From 62aa366d9b0158a81eace3b83e6b027789f7575b Mon Sep 17 00:00:00 2001 From: Daniel Ritz Date: Thu, 17 Jan 2008 12:01:18 -0500 Subject: [PATCH] Input: usbtouchscreen - fix buffer overflow, make more egalax work Fix a buffer overflow in mutli-packet handling code. The overflow can only happen with eGalax devices and is even there very unlikely (only non-report packet are affected any only when truncated after the first byte). Also changes the mutli-packet handling code not to drop unknown packets, but rather just drop one byte. This allows synchronizing on report packets in the data stream. It's required for some egalax devices to work at all. Also remove the pointless 'flags' member of the device struct and set the version number to 0.6, plus some minor cleanups. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Daniel Ritz Signed-off-by: Andrew Morton Signed-off-by: Dmitry Torokhov --- drivers/input/touchscreen/usbtouchscreen.c | 55 ++++++++++++++++++------------ 1 file changed, 33 insertions(+), 22 deletions(-) diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c index 19055e7..63f9664 100644 --- a/drivers/input/touchscreen/usbtouchscreen.c +++ b/drivers/input/touchscreen/usbtouchscreen.c @@ -11,6 +11,7 @@ * - DMC TSC-10/25 * - IRTOUCHSYSTEMS/UNITOP * - IdealTEK URTC1000 + * - General Touch * - GoTop Super_Q2/GogoPen/PenPower tablets * * Copyright (C) 2004-2007 by Daniel Ritz @@ -50,7 +51,7 @@ #include -#define DRIVER_VERSION "v0.5" +#define DRIVER_VERSION "v0.6" #define DRIVER_AUTHOR "Daniel Ritz " #define DRIVER_DESC "USB Touchscreen Driver" @@ -65,17 +66,21 @@ struct usbtouch_device_info { int min_yc, max_yc; int min_press, max_press; int rept_size; - int flags; void (*process_pkt) (struct usbtouch_usb *usbtouch, unsigned char *pkt, int len); + + /* + * used to get the packet len. possible return values: + * > 0: packet len + * = 0: skip one byte + * < 0: -return value more bytes needed + */ int (*get_pkt_len) (unsigned char *pkt, int len); + int (*read_data) (struct usbtouch_usb *usbtouch, unsigned char *pkt); int (*init) (struct usbtouch_usb *usbtouch); }; -#define USBTOUCH_FLG_BUFFER 0x01 - - /* a usbtouch device */ struct usbtouch_usb { unsigned char *data; @@ -94,15 +99,6 @@ struct usbtouch_usb { }; -#if defined(CONFIG_TOUCHSCREEN_USB_EGALAX) || defined(CONFIG_TOUCHSCREEN_USB_ETURBO) || defined(CONFIG_TOUCHSCREEN_USB_IDEALTEK) -#define MULTI_PACKET -#endif - -#ifdef MULTI_PACKET -static void usbtouch_process_multi(struct usbtouch_usb *usbtouch, - unsigned char *pkt, int len); -#endif - /* device types */ enum { DEVTPYE_DUMMY = -1, @@ -186,6 +182,10 @@ static struct usb_device_id usbtouch_devices[] = { #ifdef CONFIG_TOUCHSCREEN_USB_EGALAX +#ifndef MULTI_PACKET +#define MULTI_PACKET +#endif + #define EGALAX_PKT_TYPE_MASK 0xFE #define EGALAX_PKT_TYPE_REPT 0x80 #define EGALAX_PKT_TYPE_DIAG 0x0A @@ -323,6 +323,9 @@ static int itm_read_data(struct usbtouch_usb *dev, unsigned char *pkt) * eTurboTouch part */ #ifdef CONFIG_TOUCHSCREEN_USB_ETURBO +#ifndef MULTI_PACKET +#define MULTI_PACKET +#endif static int eturbo_read_data(struct usbtouch_usb *dev, unsigned char *pkt) { unsigned int shift; @@ -461,6 +464,9 @@ static int irtouch_read_data(struct usbtouch_usb *dev, unsigned char *pkt) * IdealTEK URTC1000 Part */ #ifdef CONFIG_TOUCHSCREEN_USB_IDEALTEK +#ifndef MULTI_PACKET +#define MULTI_PACKET +#endif static int idealtek_get_pkt_len(unsigned char *buf, int len) { if (buf[0] & 0x80) @@ -525,6 +531,11 @@ static int gotop_read_data(struct usbtouch_usb *dev, unsigned char *pkt) /***************************************************************************** * the different device descriptors */ +#ifdef MULTI_PACKET +static void usbtouch_process_multi(struct usbtouch_usb *usbtouch, + unsigned char *pkt, int len); +#endif + static struct usbtouch_device_info usbtouch_dev_info[] = { #ifdef CONFIG_TOUCHSCREEN_USB_EGALAX [DEVTYPE_EGALAX] = { @@ -533,7 +544,6 @@ static struct usbtouch_device_info usbtouch_dev_info[] = { .min_yc = 0x0, .max_yc = 0x07ff, .rept_size = 16, - .flags = USBTOUCH_FLG_BUFFER, .process_pkt = usbtouch_process_multi, .get_pkt_len = egalax_get_pkt_len, .read_data = egalax_read_data, @@ -582,7 +592,6 @@ static struct usbtouch_device_info usbtouch_dev_info[] = { .min_yc = 0x0, .max_yc = 0x07ff, .rept_size = 8, - .flags = USBTOUCH_FLG_BUFFER, .process_pkt = usbtouch_process_multi, .get_pkt_len = eturbo_get_pkt_len, .read_data = eturbo_read_data, @@ -630,7 +639,6 @@ static struct usbtouch_device_info usbtouch_dev_info[] = { .min_yc = 0x0, .max_yc = 0x0fff, .rept_size = 8, - .flags = USBTOUCH_FLG_BUFFER, .process_pkt = usbtouch_process_multi, .get_pkt_len = idealtek_get_pkt_len, .read_data = idealtek_read_data, @@ -738,11 +746,14 @@ static void usbtouch_process_multi(struct usbtouch_usb *usbtouch, pos = 0; while (pos < buf_len) { /* get packet len */ - pkt_len = usbtouch->type->get_pkt_len(buffer + pos, len); + pkt_len = usbtouch->type->get_pkt_len(buffer + pos, + buf_len - pos); - /* unknown packet: drop everything */ - if (unlikely(!pkt_len)) - goto out_flush_buf; + /* unknown packet: skip one byte */ + if (unlikely(!pkt_len)) { + pos++; + continue; + } /* full packet: process */ if (likely((pkt_len > 0) && (pkt_len <= buf_len - pos))) { @@ -857,7 +868,7 @@ static int usbtouch_probe(struct usb_interface *intf, if (!usbtouch->data) goto out_free; - if (type->flags & USBTOUCH_FLG_BUFFER) { + if (type->get_pkt_len) { usbtouch->buffer = kmalloc(type->rept_size, GFP_KERNEL); if (!usbtouch->buffer) goto out_free_buffers; -- 2.7.4