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,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 5159BC43381 for ; Mon, 25 Feb 2019 21:51:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D0742083D for ; Mon, 25 Feb 2019 21:51:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551131474; bh=u7c+dMCHHXyQyv4l/0x5zvRevCIOcPMqIeKzyq7a2ug=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=I2NQlzOY3VMeJrVu+tuD3uc/o2heUmaCqO3cYLc/RQT/fbGyyyfXUiGOV/YAxtZWv c5kjRb0X+oQ9gb4TZ+iGZvA9jBI6oKBQRiX+eLMt1nf3sukN94xOkdW9m90wb3fRS8 aH0qwvYfS7XqKPzR29S3uAne1bwiV4Kdwki9CWes= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731115AbfBYVXj (ORCPT ); Mon, 25 Feb 2019 16:23:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:58080 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731132AbfBYVXj (ORCPT ); Mon, 25 Feb 2019 16:23:39 -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 3F1F921841; Mon, 25 Feb 2019 21:23:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1551129818; bh=u7c+dMCHHXyQyv4l/0x5zvRevCIOcPMqIeKzyq7a2ug=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ii7byhXg38wPi1gh+3Sw+sj6Plhu93IhqjZvJFzYSU7FA6GfN8hRSwhD96mzJVagP NZbl6eH2g0s2SwCRAZrVRTX+uQCy/fBH7nQIcmiZJgkO/lGGQQOTDDAnIwNudxZhFc wh2rxWb5pZ2aZbUOLbc6JJqLl+6AxPgr8lWHHxuI= 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 4.19 078/152] pvcalls-front: fix potential null dereference Date: Mon, 25 Feb 2019 22:11:10 +0100 Message-Id: <20190225195048.497714097@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190225195043.645958524@linuxfoundation.org> References: <20190225195043.645958524@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-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