From patchwork Tue May 2 14:57:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ruihan Li X-Patchwork-Id: 13229025 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 3B051C7EE23 for ; Tue, 2 May 2023 14:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234528AbjEBO6E (ORCPT ); Tue, 2 May 2023 10:58:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234138AbjEBO6B (ORCPT ); Tue, 2 May 2023 10:58:01 -0400 Received: from pku.edu.cn (mx19.pku.edu.cn [162.105.129.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CDC582733 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=+23j70KJbA3hTfSGNHgn4j0Bbr5o3LtuB5 dNkDC+QWE=; b=RHMoB8tpZc7+Vwm4SpuMtjw9OraKJpBFCJDuNlDCNttPZ11stM 7bU6oyo97473y0TvMD5rVp0i1lmPb9gitcKwlWCuggHvSbAS9lpf6qvx7Bjzl47H Kihkoe9PCZAhF9f20hG2qZLqPaGzHWnUdLuoc0b6mF+kBOzwc38oqNz/k= Received: from localhost.localdomain (unknown [10.7.101.92]) by front01 (Coremail) with SMTP id 5oFpogBXX5fjJFFk6i5LAQ--.10226S3; 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 , syzbot+690b90b14f14f43f4688@syzkaller.appspotmail.com Subject: [PATCH v3 1/6] Bluetooth: Fix potential double free caused by hci_conn_unlink Date: Tue, 2 May 2023 22:57:32 +0800 Message-Id: <20230502145737.140856-2-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--.10226S3 X-Coremail-Antispam: 1UD129KBjvJXoWxJrWkCrWrXrW8JryrKr1xXwb_yoW8ur45pa y3WayfurWktrnavF4jyw48WFs0vw1kZFy3Krn5tryrXws0vr48Ar40kryjqrZ8ZrZ5WF4Y vF4Utr18KF4UG37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvE1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1l84ACjcxK6I8E 87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1lnxkEFVAIw20F6c xK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2Wl Yx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbV WUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc2xSY4AK6svP MxAIw28IcxkI7VAKI48JMxAIw28IcVCjz48v1sIEY20_Kr1UJr1l4I8I3I0E4IkC6x0Yz7 v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF 1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIx AIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI 42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWI evJa73UjIFyTuYvjfUFYFADUUUU X-CM-SenderInfo: yssqiiarrvmko6sn3hxhgxhubq/1tbiAgETBVPy77xtrwAAsl Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org The hci_conn_unlink function is being called by hci_conn_del, which means it should not call hci_conn_del with the input parameter conn again. If it does, conn may have already been released when hci_conn_unlink returns, leading to potential UAF and double-free issues. This patch resolves the problem by modifying hci_conn_unlink to release only conn's child links when necessary, but never release conn itself. Reported-by: syzbot+690b90b14f14f43f4688@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-bluetooth/000000000000484a8205faafe216@google.com/ Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon") Signed-off-by: Ruihan Li Reported-by: syzbot+690b90b14f14f43f4688@syzkaller.appspotmail.com Reported-by: Luiz Augusto von Dentz Reported-by: syzbot+8bb72f86fc823817bc5d@syzkaller.appspotmail.com --- net/bluetooth/hci_conn.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 640b951bf..70e1655a9 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1083,8 +1083,18 @@ static void hci_conn_unlink(struct hci_conn *conn) if (!conn->parent) { struct hci_link *link, *t; - list_for_each_entry_safe(link, t, &conn->link_list, list) - hci_conn_unlink(link->conn); + list_for_each_entry_safe(link, t, &conn->link_list, list) { + struct hci_conn *child = link->conn; + + hci_conn_unlink(child); + + /* Due to race, SCO connection might be not established + * yet at this point. Delete it now, otherwise it is + * possible for it to be stuck and can't be deleted. + */ + if (child->handle == HCI_CONN_HANDLE_UNSET) + hci_conn_del(child); + } return; } @@ -1100,13 +1110,6 @@ static void hci_conn_unlink(struct hci_conn *conn) kfree(conn->link); conn->link = NULL; - - /* Due to race, SCO connection might be not established - * yet at this point. Delete it now, otherwise it is - * possible for it to be stuck and can't be deleted. - */ - if (conn->handle == HCI_CONN_HANDLE_UNSET) - hci_conn_del(conn); } int hci_conn_del(struct hci_conn *conn)