From patchwork Wed May 4 16:45:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 569688 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 75E93C43217 for ; Wed, 4 May 2022 17:10:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356335AbiEDRNo (ORCPT ); Wed, 4 May 2022 13:13:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356613AbiEDRJf (ORCPT ); Wed, 4 May 2022 13:09:35 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D821E26FC; Wed, 4 May 2022 09:55:14 -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 B8FF461899; Wed, 4 May 2022 16:55:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FB20C385A4; Wed, 4 May 2022 16:55:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651683314; bh=mBt5odG1NpN2Xxc1qTN/8ZCV/ARaiXb8egGhXjljbvQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RElK8c5vOi73NJy9DDZr5Gi7+IkfUtn1GVrQweyklIZZMfPzm3ujNhzUB64Z3LV7N kYA6tws0XDoc2eX3P31e2GVaU/WklBYGiPlDBk/72akLODDQtr7Ldg5x/X+JmsMvf6 xgcGYFFp3CrA6ogjoxDvi4oEwF1O6jGZvfXOU6t8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Starke Subject: [PATCH 5.15 166/177] tty: n_gsm: fix wrong command retry handling Date: Wed, 4 May 2022 18:45:59 +0200 Message-Id: <20220504153108.382459489@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220504153053.873100034@linuxfoundation.org> References: <20220504153053.873100034@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Daniel Starke commit d0bcdffcad5a22f202e3bf37190c0dd8c080ea92 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 5.7.3 states that the valid range for the maximum number of retransmissions (N2) is from 0 to 255 (both including). gsm_config() fails to limit this range correctly. Furthermore, gsm_control_retransmit() handles this number incorrectly by performing N2 - 1 retransmission attempts. Setting N2 to zero results in more than 255 retransmission attempts. Fix the range check in gsm_config() and the value handling in gsm_control_send() and gsm_control_retransmit() to comply with 3GPP 27.010. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20220414094225.4527-11-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1329,7 +1329,6 @@ static void gsm_control_retransmit(struc spin_lock_irqsave(&gsm->control_lock, flags); ctrl = gsm->pending_cmd; if (ctrl) { - gsm->cretries--; if (gsm->cretries == 0) { gsm->pending_cmd = NULL; ctrl->error = -ETIMEDOUT; @@ -1338,6 +1337,7 @@ static void gsm_control_retransmit(struc wake_up(&gsm->event); return; } + gsm->cretries--; gsm_control_transmit(gsm, ctrl); mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); } @@ -1378,7 +1378,7 @@ retry: /* If DLCI0 is in ADM mode skip retries, it won't respond */ if (gsm->dlci[0]->mode == DLCI_MODE_ADM) - gsm->cretries = 1; + gsm->cretries = 0; else gsm->cretries = gsm->n2; @@ -2278,7 +2278,7 @@ static int gsm_config(struct gsm_mux *gs /* Check the MRU/MTU range looks sane */ if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) return -EINVAL; - if (c->n2 < 3) + if (c->n2 > 255) return -EINVAL; if (c->encapsulation > 1) /* Basic, advanced, no I */ return -EINVAL;