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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5ED2C77B7D for ; Mon, 15 May 2023 17:23:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244108AbjEORXD (ORCPT ); Mon, 15 May 2023 13:23:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243854AbjEORWr (ORCPT ); Mon, 15 May 2023 13:22:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69168DD91 for ; Mon, 15 May 2023 10:20:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7F65162C12 for ; Mon, 15 May 2023 17:20:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7161FC433D2; Mon, 15 May 2023 17:20:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684171248; bh=ecRzZTC14Y082V1XWJK204NohrP7IYeyAEnOOPYXe8A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jQIWge3EzHHcBK4iZULrGBfUsYHfXXm6zYDEW3zKC5nmzWce7cz8br9IVDU+4ALIE iQR6lXhm/Z7VhHP6n0TXe+bNnyNLuFItO09/e+C4rt9TgHmuuzkeQE+6CAfL//Czsd v11VVGGCK1eS1Pqp6Gu0XxzQWRnlEeWm2ecEp7WA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+4a06d4373fd52f0b2f9c@syzkaller.appspotmail.com, Amir Goldstein , Jan Kara Subject: [PATCH 6.2 149/242] inotify: Avoid reporting event with invalid wd Date: Mon, 15 May 2023 18:27:55 +0200 Message-Id: <20230515161726.363428783@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161721.802179972@linuxfoundation.org> References: <20230515161721.802179972@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Kara commit c915d8f5918bea7c3962b09b8884ca128bfd9b0c upstream. When inotify_freeing_mark() races with inotify_handle_inode_event() it can happen that inotify_handle_inode_event() sees that i_mark->wd got already reset to -1 and reports this value to userspace which can confuse the inotify listener. Avoid the problem by validating that wd is sensible (and pretend the mark got removed before the event got generated otherwise). CC: stable@vger.kernel.org Fixes: 7e790dd5fc93 ("inotify: fix error paths in inotify_update_watch") Message-Id: <20230424163219.9250-1-jack@suse.cz> Reported-by: syzbot+4a06d4373fd52f0b2f9c@syzkaller.appspotmail.com Reviewed-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/notify/inotify/inotify_fsnotify.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -65,7 +65,7 @@ int inotify_handle_inode_event(struct fs struct fsnotify_event *fsn_event; struct fsnotify_group *group = inode_mark->group; int ret; - int len = 0; + int len = 0, wd; int alloc_len = sizeof(struct inotify_event_info); struct mem_cgroup *old_memcg; @@ -81,6 +81,13 @@ int inotify_handle_inode_event(struct fs fsn_mark); /* + * We can be racing with mark being detached. Don't report event with + * invalid wd. + */ + wd = READ_ONCE(i_mark->wd); + if (wd == -1) + return 0; + /* * Whoever is interested in the event, pays for the allocation. Do not * trigger OOM killer in the target monitoring memcg as it may have * security repercussion. @@ -110,7 +117,7 @@ int inotify_handle_inode_event(struct fs fsn_event = &event->fse; fsnotify_init_event(fsn_event); event->mask = mask; - event->wd = i_mark->wd; + event->wd = wd; event->sync_cookie = cookie; event->name_len = len; if (len)