From patchwork Tue May 2 14:57:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ruihan Li X-Patchwork-Id: 13229023 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4833FC77B73 for ; Tue, 2 May 2023 14:58:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234518AbjEBO6C (ORCPT ); Tue, 2 May 2023 10:58:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233981AbjEBO6B (ORCPT ); Tue, 2 May 2023 10:58:01 -0400 Received: from pku.edu.cn (mx18.pku.edu.cn [162.105.129.181]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6C4FD26BF for ; Tue, 2 May 2023 07:57:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pku.edu.cn; s=dkim; h=Received:From:To:Cc:Subject:Date: Message-Id:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=avNJ51aScZutbdGQ55v1LNc39r1/FL5jKi j8SkDff7k=; b=qceQn9oUNhzP03vjImu4OMXOYNPqf6B8DKaqOKZLqXu+T390eb 07oyCTclMcQ4a617IxSEGo8rwqO3qGUcIpNnnjQ1caW9JQF5xhLtSLKrNz0Xsf8i +8PNWVGwYsbjgttGffkx82PN2CcIEHtz/+cbCdckVcJqs4Gr5FDWIbuK8= Received: from localhost.localdomain (unknown [10.7.101.92]) by front01 (Coremail) with SMTP id 5oFpogBXX5fjJFFk6i5LAQ--.10226S4; Tue, 02 May 2023 22:57:47 +0800 (CST) From: Ruihan Li To: linux-bluetooth@vger.kernel.org Cc: Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , Ruihan Li Subject: [PATCH v3 2/6] Bluetooth: Refcnt drop must be placed last in hci_conn_unlink Date: Tue, 2 May 2023 22:57:33 +0800 Message-Id: <20230502145737.140856-3-lrh2000@pku.edu.cn> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230502145737.140856-1-lrh2000@pku.edu.cn> References: <20230502145737.140856-1-lrh2000@pku.edu.cn> MIME-Version: 1.0 X-CM-TRANSID: 5oFpogBXX5fjJFFk6i5LAQ--.10226S4 X-Coremail-Antispam: 1UD129KBjvJXoW7Cr4fKr1ftrW5WFWUGF15urg_yoW8GFW8pa y5uay3AFWkJrn0vF1qy3WkWrykCF1kZFy29r1rAryrJa1rtr4jyr4rCF1UKw15ZrWkGF1f ZF4vqwn5KFWDGFDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9j1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2 z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2vYz4IE04k24V AvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xf McIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7 v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkIecxEwVCm -wCF04k20xvY0x0EwIxGrwCF04k20xvE74AGY7Cv6cx26w4UJr1UMxC20s026xCaFVCjc4 AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE 17CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMI IF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4l IxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvf C2KfnxnUUI43ZEXa7VU1c4S5UUUUU== X-CM-SenderInfo: yssqiiarrvmko6sn3hxhgxhubq/1tbiAgETBVPy77xtrgAAsk Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org If hci_conn_put(conn->parent) reduces conn->parent's reference count to zero, it can immediately deallocate conn->parent. At the same time, conn->link->list has its head in conn->parent, causing use-after-free problems in the latter list_del_rcu(&conn->link->list). This problem can be easily solved by reordering the two operations, i.e., first performing the list removal with list_del_rcu and then decreasing the refcnt with hci_conn_put. Reported-by: Luiz Augusto von Dentz Closes: https://lore.kernel.org/linux-bluetooth/CABBYNZ+1kce8_RJrLNOXd_8=Mdpb=2bx4Nto-hFORk=qiOkoCg@mail.gmail.com/ Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon") Signed-off-by: Ruihan Li --- net/bluetooth/hci_conn.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 70e1655a9..44d0643fc 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1102,12 +1102,12 @@ static void hci_conn_unlink(struct hci_conn *conn) if (!conn->link) return; - hci_conn_put(conn->parent); - conn->parent = NULL; - list_del_rcu(&conn->link->list); synchronize_rcu(); + hci_conn_put(conn->parent); + conn->parent = NULL; + kfree(conn->link); conn->link = NULL; }