| author | hannes@stressinduktion.org <hannes@stressinduktion.org> | |
| Wed, 1 Apr 2015 15:07:44 +0000 (17:07 +0200) | ||
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| Wed, 29 Apr 2015 08:31:46 +0000 (10:31 +0200) | ||
| commit | c91f81773cd4bbebfe744e9ab30a7ce093f9b930 | |
| tree | a21775dbb33156bef196464337e9f38059e8f10d | tree | snapshot (tar.xz tar.gz zip) |
| parent | e6250f868ccc8a609c88524a785a6e0d915ad3cb | commit | diff |
ipv6: protect skb->sk accesses from recursive dereference inside the stack
[ Upstream commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 ]
We should not consult skb->sk for output decisions in xmit recursion
levels > 0 in the stack. Otherwise local socket settings could influence
the result of e.g. tunnel encapsulation process.
ipv6 does not conform with this in three places:
1) ip6_fragment: we do consult ipv6_npinfo for frag_size
2) sk_mc_loop in ipv6 uses skb->sk and checks if we should
loop the packet back to the local socket
3) ip6_skb_dst_mtu could query the settings from the user socket and
force a wrong MTU
Furthermore:
In sk_mc_loop we could potentially land in WARN_ON(1) if we use a
PF_PACKET socket ontop of an IPv6-backed vxlan device.
Reuse xmit_recursion as we are currently only interested in protecting
tunnel devices.
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 ]
We should not consult skb->sk for output decisions in xmit recursion
levels > 0 in the stack. Otherwise local socket settings could influence
the result of e.g. tunnel encapsulation process.
ipv6 does not conform with this in three places:
1) ip6_fragment: we do consult ipv6_npinfo for frag_size
2) sk_mc_loop in ipv6 uses skb->sk and checks if we should
loop the packet back to the local socket
3) ip6_skb_dst_mtu could query the settings from the user socket and
force a wrong MTU
Furthermore:
In sk_mc_loop we could potentially land in WARN_ON(1) if we use a
PF_PACKET socket ontop of an IPv6-backed vxlan device.
Reuse xmit_recursion as we are currently only interested in protecting
tunnel devices.
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>