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 DB6EAC83013 for ; Wed, 2 Dec 2020 09:23:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A617B22203 for ; Wed, 2 Dec 2020 09:23:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388087AbgLBJX0 (ORCPT ); Wed, 2 Dec 2020 04:23:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387839AbgLBJXY (ORCPT ); Wed, 2 Dec 2020 04:23:24 -0500 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F74EC0617A7; Wed, 2 Dec 2020 01:22:44 -0800 (PST) Received: by mail-wr1-x441.google.com with SMTP id e7so2702316wrv.6; Wed, 02 Dec 2020 01:22:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=oUt//bTkwsRrgK4y9pyKInt9C1fdhCh6LTSbXfNlTqo=; b=ufG4i0y3zJrlALGylJn7ES1745xVG946OmhVcwAMLhGlH2sFi++rx+cAO0KrqhYLX+ fiipOTBSi4LPOoGmW8xO2gPFzBBEMBeNHTTpn/zQFeSt8VmV4WPGfxHXpuupTEV8hqUy Aac3nrQ9T1HZZU4fusSV7gsuOLm+d7l2pX4z1GvgIkGbQzfdHMdlVSMU404yy+3ALsDQ cl5Si24dSS8h5/ufvUe2MxMvMwhHGKHHgVXkTXLYi0fw0YGm2nIGfEcPy5ov2PoZ2P1P 2EnIPXpLF6XTj+uLaCj8XU50dmEphacaICxHWuvDZ0/NsF3sixHeYauufSYE3X6BctOa jbJw== 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=oUt//bTkwsRrgK4y9pyKInt9C1fdhCh6LTSbXfNlTqo=; b=BHtmohwDMi4mp4tVL86omrfnAq38yTdKDyUPINMsvGFDVY2UZT+zRUarVJAlo9hYQk 8p2EuugUlij2UEq3XoElwcPhTNk9ZkOUhQt68YC6SoW0LH7J/F/WQtiBJ1tRCPT+jt9i ZNizJum1gEfSQ9HoM/792AbNks1J8wNuPdxllV7HCbbIlI9/iKVFbyClD8oJnqgeakig w0ZZDdXk/UkBq/0aIMpAWqESm4Ol/70v6E1LyFyndd3Ld7h4J37NFSuo1jnzjnPgueHz RDny+j3fKOS09fp+qzlQg1PyvdqhK64hLs0dSdBhHXUvBQY2+iyM//6J4g4BOZ2Io6TB SAOA== X-Gm-Message-State: AOAM530Fm5DDDpmcn0kGPc6wirXd0rUD2VofovLaoYWTO/v2ZmdPAvHM z+N5eRidiegL12E38cuNt9XvO21BT729Qg== X-Google-Smtp-Source: ABdhPJxHt2HeKkB4ghXjj9Q/31vYIkMuwZ5FrOKmLC8kooPrqKs12C2X1f3fjmDMuNZCaq65uT5GYA== X-Received: by 2002:adf:94c3:: with SMTP id 61mr2174397wrr.143.1606900962378; Wed, 02 Dec 2020 01:22:42 -0800 (PST) Received: from andrea.corp.microsoft.com (host-95-239-64-30.retail.telecomitalia.it. [95.239.64.30]) by smtp.gmail.com with ESMTPSA id e27sm1535936wrc.9.2020.12.02.01.22.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Dec 2020 01:22:42 -0800 (PST) From: "Andrea Parri (Microsoft)" To: linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org Cc: "K . Y . Srinivasan" , Haiyang Zhang , Stephen Hemminger , Wei Liu , Michael Kelley , Juan Vazquez , Saruhan Karademir , "Andrea Parri (Microsoft)" Subject: [PATCH v2 3/7] Drivers: hv: vmbus: Avoid double fetch of payload_size in vmbus_on_msg_dpc() Date: Wed, 2 Dec 2020 10:22:10 +0100 Message-Id: <20201202092214.13520-4-parri.andrea@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201202092214.13520-1-parri.andrea@gmail.com> References: <20201202092214.13520-1-parri.andrea@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vmbus_on_msg_dpc() double fetches from payload_size. The double fetch can lead to a buffer overflow when (mem)copying the hv_message object. Avoid the double fetch by saving the value of payload_size into a local variable. Reported-by: Juan Vazquez Signed-off-by: Andrea Parri (Microsoft) --- drivers/hv/vmbus_drv.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 82b23baa446d7..0e39f1d6182e9 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1056,6 +1056,7 @@ void vmbus_on_msg_dpc(unsigned long data) void *page_addr = hv_cpu->synic_message_page; struct hv_message *msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT; + __u8 payload_size = msg->header.payload_size; struct vmbus_channel_message_header *hdr; enum vmbus_channel_message_type msgtype; const struct vmbus_channel_message_table_entry *entry; @@ -1089,9 +1090,8 @@ void vmbus_on_msg_dpc(unsigned long data) goto msg_handled; } - if (msg->header.payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) { - WARN_ONCE(1, "payload size is too large (%d)\n", - msg->header.payload_size); + if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) { + WARN_ONCE(1, "payload size is too large (%d)\n", payload_size); goto msg_handled; } @@ -1100,21 +1100,18 @@ void vmbus_on_msg_dpc(unsigned long data) if (!entry->message_handler) goto msg_handled; - if (msg->header.payload_size < entry->min_payload_len) { - WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", - msgtype, msg->header.payload_size); + if (payload_size < entry->min_payload_len) { + WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", msgtype, payload_size); goto msg_handled; } if (entry->handler_type == VMHT_BLOCKING) { - ctx = kmalloc(sizeof(*ctx) + msg->header.payload_size, - GFP_ATOMIC); + ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC); if (ctx == NULL) return; INIT_WORK(&ctx->work, vmbus_onmessage_work); - memcpy(&ctx->msg, msg, sizeof(msg->header) + - msg->header.payload_size); + memcpy(&ctx->msg, msg, sizeof(msg->header) + payload_size); /* * The host can generate a rescind message while we -- 2.25.1