diff options
| author | hannes@stressinduktion.org <hannes@stressinduktion.org> | 2015-04-01 17:07:44 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-04-29 10:31:46 +0200 |
| commit | c91f81773cd4bbebfe744e9ab30a7ce093f9b930 (patch) | |
| tree | a21775dbb33156bef196464337e9f38059e8f10d /net/core/sock.c | |
| parent | e6250f868ccc8a609c88524a785a6e0d915ad3cb (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>
Diffstat (limited to 'net/core/sock.c')
| -rw-r--r-- | net/core/sock.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index c8069561bdb7..650dd58ebd05 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -659,6 +659,25 @@ static inline void sock_valbool_flag(struct sock *sk, int bit, int valbool) sock_reset_flag(sk, bit); } +bool sk_mc_loop(struct sock *sk) +{ + if (dev_recursion_level()) + return false; + if (!sk) + return true; + switch (sk->sk_family) { + case AF_INET: + return inet_sk(sk)->mc_loop; +#if IS_ENABLED(CONFIG_IPV6) + case AF_INET6: + return inet6_sk(sk)->mc_loop; +#endif + } + WARN_ON(1); + return true; +} +EXPORT_SYMBOL(sk_mc_loop); + /* * This is meant for all protocols to use and covers goings on * at the socket level. Everything here is generic. |