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authorTuong Lien <tuong.t.lien@dektech.com.au>2020-09-18 04:17:28 +0300
committerDavid S. Miller <davem@davemloft.net>2020-09-18 23:58:37 +0300
commit1ef6f7c9390ff5308c940ff8d0a53533a4673ad9 (patch)
treed69690f08cf4483165165553d17a98863720d61e /net/tipc/link.c
parentdaef1ee3798b25e8464b8eb618eaa74b8f423ac7 (diff)
downloadlinux-1ef6f7c9390ff5308c940ff8d0a53533a4673ad9.tar.xz
tipc: add automatic session key exchange
With support from the master key option in the previous commit, it becomes easy to make frequent updates/exchanges of session keys between authenticated cluster nodes. Basically, there are two situations where the key exchange will take in place: - When a new node joins the cluster (with the master key), it will need to get its peer's TX key, so that be able to decrypt further messages from that peer. - When a new session key is generated (by either user manual setting or later automatic rekeying feature), the key will be distributed to all peer nodes in the cluster. A key to be exchanged is encapsulated in the data part of a 'MSG_CRYPTO /KEY_DISTR_MSG' TIPC v2 message, then xmit-ed as usual and encrypted by using the master key before sending out. Upon receipt of the message it will be decrypted in the same way as regular messages, then attached as the sender's RX key in the receiver node. In this way, the key exchange is reliable by the link layer, as well as security, integrity and authenticity by the crypto layer. Also, the forward security will be easily achieved by user changing the master key actively but this should not be required very frequently. The key exchange feature is independent on the presence of a master key Note however that the master key still is needed for new nodes to be able to join the cluster. It is also optional, and can be turned off/on via the sysfs: 'net/tipc/key_exchange_enabled' [default 1: enabled]. Backward compatibility is guaranteed because for nodes that do not have master key support, key exchange using master key ie. tx_key = 0 if any will be shortly discarded at the message validation step. In other words, the key exchange feature will be automatically disabled to those nodes. v2: fix the "implicit declaration of function 'tipc_crypto_key_flush'" error in node.c. The function only exists when built with the TIPC "CONFIG_TIPC_CRYPTO" option. v3: use 'info->extack' for a message emitted due to netlink operations instead (- David's comment). Reported-by: kernel test robot <lkp@intel.com> Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/link.c')
-rw-r--r--net/tipc/link.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/net/tipc/link.c b/net/tipc/link.c
index a2989f22ebb6..97dc4b5fb20b 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1250,6 +1250,11 @@ static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
case MSG_FRAGMENTER:
case BCAST_PROTOCOL:
return false;
+#ifdef CONFIG_TIPC_CRYPTO
+ case MSG_CRYPTO:
+ tipc_crypto_msg_rcv(l->net, skb);
+ return true;
+#endif
default:
pr_warn("Dropping received illegal msg type\n");
kfree_skb(skb);