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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 86C15C433E0 for ; Mon, 10 Aug 2020 15:41:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 591A420774 for ; Mon, 10 Aug 2020 15:41:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597074065; bh=1fgeCoTwmpji+1gz0ECi45OvDJ5prtYx5oK3gPIZZ2Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nTIsj89L0UOqdnfHmvCAoVLsD1hIIW3IzjLZYKxip1l8KUDu+akFROqOhcu/zr3q+ 9LLYWc/e/L4ySZaua4C88QLKdR7Rl9dbNbNzJvQX5PHsKoH8deYwNTyPRweYw40y75 LW5xLXWH/GXQpka+zgjIEl2lOaFUE37JpoJHfXZU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728343AbgHJPXc (ORCPT ); Mon, 10 Aug 2020 11:23:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:54790 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728309AbgHJPXZ (ORCPT ); Mon, 10 Aug 2020 11:23:25 -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 8F4B9214F1; Mon, 10 Aug 2020 15:23:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597073005; bh=1fgeCoTwmpji+1gz0ECi45OvDJ5prtYx5oK3gPIZZ2Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N43ckUzR9RtZXISUfPXfP8SEbpo2dd5BrrEB+L8M27zheL/nlCSKF8O7gecO7A258 P6PQ/0ierQNGL+Q6cu55t96F64sjV8ugg1HqdhbX8yytuFbBF5CQtUkcUy4eKIg2T7 3a23p3wqXdJpzBRb3hg3t0Qxfa5m1PfLZv1EMxWQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+e6f77e16ff68b2434a2c@syzkaller.appspotmail.com, Christoph Hellwig , Dominique Martinet , Sasha Levin Subject: [PATCH 5.7 32/79] net/9p: validate fds in p9_fd_open Date: Mon, 10 Aug 2020 17:20:51 +0200 Message-Id: <20200810151813.876491816@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200810151812.114485777@linuxfoundation.org> References: <20200810151812.114485777@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Christoph Hellwig [ Upstream commit a39c46067c845a8a2d7144836e9468b7f072343e ] p9_fd_open just fgets file descriptors passed in from userspace, but doesn't verify that they are valid for read or writing. This gets cought down in the VFS when actually attempting a read or write, but a new warning added in linux-next upsets syzcaller. Fix this by just verifying the fds early on. Link: http://lkml.kernel.org/r/20200710085722.435850-1-hch@lst.de Reported-by: syzbot+e6f77e16ff68b2434a2c@syzkaller.appspotmail.com Signed-off-by: Christoph Hellwig [Dominique: amend goto as per Doug Nazar's review] Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin --- net/9p/trans_fd.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index 3f67803123be2..12ecacf0c55fb 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -816,20 +816,28 @@ static int p9_fd_open(struct p9_client *client, int rfd, int wfd) return -ENOMEM; ts->rd = fget(rfd); + if (!ts->rd) + goto out_free_ts; + if (!(ts->rd->f_mode & FMODE_READ)) + goto out_put_rd; ts->wr = fget(wfd); - if (!ts->rd || !ts->wr) { - if (ts->rd) - fput(ts->rd); - if (ts->wr) - fput(ts->wr); - kfree(ts); - return -EIO; - } + if (!ts->wr) + goto out_put_rd; + if (!(ts->wr->f_mode & FMODE_WRITE)) + goto out_put_wr; client->trans = ts; client->status = Connected; return 0; + +out_put_wr: + fput(ts->wr); +out_put_rd: + fput(ts->rd); +out_free_ts: + kfree(ts); + return -EIO; } static int p9_socket_open(struct p9_client *client, struct socket *csocket) -- 2.25.1