[PATCH 3.2 089/199] HID: hid-cypress: validate length of report

From: Ben Hutchings
Date: Fri Mar 10 2017 - 08:01:28 EST


3.2.87-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

commit 1ebb71143758f45dc0fa76e2f48429e13b16d110 upstream.

Make sure we have enough of a report structure to validate before
looking at it.

Reported-by: Benoit Camredon <benoit.camredon@xxxxxxxxxx>
Tested-by: Benoit Camredon <benoit.camredon@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/hid/hid-cypress.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/hid/hid-cypress.c
+++ b/drivers/hid/hid-cypress.c
@@ -40,6 +40,9 @@ static __u8 *cp_report_fixup(struct hid_
if (!(quirks & CP_RDESC_SWAPPED_MIN_MAX))
return rdesc;

+ if (*rsize < 4)
+ return rdesc;
+
for (i = 0; i < *rsize - 4; i++)
if (rdesc[i] == 0x29 && rdesc[i + 2] == 0x19) {
__u8 tmp;