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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 16E61C47083 for ; Wed, 2 Jun 2021 03:41:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBBB861008 for ; Wed, 2 Jun 2021 03:41:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229885AbhFBDne (ORCPT ); Tue, 1 Jun 2021 23:43:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229625AbhFBDnc (ORCPT ); Tue, 1 Jun 2021 23:43:32 -0400 Received: from mail-pg1-x52d.google.com (mail-pg1-x52d.google.com [IPv6:2607:f8b0:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 47869C061574 for ; Tue, 1 Jun 2021 20:41:49 -0700 (PDT) Received: by mail-pg1-x52d.google.com with SMTP id 29so1108515pgu.11 for ; Tue, 01 Jun 2021 20:41:49 -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:mime-version :content-transfer-encoding; bh=zLdktgE0a9sEXZ0/b+s3AebnOjlZIpwVaCTKFoWaY6o=; b=PyV8FeSKyEIVaDpLD1OQklsC0+U/xDfysW1/zZXRwfV+KdD6NggGTMgx0BhlkyFcVW SuRX+ExKpACmEe4VXNzThsolvdMl99oWRC4cLxxUJxJlxkG0WEAH1BeLWZGowj3e2+g6 FJO0au3vJfJ7e2KFHuA73+gMVKDUzYq2QluuHh17e5HzHEMzFAru7FLzovFHeQfaJo9T vCQqxmaUsbR50lSrCAYy3QdXiuzV+sGsjOpaavnZMj/xQtrfLs+PJJ7/WqjISF4F35zF N2NNaZShZivIOJpEWbo8EQErq/+YBkkSsgADbfH0ePpBC4RyEdspM4G+RqHvPec+CQgF o7zA== 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=zLdktgE0a9sEXZ0/b+s3AebnOjlZIpwVaCTKFoWaY6o=; b=j6oYIJIADqS9dtYLJABEPR5ffyeydZvweOJNeICanp0gIt1pkNpGhwYv+5U1VMljD+ dE44pIlQtRnvRqEXvZ3ttvebyLxz2Hkbz/t+MOk7pa6AroV9cPArr9EjHLkwsH6XO9Eg 0K1BvzLuvjy/Hu+dVKIXwliNcDA4JztmhLH23ckUYhqY4qTwVPtBiYkj7ZY/Q4bpC3HQ 1eC4BRWpPuQpS8Qyeg5v45V6VE/NLe8dNUh1+90em92/XT5wshQuknrghMd//TC1zhZi tgPQXCOWvFfW/WBXouKc9fpGeKlWNRHhpukhJIwQyKr23nuvX+/Z/NkdmnyjaylD21L/ r3KA== X-Gm-Message-State: AOAM532sXdLuz1kzDWDqeCnVFMHTUQrvXskxHC1v5SC/7oxPzvB1VSKw bOsCh6mBR5xEEJydvGdd36A= X-Google-Smtp-Source: ABdhPJzPeLvDeBppfezgwtWuGF9uxgIOTAtzej3GgkpTc/DSKL2YdMFF0UIb8N/mqAv4ufvrNDH0ew== X-Received: by 2002:aa7:80d3:0:b029:28e:f117:4961 with SMTP id a19-20020aa780d30000b029028ef1174961mr25291555pfn.37.1622605308627; Tue, 01 Jun 2021 20:41:48 -0700 (PDT) Received: from localhost.localdomain ([45.135.186.140]) by smtp.gmail.com with ESMTPSA id 141sm10746460pgf.20.2021.06.01.20.41.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Jun 2021 20:41:48 -0700 (PDT) From: Dongliang Mu To: perex@perex.cz, tiwai@suse.com, dan.carpenter@oracle.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Cc: Dongliang Mu , syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com Subject: [PATCH v2] ALSA: control led: fix memory leak in snd_ctl_led_register Date: Wed, 2 Jun 2021 11:41:36 +0800 Message-Id: <20210602034136.2762497-1-mudongliangabcd@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The snd_ctl_led_sysfs_add and snd_ctl_led_sysfs_remove should contain the refcount operations in pair. However, snd_ctl_led_sysfs_remove fails to decrease the refcount to zero, which causes device_release never to be invoked. This leads to memory leak to some resources, like struct device_private. In addition, we also free some other similar memory leaks in snd_ctl_led_init/snd_ctl_led_exit. Fix this by replacing device_del to device_unregister in snd_ctl_led_sysfs_remove/snd_ctl_led_init/snd_ctl_led_exit. Note that, when CONFIG_DEBUG_KOBJECT_RELEASE is enabled, put_device will call kobject_release and delay the release of kobject, which will cause use-after-free when the memory backing the kobject is freed at once. Reported-by: syzbot+08a7d8b51ea048a74ffb@syzkaller.appspotmail.com Fixes: a135dfb5de1 ("ALSA: led control - add sysfs kcontrol LED marking layer") Signed-off-by: Dongliang Mu --- v1->v2: fix other similar memory leaks; move kfree(led_card) to a release function. sound/core/control_led.c | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/sound/core/control_led.c b/sound/core/control_led.c index 25f57c14f294..a90e31dbde61 100644 --- a/sound/core/control_led.c +++ b/sound/core/control_led.c @@ -17,6 +17,9 @@ MODULE_LICENSE("GPL"); #define MAX_LED (((SNDRV_CTL_ELEM_ACCESS_MIC_LED - SNDRV_CTL_ELEM_ACCESS_SPK_LED) \ >> SNDRV_CTL_ELEM_ACCESS_LED_SHIFT) + 1) +#define to_led_card_dev(_dev) \ + container_of(_dev, struct snd_ctl_led_card, dev) + enum snd_ctl_led_mode { MODE_FOLLOW_MUTE = 0, MODE_FOLLOW_ROUTE, @@ -371,6 +374,21 @@ static void snd_ctl_led_disconnect(struct snd_card *card) snd_ctl_led_refresh(); } +static void snd_ctl_led_card_release(struct device *dev) +{ + struct snd_ctl_led_card *led_card = to_led_card_dev(dev); + + kfree(led_card); +} + +static void snd_ctl_led_release(struct device *dev) +{ +} + +static void snd_ctl_led_dev_release(struct device *dev) +{ +} + /* * sysfs */ @@ -663,6 +681,7 @@ static void snd_ctl_led_sysfs_add(struct snd_card *card) led_card->number = card->number; led_card->led = led; device_initialize(&led_card->dev); + led_card->dev.release = snd_ctl_led_card_release; if (dev_set_name(&led_card->dev, "card%d", card->number) < 0) goto cerr; led_card->dev.parent = &led->dev; @@ -681,7 +700,6 @@ static void snd_ctl_led_sysfs_add(struct snd_card *card) put_device(&led_card->dev); cerr2: printk(KERN_ERR "snd_ctl_led: unable to add card%d", card->number); - kfree(led_card); } } @@ -700,8 +718,7 @@ static void snd_ctl_led_sysfs_remove(struct snd_card *card) snprintf(link_name, sizeof(link_name), "led-%s", led->name); sysfs_remove_link(&card->ctl_dev.kobj, link_name); sysfs_remove_link(&led_card->dev.kobj, "card"); - device_del(&led_card->dev); - kfree(led_card); + device_unregister(&led_card->dev); led->cards[card->number] = NULL; } } @@ -723,6 +740,7 @@ static int __init snd_ctl_led_init(void) device_initialize(&snd_ctl_led_dev); snd_ctl_led_dev.class = sound_class; + snd_ctl_led_dev.release = snd_ctl_led_dev_release; dev_set_name(&snd_ctl_led_dev, "ctl-led"); if (device_add(&snd_ctl_led_dev)) { put_device(&snd_ctl_led_dev); @@ -733,15 +751,16 @@ static int __init snd_ctl_led_init(void) INIT_LIST_HEAD(&led->controls); device_initialize(&led->dev); led->dev.parent = &snd_ctl_led_dev; + led->dev.release = snd_ctl_led_release; led->dev.groups = snd_ctl_led_dev_attr_groups; dev_set_name(&led->dev, led->name); if (device_add(&led->dev)) { put_device(&led->dev); for (; group > 0; group--) { led = &snd_ctl_leds[group - 1]; - device_del(&led->dev); + device_unregister(&led->dev); } - device_del(&snd_ctl_led_dev); + device_unregister(&snd_ctl_led_dev); return -ENOMEM; } } @@ -767,9 +786,9 @@ static void __exit snd_ctl_led_exit(void) } for (group = 0; group < MAX_LED; group++) { led = &snd_ctl_leds[group]; - device_del(&led->dev); + device_unregister(&led->dev); } - device_del(&snd_ctl_led_dev); + device_unregister(&snd_ctl_led_dev); snd_ctl_led_clean(NULL); } -- 2.25.1