diff options
| author | Xin Long <lucien.xin@gmail.com> | 2018-02-12 17:15:40 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-02-12 11:17:28 -0500 |
| commit | 1b12580af1d0677c3c3a19e35bfe5d59b03f737f (patch) | |
| tree | ac6ce08d61e478296fa4130e1350d40f2365f702 | |
| parent | 7ac8ff95f48cbfa609a060fd6a1e361dd62feeb3 (diff) | |
bridge: check brport attr show in brport_show
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>
| -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 0254c35b2bf0..126a8ea73c96 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -255,6 +255,9 @@ 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); } |