From f11c6f07cb7d33abb503e87909aba80c8605d141 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Wed, 11 Sep 2013 21:56:58 +0200 Subject: HID: multitouch: validate indexes details commit 8821f5dc187bdf16cfb32ef5aa8c3035273fa79a upstream. When working on report indexes, always validate that they are in bounds. Without this, a HID device could report a malicious feature report that could trick the driver into a heap overflow: [ 634.885003] usb 1-1: New USB device found, idVendor=0596, idProduct=0500 ... [ 676.469629] BUG kmalloc-192 (Tainted: G W ): Redzone overwritten Note that we need to change the indexes from s8 to s16 as they can be between -1 and 255. CVE-2013-2897 Cc: stable@vger.kernel.org Signed-off-by: Benjamin Tissoires Acked-by: Kees Cook Signed-off-by: Jiri Kosina [bwh: Backported to 3.2: mt_device::{cc,cc_value,inputmode}_index do not exist and the corresponding indices do not need to be validated. mt_device::maxcontact_report_id does not exist either. So all we need to do is to widen mt_device::inputmode.] Signed-off-by: Ben Hutchings [yjw: Backport to 3.4: maxcontact_report_id exists, need to be validated] Signed-off-by: Yijing Wang Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-multitouch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c index e754dff1da5f..f5f7af15c6a7 100644 --- a/drivers/hid/hid-multitouch.c +++ b/drivers/hid/hid-multitouch.c @@ -82,8 +82,8 @@ struct mt_device { multitouch fields */ unsigned last_field_index; /* last field index of the report */ unsigned last_slot_field; /* the last field of a slot */ - __s8 inputmode; /* InputMode HID feature, -1 if non-existent */ - __s8 maxcontact_report_id; /* Maximum Contact Number HID feature, + __s16 inputmode; /* InputMode HID feature, -1 if non-existent */ + __s16 maxcontact_report_id; /* Maximum Contact Number HID feature, -1 if non-existent */ __u8 num_received; /* how many contacts we received */ __u8 num_expected; /* expected last contact index */ -- cgit v1.2.3