tipc: introduce TIPC encryption & authentication
This commit offers an option to encrypt and authenticate all messaging,
including the neighbor discovery messages. The currently most advanced
algorithm supported is the AEAD AES-GCM (like IPSec or TLS). All
encryption/decryption is done at the bearer layer, just before leaving
or after entering TIPC.
Supported features:
- Encryption & authentication of all TIPC messages (header + data);
- Two symmetric-key modes: Cluster and Per-node;
- Automatic key switching;
- Key-expired revoking (sequence number wrapped);
- Lock-free encryption/decryption (RCU);
- Asynchronous crypto, Intel AES-NI supported;
- Multiple cipher transforms;
- Logs & statistics;
Two key modes:
- Cluster key mode: One single key is used for both TX & RX in all
nodes in the cluster.
- Per-node key mode: Each nodes in the cluster has one specific TX key.
For RX, a node requires its peers' TX key to be able to decrypt the
messages from those peers.
Key setting from user-space is performed via netlink by a user program
(e.g. the iproute2 'tipc' tool).
Internal key state machine:
Attach Align(RX)
+-+ +-+
| V | V
+---------+ Attach +---------+
| IDLE |---------------->| PENDING |(user = 0)
+---------+ +---------+
A A Switch| A
| | | |
| | Free(switch/revoked) | |
(Free)| +----------------------+ | |Timeout
| (TX) | | |(RX)
| | | |
| | v |
+---------+ Switch +---------+
| PASSIVE |<----------------| ACTIVE |
+---------+ (RX) +---------+
(user = 1) (user >= 1)
The number of TFMs is 10 by default and can be changed via the procfs
'net/tipc/max_tfms'. At this moment, as for simplicity, this file is
also used to print the crypto statistics at runtime:
echo 0xfff1 > /proc/sys/net/tipc/max_tfms
The patch defines a new TIPC version (v7) for the encryption message (-
backward compatibility as well). The message is basically encapsulated
as follows:
+----------------------------------------------------------+
| TIPCv7 encryption | Original TIPCv2 | Authentication |
| header | packet (encrypted) | Tag |
+----------------------------------------------------------+
The throughput is about ~40% for small messages (compared with non-
encryption) and ~9% for large messages. With the support from hardware
crypto i.e. the Intel AES-NI CPU instructions, the throughput increases
upto ~85% for small messages and ~55% for large messages.
By default, the new feature is inactive (i.e. no encryption) until user
sets a key for TIPC. There is however also a new option - "TIPC_CRYPTO"
in the kernel configuration to enable/disable the new code when needed.
MAINTAINERS | add two new files 'crypto.h' & 'crypto.c' in tipc
Acked-by: Ying Xue <ying.xue@windreiver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/link.c b/net/tipc/link.c
index e7bb4cb..fb72031 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -44,6 +44,7 @@
#include "netlink.h"
#include "monitor.h"
#include "trace.h"
+#include "crypto.h"
#include <linux/pkt_sched.h>
@@ -397,6 +398,15 @@ int tipc_link_mtu(struct tipc_link *l)
return l->mtu;
}
+int tipc_link_mss(struct tipc_link *l)
+{
+#ifdef CONFIG_TIPC_CRYPTO
+ return l->mtu - INT_H_SIZE - EMSG_OVERHEAD;
+#else
+ return l->mtu - INT_H_SIZE;
+#endif
+}
+
u16 tipc_link_rcv_nxt(struct tipc_link *l)
{
return l->rcv_nxt;
@@ -948,6 +958,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
u16 seqno = l->snd_nxt;
int pkt_cnt = skb_queue_len(list);
int imp = msg_importance(hdr);
+ unsigned int mss = tipc_link_mss(l);
unsigned int maxwin = l->window;
unsigned int mtu = l->mtu;
bool new_bundle;
@@ -1000,8 +1011,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list,
continue;
}
if (tipc_msg_try_bundle(l->backlog[imp].target_bskb, &skb,
- mtu - INT_H_SIZE, l->addr,
- &new_bundle)) {
+ mss, l->addr, &new_bundle)) {
if (skb) {
/* Keep a ref. to the skb for next try */
l->backlog[imp].target_bskb = skb;
@@ -1154,7 +1164,7 @@ static int tipc_link_bc_retrans(struct tipc_link *l, struct tipc_link *r,
if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
continue;
TIPC_SKB_CB(skb)->nxt_retr = TIPC_BC_RETR_LIM;
- _skb = __pskb_copy(skb, LL_MAX_HEADER + MIN_H_SIZE, GFP_ATOMIC);
+ _skb = pskb_copy(skb, GFP_ATOMIC);
if (!_skb)
return 0;
hdr = buf_msg(_skb);
@@ -1430,8 +1440,7 @@ static int tipc_link_advance_transmq(struct tipc_link *l, u16 acked, u16 gap,
if (time_before(jiffies, TIPC_SKB_CB(skb)->nxt_retr))
continue;
TIPC_SKB_CB(skb)->nxt_retr = TIPC_UC_RETR_TIME;
- _skb = __pskb_copy(skb, LL_MAX_HEADER + MIN_H_SIZE,
- GFP_ATOMIC);
+ _skb = pskb_copy(skb, GFP_ATOMIC);
if (!_skb)
continue;
hdr = buf_msg(_skb);
