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| author | Michal Kubeček <mkubecek@suse.cz> | 2016-12-02 09:33:41 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-12-02 20:03:20 +0100 |
| commit | 3de81b758853f0b29c61e246679d20b513c4cfec (patch) | |
| tree | fe4107dc49e976bfeeacd6cae7b18ac8dd179851 /net/tipc/bearer.c | |
| parent | Merge tag 'linux-can-fixes-for-4.9-20161201' of git://git.kernel.org/pub/scm/... (diff) | |
| download | linux-3de81b758853f0b29c61e246679d20b513c4cfec.tar.xz linux-3de81b758853f0b29c61e246679d20b513c4cfec.zip | |
tipc: check minimum bearer MTU
Qian Zhang (张谦) reported a potential socket buffer overflow in
tipc_msg_build() which is also known as CVE-2016-8632: due to
insufficient checks, a buffer overflow can occur if MTU is too short for
even tipc headers. As anyone can set device MTU in a user/net namespace,
this issue can be abused by a regular user.
As agreed in the discussion on Ben Hutchings' original patch, we should
check the MTU at the moment a bearer is attached rather than for each
processed packet. We also need to repeat the check when bearer MTU is
adjusted to new device MTU. UDP case also needs a check to avoid
overflow when calculating bearer MTU.
Fixes: b97bf3fd8f6a ("[TIPC] Initial merge")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reported-by: Qian Zhang (张谦) <zhangqian-c@360.cn>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/bearer.c')
| -rw-r--r-- | net/tipc/bearer.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 975dbeb60ab0..52d74760fb68 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -421,6 +421,10 @@ int tipc_enable_l2_media(struct net *net, struct tipc_bearer *b, dev = dev_get_by_name(net, driver_name); if (!dev) return -ENODEV; + if (tipc_mtu_bad(dev, 0)) { + dev_put(dev); + return -EINVAL; + } /* Associate TIPC bearer with L2 bearer */ rcu_assign_pointer(b->media_ptr, dev); @@ -610,8 +614,6 @@ static int tipc_l2_device_event(struct notifier_block *nb, unsigned long evt, if (!b) return NOTIFY_DONE; - b->mtu = dev->mtu; - switch (evt) { case NETDEV_CHANGE: if (netif_carrier_ok(dev)) @@ -624,6 +626,11 @@ static int tipc_l2_device_event(struct notifier_block *nb, unsigned long evt, tipc_reset_bearer(net, b); break; case NETDEV_CHANGEMTU: + if (tipc_mtu_bad(dev, 0)) { + bearer_disable(net, b); + break; + } + b->mtu = dev->mtu; tipc_reset_bearer(net, b); break; case NETDEV_CHANGEADDR: |