commit 851d0813ab80b47d3d85617d81836891bfb59094
author Peilin Ye <yepeilin.cs@gmail.com> Wed Jul 29 07:37:12 2020 -0400
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Thu Sep 03 11:27:10 2020 +0200
tree d116b5f02391899c0aa343c01c25098c9c354a89
parent c98b6ebd9b555db3ddc7751d31e5e424c1c81245

HID: hiddev: Fix slab-out-of-bounds write in hiddev_ioctl_usage()

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

diff --git a/drivers/hid/usbhid/hiddev.c b/drivers/hid/usbhid/hiddev.c
index 35b1fa6..4711fb1 100644
--- a/drivers/hid/usbhid/hiddev.c
+++ b/drivers/hid/usbhid/hiddev.c
@@ -519,12 +519,16 @@
 
 		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;