From 734942cc4ea6478eed125af258da1bdbb4afe578 Mon Sep 17 00:00:00 2001 From: Dave Watson Date: Wed, 14 Jun 2017 11:37:14 -0700 Subject: [PATCH 1/4] tcp: ULP infrastructure Add the infrustructure for attaching Upper Layer Protocols (ULPs) over TCP sockets. Based on a similar infrastructure in tcp_cong. The idea is that any ULP can add its own logic by changing the TCP proto_ops structure to its own methods. Example usage: setsockopt(sock, SOL_TCP, TCP_ULP, "tls", sizeof("tls")); modules will call: tcp_register_ulp(&tcp_tls_ulp_ops); to register/unregister their ulp, with an init function and name. A list of registered ulps will be returned by tcp_get_available_ulp, which is hooked up to /proc. Example: $ cat /proc/sys/net/ipv4/tcp_available_ulp tls There is currently no functionality to remove or chain ULPs, but it should be possible to add these in the future if needed. Signed-off-by: Boris Pismenny Signed-off-by: Dave Watson Signed-off-by: David S. Miller --- include/net/inet_connection_sock.h | 4 + include/net/tcp.h | 25 ++++++ include/uapi/linux/tcp.h | 1 + net/ipv4/Makefile | 2 +- net/ipv4/sysctl_net_ipv4.c | 25 ++++++ net/ipv4/tcp.c | 28 ++++++ net/ipv4/tcp_ipv4.c | 2 + net/ipv4/tcp_ulp.c | 134 +++++++++++++++++++++++++++++ 8 files changed, 220 insertions(+), 1 deletion(-) create mode 100644 net/ipv4/tcp_ulp.c diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index c7a577976bec..13e4c89a8231 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -75,6 +75,8 @@ struct inet_connection_sock_af_ops { * @icsk_pmtu_cookie Last pmtu seen by socket * @icsk_ca_ops Pluggable congestion control hook * @icsk_af_ops Operations which are AF_INET{4,6} specific + * @icsk_ulp_ops Pluggable ULP control hook + * @icsk_ulp_data ULP private data * @icsk_ca_state: Congestion control state * @icsk_retransmits: Number of unrecovered [RTO] timeouts * @icsk_pending: Scheduled timer event @@ -97,6 +99,8 @@ struct inet_connection_sock { __u32 icsk_pmtu_cookie; const struct tcp_congestion_ops *icsk_ca_ops; const struct inet_connection_sock_af_ops *icsk_af_ops; + const struct tcp_ulp_ops *icsk_ulp_ops; + void *icsk_ulp_data; unsigned int (*icsk_sync_mss)(struct sock *sk, u32 pmtu); __u8 icsk_ca_state:6, icsk_ca_setsockopt:1, diff --git a/include/net/tcp.h b/include/net/tcp.h index 3ab677d11d02..b439f46f149c 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1991,4 +1991,29 @@ static inline void tcp_listendrop(const struct sock *sk) enum hrtimer_restart tcp_pace_kick(struct hrtimer *timer); +/* + * Interface for adding Upper Level Protocols over TCP + */ + +#define TCP_ULP_NAME_MAX 16 +#define TCP_ULP_MAX 128 +#define TCP_ULP_BUF_MAX (TCP_ULP_NAME_MAX*TCP_ULP_MAX) + +struct tcp_ulp_ops { + struct list_head list; + + /* initialize ulp */ + int (*init)(struct sock *sk); + /* cleanup ulp */ + void (*release)(struct sock *sk); + + char name[TCP_ULP_NAME_MAX]; + struct module *owner; +}; +int tcp_register_ulp(struct tcp_ulp_ops *type); +void tcp_unregister_ulp(struct tcp_ulp_ops *type); +int tcp_set_ulp(struct sock *sk, const char *name); +void tcp_get_available_ulp(char *buf, size_t len); +void tcp_cleanup_ulp(struct sock *sk); + #endif /* _TCP_H */ diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 38a2b07afdff..8204dcebc6f3 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -117,6 +117,7 @@ enum { #define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */ #define TCP_REPAIR_WINDOW 29 /* Get/set window parameters */ #define TCP_FASTOPEN_CONNECT 30 /* Attempt FastOpen with connect */ +#define TCP_ULP 31 /* Attach a ULP to a TCP connection */ struct tcp_repair_opt { __u32 opt_code; diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index f83de23a30e7..afcb435adfbe 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -8,7 +8,7 @@ obj-y := route.o inetpeer.o protocol.o \ inet_timewait_sock.o inet_connection_sock.o \ tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \ tcp_minisocks.o tcp_cong.o tcp_metrics.o tcp_fastopen.o \ - tcp_rate.o tcp_recovery.o \ + tcp_rate.o tcp_recovery.o tcp_ulp.o \ tcp_offload.o datagram.o raw.o udp.o udplite.o \ udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \ fib_frontend.o fib_semantics.o fib_trie.o fib_notifier.o \ diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 7065234a89a5..9bf809726066 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -360,6 +360,25 @@ static int proc_tfo_blackhole_detect_timeout(struct ctl_table *table, ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (write && ret == 0) tcp_fastopen_active_timeout_reset(); + + return ret; +} + +static int proc_tcp_available_ulp(struct ctl_table *ctl, + int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + struct ctl_table tbl = { .maxlen = TCP_ULP_BUF_MAX, }; + int ret; + + tbl.data = kmalloc(tbl.maxlen, GFP_USER); + if (!tbl.data) + return -ENOMEM; + tcp_get_available_ulp(tbl.data, TCP_ULP_BUF_MAX); + ret = proc_dostring(&tbl, write, buffer, lenp, ppos); + kfree(tbl.data); + return ret; } @@ -685,6 +704,12 @@ static struct ctl_table ipv4_table[] = { .mode = 0644, .proc_handler = proc_dointvec_ms_jiffies, }, + { + .procname = "tcp_available_ulp", + .maxlen = TCP_ULP_BUF_MAX, + .mode = 0444, + .proc_handler = proc_tcp_available_ulp, + }, { .procname = "icmp_msgs_per_sec", .data = &sysctl_icmp_msgs_per_sec, diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index cc8fd8b747a4..b06ee3086a0e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2482,6 +2482,24 @@ static int do_tcp_setsockopt(struct sock *sk, int level, release_sock(sk); return err; } + case TCP_ULP: { + char name[TCP_ULP_NAME_MAX]; + + if (optlen < 1) + return -EINVAL; + + val = strncpy_from_user(name, optval, + min_t(long, TCP_ULP_NAME_MAX - 1, + optlen)); + if (val < 0) + return -EFAULT; + name[val] = 0; + + lock_sock(sk); + err = tcp_set_ulp(sk, name); + release_sock(sk); + return err; + } default: /* fallthru */ break; @@ -3038,6 +3056,16 @@ static int do_tcp_getsockopt(struct sock *sk, int level, return -EFAULT; return 0; + case TCP_ULP: + if (get_user(len, optlen)) + return -EFAULT; + len = min_t(unsigned int, len, TCP_ULP_NAME_MAX); + if (put_user(len, optlen)) + return -EFAULT; + if (copy_to_user(optval, icsk->icsk_ulp_ops->name, len)) + return -EFAULT; + return 0; + case TCP_THIN_LINEAR_TIMEOUTS: val = tp->thin_lto; break; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 1dc8c449e16a..eec2ff907279 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1860,6 +1860,8 @@ void tcp_v4_destroy_sock(struct sock *sk) tcp_cleanup_congestion_control(sk); + tcp_cleanup_ulp(sk); + /* Cleanup up the write buffer. */ tcp_write_queue_purge(sk); diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c new file mode 100644 index 000000000000..e855ea70819b --- /dev/null +++ b/net/ipv4/tcp_ulp.c @@ -0,0 +1,134 @@ +/* + * Pluggable TCP upper layer protocol support. + * + * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. + * Copyright (c) 2016-2017, Dave Watson . All rights reserved. + * + */ + +#include +#include +#include +#include +#include +#include + +static DEFINE_SPINLOCK(tcp_ulp_list_lock); +static LIST_HEAD(tcp_ulp_list); + +/* Simple linear search, don't expect many entries! */ +static struct tcp_ulp_ops *tcp_ulp_find(const char *name) +{ + struct tcp_ulp_ops *e; + + list_for_each_entry_rcu(e, &tcp_ulp_list, list) { + if (strcmp(e->name, name) == 0) + return e; + } + + return NULL; +} + +static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name) +{ + const struct tcp_ulp_ops *ulp = NULL; + + rcu_read_lock(); + ulp = tcp_ulp_find(name); + +#ifdef CONFIG_MODULES + if (!ulp && capable(CAP_NET_ADMIN)) { + rcu_read_unlock(); + request_module("%s", name); + rcu_read_lock(); + ulp = tcp_ulp_find(name); + } +#endif + if (!ulp || !try_module_get(ulp->owner)) + ulp = NULL; + + rcu_read_unlock(); + return ulp; +} + +/* Attach new upper layer protocol to the list + * of available protocols. + */ +int tcp_register_ulp(struct tcp_ulp_ops *ulp) +{ + int ret = 0; + + spin_lock(&tcp_ulp_list_lock); + if (tcp_ulp_find(ulp->name)) { + pr_notice("%s already registered or non-unique name\n", + ulp->name); + ret = -EEXIST; + } else { + list_add_tail_rcu(&ulp->list, &tcp_ulp_list); + } + spin_unlock(&tcp_ulp_list_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(tcp_register_ulp); + +void tcp_unregister_ulp(struct tcp_ulp_ops *ulp) +{ + spin_lock(&tcp_ulp_list_lock); + list_del_rcu(&ulp->list); + spin_unlock(&tcp_ulp_list_lock); + + synchronize_rcu(); +} +EXPORT_SYMBOL_GPL(tcp_unregister_ulp); + +/* Build string with list of available upper layer protocl values */ +void tcp_get_available_ulp(char *buf, size_t maxlen) +{ + struct tcp_ulp_ops *ulp_ops; + size_t offs = 0; + + rcu_read_lock(); + list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) { + offs += snprintf(buf + offs, maxlen - offs, + "%s%s", + offs == 0 ? "" : " ", ulp_ops->name); + } + rcu_read_unlock(); +} + +void tcp_cleanup_ulp(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + if (!icsk->icsk_ulp_ops) + return; + + if (icsk->icsk_ulp_ops->release) + icsk->icsk_ulp_ops->release(sk); + module_put(icsk->icsk_ulp_ops->owner); +} + +/* Change upper layer protocol for socket */ +int tcp_set_ulp(struct sock *sk, const char *name) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + const struct tcp_ulp_ops *ulp_ops; + int err = 0; + + if (icsk->icsk_ulp_ops) + return -EEXIST; + + ulp_ops = __tcp_ulp_find_autoload(name); + if (!ulp_ops) + err = -ENOENT; + else + err = ulp_ops->init(sk); + + if (err) + goto out; + + icsk->icsk_ulp_ops = ulp_ops; + out: + return err; +} From e3b5616a347603a521fe3ac46f3194a60900e3a7 Mon Sep 17 00:00:00 2001 From: Dave Watson Date: Wed, 14 Jun 2017 11:37:26 -0700 Subject: [PATCH 2/4] tcp: export do_tcp_sendpages and tcp_rate_check_app_limited functions Export do_tcp_sendpages and tcp_rate_check_app_limited, since tls will need to sendpages while the socket is already locked. tcp_sendpage is exported, but requires the socket lock to not be held already. Signed-off-by: Aviad Yehezkel Signed-off-by: Ilya Lesokhin Signed-off-by: Boris Pismenny Signed-off-by: Dave Watson Signed-off-by: David S. Miller --- include/net/tcp.h | 2 ++ net/ipv4/tcp.c | 5 +++-- net/ipv4/tcp_rate.c | 1 + 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index b439f46f149c..e17ec286e8df 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -350,6 +350,8 @@ int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, int flags); +ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, + size_t size, int flags); void tcp_release_cb(struct sock *sk); void tcp_wfree(struct sk_buff *skb); void tcp_write_timer_handler(struct sock *sk); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index b06ee3086a0e..11e4ee281aa0 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -901,8 +901,8 @@ static int tcp_send_mss(struct sock *sk, int *size_goal, int flags) return mss_now; } -static ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, - size_t size, int flags) +ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, + size_t size, int flags) { struct tcp_sock *tp = tcp_sk(sk); int mss_now, size_goal; @@ -1032,6 +1032,7 @@ out_err: } return sk_stream_error(sk, flags, err); } +EXPORT_SYMBOL_GPL(do_tcp_sendpages); int tcp_sendpage(struct sock *sk, struct page *page, int offset, size_t size, int flags) diff --git a/net/ipv4/tcp_rate.c b/net/ipv4/tcp_rate.c index ad99569d4c1e..3330a370d306 100644 --- a/net/ipv4/tcp_rate.c +++ b/net/ipv4/tcp_rate.c @@ -185,3 +185,4 @@ void tcp_rate_check_app_limited(struct sock *sk) tp->app_limited = (tp->delivered + tcp_packets_in_flight(tp)) ? : 1; } +EXPORT_SYMBOL_GPL(tcp_rate_check_app_limited); From 3c4d7559159bfe1e3b94df3a657b2cda3a34e218 Mon Sep 17 00:00:00 2001 From: Dave Watson Date: Wed, 14 Jun 2017 11:37:39 -0700 Subject: [PATCH 3/4] tls: kernel TLS support Software implementation of transport layer security, implemented using ULP infrastructure. tcp proto_ops are replaced with tls equivalents of sendmsg and sendpage. Only symmetric crypto is done in the kernel, keys are passed by setsockopt after the handshake is complete. All control messages are supported via CMSG data - the actual symmetric encryption is the same, just the message type needs to be passed separately. For user API, please see Documentation patch. Pieces that can be shared between hw and sw implementation are in tls_main.c Signed-off-by: Boris Pismenny Signed-off-by: Ilya Lesokhin Signed-off-by: Aviad Yehezkel Signed-off-by: Dave Watson Signed-off-by: David S. Miller --- MAINTAINERS | 10 + include/linux/socket.h | 1 + include/net/tls.h | 237 ++++++++++++ include/uapi/linux/tls.h | 79 ++++ net/Kconfig | 1 + net/Makefile | 1 + net/tls/Kconfig | 12 + net/tls/Makefile | 7 + net/tls/tls_main.c | 487 ++++++++++++++++++++++++ net/tls/tls_sw.c | 772 +++++++++++++++++++++++++++++++++++++++ 10 files changed, 1607 insertions(+) create mode 100644 include/net/tls.h create mode 100644 include/uapi/linux/tls.h create mode 100644 net/tls/Kconfig create mode 100644 net/tls/Makefile create mode 100644 net/tls/tls_main.c create mode 100644 net/tls/tls_sw.c diff --git a/MAINTAINERS b/MAINTAINERS index 10f158ee95a3..71a74555afdf 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8978,6 +8978,16 @@ F: net/ipv6/ F: include/net/ip* F: arch/x86/net/* +NETWORKING [TLS] +M: Ilya Lesokhin +M: Aviad Yehezkel +M: Dave Watson +L: netdev@vger.kernel.org +S: Maintained +F: net/tls/* +F: include/uapi/linux/tls.h +F: include/net/tls.h + NETWORKING [IPSEC] M: Steffen Klassert M: Herbert Xu diff --git a/include/linux/socket.h b/include/linux/socket.h index 082027457825..8b13db5163cc 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -334,6 +334,7 @@ struct ucred { #define SOL_ALG 279 #define SOL_NFC 280 #define SOL_KCM 281 +#define SOL_TLS 282 /* IPX options */ #define IPX_TYPE 1 diff --git a/include/net/tls.h b/include/net/tls.h new file mode 100644 index 000000000000..b89d397dd62f --- /dev/null +++ b/include/net/tls.h @@ -0,0 +1,237 @@ +/* + * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. + * Copyright (c) 2016-2017, Dave Watson . All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#ifndef _TLS_OFFLOAD_H +#define _TLS_OFFLOAD_H + +#include + +#include + + +/* Maximum data size carried in a TLS record */ +#define TLS_MAX_PAYLOAD_SIZE ((size_t)1 << 14) + +#define TLS_HEADER_SIZE 5 +#define TLS_NONCE_OFFSET TLS_HEADER_SIZE + +#define TLS_CRYPTO_INFO_READY(info) ((info)->cipher_type) + +#define TLS_RECORD_TYPE_DATA 0x17 + +#define TLS_AAD_SPACE_SIZE 13 + +struct tls_sw_context { + struct crypto_aead *aead_send; + + /* Sending context */ + char aad_space[TLS_AAD_SPACE_SIZE]; + + unsigned int sg_plaintext_size; + int sg_plaintext_num_elem; + struct scatterlist sg_plaintext_data[MAX_SKB_FRAGS]; + + unsigned int sg_encrypted_size; + int sg_encrypted_num_elem; + struct scatterlist sg_encrypted_data[MAX_SKB_FRAGS]; + + /* AAD | sg_plaintext_data | sg_tag */ + struct scatterlist sg_aead_in[2]; + /* AAD | sg_encrypted_data (data contain overhead for hdr&iv&tag) */ + struct scatterlist sg_aead_out[2]; +}; + +enum { + TLS_PENDING_CLOSED_RECORD +}; + +struct tls_context { + union { + struct tls_crypto_info crypto_send; + struct tls12_crypto_info_aes_gcm_128 crypto_send_aes_gcm_128; + }; + + void *priv_ctx; + + u16 prepend_size; + u16 tag_size; + u16 overhead_size; + u16 iv_size; + char *iv; + u16 rec_seq_size; + char *rec_seq; + + struct scatterlist *partially_sent_record; + u16 partially_sent_offset; + unsigned long flags; + + u16 pending_open_record_frags; + int (*push_pending_record)(struct sock *sk, int flags); + void (*free_resources)(struct sock *sk); + + void (*sk_write_space)(struct sock *sk); + void (*sk_proto_close)(struct sock *sk, long timeout); + + int (*setsockopt)(struct sock *sk, int level, + int optname, char __user *optval, + unsigned int optlen); + int (*getsockopt)(struct sock *sk, int level, + int optname, char __user *optval, + int __user *optlen); +}; + +int wait_on_pending_writer(struct sock *sk, long *timeo); +int tls_sk_query(struct sock *sk, int optname, char __user *optval, + int __user *optlen); +int tls_sk_attach(struct sock *sk, int optname, char __user *optval, + unsigned int optlen); + + +int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx); +int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); +int tls_sw_sendpage(struct sock *sk, struct page *page, + int offset, size_t size, int flags); +void tls_sw_close(struct sock *sk, long timeout); + +void tls_sk_destruct(struct sock *sk, struct tls_context *ctx); +void tls_icsk_clean_acked(struct sock *sk); + +int tls_push_sg(struct sock *sk, struct tls_context *ctx, + struct scatterlist *sg, u16 first_offset, + int flags); +int tls_push_pending_closed_record(struct sock *sk, struct tls_context *ctx, + int flags, long *timeo); + +static inline bool tls_is_pending_closed_record(struct tls_context *ctx) +{ + return test_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags); +} + +static inline int tls_complete_pending_work(struct sock *sk, + struct tls_context *ctx, + int flags, long *timeo) +{ + int rc = 0; + + if (unlikely(sk->sk_write_pending)) + rc = wait_on_pending_writer(sk, timeo); + + if (!rc && tls_is_pending_closed_record(ctx)) + rc = tls_push_pending_closed_record(sk, ctx, flags, timeo); + + return rc; +} + +static inline bool tls_is_partially_sent_record(struct tls_context *ctx) +{ + return !!ctx->partially_sent_record; +} + +static inline bool tls_is_pending_open_record(struct tls_context *tls_ctx) +{ + return tls_ctx->pending_open_record_frags; +} + +static inline void tls_err_abort(struct sock *sk) +{ + sk->sk_err = -EBADMSG; + sk->sk_error_report(sk); +} + +static inline bool tls_bigint_increment(unsigned char *seq, int len) +{ + int i; + + for (i = len - 1; i >= 0; i--) { + ++seq[i]; + if (seq[i] != 0) + break; + } + + return (i == -1); +} + +static inline void tls_advance_record_sn(struct sock *sk, + struct tls_context *ctx) +{ + if (tls_bigint_increment(ctx->rec_seq, ctx->rec_seq_size)) + tls_err_abort(sk); + tls_bigint_increment(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, + ctx->iv_size); +} + +static inline void tls_fill_prepend(struct tls_context *ctx, + char *buf, + size_t plaintext_len, + unsigned char record_type) +{ + size_t pkt_len, iv_size = ctx->iv_size; + + pkt_len = plaintext_len + iv_size + ctx->tag_size; + + /* we cover nonce explicit here as well, so buf should be of + * size KTLS_DTLS_HEADER_SIZE + KTLS_DTLS_NONCE_EXPLICIT_SIZE + */ + buf[0] = record_type; + buf[1] = TLS_VERSION_MINOR(ctx->crypto_send.version); + buf[2] = TLS_VERSION_MAJOR(ctx->crypto_send.version); + /* we can use IV for nonce explicit according to spec */ + buf[3] = pkt_len >> 8; + buf[4] = pkt_len & 0xFF; + memcpy(buf + TLS_NONCE_OFFSET, + ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv_size); +} + +static inline struct tls_context *tls_get_ctx(const struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + + return icsk->icsk_ulp_data; +} + +static inline struct tls_sw_context *tls_sw_ctx( + const struct tls_context *tls_ctx) +{ + return (struct tls_sw_context *)tls_ctx->priv_ctx; +} + +static inline struct tls_offload_context *tls_offload_ctx( + const struct tls_context *tls_ctx) +{ + return (struct tls_offload_context *)tls_ctx->priv_ctx; +} + +int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg, + unsigned char *record_type); + +#endif /* _TLS_OFFLOAD_H */ diff --git a/include/uapi/linux/tls.h b/include/uapi/linux/tls.h new file mode 100644 index 000000000000..cc1d21db35d8 --- /dev/null +++ b/include/uapi/linux/tls.h @@ -0,0 +1,79 @@ +/* + * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#ifndef _UAPI_LINUX_TLS_H +#define _UAPI_LINUX_TLS_H + +#include +#include +#include +#include +#include + +/* TLS socket options */ +#define TLS_TX 1 /* Set transmit parameters */ + +/* Supported versions */ +#define TLS_VERSION_MINOR(ver) ((ver) & 0xFF) +#define TLS_VERSION_MAJOR(ver) (((ver) >> 8) & 0xFF) + +#define TLS_VERSION_NUMBER(id) ((((id##_VERSION_MAJOR) & 0xFF) << 8) | \ + ((id##_VERSION_MINOR) & 0xFF)) + +#define TLS_1_2_VERSION_MAJOR 0x3 +#define TLS_1_2_VERSION_MINOR 0x3 +#define TLS_1_2_VERSION TLS_VERSION_NUMBER(TLS_1_2) + +/* Supported ciphers */ +#define TLS_CIPHER_AES_GCM_128 51 +#define TLS_CIPHER_AES_GCM_128_IV_SIZE 8 +#define TLS_CIPHER_AES_GCM_128_KEY_SIZE 16 +#define TLS_CIPHER_AES_GCM_128_SALT_SIZE 4 +#define TLS_CIPHER_AES_GCM_128_TAG_SIZE 16 +#define TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE 8 + +#define TLS_SET_RECORD_TYPE 1 + +struct tls_crypto_info { + __u16 version; + __u16 cipher_type; +}; + +struct tls12_crypto_info_aes_gcm_128 { + struct tls_crypto_info info; + unsigned char iv[TLS_CIPHER_AES_GCM_128_IV_SIZE]; + unsigned char key[TLS_CIPHER_AES_GCM_128_KEY_SIZE]; + unsigned char salt[TLS_CIPHER_AES_GCM_128_SALT_SIZE]; + unsigned char rec_seq[TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE]; +}; + +#endif /* _UAPI_LINUX_TLS_H */ diff --git a/net/Kconfig b/net/Kconfig index 102f781a0131..7d57ef34b79c 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -55,6 +55,7 @@ menu "Networking options" source "net/packet/Kconfig" source "net/unix/Kconfig" +source "net/tls/Kconfig" source "net/xfrm/Kconfig" source "net/iucv/Kconfig" source "net/smc/Kconfig" diff --git a/net/Makefile b/net/Makefile index 9086ffbb5085..bed80fa398b7 100644 --- a/net/Makefile +++ b/net/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_LLC) += llc/ obj-$(CONFIG_NET) += ethernet/ 802/ sched/ netlink/ bpf/ obj-$(CONFIG_NETFILTER) += netfilter/ obj-$(CONFIG_INET) += ipv4/ +obj-$(CONFIG_TLS) += tls/ obj-$(CONFIG_XFRM) += xfrm/ obj-$(CONFIG_UNIX) += unix/ obj-$(CONFIG_NET) += ipv6/ diff --git a/net/tls/Kconfig b/net/tls/Kconfig new file mode 100644 index 000000000000..61e532964c82 --- /dev/null +++ b/net/tls/Kconfig @@ -0,0 +1,12 @@ +# +# TLS configuration +# +config TLS + tristate "Transport Layer Security support" + depends on NET + default m + ---help--- + Enable kernel support for TLS protocol. This allows symmetric + encryption handling of the TLS protocol to be done in-kernel. + + If unsure, say M. diff --git a/net/tls/Makefile b/net/tls/Makefile new file mode 100644 index 000000000000..a930fd1c4f7b --- /dev/null +++ b/net/tls/Makefile @@ -0,0 +1,7 @@ +# +# Makefile for the TLS subsystem. +# + +obj-$(CONFIG_TLS) += tls.o + +tls-y := tls_main.o tls_sw.o diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c new file mode 100644 index 000000000000..2ebc328bda96 --- /dev/null +++ b/net/tls/tls_main.c @@ -0,0 +1,487 @@ +/* + * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. + * Copyright (c) 2016-2017, Dave Watson . All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include + +#include +#include +#include +#include +#include + +#include + +MODULE_AUTHOR("Mellanox Technologies"); +MODULE_DESCRIPTION("Transport Layer Security Support"); +MODULE_LICENSE("Dual BSD/GPL"); + +static struct proto tls_base_prot; +static struct proto tls_sw_prot; + +int wait_on_pending_writer(struct sock *sk, long *timeo) +{ + int rc = 0; + DEFINE_WAIT_FUNC(wait, woken_wake_function); + + add_wait_queue(sk_sleep(sk), &wait); + while (1) { + if (!*timeo) { + rc = -EAGAIN; + break; + } + + if (signal_pending(current)) { + rc = sock_intr_errno(*timeo); + break; + } + + if (sk_wait_event(sk, timeo, !sk->sk_write_pending, &wait)) + break; + } + remove_wait_queue(sk_sleep(sk), &wait); + return rc; +} + +int tls_push_sg(struct sock *sk, + struct tls_context *ctx, + struct scatterlist *sg, + u16 first_offset, + int flags) +{ + int sendpage_flags = flags | MSG_SENDPAGE_NOTLAST; + int ret = 0; + struct page *p; + size_t size; + int offset = first_offset; + + size = sg->length - offset; + offset += sg->offset; + + while (1) { + if (sg_is_last(sg)) + sendpage_flags = flags; + + /* is sending application-limited? */ + tcp_rate_check_app_limited(sk); + p = sg_page(sg); +retry: + ret = do_tcp_sendpages(sk, p, offset, size, sendpage_flags); + + if (ret != size) { + if (ret > 0) { + offset += ret; + size -= ret; + goto retry; + } + + offset -= sg->offset; + ctx->partially_sent_offset = offset; + ctx->partially_sent_record = (void *)sg; + return ret; + } + + put_page(p); + sk_mem_uncharge(sk, sg->length); + sg = sg_next(sg); + if (!sg) + break; + + offset = sg->offset; + size = sg->length; + } + + clear_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags); + + return 0; +} + +static int tls_handle_open_record(struct sock *sk, int flags) +{ + struct tls_context *ctx = tls_get_ctx(sk); + + if (tls_is_pending_open_record(ctx)) + return ctx->push_pending_record(sk, flags); + + return 0; +} + +int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg, + unsigned char *record_type) +{ + struct cmsghdr *cmsg; + int rc = -EINVAL; + + for_each_cmsghdr(cmsg, msg) { + if (!CMSG_OK(msg, cmsg)) + return -EINVAL; + if (cmsg->cmsg_level != SOL_TLS) + continue; + + switch (cmsg->cmsg_type) { + case TLS_SET_RECORD_TYPE: + if (cmsg->cmsg_len < CMSG_LEN(sizeof(*record_type))) + return -EINVAL; + + if (msg->msg_flags & MSG_MORE) + return -EINVAL; + + rc = tls_handle_open_record(sk, msg->msg_flags); + if (rc) + return rc; + + *record_type = *(unsigned char *)CMSG_DATA(cmsg); + rc = 0; + break; + default: + return -EINVAL; + } + } + + return rc; +} + +int tls_push_pending_closed_record(struct sock *sk, struct tls_context *ctx, + int flags, long *timeo) +{ + struct scatterlist *sg; + u16 offset; + + if (!tls_is_partially_sent_record(ctx)) + return ctx->push_pending_record(sk, flags); + + sg = ctx->partially_sent_record; + offset = ctx->partially_sent_offset; + + ctx->partially_sent_record = NULL; + return tls_push_sg(sk, ctx, sg, offset, flags); +} + +static void tls_write_space(struct sock *sk) +{ + struct tls_context *ctx = tls_get_ctx(sk); + + if (!sk->sk_write_pending && tls_is_pending_closed_record(ctx)) { + gfp_t sk_allocation = sk->sk_allocation; + int rc; + long timeo = 0; + + sk->sk_allocation = GFP_ATOMIC; + rc = tls_push_pending_closed_record(sk, ctx, + MSG_DONTWAIT | + MSG_NOSIGNAL, + &timeo); + sk->sk_allocation = sk_allocation; + + if (rc < 0) + return; + } + + ctx->sk_write_space(sk); +} + +static void tls_sk_proto_close(struct sock *sk, long timeout) +{ + struct tls_context *ctx = tls_get_ctx(sk); + long timeo = sock_sndtimeo(sk, 0); + void (*sk_proto_close)(struct sock *sk, long timeout); + + lock_sock(sk); + + if (!tls_complete_pending_work(sk, ctx, 0, &timeo)) + tls_handle_open_record(sk, 0); + + if (ctx->partially_sent_record) { + struct scatterlist *sg = ctx->partially_sent_record; + + while (1) { + put_page(sg_page(sg)); + sk_mem_uncharge(sk, sg->length); + + if (sg_is_last(sg)) + break; + sg++; + } + } + ctx->free_resources(sk); + kfree(ctx->rec_seq); + kfree(ctx->iv); + + sk_proto_close = ctx->sk_proto_close; + kfree(ctx); + + release_sock(sk); + sk_proto_close(sk, timeout); +} + +static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval, + int __user *optlen) +{ + int rc = 0; + struct tls_context *ctx = tls_get_ctx(sk); + struct tls_crypto_info *crypto_info; + int len; + + if (get_user(len, optlen)) + return -EFAULT; + + if (!optval || (len < sizeof(*crypto_info))) { + rc = -EINVAL; + goto out; + } + + if (!ctx) { + rc = -EBUSY; + goto out; + } + + /* get user crypto info */ + crypto_info = &ctx->crypto_send; + + if (!TLS_CRYPTO_INFO_READY(crypto_info)) { + rc = -EBUSY; + goto out; + } + + if (len == sizeof(crypto_info)) { + rc = copy_to_user(optval, crypto_info, sizeof(*crypto_info)); + goto out; + } + + switch (crypto_info->cipher_type) { + case TLS_CIPHER_AES_GCM_128: { + struct tls12_crypto_info_aes_gcm_128 * + crypto_info_aes_gcm_128 = + container_of(crypto_info, + struct tls12_crypto_info_aes_gcm_128, + info); + + if (len != sizeof(*crypto_info_aes_gcm_128)) { + rc = -EINVAL; + goto out; + } + lock_sock(sk); + memcpy(crypto_info_aes_gcm_128->iv, ctx->iv, + TLS_CIPHER_AES_GCM_128_IV_SIZE); + release_sock(sk); + rc = copy_to_user(optval, + crypto_info_aes_gcm_128, + sizeof(*crypto_info_aes_gcm_128)); + break; + } + default: + rc = -EINVAL; + } + +out: + return rc; +} + +static int do_tls_getsockopt(struct sock *sk, int optname, + char __user *optval, int __user *optlen) +{ + int rc = 0; + + switch (optname) { + case TLS_TX: + rc = do_tls_getsockopt_tx(sk, optval, optlen); + break; + default: + rc = -ENOPROTOOPT; + break; + } + return rc; +} + +static int tls_getsockopt(struct sock *sk, int level, int optname, + char __user *optval, int __user *optlen) +{ + struct tls_context *ctx = tls_get_ctx(sk); + + if (level != SOL_TLS) + return ctx->getsockopt(sk, level, optname, optval, optlen); + + return do_tls_getsockopt(sk, optname, optval, optlen); +} + +static int do_tls_setsockopt_tx(struct sock *sk, char __user *optval, + unsigned int optlen) +{ + struct tls_crypto_info *crypto_info, tmp_crypto_info; + struct tls_context *ctx = tls_get_ctx(sk); + struct proto *prot = NULL; + int rc = 0; + + if (!optval || (optlen < sizeof(*crypto_info))) { + rc = -EINVAL; + goto out; + } + + rc = copy_from_user(&tmp_crypto_info, optval, sizeof(*crypto_info)); + if (rc) { + rc = -EFAULT; + goto out; + } + + /* check version */ + if (tmp_crypto_info.version != TLS_1_2_VERSION) { + rc = -ENOTSUPP; + goto out; + } + + /* get user crypto info */ + crypto_info = &ctx->crypto_send; + + /* Currently we don't support set crypto info more than one time */ + if (TLS_CRYPTO_INFO_READY(crypto_info)) + goto out; + + switch (tmp_crypto_info.cipher_type) { + case TLS_CIPHER_AES_GCM_128: { + if (optlen != sizeof(struct tls12_crypto_info_aes_gcm_128)) { + rc = -EINVAL; + goto out; + } + rc = copy_from_user( + crypto_info, + optval, + sizeof(struct tls12_crypto_info_aes_gcm_128)); + + if (rc) { + rc = -EFAULT; + goto err_crypto_info; + } + break; + } + default: + rc = -EINVAL; + goto out; + } + + ctx->sk_write_space = sk->sk_write_space; + sk->sk_write_space = tls_write_space; + + ctx->sk_proto_close = sk->sk_prot->close; + + /* currently SW is default, we will have ethtool in future */ + rc = tls_set_sw_offload(sk, ctx); + prot = &tls_sw_prot; + if (rc) + goto err_crypto_info; + + sk->sk_prot = prot; + goto out; + +err_crypto_info: + memset(crypto_info, 0, sizeof(*crypto_info)); +out: + return rc; +} + +static int do_tls_setsockopt(struct sock *sk, int optname, + char __user *optval, unsigned int optlen) +{ + int rc = 0; + + switch (optname) { + case TLS_TX: + lock_sock(sk); + rc = do_tls_setsockopt_tx(sk, optval, optlen); + release_sock(sk); + break; + default: + rc = -ENOPROTOOPT; + break; + } + return rc; +} + +static int tls_setsockopt(struct sock *sk, int level, int optname, + char __user *optval, unsigned int optlen) +{ + struct tls_context *ctx = tls_get_ctx(sk); + + if (level != SOL_TLS) + return ctx->setsockopt(sk, level, optname, optval, optlen); + + return do_tls_setsockopt(sk, optname, optval, optlen); +} + +static int tls_init(struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + struct tls_context *ctx; + int rc = 0; + + /* allocate tls context */ + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) { + rc = -ENOMEM; + goto out; + } + icsk->icsk_ulp_data = ctx; + ctx->setsockopt = sk->sk_prot->setsockopt; + ctx->getsockopt = sk->sk_prot->getsockopt; + sk->sk_prot = &tls_base_prot; +out: + return rc; +} + +static struct tcp_ulp_ops tcp_tls_ulp_ops __read_mostly = { + .name = "tls", + .owner = THIS_MODULE, + .init = tls_init, +}; + +static int __init tls_register(void) +{ + tls_base_prot = tcp_prot; + tls_base_prot.setsockopt = tls_setsockopt; + tls_base_prot.getsockopt = tls_getsockopt; + + tls_sw_prot = tls_base_prot; + tls_sw_prot.sendmsg = tls_sw_sendmsg; + tls_sw_prot.sendpage = tls_sw_sendpage; + tls_sw_prot.close = tls_sk_proto_close; + + tcp_register_ulp(&tcp_tls_ulp_ops); + + return 0; +} + +static void __exit tls_unregister(void) +{ + tcp_unregister_ulp(&tcp_tls_ulp_ops); +} + +module_init(tls_register); +module_exit(tls_unregister); diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c new file mode 100644 index 000000000000..fa596fa71ba7 --- /dev/null +++ b/net/tls/tls_sw.c @@ -0,0 +1,772 @@ +/* + * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved. + * Copyright (c) 2016-2017, Dave Watson . All rights reserved. + * Copyright (c) 2016-2017, Lance Chao . All rights reserved. + * Copyright (c) 2016, Fridolin Pokorny . All rights reserved. + * Copyright (c) 2016, Nikos Mavrogiannopoulos . All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include +#include + +#include + +static inline void tls_make_aad(int recv, + char *buf, + size_t size, + char *record_sequence, + int record_sequence_size, + unsigned char record_type) +{ + memcpy(buf, record_sequence, record_sequence_size); + + buf[8] = record_type; + buf[9] = TLS_1_2_VERSION_MAJOR; + buf[10] = TLS_1_2_VERSION_MINOR; + buf[11] = size >> 8; + buf[12] = size & 0xFF; +} + +static void trim_sg(struct sock *sk, struct scatterlist *sg, + int *sg_num_elem, unsigned int *sg_size, int target_size) +{ + int i = *sg_num_elem - 1; + int trim = *sg_size - target_size; + + if (trim <= 0) { + WARN_ON(trim < 0); + return; + } + + *sg_size = target_size; + while (trim >= sg[i].length) { + trim -= sg[i].length; + sk_mem_uncharge(sk, sg[i].length); + put_page(sg_page(&sg[i])); + i--; + + if (i < 0) + goto out; + } + + sg[i].length -= trim; + sk_mem_uncharge(sk, trim); + +out: + *sg_num_elem = i + 1; +} + +static void trim_both_sgl(struct sock *sk, int target_size) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + + trim_sg(sk, ctx->sg_plaintext_data, + &ctx->sg_plaintext_num_elem, + &ctx->sg_plaintext_size, + target_size); + + if (target_size > 0) + target_size += tls_ctx->overhead_size; + + trim_sg(sk, ctx->sg_encrypted_data, + &ctx->sg_encrypted_num_elem, + &ctx->sg_encrypted_size, + target_size); +} + +static int alloc_sg(struct sock *sk, int len, struct scatterlist *sg, + int *sg_num_elem, unsigned int *sg_size, + int first_coalesce) +{ + struct page_frag *pfrag; + unsigned int size = *sg_size; + int num_elem = *sg_num_elem, use = 0, rc = 0; + struct scatterlist *sge; + unsigned int orig_offset; + + len -= size; + pfrag = sk_page_frag(sk); + + while (len > 0) { + if (!sk_page_frag_refill(sk, pfrag)) { + rc = -ENOMEM; + goto out; + } + + use = min_t(int, len, pfrag->size - pfrag->offset); + + if (!sk_wmem_schedule(sk, use)) { + rc = -ENOMEM; + goto out; + } + + sk_mem_charge(sk, use); + size += use; + orig_offset = pfrag->offset; + pfrag->offset += use; + + sge = sg + num_elem - 1; + if (num_elem > first_coalesce && sg_page(sg) == pfrag->page && + sg->offset + sg->length == orig_offset) { + sg->length += use; + } else { + sge++; + sg_unmark_end(sge); + sg_set_page(sge, pfrag->page, use, orig_offset); + get_page(pfrag->page); + ++num_elem; + if (num_elem == MAX_SKB_FRAGS) { + rc = -ENOSPC; + break; + } + } + + len -= use; + } + goto out; + +out: + *sg_size = size; + *sg_num_elem = num_elem; + return rc; +} + +static int alloc_encrypted_sg(struct sock *sk, int len) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + int rc = 0; + + rc = alloc_sg(sk, len, ctx->sg_encrypted_data, + &ctx->sg_encrypted_num_elem, &ctx->sg_encrypted_size, 0); + + return rc; +} + +static int alloc_plaintext_sg(struct sock *sk, int len) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + int rc = 0; + + rc = alloc_sg(sk, len, ctx->sg_plaintext_data, + &ctx->sg_plaintext_num_elem, &ctx->sg_plaintext_size, + tls_ctx->pending_open_record_frags); + + return rc; +} + +static void free_sg(struct sock *sk, struct scatterlist *sg, + int *sg_num_elem, unsigned int *sg_size) +{ + int i, n = *sg_num_elem; + + for (i = 0; i < n; ++i) { + sk_mem_uncharge(sk, sg[i].length); + put_page(sg_page(&sg[i])); + } + *sg_num_elem = 0; + *sg_size = 0; +} + +static void tls_free_both_sg(struct sock *sk) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + + free_sg(sk, ctx->sg_encrypted_data, &ctx->sg_encrypted_num_elem, + &ctx->sg_encrypted_size); + + free_sg(sk, ctx->sg_plaintext_data, &ctx->sg_plaintext_num_elem, + &ctx->sg_plaintext_size); +} + +static int tls_do_encryption(struct tls_context *tls_ctx, + struct tls_sw_context *ctx, size_t data_len, + gfp_t flags) +{ + unsigned int req_size = sizeof(struct aead_request) + + crypto_aead_reqsize(ctx->aead_send); + struct aead_request *aead_req; + int rc; + + aead_req = kmalloc(req_size, flags); + if (!aead_req) + return -ENOMEM; + + ctx->sg_encrypted_data[0].offset += tls_ctx->prepend_size; + ctx->sg_encrypted_data[0].length -= tls_ctx->prepend_size; + + aead_request_set_tfm(aead_req, ctx->aead_send); + aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE); + aead_request_set_crypt(aead_req, ctx->sg_aead_in, ctx->sg_aead_out, + data_len, tls_ctx->iv); + rc = crypto_aead_encrypt(aead_req); + + ctx->sg_encrypted_data[0].offset -= tls_ctx->prepend_size; + ctx->sg_encrypted_data[0].length += tls_ctx->prepend_size; + + kfree(aead_req); + return rc; +} + +static int tls_push_record(struct sock *sk, int flags, + unsigned char record_type) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + int rc; + + sg_mark_end(ctx->sg_plaintext_data + ctx->sg_plaintext_num_elem - 1); + sg_mark_end(ctx->sg_encrypted_data + ctx->sg_encrypted_num_elem - 1); + + tls_make_aad(0, ctx->aad_space, ctx->sg_plaintext_size, + tls_ctx->rec_seq, tls_ctx->rec_seq_size, + record_type); + + tls_fill_prepend(tls_ctx, + page_address(sg_page(&ctx->sg_encrypted_data[0])) + + ctx->sg_encrypted_data[0].offset, + ctx->sg_plaintext_size, record_type); + + tls_ctx->pending_open_record_frags = 0; + set_bit(TLS_PENDING_CLOSED_RECORD, &tls_ctx->flags); + + rc = tls_do_encryption(tls_ctx, ctx, ctx->sg_plaintext_size, + sk->sk_allocation); + if (rc < 0) { + /* If we are called from write_space and + * we fail, we need to set this SOCK_NOSPACE + * to trigger another write_space in the future. + */ + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); + return rc; + } + + free_sg(sk, ctx->sg_plaintext_data, &ctx->sg_plaintext_num_elem, + &ctx->sg_plaintext_size); + + ctx->sg_encrypted_num_elem = 0; + ctx->sg_encrypted_size = 0; + + /* Only pass through MSG_DONTWAIT and MSG_NOSIGNAL flags */ + rc = tls_push_sg(sk, tls_ctx, ctx->sg_encrypted_data, 0, flags); + if (rc < 0 && rc != -EAGAIN) + tls_err_abort(sk); + + tls_advance_record_sn(sk, tls_ctx); + return rc; +} + +static int tls_sw_push_pending_record(struct sock *sk, int flags) +{ + return tls_push_record(sk, flags, TLS_RECORD_TYPE_DATA); +} + +static int zerocopy_from_iter(struct sock *sk, struct iov_iter *from, + int length) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + struct page *pages[MAX_SKB_FRAGS]; + + size_t offset; + ssize_t copied, use; + int i = 0; + unsigned int size = ctx->sg_plaintext_size; + int num_elem = ctx->sg_plaintext_num_elem; + int rc = 0; + int maxpages; + + while (length > 0) { + i = 0; + maxpages = ARRAY_SIZE(ctx->sg_plaintext_data) - num_elem; + if (maxpages == 0) { + rc = -EFAULT; + goto out; + } + copied = iov_iter_get_pages(from, pages, + length, + maxpages, &offset); + if (copied <= 0) { + rc = -EFAULT; + goto out; + } + + iov_iter_advance(from, copied); + + length -= copied; + size += copied; + while (copied) { + use = min_t(int, copied, PAGE_SIZE - offset); + + sg_set_page(&ctx->sg_plaintext_data[num_elem], + pages[i], use, offset); + sg_unmark_end(&ctx->sg_plaintext_data[num_elem]); + sk_mem_charge(sk, use); + + offset = 0; + copied -= use; + + ++i; + ++num_elem; + } + } + +out: + ctx->sg_plaintext_size = size; + ctx->sg_plaintext_num_elem = num_elem; + return rc; +} + +static int memcopy_from_iter(struct sock *sk, struct iov_iter *from, + int bytes) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + struct scatterlist *sg = ctx->sg_plaintext_data; + int copy, i, rc = 0; + + for (i = tls_ctx->pending_open_record_frags; + i < ctx->sg_plaintext_num_elem; ++i) { + copy = sg[i].length; + if (copy_from_iter( + page_address(sg_page(&sg[i])) + sg[i].offset, + copy, from) != copy) { + rc = -EFAULT; + goto out; + } + bytes -= copy; + + ++tls_ctx->pending_open_record_frags; + + if (!bytes) + break; + } + +out: + return rc; +} + +int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + int ret = 0; + int required_size; + long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); + bool eor = !(msg->msg_flags & MSG_MORE); + size_t try_to_copy, copied = 0; + unsigned char record_type = TLS_RECORD_TYPE_DATA; + int record_room; + bool full_record; + int orig_size; + + if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL)) + return -ENOTSUPP; + + lock_sock(sk); + + if (tls_complete_pending_work(sk, tls_ctx, msg->msg_flags, &timeo)) + goto send_end; + + if (unlikely(msg->msg_controllen)) { + ret = tls_proccess_cmsg(sk, msg, &record_type); + if (ret) + goto send_end; + } + + while (msg_data_left(msg)) { + if (sk->sk_err) { + ret = sk->sk_err; + goto send_end; + } + + orig_size = ctx->sg_plaintext_size; + full_record = false; + try_to_copy = msg_data_left(msg); + record_room = TLS_MAX_PAYLOAD_SIZE - ctx->sg_plaintext_size; + if (try_to_copy >= record_room) { + try_to_copy = record_room; + full_record = true; + } + + required_size = ctx->sg_plaintext_size + try_to_copy + + tls_ctx->overhead_size; + + if (!sk_stream_memory_free(sk)) + goto wait_for_sndbuf; +alloc_encrypted: + ret = alloc_encrypted_sg(sk, required_size); + if (ret) { + if (ret != -ENOSPC) + goto wait_for_memory; + + /* Adjust try_to_copy according to the amount that was + * actually allocated. The difference is due + * to max sg elements limit + */ + try_to_copy -= required_size - ctx->sg_encrypted_size; + full_record = true; + } + + if (full_record || eor) { + ret = zerocopy_from_iter(sk, &msg->msg_iter, + try_to_copy); + if (ret) + goto fallback_to_reg_send; + + copied += try_to_copy; + ret = tls_push_record(sk, msg->msg_flags, record_type); + if (!ret) + continue; + if (ret == -EAGAIN) + goto send_end; + + copied -= try_to_copy; +fallback_to_reg_send: + iov_iter_revert(&msg->msg_iter, + ctx->sg_plaintext_size - orig_size); + trim_sg(sk, ctx->sg_plaintext_data, + &ctx->sg_plaintext_num_elem, + &ctx->sg_plaintext_size, + orig_size); + } + + required_size = ctx->sg_plaintext_size + try_to_copy; +alloc_plaintext: + ret = alloc_plaintext_sg(sk, required_size); + if (ret) { + if (ret != -ENOSPC) + goto wait_for_memory; + + /* Adjust try_to_copy according to the amount that was + * actually allocated. The difference is due + * to max sg elements limit + */ + try_to_copy -= required_size - ctx->sg_plaintext_size; + full_record = true; + + trim_sg(sk, ctx->sg_encrypted_data, + &ctx->sg_encrypted_num_elem, + &ctx->sg_encrypted_size, + ctx->sg_plaintext_size + + tls_ctx->overhead_size); + } + + ret = memcopy_from_iter(sk, &msg->msg_iter, try_to_copy); + if (ret) + goto trim_sgl; + + copied += try_to_copy; + if (full_record || eor) { +push_record: + ret = tls_push_record(sk, msg->msg_flags, record_type); + if (ret) { + if (ret == -ENOMEM) + goto wait_for_memory; + + goto send_end; + } + } + + continue; + +wait_for_sndbuf: + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); +wait_for_memory: + ret = sk_stream_wait_memory(sk, &timeo); + if (ret) { +trim_sgl: + trim_both_sgl(sk, orig_size); + goto send_end; + } + + if (tls_is_pending_closed_record(tls_ctx)) + goto push_record; + + if (ctx->sg_encrypted_size < required_size) + goto alloc_encrypted; + + goto alloc_plaintext; + } + +send_end: + ret = sk_stream_error(sk, msg->msg_flags, ret); + + release_sock(sk); + return copied ? copied : ret; +} + +int tls_sw_sendpage(struct sock *sk, struct page *page, + int offset, size_t size, int flags) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + int ret = 0; + long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT); + bool eor; + size_t orig_size = size; + unsigned char record_type = TLS_RECORD_TYPE_DATA; + struct scatterlist *sg; + bool full_record; + int record_room; + + if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | + MSG_SENDPAGE_NOTLAST)) + return -ENOTSUPP; + + /* No MSG_EOR from splice, only look at MSG_MORE */ + eor = !(flags & (MSG_MORE | MSG_SENDPAGE_NOTLAST)); + + lock_sock(sk); + + sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk); + + if (tls_complete_pending_work(sk, tls_ctx, flags, &timeo)) + goto sendpage_end; + + /* Call the sk_stream functions to manage the sndbuf mem. */ + while (size > 0) { + size_t copy, required_size; + + if (sk->sk_err) { + ret = sk->sk_err; + goto sendpage_end; + } + + full_record = false; + record_room = TLS_MAX_PAYLOAD_SIZE - ctx->sg_plaintext_size; + copy = size; + if (copy >= record_room) { + copy = record_room; + full_record = true; + } + required_size = ctx->sg_plaintext_size + copy + + tls_ctx->overhead_size; + + if (!sk_stream_memory_free(sk)) + goto wait_for_sndbuf; +alloc_payload: + ret = alloc_encrypted_sg(sk, required_size); + if (ret) { + if (ret != -ENOSPC) + goto wait_for_memory; + + /* Adjust copy according to the amount that was + * actually allocated. The difference is due + * to max sg elements limit + */ + copy -= required_size - ctx->sg_plaintext_size; + full_record = true; + } + + get_page(page); + sg = ctx->sg_plaintext_data + ctx->sg_plaintext_num_elem; + sg_set_page(sg, page, copy, offset); + ctx->sg_plaintext_num_elem++; + + sk_mem_charge(sk, copy); + offset += copy; + size -= copy; + ctx->sg_plaintext_size += copy; + tls_ctx->pending_open_record_frags = ctx->sg_plaintext_num_elem; + + if (full_record || eor || + ctx->sg_plaintext_num_elem == + ARRAY_SIZE(ctx->sg_plaintext_data)) { +push_record: + ret = tls_push_record(sk, flags, record_type); + if (ret) { + if (ret == -ENOMEM) + goto wait_for_memory; + + goto sendpage_end; + } + } + continue; +wait_for_sndbuf: + set_bit(SOCK_NOSPACE, &sk->sk_socket->flags); +wait_for_memory: + ret = sk_stream_wait_memory(sk, &timeo); + if (ret) { + trim_both_sgl(sk, ctx->sg_plaintext_size); + goto sendpage_end; + } + + if (tls_is_pending_closed_record(tls_ctx)) + goto push_record; + + goto alloc_payload; + } + +sendpage_end: + if (orig_size > size) + ret = orig_size - size; + else + ret = sk_stream_error(sk, flags, ret); + + release_sock(sk); + return ret; +} + +void tls_sw_free_resources(struct sock *sk) +{ + struct tls_context *tls_ctx = tls_get_ctx(sk); + struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx); + + if (ctx->aead_send) + crypto_free_aead(ctx->aead_send); + + tls_free_both_sg(sk); + + kfree(ctx); +} + +int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx) +{ + char keyval[TLS_CIPHER_AES_GCM_128_KEY_SIZE]; + struct tls_crypto_info *crypto_info; + struct tls12_crypto_info_aes_gcm_128 *gcm_128_info; + struct tls_sw_context *sw_ctx; + u16 nonce_size, tag_size, iv_size, rec_seq_size; + char *iv, *rec_seq; + int rc = 0; + + if (!ctx) { + rc = -EINVAL; + goto out; + } + + if (ctx->priv_ctx) { + rc = -EEXIST; + goto out; + } + + sw_ctx = kzalloc(sizeof(*sw_ctx), GFP_KERNEL); + if (!sw_ctx) { + rc = -ENOMEM; + goto out; + } + + ctx->priv_ctx = (struct tls_offload_context *)sw_ctx; + ctx->free_resources = tls_sw_free_resources; + + crypto_info = &ctx->crypto_send; + switch (crypto_info->cipher_type) { + case TLS_CIPHER_AES_GCM_128: { + nonce_size = TLS_CIPHER_AES_GCM_128_IV_SIZE; + tag_size = TLS_CIPHER_AES_GCM_128_TAG_SIZE; + iv_size = TLS_CIPHER_AES_GCM_128_IV_SIZE; + iv = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->iv; + rec_seq_size = TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE; + rec_seq = + ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->rec_seq; + gcm_128_info = + (struct tls12_crypto_info_aes_gcm_128 *)crypto_info; + break; + } + default: + rc = -EINVAL; + goto out; + } + + ctx->prepend_size = TLS_HEADER_SIZE + nonce_size; + ctx->tag_size = tag_size; + ctx->overhead_size = ctx->prepend_size + ctx->tag_size; + ctx->iv_size = iv_size; + ctx->iv = kmalloc(iv_size + TLS_CIPHER_AES_GCM_128_SALT_SIZE, + GFP_KERNEL); + if (!ctx->iv) { + rc = -ENOMEM; + goto out; + } + memcpy(ctx->iv, gcm_128_info->salt, TLS_CIPHER_AES_GCM_128_SALT_SIZE); + memcpy(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv, iv_size); + ctx->rec_seq_size = rec_seq_size; + ctx->rec_seq = kmalloc(rec_seq_size, GFP_KERNEL); + if (!ctx->rec_seq) { + rc = -ENOMEM; + goto free_iv; + } + memcpy(ctx->rec_seq, rec_seq, rec_seq_size); + + sg_init_table(sw_ctx->sg_encrypted_data, + ARRAY_SIZE(sw_ctx->sg_encrypted_data)); + sg_init_table(sw_ctx->sg_plaintext_data, + ARRAY_SIZE(sw_ctx->sg_plaintext_data)); + + sg_init_table(sw_ctx->sg_aead_in, 2); + sg_set_buf(&sw_ctx->sg_aead_in[0], sw_ctx->aad_space, + sizeof(sw_ctx->aad_space)); + sg_unmark_end(&sw_ctx->sg_aead_in[1]); + sg_chain(sw_ctx->sg_aead_in, 2, sw_ctx->sg_plaintext_data); + sg_init_table(sw_ctx->sg_aead_out, 2); + sg_set_buf(&sw_ctx->sg_aead_out[0], sw_ctx->aad_space, + sizeof(sw_ctx->aad_space)); + sg_unmark_end(&sw_ctx->sg_aead_out[1]); + sg_chain(sw_ctx->sg_aead_out, 2, sw_ctx->sg_encrypted_data); + + if (!sw_ctx->aead_send) { + sw_ctx->aead_send = crypto_alloc_aead("gcm(aes)", 0, 0); + if (IS_ERR(sw_ctx->aead_send)) { + rc = PTR_ERR(sw_ctx->aead_send); + sw_ctx->aead_send = NULL; + goto free_rec_seq; + } + } + + ctx->push_pending_record = tls_sw_push_pending_record; + + memcpy(keyval, gcm_128_info->key, TLS_CIPHER_AES_GCM_128_KEY_SIZE); + + rc = crypto_aead_setkey(sw_ctx->aead_send, keyval, + TLS_CIPHER_AES_GCM_128_KEY_SIZE); + if (rc) + goto free_aead; + + rc = crypto_aead_setauthsize(sw_ctx->aead_send, ctx->tag_size); + if (!rc) + goto out; + +free_aead: + crypto_free_aead(sw_ctx->aead_send); + sw_ctx->aead_send = NULL; +free_rec_seq: + kfree(ctx->rec_seq); + ctx->rec_seq = NULL; +free_iv: + kfree(ctx->iv); + ctx->iv = NULL; +out: + return rc; +} From 99c195fb4eea405160ade58f74f62aed19b1822c Mon Sep 17 00:00:00 2001 From: Dave Watson Date: Wed, 14 Jun 2017 11:37:51 -0700 Subject: [PATCH 4/4] tls: Documentation Add documentation for the tcp ULP tls interface. Signed-off-by: Boris Pismenny Signed-off-by: Dave Watson Signed-off-by: David S. Miller --- Documentation/networking/tls.txt | 135 +++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 Documentation/networking/tls.txt diff --git a/Documentation/networking/tls.txt b/Documentation/networking/tls.txt new file mode 100644 index 000000000000..77ed00631c12 --- /dev/null +++ b/Documentation/networking/tls.txt @@ -0,0 +1,135 @@ +Overview +======== + +Transport Layer Security (TLS) is a Upper Layer Protocol (ULP) that runs over +TCP. TLS provides end-to-end data integrity and confidentiality. + +User interface +============== + +Creating a TLS connection +------------------------- + +First create a new TCP socket and set the TLS ULP. + + sock = socket(AF_INET, SOCK_STREAM, 0); + setsockopt(sock, SOL_TCP, TCP_ULP, "tls", sizeof("tls")); + +Setting the TLS ULP allows us to set/get TLS socket options. Currently +only the symmetric encryption is handled in the kernel. After the TLS +handshake is complete, we have all the parameters required to move the +data-path to the kernel. There is a separate socket option for moving +the transmit and the receive into the kernel. + + /* From linux/tls.h */ + struct tls_crypto_info { + unsigned short version; + unsigned short cipher_type; + }; + + struct tls12_crypto_info_aes_gcm_128 { + struct tls_crypto_info info; + unsigned char iv[TLS_CIPHER_AES_GCM_128_IV_SIZE]; + unsigned char key[TLS_CIPHER_AES_GCM_128_KEY_SIZE]; + unsigned char salt[TLS_CIPHER_AES_GCM_128_SALT_SIZE]; + unsigned char rec_seq[TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE]; + }; + + + struct tls12_crypto_info_aes_gcm_128 crypto_info; + + crypto_info.info.version = TLS_1_2_VERSION; + crypto_info.info.cipher_type = TLS_CIPHER_AES_GCM_128; + memcpy(crypto_info.iv, iv_write, TLS_CIPHER_AES_GCM_128_IV_SIZE); + memcpy(crypto_info.rec_seq, seq_number_write, + TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE); + memcpy(crypto_info.key, cipher_key_write, TLS_CIPHER_AES_GCM_128_KEY_SIZE); + memcpy(crypto_info.salt, implicit_iv_write, TLS_CIPHER_AES_GCM_128_SALT_SIZE); + + setsockopt(sock, SOL_TLS, TLS_TX, &crypto_info, sizeof(crypto_info)); + +Sending TLS application data +---------------------------- + +After setting the TLS_TX socket option all application data sent over this +socket is encrypted using TLS and the parameters provided in the socket option. +For example, we can send an encrypted hello world record as follows: + + const char *msg = "hello world\n"; + send(sock, msg, strlen(msg)); + +send() data is directly encrypted from the userspace buffer provided +to the encrypted kernel send buffer if possible. + +The sendfile system call will send the file's data over TLS records of maximum +length (2^14). + + file = open(filename, O_RDONLY); + fstat(file, &stat); + sendfile(sock, file, &offset, stat.st_size); + +TLS records are created and sent after each send() call, unless +MSG_MORE is passed. MSG_MORE will delay creation of a record until +MSG_MORE is not passed, or the maximum record size is reached. + +The kernel will need to allocate a buffer for the encrypted data. +This buffer is allocated at the time send() is called, such that +either the entire send() call will return -ENOMEM (or block waiting +for memory), or the encryption will always succeed. If send() returns +-ENOMEM and some data was left on the socket buffer from a previous +call using MSG_MORE, the MSG_MORE data is left on the socket buffer. + +Send TLS control messages +------------------------- + +Other than application data, TLS has control messages such as alert +messages (record type 21) and handshake messages (record type 22), etc. +These messages can be sent over the socket by providing the TLS record type +via a CMSG. For example the following function sends @data of @length bytes +using a record of type @record_type. + +/* send TLS control message using record_type */ + static int klts_send_ctrl_message(int sock, unsigned char record_type, + void *data, size_t length) + { + struct msghdr msg = {0}; + int cmsg_len = sizeof(record_type); + struct cmsghdr *cmsg; + char buf[CMSG_SPACE(cmsg_len)]; + struct iovec msg_iov; /* Vector of data to send/receive into. */ + + msg.msg_control = buf; + msg.msg_controllen = sizeof(buf); + cmsg = CMSG_FIRSTHDR(&msg); + cmsg->cmsg_level = SOL_TLS; + cmsg->cmsg_type = TLS_SET_RECORD_TYPE; + cmsg->cmsg_len = CMSG_LEN(cmsg_len); + *CMSG_DATA(cmsg) = record_type; + msg.msg_controllen = cmsg->cmsg_len; + + msg_iov.iov_base = data; + msg_iov.iov_len = length; + msg.msg_iov = &msg_iov; + msg.msg_iovlen = 1; + + return sendmsg(sock, &msg, 0); + } + +Control message data should be provided unencrypted, and will be +encrypted by the kernel. + +Integrating in to userspace TLS library +--------------------------------------- + +At a high level, the kernel TLS ULP is a replacement for the record +layer of a userspace TLS library. + +A patchset to OpenSSL to use ktls as the record layer is here: + +https://github.com/Mellanox/tls-openssl + +An example of calling send directly after a handshake using +gnutls. Since it doesn't implement a full record layer, control +messages are not supported: + +https://github.com/Mellanox/tls-af_ktls_tool