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=-14.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,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 C6071C2D0DB for ; Thu, 30 Jan 2020 22:17:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 95C672082E for ; Thu, 30 Jan 2020 22:17:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="g2xzrJoi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726294AbgA3WRF (ORCPT ); Thu, 30 Jan 2020 17:17:05 -0500 Received: from mail-oi1-f196.google.com ([209.85.167.196]:36414 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725855AbgA3WRF (ORCPT ); Thu, 30 Jan 2020 17:17:05 -0500 Received: by mail-oi1-f196.google.com with SMTP id c16so5288492oic.3 for ; Thu, 30 Jan 2020 14:17:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=o2uSlVLV9EbkO/HgivpguZY4Kg4CkB9MRxWN1lA/tSo=; b=g2xzrJoiSyHK3RD1gjqQgclQjUD5x/CkTeGTcObgoSVH46AFK6QpO4L2P1m93arDHZ FsYylJpQG7lsjfmCm+9NP5oS04RiBhPL88J17dU3Wtr4ZgF2lgPJcPqW8dvLYXwKqNGc 0eFSnAsaowjYWGXFfyVJYKj2YLpd7+df/H5fIRaRypwM7+zV/WgROF4TJZbpfxWZatf+ V2R02x8W/qMw63GtIt08m/6CQS0HwpPZp3+hUIDWe+U4lWvrfXLbNgXu+nFBzHdvPCfv IBu7RZGWsWoqxwBEZzkofjuYUg6qRrmOMd6RVZLvQ8rYtWVjl0ZdTX5QXxiMJDqGCzBl 21Ng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=o2uSlVLV9EbkO/HgivpguZY4Kg4CkB9MRxWN1lA/tSo=; b=QAcRX6ZU11nv74AJdaw7H69CosixcRth+YDBmQL0CNXjw8Fngs1i3l8YROZCKt8/Nf EdVawqACy8nrexp/RZ+FKuxqga1GrIGf+Eb6d4U8uwZwRd+Dj8PAckW7bnOHIyPxVfSu /EsMbZjLWEPoI4TfGUEepnR/sGPzN7dajDfdjdpeyqr5uXWJ+gEbX7+Fu0Y7Ias3bZzH mTkISGw8QH/DTVpgZEbQw/BfdjU8br7J3+k36tw3Mc9vmQBg041U6tby8AxmHQnWQ+FP pTxcpN8VbvMmVLax8B+53uNFvVmzAcMnAczamRz6HAlW1U3C4tBYHhvwuh/VBf8IUTob DB5Q== X-Gm-Message-State: APjAAAUvlMsoIYPK/IGy1/63U0bQkLrCbIkwF5SuAnRNe3puRi8nuIGL tc9IdzYYrfJj0y5cFu+CuYk= X-Google-Smtp-Source: APXvYqwxny4qGVIVs/8QP5N1gLK6yQfp5csX1BKsnf5xKAC1tLv2sib+WbZeZCDhVVx/ww0aMP+JeA== X-Received: by 2002:aca:cf12:: with SMTP id f18mr4392210oig.81.1580422623045; Thu, 30 Jan 2020 14:17:03 -0800 (PST) Received: from localhost.localdomain ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id n7sm2063157oij.14.2020.01.30.14.17.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jan 2020 14:17:02 -0800 (PST) From: Nathan Chancellor To: Petr Mladek , Sergey Senozhatsky Cc: Steven Rostedt , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nathan Chancellor Subject: [PATCH] printk: Convert a use of sprintf to snprintf in console_unlock Date: Thu, 30 Jan 2020 15:16:44 -0700 Message-Id: <20200130221644.2273-1-natechancellor@gmail.com> X-Mailer: git-send-email 2.25.0 MIME-Version: 1.0 X-Patchwork-Bot: notify Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When CONFIG_PRINTK is disabled (e.g. when building allnoconfig), clang warns: ../kernel/printk/printk.c:2416:10: warning: 'sprintf' will always overflow; destination buffer has size 0, but format string expands to at least 33 [-Wfortify-source] len = sprintf(text, ^ 1 warning generated. It is not wrong; text has a zero size when CONFIG_PRINTK is disabled because LOG_LINE_MAX and PREFIX_MAX are both zero. Change to snprintf so that this case is explicitly handled without any risk of overflow. Link: https://github.com/ClangBuiltLinux/linux/issues/846 Link: https://github.com/llvm/llvm-project/commit/6d485ff455ea2b37fef9e06e426dae6c1241b231 Link: https://lore.kernel.org/lkml/20200130051711.GF115889@google.com/ Suggested-by: Sergey Senozhatsky Signed-off-by: Nathan Chancellor --- kernel/printk/printk.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index fada22dc4ab6..a44094727a5c 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2413,9 +2413,9 @@ void console_unlock(void) printk_safe_enter_irqsave(flags); raw_spin_lock(&logbuf_lock); if (console_seq < log_first_seq) { - len = sprintf(text, - "** %llu printk messages dropped **\n", - log_first_seq - console_seq); + len = snprintf(text, sizeof(text), + "** %llu printk messages dropped **\n", + log_first_seq - console_seq); /* messages are gone, move to first one */ console_seq = log_first_seq; -- 2.25.0