From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsALd38Ac1jULzcS/DzkQl7qhj7Km6S9l0uRVNIPgMRRly0CnS7L4lvMvaxjsVymzm8pUxw ARC-Seal: i=1; a=rsa-sha256; t=1520641197; cv=none; d=google.com; s=arc-20160816; b=D6iQtZXtL1Wrq4h6KkwBdF0gx/1cpU/of1miiOct2JtuXcSz2lmCwOFPdFhnjH4MSO +73D9up4bSUm42ct5zCV6axpR2yKUHFEnHobYoAHuoCKUAbfC+x7MWdGQFYdQXa+TnZ6 Xgd12szKmkPWCg8t85p6Iu3tLsBNKCKokcqTvhhzULsD0ND7KlM5O9auYa0J87OEaVRx SyzqcJRJtsA/oUZbJIDYPuJtO9iP1Sp6iGGYWQVNpW43KdsJUJvP5xJgDa9LNzrEPn0N sfOfC/0ZRsgEAy0D2SlRNrq7UZI0bCwmGU+IOb181F42niCvIj2ke9BmOK6wtP4qB5t0 UnZA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=nuyAestoZpZgVQheSAUCjU/XYWrWvjBxWzelSddtmog=; b=l26lqoO+WRBBlRvBqQ+8Ijd1rd3/IaBpcqOJyshL9My1mkvVxsFkKlokZE5UYfJ8YS lvt3AAvfsxcKqeC+aCeF6QrNe6xSwy69kqhkxKJvd61Yafj0w88VB9EP2KbL3r7Run8B m7lTQqWouJTHFFvZGOHH/YlvmT8Q7kkv0tPg8NdqIABdsFCn5FJaQamHJmkXPijoMLvL Iy2WD4mz4/Dd/P+7f3SvG8ukiuu2qKGbYa9l2nDRVVRssLTfTwIpwPT+zPidEPmZCp72 lsPEMTedd6XO9zd8ozvTI5LTj0LEAePIYbQ1+QCsDFNZchtZffUF4/3/1ohCga6APcTE vBfA== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 185.236.200.248 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 185.236.200.248 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiong Zhou , Xin Long , "David S. Miller" Subject: [PATCH 4.4 18/36] bridge: check brport attr show in brport_show Date: Fri, 9 Mar 2018 16:18:34 -0800 Message-Id: <20180310001808.337030039@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180310001807.213987241@linuxfoundation.org> References: <20180310001807.213987241@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1594507815386940691?= X-GMAIL-MSGID: =?utf-8?q?1594507864215811707?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xin Long [ Upstream commit 1b12580af1d0677c3c3a19e35bfe5d59b03f737f ] Now br_sysfs_if file flush doesn't have attr show. To read it will cause kernel panic after users chmod u+r this file. Xiong found this issue when running the commands: ip link add br0 type bridge ip link add type veth ip link set veth0 master br0 chmod u+r /sys/devices/virtual/net/veth0/brport/flush timeout 3 cat /sys/devices/virtual/net/veth0/brport/flush kernel crashed with NULL a pointer dereference call trace. This patch is to fix it by return -EINVAL when brport_attr->show is null, just the same as the check for brport_attr->store in brport_store(). Fixes: 9cf637473c85 ("bridge: add sysfs hook to flush forwarding table") Reported-by: Xiong Zhou Signed-off-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/bridge/br_sysfs_if.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -229,6 +229,9 @@ static ssize_t brport_show(struct kobjec struct brport_attribute *brport_attr = to_brport_attr(attr); struct net_bridge_port *p = to_brport(kobj); + if (!brport_attr->show) + return -EINVAL; + return brport_attr->show(p, buf); }