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| author | Xin Long <lucien.xin@gmail.com> | 2018-02-12 17:15:40 +0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-06-16 22:22:13 +0100 |
| commit | 8f069d6a9b383380970bcb0b75282686904499eb (patch) | |
| tree | 86e3a1d893894770249dde0467c0144e9db60fa1 /net | |
| parent | f6ece273fb5ae5c89002afc7f2ae716ee656061a (diff) | |
| download | linux-stable-8f069d6a9b383380970bcb0b75282686904499eb.tar.gz linux-stable-8f069d6a9b383380970bcb0b75282686904499eb.tar.bz2 linux-stable-8f069d6a9b383380970bcb0b75282686904499eb.zip | |
bridge: check brport attr show in brport_show
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>
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 e561cd59b8a6..65a092c5e0f5 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -225,6 +225,9 @@ 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); } |