From: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
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
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
[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 <ben@xxxxxxxxxxxxxxx>
[yjw: Backport to 3.4: maxcontact_report_id exists,
need to be validated]
Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
---
drivers/hid/hid-multitouch.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index e754dff..f5f7af1 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 */
--
1.7.1
--
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