4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Scott Bauer <sba...@plzdonthack.me>
commit 93a2001bdfd5376c3dc2158653034c20392d15c5 upstream.
This patch validates the num_values parameter from userland during the
HIDIOCGUSAGES and HIDIOCSUSAGES commands. Previously, if the report id was set
to HID_REPORT_ID_UNKNOWN, we would fail to validate the num_values parameter
leading to a heap overflow.
Signed-off-by: Scott Bauer <sba...@plzdonthack.me>
Signed-off-by: Jiri Kosina <jkos...@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/hid/usbhid/hiddev.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -516,13 +516,13 @@ static noinline int hiddev_ioctl_usage(s
goto inval;
} else if (uref->usage_index >= field->report_count)
goto inval;
-
- else if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES)
&&
- (uref_multi->num_values > HID_MAX_MULTI_USAGES
||
- uref->usage_index + uref_multi->num_values >
field->report_count))
- goto inval;
}
+ if ((cmd == HIDIOCGUSAGES || cmd == HIDIOCSUSAGES) &&
+ (uref_multi->num_values > HID_MAX_MULTI_USAGES ||
+ uref->usage_index + uref_multi->num_values >
field->report_count))
+ goto inval;
+
switch (cmd) {
case HIDIOCGUSAGE:
uref->value = field->value[uref->usage_index];
