From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f194.google.com ([209.85.208.194]:34133 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726641AbeHUNTp (ORCPT ); Tue, 21 Aug 2018 09:19:45 -0400 From: Johan Hovold To: Johan Hovold Cc: Dan Carpenter , Greg Kroah-Hartman , linux-usb@vger.kernel.org, stable Subject: [PATCH 1/2] USB: serial: io_ti: fix array underflow in completion handler Date: Tue, 21 Aug 2018 11:59:52 +0200 Message-Id: <20180821095953.19728-1-johan@kernel.org> Sender: stable-owner@vger.kernel.org List-ID: As reported by Dan Carpenter, a malicious USB device could set port_number to -3 and we would underflow the port array in the interrupt completion handler. As these devices only have one or two ports, fix this by making sure we only consider the seventh bit when determining the port number (and ignore bits 0xb0 which are typically set to 0x30). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable Reported-by: Dan Carpenter Signed-off-by: Johan Hovold --- drivers/usb/serial/io_ti.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/serial/io_ti.h b/drivers/usb/serial/io_ti.h index e53c68261017..9bbcee37524e 100644 --- a/drivers/usb/serial/io_ti.h +++ b/drivers/usb/serial/io_ti.h @@ -173,7 +173,7 @@ struct ump_interrupt { } __attribute__((packed)); -#define TIUMP_GET_PORT_FROM_CODE(c) (((c) >> 4) - 3) +#define TIUMP_GET_PORT_FROM_CODE(c) (((c) >> 6) & 0x01) #define TIUMP_GET_FUNC_FROM_CODE(c) ((c) & 0x0f) #define TIUMP_INTERRUPT_CODE_LSR 0x03 #define TIUMP_INTERRUPT_CODE_MSR 0x04 -- 2.18.0