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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,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 BACEBC43381 for ; Mon, 25 Feb 2019 21:32:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8470021848 for ; Mon, 25 Feb 2019 21:32:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130370; bh=ngd2hv2C+xOqZ6NIAey0kne+9azHNbd9E8y5BxLShlw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lHJ6ZnQsbw0nn57jUxD0exRf8A4tSkWb2yhGOr3nX4D37/p5WNw211TEpfBWL+w0c OTH4OORhMvVx2vbDN6Q4D6nurJzwO2MoeXxMNpEZe4W4rde0PTaVxdkPdYnoqS6DND YBfpB6TeVLOUHzUtej7FHyKXybYgAYfp0tLQHp/g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732323AbfBYVcs (ORCPT ); Mon, 25 Feb 2019 16:32:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:38490 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732540AbfBYVco (ORCPT ); Mon, 25 Feb 2019 16:32:44 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C692D217F5; Mon, 25 Feb 2019 21:32:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551130363; bh=ngd2hv2C+xOqZ6NIAey0kne+9azHNbd9E8y5BxLShlw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=njUoWzcR1shJ7sZOHSYT0L70zRkfuR8JEC0jxhNkTRZE8ILIONhF71KV0Gg7IxYMa cdOPFKshmfyLnN2nT02gLM9Zi6MKBbxCKFNpxXSI3L0LBl/XeTMXy2qodtZNPldqr2 qOOVYwJisany1neRkZyq+Jt6evSpMzKfcy1sObVY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Boris Ostrovsky , Wen Yang , Juergen Gross , Stefano Stabellini , xen-devel@lists.xenproject.org, Sasha Levin Subject: [PATCH 4.20 096/183] pvcalls-front: fix potential null dereference Date: Mon, 25 Feb 2019 22:11:09 +0100 Message-Id: <20190225195110.866022400@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190225195054.748060397@linuxfoundation.org> References: <20190225195054.748060397@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit b4711098066f1cf808d4dc11a1a842860a3292fe ] static checker warning: drivers/xen/pvcalls-front.c:373 alloc_active_ring() error: we previously assumed 'map->active.ring' could be null (see line 357) drivers/xen/pvcalls-front.c 351 static int alloc_active_ring(struct sock_mapping *map) 352 { 353 void *bytes; 354 355 map->active.ring = (struct pvcalls_data_intf *) 356 get_zeroed_page(GFP_KERNEL); 357 if (!map->active.ring) ^^^^^^^^^^^^^^^^^ Check 358 goto out; 359 360 map->active.ring->ring_order = PVCALLS_RING_ORDER; 361 bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 362 PVCALLS_RING_ORDER); 363 if (!bytes) 364 goto out; 365 366 map->active.data.in = bytes; 367 map->active.data.out = bytes + 368 XEN_FLEX_RING_SIZE(PVCALLS_RING_ORDER); 369 370 return 0; 371 372 out: --> 373 free_active_ring(map); ^^^ Add null check on map->active.ring before dereferencing it to avoid any NULL pointer dereferences. Fixes: 9f51c05dc41a ("pvcalls-front: Avoid get_free_pages(GFP_KERNEL) under spinlock") Reported-by: Dan Carpenter Suggested-by: Boris Ostrovsky Signed-off-by: Wen Yang Reviewed-by: Boris Ostrovsky CC: Boris Ostrovsky CC: Juergen Gross CC: Stefano Stabellini CC: Dan Carpenter CC: xen-devel@lists.xenproject.org CC: linux-kernel@vger.kernel.org Signed-off-by: Boris Ostrovsky Signed-off-by: Sasha Levin --- drivers/xen/pvcalls-front.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 6357160d466ab..91da7e44d5d4f 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -343,6 +343,9 @@ int pvcalls_front_socket(struct socket *sock) static void free_active_ring(struct sock_mapping *map) { + if (!map->active.ring) + return; + free_pages((unsigned long)map->active.data.in, map->active.ring->ring_order); free_page((unsigned long)map->active.ring); -- 2.19.1