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=-9.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 9EAFFECDE46 for ; Sun, 4 Nov 2018 13:54:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6784C20866 for ; Sun, 4 Nov 2018 13:54:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="PixJLrXJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6784C20866 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.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 S1731668AbeKDXJV (ORCPT ); Sun, 4 Nov 2018 18:09:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:49030 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731650AbeKDXJU (ORCPT ); Sun, 4 Nov 2018 18:09:20 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2A09D2085B; Sun, 4 Nov 2018 13:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541339656; bh=WssHQKdZ/1ywz1s1DNgDjAqQXSI9VrM5S23FWw4qW3Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PixJLrXJarGa3yH3X5qXXOrbsjoU2Rpd/qbKfBBXubeMxkr5t02JexWb20g3dy0gU bmbKsrzNwqpCoRvxxDaI24PN23RXKevxfBVJ8jXbsA3CnbhFlC6rz/bHtwD+BBY2nk T0KlsCIDrGZPdiO6l8GmLwk8For85xTs8WLEDKJs= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dominique Martinet , Sasha Levin Subject: [PATCH AUTOSEL 4.9 20/21] 9p locks: fix glock.client_id leak in do_lock Date: Sun, 4 Nov 2018 08:53:54 -0500 Message-Id: <20181104135355.88602-20-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181104135355.88602-1-sashal@kernel.org> References: <20181104135355.88602-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- fs/9p/vfs_file.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index d7b78d531e63..398a3eddb2df 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -204,6 +204,14 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl) 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 @@ static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl) 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 *filp, struct file_lock *fl) 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 *filp, struct file_lock *fl) 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; } -- 2.17.1