diff options
| author | hannes@stressinduktion.org <hannes@stressinduktion.org> | 2015-04-01 17:07:44 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-04-06 16:12:49 -0400 |
| commit | f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 (patch) | |
| tree | bba5ed057073e42c0113473e1cdbff0bc46ab875 /net/core/dev.c | |
| parent | 576b7cd2f6ff1e90b3fc0a000d2fe74f8a50a4bb (diff) | |
ipv6: protect skb->sk accesses from recursive dereference inside the stack
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>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 962ee9d71964..45109b70664e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2848,7 +2848,9 @@ static void skb_update_prio(struct sk_buff *skb) #define skb_update_prio(skb) #endif -static DEFINE_PER_CPU(int, xmit_recursion); +DEFINE_PER_CPU(int, xmit_recursion); +EXPORT_SYMBOL(xmit_recursion); + #define RECURSION_LIMIT 10 /** |