Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Thu, 07 Jun 2018 15:05:21 +0100 | Subject | [PATCH 3.16 227/410] bridge: check brport attr show in brport_show |
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3.16.57-rc1 review patch. If anyone has any objections, please let me know.
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From: Xin Long <lucien.xin@gmail.com>
commit 1b12580af1d0677c3c3a19e35bfe5d59b03f737f upstream.
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: Ben Hutchings <ben@decadent.org.uk> --- 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 @@ -225,6 +225,9 @@ 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); }
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