kernel 2.6.x.y versions are supported.
-In order to build the yealink.ko module do:
+In order to build the yealink.ko module do
 
   make
 
···
 the Makefile is pointing to the location where your kernel sources
 are located, default /usr/src/linux.
 
+
+1.1 Troubleshooting
+~~~~~~~~~~~~~~~~~~~
+Q: Module yealink compiled and installed without any problem but phone
+   is not initialized and does not react to any actions.
+A: If you see something like:
+   hiddev0: USB HID v1.00 Device [Yealink Network Technology Ltd. VOIP USB Phone
+   in dmesg, it means that the hid driver has grabbed the device first. Try to
+   load module yealink before any other usb hid driver. Please see the
+   instructions provided by your distribution on module configuration.
+
+Q: Phone is working now (displays version and accepts keypad input) but I can't
+   find the sysfs files.
+A: The sysfs files are located on the particular usb endpoint. On most
+   distributions you can do: "find /sys/ -name get_icons" for a hint.
 
 
 2. keyboard features

MAINTAINERS

···
 L:	[e-mail]
 S:	Maintained
 
-YEALINK PHONE DRIVER
-P:	Henk Vergonet
-M:	[e-mail]
-L:	[e-mail]
-S:	Maintained
-
 8139CP 10/100 FAST ETHERNET DRIVER
 P:	Jeff Garzik
 M:	[e-mail]
···
 P:	Jean-Paul Roubelat
 M:	[e-mail]
 L:	[e-mail]
+S:	Maintained
+
+YEALINK PHONE DRIVER
+P:	Henk Vergonet
+M:	[e-mail]
+L:	[e-mail]
 S:	Maintained
 
 YMFPCI YAMAHA PCI SOUND (Use ALSA instead)

drivers/usb/input/map_to_7segment.h

···
 
 static inline int map_to_seg7(struct seg7_conversion_map *map, int c)
 {
-	return c & 0x7f ? map->table[c] : -EINVAL;
+	return c >= 0 && c < sizeof(map->table) ? map->table[c] : -EINVAL;
 }
 
 #define SEG7_CONVERSION_MAP(_name, _map)	\