diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/mptcp/Makefile | 2 | ||||
| -rw-r--r-- | net/mptcp/crypto.c | 122 | ||||
| -rw-r--r-- | net/mptcp/protocol.c | 16 | ||||
| -rw-r--r-- | net/mptcp/protocol.h | 32 | ||||
| -rw-r--r-- | net/mptcp/subflow.c | 69 | ||||
| -rw-r--r-- | net/mptcp/token.c | 195 |
6 files changed, 428 insertions, 8 deletions
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..bbd6d01af211 --- /dev/null +++ b/net/mptcp/crypto.c @@ -0,0 +1,122 @@ +// 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.barre@uclouvain.be> + * Christoph Paasch <christoph.paasch@uclouvain.be> + * Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi> + * Gregory Detal <gregory.detal@uclouvain.be> + * Fabien Duchêne <fabien.duchene@uclouvain.be> + * Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de> + * Lavkesh Lahngir <lavkesh51@gmail.com> + * Andreas Ripke <ripke@neclab.eu> + * Vlad Dogaru <vlad.dogaru@intel.com> + * Octavian Purdila <octavian.purdila@intel.com> + * John Ronan <jronan@tssg.org> + * Catalin Nicutar <catalin.nicutar@gmail.com> + * Brandon Heller <brandonh@stanford.edu> + */ + +#include <linux/kernel.h> +#include <linux/cryptohash.h> +#include <asm/unaligned.h> + +#include "protocol.h" + +struct sha1_state { + u32 workspace[SHA_WORKSPACE_WORDS]; + u32 digest[SHA_DIGEST_WORDS]; + unsigned int count; +}; + +static void sha1_init(struct sha1_state *state) +{ + sha_init(state->digest); + state->count = 0; +} + +static void sha1_update(struct sha1_state *state, u8 *input) +{ + sha_transform(state->digest, input, state->workspace); + state->count += SHA_MESSAGE_BYTES; +} + +static void sha1_pad_final(struct sha1_state *state, u8 *input, + unsigned int length, __be32 *mptcp_hashed_key) +{ + int i; + + input[length] = 0x80; + memset(&input[length + 1], 0, SHA_MESSAGE_BYTES - length - 9); + put_unaligned_be64((length + state->count) << 3, + &input[SHA_MESSAGE_BYTES - 8]); + + sha_transform(state->digest, input, state->workspace); + for (i = 0; i < SHA_DIGEST_WORDS; ++i) + put_unaligned_be32(state->digest[i], &mptcp_hashed_key[i]); + + memzero_explicit(state->workspace, SHA_WORKSPACE_WORDS << 2); +} + +void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn) +{ + __be32 mptcp_hashed_key[SHA_DIGEST_WORDS]; + u8 input[SHA_MESSAGE_BYTES]; + struct sha1_state state; + + sha1_init(&state); + put_unaligned_be64(key, input); + sha1_pad_final(&state, input, 8, mptcp_hashed_key); + + if (token) + *token = be32_to_cpu(mptcp_hashed_key[0]); + if (idsn) + *idsn = be64_to_cpu(*((__be64 *)&mptcp_hashed_key[3])); +} + +void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2, + u32 *hash_out) +{ + u8 input[SHA_MESSAGE_BYTES * 2]; + struct sha1_state state; + u8 key1be[8]; + u8 key2be[8]; + int i; + + put_unaligned_be64(key1, key1be); + put_unaligned_be64(key2, key2be); + + /* Generate key xored with ipad */ + memset(input, 0x36, SHA_MESSAGE_BYTES); + for (i = 0; i < 8; i++) + input[i] ^= key1be[i]; + for (i = 0; i < 8; i++) + input[i + 8] ^= key2be[i]; + + put_unaligned_be32(nonce1, &input[SHA_MESSAGE_BYTES]); + put_unaligned_be32(nonce2, &input[SHA_MESSAGE_BYTES + 4]); + + sha1_init(&state); + sha1_update(&state, input); + + /* emit sha256(K1 || msg) on the second input block, so we can + * reuse 'input' for the last hashing + */ + sha1_pad_final(&state, &input[SHA_MESSAGE_BYTES], 8, + (__force __be32 *)&input[SHA_MESSAGE_BYTES]); + + /* Prepare second part of hmac */ + memset(input, 0x5C, SHA_MESSAGE_BYTES); + for (i = 0; i < 8; i++) + input[i] ^= key1be[i]; + for (i = 0; i < 8; i++) + input[i + 8] ^= key2be[i]; + + sha1_init(&state); + sha1_update(&state, input); + sha1_pad_final(&state, &input[SHA_MESSAGE_BYTES], SHA_DIGEST_WORDS << 2, + (__be32 *)hash_out); +} diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index e08a25eabcd5..3f66b6a3bb28 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -201,6 +201,7 @@ static void mptcp_close(struct sock *sk, long timeout) struct mptcp_subflow_context *subflow, *tmp; struct mptcp_sock *msk = mptcp_sk(sk); + mptcp_token_destroy(msk->token); inet_sk_state_store(sk, TCP_CLOSE); lock_sock(sk); @@ -281,8 +282,10 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, msk = mptcp_sk(new_mptcp_sock); msk->remote_key = subflow->remote_key; msk->local_key = subflow->local_key; + msk->token = subflow->token; msk->subflow = NULL; + mptcp_token_update_accept(newsk, new_mptcp_sock); newsk = new_mptcp_sock; mptcp_copy_inaddrs(newsk, ssk); list_add(&subflow->node, &msk->conn_list); @@ -299,6 +302,10 @@ 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); @@ -331,6 +338,7 @@ void mptcp_finish_connect(struct sock *ssk) */ WRITE_ONCE(msk->remote_key, subflow->remote_key); WRITE_ONCE(msk->local_key, subflow->local_key); + WRITE_ONCE(msk->token, subflow->token); } static void mptcp_sock_graft(struct sock *sk, struct socket *parent) @@ -349,6 +357,7 @@ 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, @@ -568,6 +577,12 @@ void __init mptcp_init(void) static struct proto_ops mptcp_v6_stream_ops; static struct proto mptcp_v6_prot; +static void mptcp_v6_destroy(struct sock *sk) +{ + mptcp_destroy(sk); + inet6_destroy_sock(sk); +} + static struct inet_protosw mptcp_v6_protosw = { .type = SOCK_STREAM, .protocol = IPPROTO_MPTCP, @@ -583,6 +598,7 @@ int mptcpv6_init(void) mptcp_v6_prot = mptcp_prot; strcpy(mptcp_v6_prot.name, "MPTCPv6"); mptcp_v6_prot.slab = NULL; + mptcp_v6_prot.destroy = mptcp_v6_destroy; mptcp_v6_prot.obj_size = sizeof(struct mptcp_sock) + sizeof(struct ipv6_pinfo); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index bd66e7415515..5f43fa0275c0 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 <net/tcp.h> +#include <net/inet_connection_sock.h> + #define MPTCP_SUPPORTED_VERSION 0 /* MPTCP option bits */ @@ -42,6 +46,7 @@ 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 { backup : 1; 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 */ mp_capable : 1, /* remote is MPTCP capable */ fourth_ack : 1, /* send initial DSS */ @@ -112,4 +121,27 @@ void mptcp_get_options(const struct sk_buff *skb, void mptcp_finish_connect(struct sock *sk); +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_sha(u64 key, u32 *token, u64 *idsn); +static inline void mptcp_crypto_key_gen_sha(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_sha(*key, token, idsn); +} + +void mptcp_crypto_hmac_sha(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 df3192305967..89b91bc7a831 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> @@ -18,6 +20,33 @@ #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 subflow->icsk_af_ops->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_init_req(struct request_sock *req, const struct sock *sk_listener, struct sk_buff *skb) @@ -42,7 +71,12 @@ static void subflow_init_req(struct request_sock *req, #endif 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; + subflow_req->remote_key = rx_opt.mptcp.sndr_key; } } @@ -150,16 +184,28 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, 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); + + /* we have null ctx on TCP fallback, not fatal on MPC + * handshake + */ + if (!ctx) + return child; + + if (ctx->mp_capable) { + if (mptcp_token_new_accept(ctx->token)) + goto close_child; } } return child; + +close_child: + pr_debug("closing child socket"); + tcp_send_active_reset(child, GFP_ATOMIC); + inet_csk_prepare_forced_close(child); + tcp_done(child); + return NULL; } static struct inet_connection_sock_af_ops subflow_specific; @@ -224,6 +270,7 @@ 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; return 0; @@ -286,6 +333,9 @@ static void subflow_ulp_release(struct sock *sk) if (!ctx) return; + if (ctx->conn) + sock_put(ctx->conn); + kfree_rcu(ctx, rcu); } @@ -323,6 +373,7 @@ 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; } static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = { @@ -346,6 +397,8 @@ 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; } @@ -362,6 +415,7 @@ void mptcp_subflow_init(void) subflow_specific.conn_request = subflow_v4_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 IS_ENABLED(CONFIG_MPTCP_IPV6) subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops; @@ -371,6 +425,7 @@ void mptcp_subflow_init(void) subflow_v6_specific.conn_request = subflow_v6_conn_request; subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock; subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect; + subflow_v6_specific.rebuild_header = subflow_rebuild_header; subflow_v6m_specific = subflow_v6_specific; subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; diff --git a/net/mptcp/token.c b/net/mptcp/token.c new file mode 100644 index 000000000000..84d887806090 --- /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.barre@uclouvain.be> + * Christoph Paasch <christoph.paasch@uclouvain.be> + * Jaakko Korkeaniemi <jaakko.korkeaniemi@aalto.fi> + * Gregory Detal <gregory.detal@uclouvain.be> + * Fabien Duchêne <fabien.duchene@uclouvain.be> + * Andreas Seelinger <Andreas.Seelinger@rwth-aachen.de> + * Lavkesh Lahngir <lavkesh51@gmail.com> + * Andreas Ripke <ripke@neclab.eu> + * Vlad Dogaru <vlad.dogaru@intel.com> + * Octavian Purdila <octavian.purdila@intel.com> + * John Ronan <jronan@tssg.org> + * Catalin Nicutar <catalin.nicutar@gmail.com> + * Brandon Heller <brandonh@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_sha(&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_sha(&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(rcu_access_pointer(*slot) != &token_used); + radix_tree_replace_slot(&token_tree, 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); +} |