diff options
| author | Xin Long <lucien.xin@gmail.com> | 2018-02-12 17:15:40 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-08 22:41:07 -0800 |
| commit | 4c13e689e5f0f997d4cc8ee4646fcae88c16d737 (patch) | |
| tree | a7debfe48a30f7a7d96d8b372c506b359d817c31 /net | |
| parent | 71978491bb6600d39ef68f421c23aeb11c10053f (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>
Diffstat (limited to '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 5d5d413a6cf8..a097a8613a02 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -235,6 +235,9 @@ 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); } |