[PATCH 4.14 90/91] HID: hiddev: Fix slab-out-of-bounds write in hiddev_ioctl_usage()

Greg Kroah-Hartman
2020-09-01T15:23:42Z

From: Peilin Ye <yepeilin.cs@gmail.com>

commit 25a097f5204675550afb879ee18238ca917cba7a upstream.

`uref->usage_index` is not always being properly checked, causing
hiddev_ioctl_usage() to go out of bounds under some cases. Fix it.

Reported-by: syzbot+34ee1b45d88571c2fa8b@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=f2aebe90b8c56806b050a20b36f51ed6acabe802
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hid/usbhid/hiddev.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -532,12 +532,16 @@ static noinline int hiddev_ioctl_usage(s

switch (cmd) {
case HIDIOCGUSAGE:
+ if (uref->usage_index >= field->report_count)
+ goto inval;
uref->value = field->value[uref->usage_index];
if (copy_to_user(user_arg, uref, sizeof(*uref)))
goto fault;
goto goodreturn;

case HIDIOCSUSAGE:
+ if (uref->usage_index >= field->report_count)
+ goto inval;
field->value[uref->usage_index] = uref->value;
goto goodreturn;