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=-9.8 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,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 78EAAC7618B for ; Wed, 24 Jul 2019 12:13:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 409A721850 for ; Wed, 24 Jul 2019 12:13:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="s8XDVAag" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728043AbfGXMNg (ORCPT ); Wed, 24 Jul 2019 08:13:36 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:45947 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726578AbfGXMNg (ORCPT ); Wed, 24 Jul 2019 08:13:36 -0400 Received: by mail-pf1-f193.google.com with SMTP id r1so20858195pfq.12 for ; Wed, 24 Jul 2019 05:13:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=yOe9je3y3azuxEkbZtWAgzy/O8tv7xt/7UDFJgcMfj4=; b=s8XDVAagfffx5f9BWX1AzPwmmHmm5GOZ3QuKYZ4yMZ69IcT4jkecK2Bg8Yy/vpcKC+ dthic2I4LPTJcLT4z0STllQckoVS7Fw4OyKGPqxUtz3vexpptdyxut782KbjsCJQco7w BoC8SjYltzNvBjuQjU1TTYTgOy5t/dwdTcMPW/AEvuGJ19zZdBs/ctzvexJ8E49ckblB OQRe/jbhe/tMsiDL5ZirfuNh0b6HqCQvls6OEVnYFFB9N4WT7Rw9hd93wmj3ld1pU6bW 57jEMd9adYRQJ6uVhCrAG07o4wwok59qaNSYx4VnSwbvmdAT3lEzYRTvss0db4JLOrhe QITQ== 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; bh=yOe9je3y3azuxEkbZtWAgzy/O8tv7xt/7UDFJgcMfj4=; b=QFUb6sHJBf3wcIptW4MXDImJiivxlr09/A9395znfWXvGjS24oIVALPLgRTuCjXJMo eCdfR5dfXnCZ9YYGNU4gw8KQkzZwQdwb5K8wkJkAF9DweUxHd5fZ+aM4P6TFQwy9DuhW 79bsVMKO48WwAJy7FmnamdTc7xdH5ZagSyB+RDa5jnhMKEqHyJwcN4AfH6u89gPwzG10 sLs6W1fEAY1XDZrkcEjg8HZ0RsR3FqPMBubL37NvVhwUIDqgXdEzNEBZIY2jqNsy+EkO Ia/G1nb0McVyp+O48OnBQsYX/bt4WLNdZpNv0EK3FEZW+G0fv/FjYm6zPi0oqlF0Lnzp qK3w== X-Gm-Message-State: APjAAAUocgIBY+r+ios634RoiVtJhZgzEABGbfb3nlWtK0v+W+v0WikS ose5N1jVQeH8rBzg+lJwIQ4= X-Google-Smtp-Source: APXvYqwlapnzHOWglZEataQxo8AjBg+B2YemqkqgWG33hfLPCnq47yi/DxSiTBSZj4GhDAGlntYt0g== X-Received: by 2002:a63:1749:: with SMTP id 9mr28651971pgx.0.1563970415766; Wed, 24 Jul 2019 05:13:35 -0700 (PDT) Received: from oslab.tsinghua.edu.cn ([2402:f000:4:72:808::3ca]) by smtp.gmail.com with ESMTPSA id g66sm47009665pfb.44.2019.07.24.05.13.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Jul 2019 05:13:35 -0700 (PDT) From: Jia-Ju Bai To: perex@perex.cz, tiwai@suse.com, bhelgaas@google.com, tglx@linutronix.de, rfontana@redhat.com, gregkh@linuxfoundation.org, kirr@nexedi.com Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] ALSA: core: Fix possible null-pointer dereferences in snd_timer_proc_read() Date: Wed, 24 Jul 2019 20:13:27 +0800 Message-Id: <20190724121327.9894-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In snd_timer_proc_read(), there is an if statement on line 1204 to check whether timer->card is NULL: if (timer->card && timer->card->shutdown) When timer->card is NULL, it is used on lines 1212 and 1215: timer->card->number Thus, possible null-pointer dereferences may occur. To fix these bugs, timer->card is checked before being used. These bugs are found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai --- sound/core/timer.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/sound/core/timer.c b/sound/core/timer.c index 5c9fbf3f4340..967d06a3cdec 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -1208,11 +1208,13 @@ static void snd_timer_proc_read(struct snd_info_entry *entry, snd_iprintf(buffer, "G%i: ", timer->tmr_device); break; case SNDRV_TIMER_CLASS_CARD: - snd_iprintf(buffer, "C%i-%i: ", - timer->card->number, timer->tmr_device); + snd_iprintf(buffer, "C%i-%i: ", + timer->card ? timer->card->number : -1, + timer->tmr_device); break; case SNDRV_TIMER_CLASS_PCM: - snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number, + snd_iprintf(buffer, "P%i-%i-%i: ", + timer->card ? timer->card->number : -1, timer->tmr_device, timer->tmr_subdevice); break; default: -- 2.17.0