From patchwork Thu Apr 14 09:42:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Starke" X-Patchwork-Id: 561409 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 C47B4C433FE for ; Thu, 14 Apr 2022 09:44:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239482AbiDNJqZ (ORCPT ); Thu, 14 Apr 2022 05:46:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241917AbiDNJqT (ORCPT ); Thu, 14 Apr 2022 05:46:19 -0400 X-Greylist: delayed 60 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 14 Apr 2022 02:43:54 PDT Received: from mta-64-225.siemens.flowmailer.net (mta-64-225.siemens.flowmailer.net [185.136.64.225]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF8976EB29 for ; Thu, 14 Apr 2022 02:43:54 -0700 (PDT) Received: by mta-64-225.siemens.flowmailer.net with ESMTPSA id 2022041409424729e8b058f02a169858 for ; Thu, 14 Apr 2022 11:42:52 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=fm1; d=siemens.com; i=daniel.starke@siemens.com; h=Date:From:Subject:To:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:Cc:References:In-Reply-To; bh=wiF23XObNbK0UPCKxihGtA9aFYAmV/dIBUR0MDgOqIs=; b=GrKeR/n/sbvCoxbddvGvy3y6V4S0/lRGJEyrSW9xatcp7KFXlbvYJ8EuLIzZUWqeoqKA6Q 6GIkCD1Y2PLMBefrImjhGlqrdioLJOHWcpG/m6DHMwmFsABXUnWBGQ2+RzPnMOxXa3A/3E5n XV4yvkOOyGmLpudAKIThBdO/JvD84=; From: "D. Starke" To: linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org Cc: linux-kernel@vger.kernel.org, Daniel Starke Subject: [PATCH 11/20] tty: n_gsm: fix wrong command retry handling Date: Thu, 14 Apr 2022 02:42:16 -0700 Message-Id: <20220414094225.4527-11-daniel.starke@siemens.com> In-Reply-To: <20220414094225.4527-1-daniel.starke@siemens.com> References: <20220414094225.4527-1-daniel.starke@siemens.com> MIME-Version: 1.0 X-Flowmailer-Platform: Siemens Feedback-ID: 519:519-314044:519-21489:flowmailer Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org From: Daniel Starke 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 --- drivers/tty/n_gsm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 1430d7f83bd2..628bda5f0622 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -1354,7 +1354,6 @@ static void gsm_control_retransmit(struct timer_list *t) 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; @@ -1363,6 +1362,7 @@ static void gsm_control_retransmit(struct timer_list *t) wake_up(&gsm->event); return; } + gsm->cretries--; gsm_control_transmit(gsm, ctrl); mod_timer(&gsm->t2_timer, jiffies + gsm->t2 * HZ / 100); } @@ -1403,7 +1403,7 @@ static struct gsm_control *gsm_control_send(struct gsm_mux *gsm, /* 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; @@ -2343,7 +2343,7 @@ static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) /* 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;