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,USER_AGENT_GIT autolearn=unavailable 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 5372AC433EF for ; Fri, 3 Sep 2021 03:23:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A57961056 for ; Fri, 3 Sep 2021 03:23:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346799AbhICDYh (ORCPT ); Thu, 2 Sep 2021 23:24:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242941AbhICDYe (ORCPT ); Thu, 2 Sep 2021 23:24:34 -0400 Received: from mail-qt1-x831.google.com (mail-qt1-x831.google.com [IPv6:2607:f8b0:4864:20::831]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC1F7C061575; Thu, 2 Sep 2021 20:23:34 -0700 (PDT) Received: by mail-qt1-x831.google.com with SMTP id t9so3516264qtp.2; Thu, 02 Sep 2021 20:23:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=5S0yh8cttWmglArpNLxzYf76csSVpKARM1NaNWL0GBs=; b=oQWWZyP30E0aHZRFdGfb1OHZ+nKzijseaPwgwjp1JbgRCSOSdj1BSAU1rqSzgOlKjq aigUrhJT2HD2MGz0rXbO5mJGuWENQrTlo0oHJAPJUaJDa6lUbjCOLPqtRb9HFDUegwEn FaSMShOYR9SATH/MXsvarvLKIN04nXGseLNRzvx9UwbQrE8JCqHGIkz4FTHOfCAL7Urm NVI4/Q7WhUw9aMHympmqEXgC3nSVqKMuSz1mvllwuyrlXp6WdimmyyhfNOMj0fMnphh2 kd+xIlNykz/5b4QR40lP25mbfh48b4h1hT5d4vBm+ldIMw6yRVk9Y0POeVEdPCFlHLsr siTA== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=5S0yh8cttWmglArpNLxzYf76csSVpKARM1NaNWL0GBs=; b=HN4Go3sBJKd6l60xINQfmdM8rVbOiXGfGIB0U0NiMi1nCrvtDTA6EJ6j4gBr9GxpYJ bwruRRh1vp6z3rynlFpFVLWodTQmWBqNqf+O1g6WkVhaWacqrezYunphImiI+A8pf4qS q+2z585EJR6k6/0sp+ZkjnZY+6VIg//lkedesu8ifskZ6FS4sj7NX4Z916iBRzMtnPYm J8KukYBTInBXD1H/B/0JJmaeVip7vR6ryqS6SKm0IOmi2sKTspUM61CV9rntOEz9vHaK WtW5fJw4qrmvwkwg60Cc5p7XytZ+jRqKxAKgW2/b+DdUKIx5a21DCOtLRhjKQBU1h3wo oBnw== X-Gm-Message-State: AOAM531uRZWVZz1ykpmLS1Rs0kwLH9xIuZkCLvlB5BfYPt5gT+Uw0tdO CySCATS4Lc/k+qnyg+GuGxc= X-Google-Smtp-Source: ABdhPJww0+/x/yCK6CPLni/Sb51oAxmWmREIIBENRcEu4cPbM9CxRbAGrPw5jw8a6tqaHfBXwCw3ow== X-Received: by 2002:ac8:4618:: with SMTP id p24mr1789410qtn.205.1630639414168; Thu, 02 Sep 2021 20:23:34 -0700 (PDT) Received: from localhost.localdomain (pool-72-82-21-11.prvdri.fios.verizon.net. [72.82.21.11]) by smtp.gmail.com with ESMTPSA id v5sm2984729qkh.39.2021.09.02.20.23.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Sep 2021 20:23:33 -0700 (PDT) From: Desmond Cheong Zhi Xi To: marcel@holtmann.org, johan.hedberg@gmail.com, luiz.dentz@gmail.com, davem@davemloft.net, kuba@kernel.org Cc: Desmond Cheong Zhi Xi , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, eric.dumazet@gmail.com Subject: [PATCH 1/2] Bluetooth: call sock_hold earlier in sco_conn_del Date: Thu, 2 Sep 2021 23:13:05 -0400 Message-Id: <20210903031306.78292-2-desmondcheongzx@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210903031306.78292-1-desmondcheongzx@gmail.com> References: <20210903031306.78292-1-desmondcheongzx@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In sco_conn_del, conn->sk is read while holding on to the sco_conn.lock to avoid races with a socket that could be released concurrently. However, in between unlocking sco_conn.lock and calling sock_hold, it's possible for the socket to be freed, which would cause a use-after-free write when sock_hold is finally called. To fix this, the reference count of the socket should be increased while the sco_conn.lock is still held. Signed-off-by: Desmond Cheong Zhi Xi --- net/bluetooth/sco.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c index b62c91c627e2..4a057f99b60a 100644 --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -187,10 +187,11 @@ static void sco_conn_del(struct hci_conn *hcon, int err) /* Kill socket */ sco_conn_lock(conn); sk = conn->sk; + if (sk) + sock_hold(sk); sco_conn_unlock(conn); if (sk) { - sock_hold(sk); lock_sock(sk); sco_sock_clear_timer(sk); sco_chan_del(sk, err); -- 2.25.1