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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 1E7CDC43441 for ; Mon, 19 Nov 2018 16:31:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB2142086A for ; Mon, 19 Nov 2018 16:31:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="i6gVBc1/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB2142086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730525AbeKTCzv (ORCPT ); Mon, 19 Nov 2018 21:55:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:53766 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729895AbeKTCzu (ORCPT ); Mon, 19 Nov 2018 21:55:50 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 7666B20831; Mon, 19 Nov 2018 16:31:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542645103; bh=btImX78YnPac5lrO0v4lk/gzuoQPQHkwzrLZOxo0lv8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i6gVBc1/7LQV6X0cXg0ZZ7Xugmw1Z3aY14aoXS18khalLBxHa6nZ5BlK6qYw5lTPd bzHnWf2BrgvxNMBc9mi8+BpA1VEsZlugld8nRSbiE1t3WDSgWIg+7B7DYD86aeebDm 6ZyUfhDJqy8UQDwZw8vC8K8H9yHmV4Pg8iFfnHmU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominique Martinet , Sasha Levin Subject: [PATCH 4.19 038/205] 9p locks: fix glock.client_id leak in do_lock Date: Mon, 19 Nov 2018 17:25:45 +0100 Message-Id: <20181119162624.205418076@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162616.586062722@linuxfoundation.org> References: <20181119162616.586062722@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dominique Martinet [ Upstream commit b4dc44b3cac9e8327e0655f530ed0c46f2e6214c ] the 9p client code overwrites our glock.client_id pointing to a static buffer by an allocated string holding the network provided value which we do not care about; free and reset the value as appropriate. This is almost identical to the leak in v9fs_file_getlock() fixed by Al Viro in commit ce85dd58ad5a6 ("9p: we are leaking glock.client_id in v9fs_file_getlock()"), which was returned as an error by a coverity false positive -- while we are here attempt to make the code slightly more robust to future change of the net/9p/client code and hopefully more clear to coverity that there is no problem. Link: http://lkml.kernel.org/r/1536339057-21974-5-git-send-email-asmadeus@codewreck.org Signed-off-by: Dominique Martinet Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/9p/vfs_file.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -204,6 +204,14 @@ static int v9fs_file_do_lock(struct file break; if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0) break; + /* + * p9_client_lock_dotl overwrites flock.client_id with the + * server message, free and reuse the client name + */ + if (flock.client_id != fid->clnt->name) { + kfree(flock.client_id); + flock.client_id = fid->clnt->name; + } } /* map 9p status to VFS status */ @@ -235,6 +243,8 @@ out_unlock: locks_lock_file_wait(filp, fl); fl->fl_type = fl_type; } + if (flock.client_id != fid->clnt->name) + kfree(flock.client_id); out: return res; } @@ -269,7 +279,7 @@ static int v9fs_file_getlock(struct file res = p9_client_getlock_dotl(fid, &glock); if (res < 0) - return res; + goto out; /* map 9p lock type to os lock type */ switch (glock.type) { case P9_LOCK_TYPE_RDLCK: @@ -290,7 +300,9 @@ static int v9fs_file_getlock(struct file fl->fl_end = glock.start + glock.length - 1; fl->fl_pid = -glock.proc_id; } - kfree(glock.client_id); +out: + if (glock.client_id != fid->clnt->name) + kfree(glock.client_id); return res; }