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 C3ECBC43381 for ; Tue, 12 Mar 2019 17:36:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94ED42087C for ; Tue, 12 Mar 2019 17:36:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552412215; bh=PnyJkZHFpAkVKkBVJuoEiWm+YSFTIjGbUslaJpOhQG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Fon1Y89IYtmyuiZtLW+Ri27ah/mDbZfWVWykWGwjce4CJx0q5IljcE97aPY0dJjNV XirufZtCoa4Acz5VGAhfHwP3KWR07sOenL2m0wEUbXPFprB3VKpOqP9xxpb4/l6chS jnnwHZewvOpZnjo+UAS471pphz9066eXtuyjKtgY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729674AbfCLRgy (ORCPT ); Tue, 12 Mar 2019 13:36:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:59094 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727561AbfCLRQl (ORCPT ); Tue, 12 Mar 2019 13:16:41 -0400 Received: from localhost (unknown [104.133.8.98]) (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 23DB221850; Tue, 12 Mar 2019 17:16:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552411000; bh=PnyJkZHFpAkVKkBVJuoEiWm+YSFTIjGbUslaJpOhQG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KQ3GfW/9dvpe6B4IiLDyKy855khjtzedE5oyBbkyqNNYRk60yNArA1zNIY46j0G9n CSq5sGX3JVM9YRijB3m05OPm36Eqpb6WIXyamkR6wAuoIuLUzb+EanHnGcg3n1/qHW oPDW/7nMIEP9ZiJxAS62EkOyQnDxu1z3vR38zhb8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Tetsuo Handa , Andrew Morton , David Rientjes , Sasha Levin , syzbot+16c3a70e1e9b29346c43@syzkaller.appspotmail.com Subject: [PATCH 4.14 100/135] relay: check return of create_buf_file() properly Date: Tue, 12 Mar 2019 10:09:07 -0700 Message-Id: <20190312170350.394798703@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190312170341.127810985@linuxfoundation.org> References: <20190312170341.127810985@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 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 2c1cf00eeacb784781cf1c9896b8af001246d339 ] If create_buf_file() returns an error, don't try to reference it later as a valid dentry pointer. This problem was exposed when debugfs started to return errors instead of just NULL for some calls when they do not succeed properly. Also, the check for WARN_ON(dentry) was just wrong :) Reported-by: Kees Cook Reported-and-tested-by: syzbot+16c3a70e1e9b29346c43@syzkaller.appspotmail.com Reported-by: Tetsuo Handa Cc: Andrew Morton Cc: David Rientjes Fixes: ff9fb72bc077 ("debugfs: return error values, not NULL") Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- kernel/relay.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/relay.c b/kernel/relay.c index 1537158c67b3..61d37e6da22d 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -427,6 +427,8 @@ static struct dentry *relay_create_buf_file(struct rchan *chan, dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR, buf, &chan->is_global); + if (IS_ERR(dentry)) + dentry = NULL; kfree(tmpname); @@ -460,7 +462,7 @@ static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu) dentry = chan->cb->create_buf_file(NULL, NULL, S_IRUSR, buf, &chan->is_global); - if (WARN_ON(dentry)) + if (IS_ERR_OR_NULL(dentry)) goto free_buf; } -- 2.19.1