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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 62CF5C7618E for ; Tue, 23 Jul 2019 12:26:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33812223A1 for ; Tue, 23 Jul 2019 12:26:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="V9weTodO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728323AbfGWM0B (ORCPT ); Tue, 23 Jul 2019 08:26:01 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:41330 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726438AbfGWM0B (ORCPT ); Tue, 23 Jul 2019 08:26:01 -0400 Received: by mail-pf1-f195.google.com with SMTP id m30so19082525pff.8 for ; Tue, 23 Jul 2019 05:26:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=d+pnG65HXsnRmlzhaNNzk6y1yw6MWg2lSfilUvi/rLw=; b=V9weTodOYCYaFd7X60mM2I0iNT2dJQddnTuM96ykARlIZO67gGvp+UQa2YlwCxGAaF Uk+SHoks11jMp8cTcExW76F8m+UwjFNGkT639eWlWP0AmGb5c13LsC8p9rx+1LMac0JX cj/teAaKGGjSunYWoqBM4aD8BpXrJ4vZVkErEJAVlzZi7E2+ieYK6hIwC6GSDfniTuu+ /yyf1+SDD2Yj5F8v/ZdaFgdMFyFHBE9DHRHPe3VGLxh1FQCyhdgANw8O7wFYNF+z9hyU ZdisoYQHQu/NPOt4wd346std2iUJ2Qzph4fOv1kiEiTfWTAdCHUmtdS4lxDfyBYjQeCb vzxw== 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; bh=d+pnG65HXsnRmlzhaNNzk6y1yw6MWg2lSfilUvi/rLw=; b=Q8hVCMLnHXO6njzoWFYasruOK5KRZecbJ1oGolJlQEIb48rV9wrfNeB+WE21C4WfWS mpl6O+ErYXbNzjb+ZZw6uEvhCgBj0ctHH9VIQks24akCqdVJODTWpiNJ33+lyuIeVwU5 vfr4pT1pFBSCrieEHKu6HnP9Q92zvR3IVGyo2b/ylBPb2O+gCIHA3UL84uQk+5xag9BU S0zr18wws33G4zCaBtxkj2paHlJy310Jilor9GVxk5Lv/U+gX1s3mixWcMybTIRu0Wtd /cIEtfyo9Rn6fiHRYyHiEO7tRJyU1GGx8NBj+y5KTxbSVDpLrSEatyYTt3tsMmVkBUjl y1SQ== X-Gm-Message-State: APjAAAUWNkPdWUH10gHKXfZ/XeqD55/psP5or9Lqt+rhJ2tHvMnUYhOd NeB/9jNmrCAQ53CIc4HDbYY= X-Google-Smtp-Source: APXvYqwsAvz00r+/iJSmZPzm8Ll2VIOWh2HmWmohM5cYcM4y9UywSWl2Dd7u7Nbtl+V7bw2okgG3TA== X-Received: by 2002:a17:90a:b387:: with SMTP id e7mr84704034pjr.113.1563884760953; Tue, 23 Jul 2019 05:26:00 -0700 (PDT) Received: from oslab.tsinghua.edu.cn ([2402:f000:4:72:808::3ca]) by smtp.gmail.com with ESMTPSA id g18sm75138115pgm.9.2019.07.23.05.25.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 23 Jul 2019 05:26:00 -0700 (PDT) From: Jia-Ju Bai To: dhowells@redhat.com Cc: linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] fs: afs: Fix a possible null-pointer dereference in afs_put_read() Date: Tue, 23 Jul 2019 20:25:53 +0800 Message-Id: <20190723122553.14565-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Jia-Ju Bai --- 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 56b69576274d..dd3c55c9101c 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -191,11 +191,13 @@ 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); } } -- 2.17.0