diff options
| author | Xin Long <lucien.xin@gmail.com> | 2018-02-12 17:15:40 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-11 16:21:31 +0100 |
| commit | 9f32011496ba86d2f7992d06e9d40bea28cad66e (patch) | |
| tree | 5331210cc2df3a9b165959eef8725d233a12a2f6 | |
| parent | 59e162377323531cde25a9ee5651a993d1774563 (diff) | |
bridge: check brport attr show in brport_show
[ 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 <xzhou@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/bridge/br_sysfs_if.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c index 8bd569695e76..abf711112418 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -230,6 +230,9 @@ static ssize_t brport_show(struct kobject *kobj, 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); } |