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authorJohannes Berg <johannes.berg@intel.com>2016-02-04 13:31:17 +0100
committerDavid S. Miller <davem@davemloft.net>2016-02-11 04:27:35 -0500
commit12b74dfadb5a7a23baf4db941dc9fd9d371f249a (patch)
tree40009e4d2e0eb925967d1ffde4f0c3b415f47ee3 /Documentation
parentccad0993567812e88617f105c01b04f1528538b6 (diff)
ipv4: add option to drop unicast encapsulated in L2 multicast
In order to solve a problem with 802.11, the so-called hole-196 attack, add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if enabled, causes the stack to drop IPv4 unicast packets encapsulated in link-layer multi- or broadcast frames. Such frames can (as an attack) be created by any member of the same wireless network and transmitted as valid encrypted frames since the symmetric key for broadcast frames is shared between all stations. Additionally, enabling this option provides compliance with a SHOULD clause of RFC 1122. Reviewed-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/networking/ip-sysctl.txt7
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 73b36d7c7b0d..d5910d63214d 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1216,6 +1216,13 @@ promote_secondaries - BOOLEAN
promote a corresponding secondary IP address instead of
removing all the corresponding secondary IP addresses.
+drop_unicast_in_l2_multicast - BOOLEAN
+ Drop any unicast IP packets that are received in link-layer
+ multicast (or broadcast) frames.
+ This behavior (for multicast) is actually a SHOULD in RFC
+ 1122, but is disabled by default for compatibility reasons.
+ Default: off (0)
+
tag - INTEGER
Allows you to write a number, which can be used as required.