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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 70922C3A5A8 for ; Wed, 4 Sep 2019 18:21:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C89120882 for ; Wed, 4 Sep 2019 18:21:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567621286; bh=VByHN+JhKK1rTl7BBvMhaT4Wo6ZFnH8N0Gy5znAXg8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lDHTX6gqORTG7z5KQ5wZyNLLo5hPjb68jrVJyBrqRq4EfBPasiA/lclBRn07E/DU3 JCU8CrsvNa2QENfkyy90XUrEtUSSLfQ+GljCoI+PsKjnq0UsaFXXvGxns7YG8kh5+Q a9q6/TQtIWF5dz9+Bq/+2ZO2eP0PUM4Ee7z9HSXw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388691AbfIDSGj (ORCPT ); Wed, 4 Sep 2019 14:06:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:48712 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389452AbfIDSGi (ORCPT ); Wed, 4 Sep 2019 14:06:38 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 B9606208E4; Wed, 4 Sep 2019 18:06:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567620398; bh=VByHN+JhKK1rTl7BBvMhaT4Wo6ZFnH8N0Gy5znAXg8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KjriZjMBUeGFO3fbIhfWaj/3YZl58UrBUeDqEfDLyDAcq5pD75qAzmgd2VB5DZ8vS Vbuflgbs8uboS256i+1r1mMcRjs7vcq+K8Awor4Tssjh2+amhqKs0SQWb/aW+txxRw YN/FahizGi1voO2gFjyLbR9Izt8zSnviOeeoaRbY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jia-Ju Bai , David Howells , Sasha Levin Subject: [PATCH 4.19 05/93] fs: afs: Fix a possible null-pointer dereference in afs_put_read() Date: Wed, 4 Sep 2019 19:53:07 +0200 Message-Id: <20190904175303.450657522@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190904175302.845828956@linuxfoundation.org> References: <20190904175302.845828956@linuxfoundation.org> User-Agent: quilt/0.66 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 [ Upstream commit a6eed4ab5dd4bfb696c1a3f49742b8d1846a66a0 ] In afs_read_dir(), there is an if statement on line 255 to check whether req->pages is NULL: if (!req->pages) goto error; If req->pages is NULL, afs_put_read() on line 337 is executed. In afs_put_read(), req->pages[i] is used on line 195. Thus, a possible null-pointer dereference may occur in this case. To fix this possible bug, an if statement is added in afs_put_read() to check req->pages. This bug is found by a static analysis tool STCheck written by us. Fixes: f3ddee8dc4e2 ("afs: Fix directory handling") Signed-off-by: Jia-Ju Bai Signed-off-by: David Howells Signed-off-by: Sasha Levin --- fs/afs/file.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/afs/file.c b/fs/afs/file.c index 7d4f26198573d..843d3b970b845 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -193,11 +193,13 @@ void afs_put_read(struct afs_read *req) int i; if (refcount_dec_and_test(&req->usage)) { - for (i = 0; i < req->nr_pages; i++) - if (req->pages[i]) - put_page(req->pages[i]); - if (req->pages != req->array) - kfree(req->pages); + if (req->pages) { + for (i = 0; i < req->nr_pages; i++) + if (req->pages[i]) + put_page(req->pages[i]); + if (req->pages != req->array) + kfree(req->pages); + } kfree(req); } } -- 2.20.1