From patchwork Fri Nov 18 20:01:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sungwoo Kim X-Patchwork-Id: 13048756 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 58CDEC4332F for ; Fri, 18 Nov 2022 20:04:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231223AbiKRUEJ (ORCPT ); Fri, 18 Nov 2022 15:04:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44198 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230322AbiKRUEH (ORCPT ); Fri, 18 Nov 2022 15:04:07 -0500 Received: from mail-io1-f46.google.com (mail-io1-f46.google.com [209.85.166.46]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45549DC6; Fri, 18 Nov 2022 12:04:05 -0800 (PST) Received: by mail-io1-f46.google.com with SMTP id b2so4604536iof.12; Fri, 18 Nov 2022 12:04:05 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=AhdkGygTY3zoLbGAB/+Raeg5fzHG6ZjkIK/WhyIG7oM=; b=qMQUo+5n/Qgrw6orGT5BagNpQES5PYD3ObMq9VBTMugxag5GNnzhDRJJHpaCPgQd3O OWnjrI7GsMeHJ6LG5II/Lg0l1gIgWPP2MUOZsqygOL7XhyYc+NeTcBu/u1WOnOZdevvR IvkN121o63/tvk2nf45xa6T/z3gSPY6aPBHeG91GpGz2rdfXc5VG6g7kl7DGzHrHnOt2 hHOt2y6tWMk8T25uXiQtT4A1CtpiOLW2hoNTStO2+L7UaHqFbnj6/FBdIJhRyMI3ATX+ 4GWqx40BXAf37tN6c5ZZy1fbka3Q8jtyRIoiI97lhHomuCMtm7ajJiVilT5VvoIzOZS5 51FQ== X-Gm-Message-State: ANoB5pkTcmOXXfnzVq2qiZKgtbh2rK/4tmzOXoVW8rshgaZ3YC4DVUZB 9EYjoyEiHm3RJ8CdvbI0Lh8= X-Google-Smtp-Source: AA0mqf5Br29FRXK/1NcL4h/veA3rOteAy8JC0XUr5l+LfnOm1RRMi55jyOIwQU0JwxDIIpRa32SFaA== X-Received: by 2002:a6b:8d09:0:b0:68b:7b1f:92b9 with SMTP id p9-20020a6b8d09000000b0068b7b1f92b9mr4167072iod.163.1668801844397; Fri, 18 Nov 2022 12:04:04 -0800 (PST) Received: from noodle.cs.purdue.edu (switch-lwsn2133-z1r11.cs.purdue.edu. [128.10.127.250]) by smtp.googlemail.com with ESMTPSA id i13-20020a02b68d000000b003638d00b759sm1517966jam.54.2022.11.18.12.04.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Nov 2022 12:04:03 -0800 (PST) From: Sungwoo Kim Cc: Sungwoo Kim , Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] Bluetooth: L2CAP: Fix u8 overflow Date: Fri, 18 Nov 2022 15:01:47 -0500 Message-Id: <20221118200145.1741199-1-iam@sung-woo.kim> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org By keep sending L2CAP_CONF_REQ packets, chan->num_conf_rsp increases multiple times and eventually it will wrap around the maximum number (i.e., 255). This patch prevents this by adding a boundary check with L2CAP_MAX_CONF_RSP Btmon log: Bluetooth monitor ver 5.64 = Note: Linux version 6.1.0-rc2 (x86_64) 0.264594 = Note: Bluetooth subsystem version 2.22 0.264636 @ MGMT Open: btmon (privileged) version 1.22 {0x0001} 0.272191 = New Index: 00:00:00:00:00:00 (Primary,Virtual,hci0) [hci0] 13.877604 @ RAW Open: 9496 (privileged) version 2.22 {0x0002} 13.890741 = Open Index: 00:00:00:00:00:00 [hci0] 13.900426 (...) > ACL Data RX: Handle 200 flags 0x00 dlen 1033 #32 [hci0] 14.273106 invalid packet size (12 != 1033) 08 00 01 00 02 01 04 00 01 10 ff ff ............ > ACL Data RX: Handle 200 flags 0x00 dlen 1547 #33 [hci0] 14.273561 invalid packet size (14 != 1547) 0a 00 01 00 04 01 06 00 40 00 00 00 00 00 ........@..... > ACL Data RX: Handle 200 flags 0x00 dlen 2061 #34 [hci0] 14.274390 invalid packet size (16 != 2061) 0c 00 01 00 04 01 08 00 40 00 00 00 00 00 00 04 ........@....... > ACL Data RX: Handle 200 flags 0x00 dlen 2061 #35 [hci0] 14.274932 invalid packet size (16 != 2061) 0c 00 01 00 04 01 08 00 40 00 00 00 07 00 03 00 ........@....... = bluetoothd: Bluetooth daemon 5.43 14.401828 > ACL Data RX: Handle 200 flags 0x00 dlen 1033 #36 [hci0] 14.275753 invalid packet size (12 != 1033) 08 00 01 00 04 01 04 00 40 00 00 00 ........@... Signed-off-by: Sungwoo Kim --- net/bluetooth/l2cap_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 9c24947aa..9fdede5fe 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -4453,7 +4453,8 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, chan->ident = cmd->ident; l2cap_send_cmd(conn, cmd->ident, L2CAP_CONF_RSP, len, rsp); - chan->num_conf_rsp++; + if (chan->num_conf_rsp < L2CAP_CONF_MAX_CONF_RSP) + chan->num_conf_rsp++; /* Reset config buffer. */ chan->conf_len = 0;