From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 795CEC433FE for ; Tue, 10 May 2022 13:24:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243178AbiEJN2o (ORCPT ); Tue, 10 May 2022 09:28:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243693AbiEJN1R (ORCPT ); Tue, 10 May 2022 09:27:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A082E25D111; Tue, 10 May 2022 06:20:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 39B786165A; Tue, 10 May 2022 13:20:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48DFCC385A6; Tue, 10 May 2022 13:20:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652188819; bh=sN5HR7f9AJoRolKAArwQTOKUueVNLwfQy/wUH8Trtu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1u+t7QMRhMxyIBZmSzfUqsMQV2i2rlwSHHVXEkXrCsP/Uhs7EPnByEOjcvDbSm2CX +DVbQDyW1tDIYCmjSTEU5Mpv7Q6NAqUyql1FBc6faXubkySVFbMlUnHz5IxnLYD6wf VVt1SGUM6088/ib4NpgZb81bLPnrGr5uONE4Hs2w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Starke Subject: [PATCH 4.19 55/88] tty: n_gsm: fix wrong command frame length field encoding Date: Tue, 10 May 2022 15:07:40 +0200 Message-Id: <20220510130735.343311933@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220510130733.735278074@linuxfoundation.org> References: <20220510130733.735278074@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Daniel Starke commit 398867f59f956985f4c324f173eff7b946e14bd8 upstream. n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010. See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516 The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapter 5.4.6.1 states that each command frame shall be made up from type, length and value. Looking for example in chapter 5.4.6.3.5 at the description for the encoding of a flow control on command it becomes obvious, that the type and length field is always present whereas the value may be zero bytes long. The current implementation omits the length field if the value is not present. This is wrong. Correct this by always sending the length in gsm_control_transmit(). So far only the modem status command (MSC) has included a value and encoded its length directly. Therefore, also change gsmtty_modem_update(). Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20220414094225.4527-12-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1302,11 +1302,12 @@ static void gsm_control_response(struct static void gsm_control_transmit(struct gsm_mux *gsm, struct gsm_control *ctrl) { - struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 1, gsm->ftype); + struct gsm_msg *msg = gsm_data_alloc(gsm, 0, ctrl->len + 2, gsm->ftype); if (msg == NULL) return; - msg->data[0] = (ctrl->cmd << 1) | 2 | EA; /* command */ - memcpy(msg->data + 1, ctrl->data, ctrl->len); + msg->data[0] = (ctrl->cmd << 1) | CR | EA; /* command */ + msg->data[1] = (ctrl->len << 1) | EA; + memcpy(msg->data + 2, ctrl->data, ctrl->len); gsm_data_queue(gsm->dlci[0], msg); } @@ -2860,19 +2861,17 @@ static struct tty_ldisc_ops tty_ldisc_pa static int gsmtty_modem_update(struct gsm_dlci *dlci, u8 brk) { - u8 modembits[5]; + u8 modembits[3]; struct gsm_control *ctrl; int len = 2; - if (brk) + modembits[0] = (dlci->addr << 2) | 2 | EA; /* DLCI, Valid, EA */ + modembits[1] = (gsm_encode_modem(dlci) << 1) | EA; + if (brk) { + modembits[2] = (brk << 4) | 2 | EA; /* Length, Break, EA */ len++; - - modembits[0] = len << 1 | EA; /* Data bytes */ - modembits[1] = dlci->addr << 2 | 3; /* DLCI, EA, 1 */ - modembits[2] = gsm_encode_modem(dlci) << 1 | EA; - if (brk) - modembits[3] = brk << 4 | 2 | EA; /* Valid, EA */ - ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len + 1); + } + ctrl = gsm_control_send(dlci->gsm, CMD_MSC, modembits, len); if (ctrl == NULL) return -ENOMEM; return gsm_control_wait(dlci->gsm, ctrl);