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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 C25C0C282CA for ; Wed, 13 Feb 2019 02:39:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E6E5222C7 for ; Wed, 13 Feb 2019 02:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025555; bh=hudbPPq2wsnn673GkKZ6TJB4xcclMV3mS4tVqlm3Mow=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PbnJtET62UwHkLrK+KIDszSRjYB+b3sdTbz3tOTkfW4nJft0aaVp8NW7ojfmdCAM5 pWGQrqdc/8IwbObk1AQlYeh4/onndVqhiPxMhLzjJ7EbCkJD9zntNUCrQnwNBunEyI HzFV0HUiZQ/cWJpkd/b7wNka53DsHH6q9IfhHWjM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388643AbfBMCjN (ORCPT ); Tue, 12 Feb 2019 21:39:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:42380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388616AbfBMCis (ORCPT ); Tue, 12 Feb 2019 21:38:48 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 327EB222C9; Wed, 13 Feb 2019 02:38:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025527; bh=hudbPPq2wsnn673GkKZ6TJB4xcclMV3mS4tVqlm3Mow=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YcQ7DzDvgs59WMtyDoh75xGvRy60vaL715kJgVtdSrEGZhk4B7G35hjzxQtXAgWRF Ul4K0P5z/HSqcDTvIGgB4Ds7F6Leu78x1OBTcnRY2tGXEP4zdXgRM8jWsaxDutgSZA /Y+/VOC0QpE+skSGnjtira2gX+EULtl/LCwA6Grg= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Wen Yang , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Dan Carpenter , xen-devel@lists.xenproject.org, Sasha Levin Subject: [PATCH AUTOSEL 4.19 63/83] pvcalls-front: fix potential null dereference Date: Tue, 12 Feb 2019 21:36:41 -0500 Message-Id: <20190213023701.20286-63-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190213023701.20286-1-sashal@kernel.org> References: <20190213023701.20286-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wen Yang [ 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 6357160d466a..91da7e44d5d4 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