From: Peter Krystad <peter.krys...@linux.intel.com>
Generate the local keys, IDSN, and token when creating a new socket.
Introduce the token tree to track all tokens in use using a radix tree
with the MPTCP token itself as the index.
Will be used to obtain the MPTCP parent socket to handle incoming joins.
Signed-off-by: Peter Krystad <peter.krys...@linux.intel.com>
Signed-off-by: Davide Caratti <dcara...@redhat.com>
Signed-off-by: Florian Westphal <f...@strlen.de>
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
net/mptcp/Makefile | 2 +-
net/mptcp/crypto.c | 128 ++++++++++++++++++++++++++++
net/mptcp/protocol.c | 11 +++
net/mptcp/protocol.h | 32 +++++++
net/mptcp/subflow.c | 65 +++++++++++++--
net/mptcp/token.c | 195 +++++++++++++++++++++++++++++++++++++++++++
6 files changed, 424 insertions(+), 9 deletions(-)
create mode 100644 net/mptcp/crypto.c
create mode 100644 net/mptcp/token.c
diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index e1ee5aade8b0..178ae81d8b66 100644
--- a/net/mptcp/Makefile
+++ b/net/mptcp/Makefile
@@ -1,4 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_MPTCP) += mptcp.o
-mptcp-y := protocol.o subflow.o options.o
+mptcp-y := protocol.o subflow.o options.o token.o crypto.o
diff --git a/net/mptcp/crypto.c b/net/mptcp/crypto.c
new file mode 100644
index 000000000000..0d7b10939ba6
--- /dev/null
+++ b/net/mptcp/crypto.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP cryptographic functions
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ *
+ * Note: This code is based on mptcp_ctrl.c, mptcp_ipv4.c, and
+ * mptcp_ipv6 from multipath-tcp.org, authored by:
+ *
+ * Sébastien Barré <sebastien.ba...@uclouvain.be>
+ * Christoph Paasch <christoph.paa...@uclouvain.be>
+ * Jaakko Korkeaniemi <jaakko.korkeani...@aalto.fi>
+ * Gregory Detal <gregory.de...@uclouvain.be>
+ * Fabien Duchêne <fabien.duch...@uclouvain.be>
+ * Andreas Seelinger <andreas.seelin...@rwth-aachen.de>
+ * Lavkesh Lahngir <lavkes...@gmail.com>
+ * Andreas Ripke <ri...@neclab.eu>
+ * Vlad Dogaru <vlad.dog...@intel.com>
+ * Octavian Purdila <octavian.purd...@intel.com>
+ * John Ronan <jro...@tssg.org>
+ * Catalin Nicutar <catalin.nicu...@gmail.com>
+ * Brandon Heller <brand...@stanford.edu>
+ */
+
+#include <linux/kernel.h>
+#include <linux/cryptohash.h>
+#include <linux/random.h>
+#include <linux/siphash.h>
+#include <asm/unaligned.h>
+
+#include "protocol.h"
+
+void mptcp_crypto_key_sha1(u64 key, u32 *token, u64 *idsn)
+{
+ u32 workspace[SHA_WORKSPACE_WORDS];
+ u32 mptcp_hashed_key[SHA_DIGEST_WORDS];
+ u8 input[64];
+
+ memset(workspace, 0, sizeof(workspace));
+
+ /* Initialize input with appropriate padding */
+ memset(&input[9], 0, sizeof(input) - 10); /* -10, because the last byte
+ * is explicitly set too
+ */
+ put_unaligned_be64(key, input);
+ input[8] = 0x80; /* Padding: First bit after message = 1 */
+ input[63] = 0x40; /* Padding: Length of the message = 64 bits */
+
+ sha_init(mptcp_hashed_key);
+ sha_transform(mptcp_hashed_key, input, workspace);
+
+ if (token)
+ *token = mptcp_hashed_key[0];
+ if (idsn)
+ *idsn = ((u64)mptcp_hashed_key[3] << 32) + mptcp_hashed_key[4];
+}
+
+void mptcp_crypto_hmac_sha1(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
+ u32 *hash_out)
+{
+ u32 workspace[SHA_WORKSPACE_WORDS];
+ u8 input[128]; /* 2 512-bit blocks */
+ int i;
+ int index;
+ u8 key_1[8];
+ u8 key_2[8];
+ u8 nonce_1[4];
+ u8 nonce_2[4];
+
+ memset(workspace, 0, sizeof(workspace));
+
+ put_unaligned_be64(key1, key_1);
+ put_unaligned_be64(key2, key_2);
+ put_unaligned_be32(nonce1, nonce_1);
+ put_unaligned_be32(nonce2, nonce_2);
+
+ /* Generate key xored with ipad */
+ memset(input, 0x36, 64);
+ for (i = 0; i < 8; i++)
+ input[i] ^= key_1[i];
+ for (i = 0; i < 8; i++)
+ input[i + 8] ^= key_2[i];
+
+ index = 64;
+ memcpy(&input[index], nonce_1, 4);
+ index = 68;
+ memcpy(&input[index], nonce_2, 4);
+ index = 72;
+
+ input[index] = 0x80; /* Padding: First bit after message = 1 */
+ memset(&input[index + 1], 0, (126 - index));
+
+ /* Padding: Length of the message = 512 + message length (bits) */
+ input[126] = 0x02;
+ input[127] = ((index - 64) * 8); /* Message length (bits) */
+
+ sha_init(hash_out);
+ sha_transform(hash_out, input, workspace);
+ memset(workspace, 0, sizeof(workspace));
+
+ sha_transform(hash_out, &input[64], workspace);
+ memset(workspace, 0, sizeof(workspace));
+
+ for (i = 0; i < 5; i++)
+ hash_out[i] = (__force u32)cpu_to_be32(hash_out[i]);
+
+ /* Prepare second part of hmac */
+ memset(input, 0x5C, 64);
+ for (i = 0; i < 8; i++)
+ input[i] ^= key_1[i];
+ for (i = 0; i < 8; i++)
+ input[i + 8] ^= key_2[i];
+
+ memcpy(&input[64], hash_out, 20);
+ input[84] = 0x80;
+ memset(&input[85], 0, 41);
+
+ /* Padding: Length of the message = 512 + 160 bits */
+ input[126] = 0x02;
+ input[127] = 0xA0;
+
+ sha_init(hash_out);
+ sha_transform(hash_out, input, workspace);
+ memset(workspace, 0, sizeof(workspace));
+
+ sha_transform(hash_out, &input[64], workspace);
+
+ for (i = 0; i < 5; i++)
+ hash_out[i] = (__force u32)cpu_to_be32(hash_out[i]);
+}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 5605391fc32a..0a9c447db159 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -133,6 +133,7 @@ static void mptcp_close(struct sock *sk, long timeout)
struct mptcp_sock *msk = mptcp_sk(sk);
struct socket *ssk = NULL;
+ mptcp_token_destroy(msk->token);
inet_sk_state_store(sk, TCP_CLOSE);
lock_sock(sk);
@@ -198,6 +199,10 @@ static struct sock *mptcp_accept(struct sock *sk, int
flags, int *err,
msk->local_key = subflow->local_key;
msk->subflow = NULL;
+ msk->token = subflow->token;
+
+ mptcp_token_update_accept(new_sock->sk, new_mptcp_sock);
+ msk->subflow = NULL;
newsk = new_mptcp_sock;
subflow->conn = new_mptcp_sock;
list_add(&subflow->node, &msk->conn_list);
@@ -215,6 +220,10 @@ static struct sock *mptcp_accept(struct sock *sk, int
flags, int *err,
return newsk;
}
+static void mptcp_destroy(struct sock *sk)
+{
+}
+
static int mptcp_get_port(struct sock *sk, unsigned short snum)
{
struct mptcp_sock *msk = mptcp_sk(sk);
@@ -258,6 +267,7 @@ void mptcp_finish_connect(struct sock *sk, int mp_capable)
msk->remote_key = subflow->remote_key;
msk->local_key = subflow->local_key;
+ msk->token = subflow->token;
list_add(&subflow->node, &msk->conn_list);
msk->subflow = NULL;
bh_unlock_sock(sk);
@@ -273,6 +283,7 @@ static struct proto mptcp_prot = {
.close = mptcp_close,
.accept = mptcp_accept,
.shutdown = tcp_shutdown,
+ .destroy = mptcp_destroy,
.sendmsg = mptcp_sendmsg,
.recvmsg = mptcp_recvmsg,
.hash = inet_hash,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index d228d1d3c8c3..dea6d4f32f38 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -7,6 +7,10 @@
#ifndef __MPTCP_PROTOCOL_H
#define __MPTCP_PROTOCOL_H
+#include <linux/random.h>
+#include <linux/tcp.h>
+#include <net/inet_connection_sock.h>
+
/* MPTCP option bits */
#define OPTION_MPTCP_MPC_SYN BIT(0)
#define OPTION_MPTCP_MPC_SYNACK BIT(1)
@@ -40,6 +44,7 @@ struct mptcp_sock {
struct inet_connection_sock sk;
u64 local_key;
u64 remote_key;
+ u32 token;
struct list_head conn_list;
struct socket *subflow; /* outgoing connect/listener/!mp_capable */
};
@@ -61,6 +66,8 @@ struct mptcp_subflow_request_sock {
version : 4;
u64 local_key;
u64 remote_key;
+ u64 idsn;
+ u32 token;
};
static inline struct mptcp_subflow_request_sock *
@@ -74,6 +81,8 @@ struct mptcp_subflow_context {
struct list_head node;/* conn_list of subflows */
u64 local_key;
u64 remote_key;
+ u64 idsn;
+ u32 token;
u32 request_mptcp : 1, /* send MP_CAPABLE */
request_cksum : 1,
request_version : 4,
@@ -108,4 +117,27 @@ void mptcp_get_options(const struct sk_buff *skb,
void mptcp_finish_connect(struct sock *sk, int mp_capable);
+int mptcp_token_new_request(struct request_sock *req);
+void mptcp_token_destroy_request(u32 token);
+int mptcp_token_new_connect(struct sock *sk);
+int mptcp_token_new_accept(u32 token);
+void mptcp_token_update_accept(struct sock *sk, struct sock *conn);
+void mptcp_token_destroy(u32 token);
+
+void mptcp_crypto_key_sha1(u64 key, u32 *token, u64 *idsn);
+static inline void mptcp_crypto_key_gen_sha1(u64 *key, u32 *token, u64 *idsn)
+{
+ /* we might consider a faster version that computes the key as a
+ * hash of some information available in the MPTCP socket. Use
+ * random data at the moment, as it's probably the safest option
+ * in case multiple sockets are opened in different namespaces at
+ * the same time.
+ */
+ get_random_bytes(key, sizeof(u64));
+ mptcp_crypto_key_sha1(*key, token, idsn);
+}
+
+void mptcp_crypto_hmac_sha1(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
+ u32 *hash_out);
+
#endif /* __MPTCP_PROTOCOL_H */
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index b4e86456d4d6..43fb1ae51b03 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -4,6 +4,8 @@
* Copyright (c) 2017 - 2019, Intel Corporation.
*/
+#define pr_fmt(fmt) "MPTCP: " fmt
+
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
@@ -15,6 +17,33 @@
#include <net/mptcp.h>
#include "protocol.h"
+static int subflow_rebuild_header(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ int err = 0;
+
+ if (subflow->request_mptcp && !subflow->token) {
+ pr_debug("subflow=%p", sk);
+ err = mptcp_token_new_connect(sk);
+ }
+
+ if (err)
+ return err;
+
+ return inet_sk_rebuild_header(sk);
+}
+
+static void subflow_req_destructor(struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+
+ pr_debug("subflow_req=%p", subflow_req);
+
+ if (subflow_req->mp_capable)
+ mptcp_token_destroy_request(subflow_req->token);
+ tcp_request_sock_ops.destructor(req);
+}
+
static void subflow_v4_init_req(struct request_sock *req,
const struct sock *sk_listener,
struct sk_buff *skb)
@@ -32,7 +61,12 @@ static void subflow_v4_init_req(struct request_sock *req,
mptcp_get_options(skb, &rx_opt);
if (rx_opt.mptcp.mp_capable && listener->request_mptcp) {
- subflow_req->mp_capable = 1;
+ int err;
+
+ err = mptcp_token_new_request(req);
+ if (err == 0)
+ subflow_req->mp_capable = 1;
+
if (rx_opt.mptcp.version >= listener->request_version)
subflow_req->version = listener->request_version;
else
@@ -98,16 +132,25 @@ static struct sock *subflow_syn_recv_sock(const struct
sock *sk,
child = tcp_v4_syn_recv_sock(sk, skb, req, dst, req_unhash, own_req);
if (child && *own_req) {
- if (!mptcp_subflow_ctx(child)) {
- pr_debug("Closing child socket");
- inet_sk_set_state(child, TCP_CLOSE);
- sock_set_flag(child, SOCK_DEAD);
- inet_csk_destroy_sock(child);
- child = NULL;
+ struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
+
+ if (!ctx)
+ goto close_child;
+
+ if (ctx->mp_capable) {
+ if (mptcp_token_new_accept(ctx->token))
+ goto close_child;
}
}
return child;
+
+close_child:
+ pr_debug("closing child socket");
+ inet_sk_set_state(child, TCP_CLOSE);
+ sock_set_flag(child, SOCK_DEAD);
+ inet_csk_destroy_sock(child);
+ return NULL;
}
static struct inet_connection_sock_af_ops subflow_specific;
@@ -134,6 +177,7 @@ int mptcp_subflow_create_socket(struct sock *sk, struct
socket **new_sock)
pr_debug("subflow=%p", subflow);
*new_sock = sf;
+ sock_hold(sk);
subflow->conn = sk;
subflow->request_mptcp = 1; // @@ if MPTCP enabled
subflow->request_cksum = 1; // @@ if checksum enabled
@@ -188,7 +232,8 @@ static void subflow_ulp_release(struct sock *sk)
{
struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(sk);
- pr_debug("subflow=%p", ctx);
+ if (ctx->conn)
+ sock_put(ctx->conn);
kfree(ctx);
}
@@ -213,6 +258,7 @@ static void subflow_ulp_clone(const struct request_sock
*req,
new_ctx->fourth_ack = 1;
new_ctx->remote_key = subflow_req->remote_key;
new_ctx->local_key = subflow_req->local_key;
+ new_ctx->token = subflow_req->token;
}
}
@@ -237,6 +283,8 @@ static int subflow_ops_init(struct request_sock_ops
*subflow_ops)
if (!subflow_ops->slab)
return -ENOMEM;
+ subflow_ops->destructor = subflow_req_destructor;
+
return 0;
}
@@ -253,6 +301,7 @@ void mptcp_subflow_init(void)
subflow_specific.conn_request = subflow_conn_request;
subflow_specific.syn_recv_sock = subflow_syn_recv_sock;
subflow_specific.sk_rx_dst_set = subflow_finish_connect;
+ subflow_specific.rebuild_header = subflow_rebuild_header;
if (tcp_register_ulp(&subflow_ulp_ops) != 0)
panic("MPTCP: failed to register subflows to ULP\n");
diff --git a/net/mptcp/token.c b/net/mptcp/token.c
new file mode 100644
index 000000000000..7e579deef6a2
--- /dev/null
+++ b/net/mptcp/token.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP token management
+ * Copyright (c) 2017 - 2019, Intel Corporation.
+ *
+ * Note: This code is based on mptcp_ctrl.c from multipath-tcp.org,
+ * authored by:
+ *
+ * Sébastien Barré <sebastien.ba...@uclouvain.be>
+ * Christoph Paasch <christoph.paa...@uclouvain.be>
+ * Jaakko Korkeaniemi <jaakko.korkeani...@aalto.fi>
+ * Gregory Detal <gregory.de...@uclouvain.be>
+ * Fabien Duchêne <fabien.duch...@uclouvain.be>
+ * Andreas Seelinger <andreas.seelin...@rwth-aachen.de>
+ * Lavkesh Lahngir <lavkes...@gmail.com>
+ * Andreas Ripke <ri...@neclab.eu>
+ * Vlad Dogaru <vlad.dog...@intel.com>
+ * Octavian Purdila <octavian.purd...@intel.com>
+ * John Ronan <jro...@tssg.org>
+ * Catalin Nicutar <catalin.nicu...@gmail.com>
+ * Brandon Heller <brand...@stanford.edu>
+ */
+
+#define pr_fmt(fmt) "MPTCP: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/radix-tree.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <net/sock.h>
+#include <net/inet_common.h>
+#include <net/protocol.h>
+#include <net/mptcp.h>
+#include "protocol.h"
+
+static RADIX_TREE(token_tree, GFP_ATOMIC);
+static RADIX_TREE(token_req_tree, GFP_ATOMIC);
+static DEFINE_SPINLOCK(token_tree_lock);
+static int token_used __read_mostly;
+
+/**
+ * mptcp_token_new_request - create new key/idsn/token for subflow_request
+ * @req - the request socket
+ *
+ * This function is called when a new mptcp connection is coming in.
+ *
+ * It creates a unique token to identify the new mptcp connection,
+ * a secret local key and the initial data sequence number (idsn).
+ *
+ * Returns 0 on success.
+ */
+int mptcp_token_new_request(struct request_sock *req)
+{
+ struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
+ int err;
+
+ while (1) {
+ u32 token;
+
+ mptcp_crypto_key_gen_sha1(&subflow_req->local_key,
+ &subflow_req->token,
+ &subflow_req->idsn);
+ pr_debug("req=%p local_key=%llu, token=%u, idsn=%llu\n",
+ req, subflow_req->local_key, subflow_req->token,
+ subflow_req->idsn);
+
+ token = subflow_req->token;
+ spin_lock_bh(&token_tree_lock);
+ if (!radix_tree_lookup(&token_req_tree, token) &&
+ !radix_tree_lookup(&token_tree, token))
+ break;
+ spin_unlock_bh(&token_tree_lock);
+ }
+
+ err = radix_tree_insert(&token_req_tree,
+ subflow_req->token, &token_used);
+ spin_unlock_bh(&token_tree_lock);
+ return err;
+}
+
+/**
+ * mptcp_token_new_connect - create new key/idsn/token for subflow
+ * @sk - the socket that will initiate a connection
+ *
+ * This function is called when a new outgoing mptcp connection is
+ * initiated.
+ *
+ * It creates a unique token to identify the new mptcp connection,
+ * a secret local key and the initial data sequence number (idsn).
+ *
+ * On success, the mptcp connection can be found again using
+ * the computed token at a later time, this is needed to process
+ * join requests.
+ *
+ * returns 0 on success.
+ */
+int mptcp_token_new_connect(struct sock *sk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct sock *mptcp_sock = subflow->conn;
+ int err;
+
+ while (1) {
+ u32 token;
+
+ mptcp_crypto_key_gen_sha1(&subflow->local_key, &subflow->token,
+ &subflow->idsn);
+
+ pr_debug("ssk=%p, local_key=%llu, token=%u, idsn=%llu\n",
+ sk, subflow->local_key, subflow->token, subflow->idsn);
+
+ token = subflow->token;
+ spin_lock_bh(&token_tree_lock);
+ if (!radix_tree_lookup(&token_req_tree, token) &&
+ !radix_tree_lookup(&token_tree, token))
+ break;
+ spin_unlock_bh(&token_tree_lock);
+ }
+ err = radix_tree_insert(&token_tree, subflow->token, mptcp_sock);
+ spin_unlock_bh(&token_tree_lock);
+
+ return err;
+}
+
+/**
+ * mptcp_token_new_accept - insert token for later processing
+ * @token: the token to insert to the tree
+ *
+ * Called when a SYN packet creates a new logical connection, i.e.
+ * is not a join request.
+ *
+ * We don't have an mptcp socket yet at that point.
+ * This is paired with mptcp_token_update_accept, called on accept().
+ */
+int mptcp_token_new_accept(u32 token)
+{
+ int err;
+
+ spin_lock_bh(&token_tree_lock);
+ err = radix_tree_insert(&token_tree, token, &token_used);
+ spin_unlock_bh(&token_tree_lock);
+
+ return err;
+}
+
+/**
+ * mptcp_token_update_accept - update token to map to mptcp socket
+ * @conn: the new struct mptcp_sock
+ * @sk: the initial subflow for this mptcp socket
+ *
+ * Called when the first mptcp socket is created on accept to
+ * refresh the dummy mapping (done to reserve the token) with
+ * the mptcp_socket structure that wasn't allocated before.
+ */
+void mptcp_token_update_accept(struct sock *sk, struct sock *conn)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ void __rcu **slot;
+
+ spin_lock_bh(&token_tree_lock);
+ slot = radix_tree_lookup_slot(&token_tree, subflow->token);
+ WARN_ON_ONCE(!slot);
+ if (slot) {
+ WARN_ON_ONCE(*slot != &token_used);
+ *slot = conn;
+ }
+ spin_unlock_bh(&token_tree_lock);
+}
+
+/**
+ * mptcp_token_destroy_request - remove mptcp connection/token
+ * @token - token of mptcp connection to remove
+ *
+ * Remove not-yet-fully-established incoming connection identified
+ * by @token.
+ */
+void mptcp_token_destroy_request(u32 token)
+{
+ spin_lock_bh(&token_tree_lock);
+ radix_tree_delete(&token_req_tree, token);
+ spin_unlock_bh(&token_tree_lock);
+}
+
+/**
+ * mptcp_token_destroy - remove mptcp connection/token
+ * @token - token of mptcp connection to remove
+ *
+ * Remove the connection identified by @token.
+ */
+void mptcp_token_destroy(u32 token)
+{
+ spin_lock_bh(&token_tree_lock);
+ radix_tree_delete(&token_tree, token);
+ spin_unlock_bh(&token_tree_lock);
+}
--
2.23.0
