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 X-Spam-Level: X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 382B8C433DB for ; Tue, 23 Mar 2021 12:58:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF0D260C3E for ; Tue, 23 Mar 2021 12:58:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231260AbhCWM5s (ORCPT ); Tue, 23 Mar 2021 08:57:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:41446 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231475AbhCWM52 (ORCPT ); Tue, 23 Mar 2021 08:57:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 79F01619B9; Tue, 23 Mar 2021 12:57:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616504247; bh=KFyvKHQFlrz0ttTR9uhddPSigUqRv7aIt+l1vkmpXBk=; h=From:To:Cc:Subject:Date:From; b=KzngoMGoICqflWzvgtnmxdzBD0Ik6qmeV1Q45PSqrJA6jkO921Zxc7XC6RmKlaiN3 TuPEyhyZeFH6pAyRnaJF2z4lK/rxYrtvCX5+OvSipM7Vz8n8LpbLC9mxsz0V/GZCnp j+Mc+g2p5CJnnC7/cePlpS3ocrOwuPWpwty3rKbi0vMkfldKx0D7ebgLB4HVe5dFWO 4MW4Oy2odfU4BX7f4qM05/ENEJ2HKODbPaY8VJ5VhcTbq+zv7uFALV3I09Dj4rlCMm 8yUdJt3zfdUuCHjvShh1F5v+wHjuo4Wjo38tpSvIRMvjWgcHTXQk0pHWjmk2bG19Xb +OCkh9F580gtQ== From: Arnd Bergmann To: Kalle Valo , "David S. Miller" , Jakub Kicinski , Luciano Coelho , Arik Nemtsov Cc: Arnd Bergmann , Lee Jones , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next] wlcore: fix overlapping snprintf arguments in debugfs Date: Tue, 23 Mar 2021 13:57:14 +0100 Message-Id: <20210323125723.1961432-1-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org From: Arnd Bergmann gcc complains about undefined behavior in calling snprintf() with the same buffer as input and output: drivers/net/wireless/ti/wl18xx/debugfs.c: In function 'diversity_num_of_packets_per_ant_read': drivers/net/wireless/ti/wl18xx/../wlcore/debugfs.h:86:3: error: 'snprintf' argument 4 overlaps destination object 'buf' [-Werror=restrict] 86 | snprintf(buf, sizeof(buf), "%s[%d] = %d\n", \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 87 | buf, i, stats->sub.name[i]); \ | ~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/wireless/ti/wl18xx/debugfs.c:24:2: note: in expansion of macro 'DEBUGFS_FWSTATS_FILE_ARRAY' 24 | DEBUGFS_FWSTATS_FILE_ARRAY(a, b, c, wl18xx_acx_statistics) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/wireless/ti/wl18xx/debugfs.c:159:1: note: in expansion of macro 'WL18XX_DEBUGFS_FWSTATS_FILE_ARRAY' 159 | WL18XX_DEBUGFS_FWSTATS_FILE_ARRAY(diversity, num_of_packets_per_ant, There are probably other ways of handling the debugfs file, without using on-stack buffers, but a simple workaround here is to remember the current position in the buffer and just keep printing in there. Fixes: bcca1bbdd412 ("wlcore: add debugfs macro to help print fw statistics arrays") Signed-off-by: Arnd Bergmann --- drivers/net/wireless/ti/wlcore/boot.c | 13 ++++++++----- drivers/net/wireless/ti/wlcore/debugfs.h | 7 ++++--- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/net/wireless/ti/wlcore/boot.c b/drivers/net/wireless/ti/wlcore/boot.c index e14d88e558f0..85abd0a2d1c9 100644 --- a/drivers/net/wireless/ti/wlcore/boot.c +++ b/drivers/net/wireless/ti/wlcore/boot.c @@ -72,6 +72,7 @@ static int wlcore_validate_fw_ver(struct wl1271 *wl) unsigned int *min_ver = (wl->fw_type == WL12XX_FW_TYPE_MULTI) ? wl->min_mr_fw_ver : wl->min_sr_fw_ver; char min_fw_str[32] = ""; + int off = 0; int i; /* the chip must be exactly equal */ @@ -105,13 +106,15 @@ static int wlcore_validate_fw_ver(struct wl1271 *wl) return 0; fail: - for (i = 0; i < NUM_FW_VER; i++) + for (i = 0; i < NUM_FW_VER && off < sizeof(min_fw_str); i++) if (min_ver[i] == WLCORE_FW_VER_IGNORE) - snprintf(min_fw_str, sizeof(min_fw_str), - "%s*.", min_fw_str); + off += snprintf(min_fw_str + off, + sizeof(min_fw_str) - off, + "*."); else - snprintf(min_fw_str, sizeof(min_fw_str), - "%s%u.", min_fw_str, min_ver[i]); + off += snprintf(min_fw_str + off, + sizeof(min_fw_str) - off, + "%u.", min_ver[i]); wl1271_error("Your WiFi FW version (%u.%u.%u.%u.%u) is invalid.\n" "Please use at least FW %s\n" diff --git a/drivers/net/wireless/ti/wlcore/debugfs.h b/drivers/net/wireless/ti/wlcore/debugfs.h index b143293e694f..715edfa5f89f 100644 --- a/drivers/net/wireless/ti/wlcore/debugfs.h +++ b/drivers/net/wireless/ti/wlcore/debugfs.h @@ -78,13 +78,14 @@ static ssize_t sub## _ ##name## _read(struct file *file, \ struct wl1271 *wl = file->private_data; \ struct struct_type *stats = wl->stats.fw_stats; \ char buf[DEBUGFS_FORMAT_BUFFER_SIZE] = ""; \ + int pos = 0; \ int i; \ \ wl1271_debugfs_update_stats(wl); \ \ - for (i = 0; i < len; i++) \ - snprintf(buf, sizeof(buf), "%s[%d] = %d\n", \ - buf, i, stats->sub.name[i]); \ + for (i = 0; i < len && pos < sizeof(buf); i++) \ + pos += snprintf(buf + pos, sizeof(buf), \ + "[%d] = %d\n", i, stats->sub.name[i]); \ \ return wl1271_format_buffer(userbuf, count, ppos, "%s", buf); \ } \ -- 2.29.2