From patchwork Mon Oct 9 20:31:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 13414405 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 0F58ACD6136 for ; Mon, 9 Oct 2023 20:31:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346683AbjJIUbp (ORCPT ); Mon, 9 Oct 2023 16:31:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346656AbjJIUbp (ORCPT ); Mon, 9 Oct 2023 16:31:45 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10D95BA; Mon, 9 Oct 2023 13:31:44 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BE88C433C8; Mon, 9 Oct 2023 20:31:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696883503; bh=xaK2DMT9p8cdvjJ5eMYdV4mFYDZb/2yZjgUx3PDg2U4=; h=From:To:Cc:Subject:Date:From; b=box2g981w42aOfic7W3fkG/XekqUpb4n8/3IUFQZ/90A46ASXNrLJonm/21Fh7jon YmP6417D/od5m4stjAkk7Ebq/hHf8rcbGDfHRttqYwR8Yo2s1aHAD5JIKZZCh4Aa2y 3345UqrKQW00s0+Qx8nKvt3SxY9K09IJhyOPCM/djK5wfN/YRsBI2g2ue0A0smfvON cCkEZ1whXbkZwxExrFkMqcs2wUcy9XXHp4hSXpMYpZIMjDRNwTYS0luoL7zAUu2ztC jaKOrxpIcyp/8MdawfbgkiD/mWFKKVXHqjvLfkDqzF+wbaz5i3sYOVcn9Fb/xWQg36 XJ384d3P4TIBg== From: Arnd Bergmann To: Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , "Lee, Chun-Yi" Cc: Arnd Bergmann , Kees Cook , Luiz Augusto von Dentz , stable@vger.kernel.org, Iulia Tanasescu , Pauli Virtanen , Jakub Kicinski , Claudia Draghicescu , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] [v2] Bluetooth: avoid memcmp() out of bounds warning Date: Mon, 9 Oct 2023 22:31:31 +0200 Message-Id: <20231009203137.3125516-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org From: Arnd Bergmann bacmp() is a wrapper around memcpy(), which contain compile-time checks for buffer overflow. Since the hci_conn_request_evt() also calls bt_dev_dbg() with an implicit NULL pointer check, the compiler is now aware of a case where 'hdev' is NULL and treats this as meaning that zero bytes are available: In file included from net/bluetooth/hci_event.c:32: In function 'bacmp', inlined from 'hci_conn_request_evt' at net/bluetooth/hci_event.c:3276:7: include/net/bluetooth/bluetooth.h:364:16: error: 'memcmp' specified bound 6 exceeds source size 0 [-Werror=stringop-overread] 364 | return memcmp(ba1, ba2, sizeof(bdaddr_t)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Add another NULL pointer check before the bacmp() to ensure the compiler understands the code flow enough to not warn about it. Since the patch that introduced the warning is marked for stable backports, this one should also go that way to avoid introducing build regressions. Fixes: d70e44fef8621 ("Bluetooth: Reject connection with the device which has same BD_ADDR") Cc: Kees Cook Cc: "Lee, Chun-Yi" Cc: Luiz Augusto von Dentz Cc: Marcel Holtmann Cc: stable@vger.kernel.org Signed-off-by: Arnd Bergmann Reviewed-by: Kees Cook --- v2: rewrite completely --- net/bluetooth/hci_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 6f4409b4c3648..9b34c9f8ee02c 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -3273,7 +3273,7 @@ static void hci_conn_request_evt(struct hci_dev *hdev, void *data, /* Reject incoming connection from device with same BD ADDR against * CVE-2020-26555 */ - if (!bacmp(&hdev->bdaddr, &ev->bdaddr)) { + if (hdev && !bacmp(&hdev->bdaddr, &ev->bdaddr)) { bt_dev_dbg(hdev, "Reject connection with same BD_ADDR %pMR\n", &ev->bdaddr); hci_reject_conn(hdev, &ev->bdaddr);