From c845f5f3590ef4669fe5464f8a42be6442cd174b Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 23 Oct 2023 20:21:54 +0100 Subject: [PATCH] net/tcp: Add TCP-AO config and structures Introduce new kernel config option and common structures as well as helpers to be used by TCP-AO code. Co-developed-by: Francesco Ruggeri Signed-off-by: Francesco Ruggeri Co-developed-by: Salam Noureddine Signed-off-by: Salam Noureddine Signed-off-by: Dmitry Safonov Acked-by: David Ahern Signed-off-by: David S. Miller --- include/linux/tcp.h | 9 +++- include/net/tcp.h | 8 +--- include/net/tcp_ao.h | 90 ++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/tcp.h | 2 + net/ipv4/Kconfig | 13 ++++++ 5 files changed, 114 insertions(+), 8 deletions(-) create mode 100644 include/net/tcp_ao.h diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 6df715b6e51d..64e7b560fa79 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -447,13 +447,18 @@ struct tcp_sock { bool syn_smc; /* SYN includes SMC */ #endif -#ifdef CONFIG_TCP_MD5SIG -/* TCP AF-Specific parts; only used by MD5 Signature support so far */ +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) +/* TCP AF-Specific parts; only used by TCP-AO/MD5 Signature support so far */ const struct tcp_sock_af_ops *af_specific; +#ifdef CONFIG_TCP_MD5SIG /* TCP MD5 Signature Option information */ struct tcp_md5sig_info __rcu *md5sig_info; #endif +#ifdef CONFIG_TCP_AO + struct tcp_ao_info __rcu *ao_info; +#endif +#endif /* TCP fastopen related information */ struct tcp_fastopen_request *fastopen_req; diff --git a/include/net/tcp.h b/include/net/tcp.h index f6e2db5292b5..3153712faa3d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -37,6 +37,7 @@ #include #include #include +#include #include #include #include @@ -1688,12 +1689,7 @@ static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) tp->retransmit_skb_hint = NULL; } -union tcp_md5_addr { - struct in_addr a4; -#if IS_ENABLED(CONFIG_IPV6) - struct in6_addr a6; -#endif -}; +#define tcp_md5_addr tcp_ao_addr /* - key database */ struct tcp_md5sig_key { diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h new file mode 100644 index 000000000000..af76e1c47bea --- /dev/null +++ b/include/net/tcp_ao.h @@ -0,0 +1,90 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _TCP_AO_H +#define _TCP_AO_H + +#define TCP_AO_KEY_ALIGN 1 +#define __tcp_ao_key_align __aligned(TCP_AO_KEY_ALIGN) + +union tcp_ao_addr { + struct in_addr a4; +#if IS_ENABLED(CONFIG_IPV6) + struct in6_addr a6; +#endif +}; + +struct tcp_ao_hdr { + u8 kind; + u8 length; + u8 keyid; + u8 rnext_keyid; +}; + +struct tcp_ao_key { + struct hlist_node node; + union tcp_ao_addr addr; + u8 key[TCP_AO_MAXKEYLEN] __tcp_ao_key_align; + unsigned int tcp_sigpool_id; + unsigned int digest_size; + u8 prefixlen; + u8 family; + u8 keylen; + u8 keyflags; + u8 sndid; + u8 rcvid; + u8 maclen; + struct rcu_head rcu; + u8 traffic_keys[]; +}; + +static inline u8 *rcv_other_key(struct tcp_ao_key *key) +{ + return key->traffic_keys; +} + +static inline u8 *snd_other_key(struct tcp_ao_key *key) +{ + return key->traffic_keys + key->digest_size; +} + +static inline int tcp_ao_maclen(const struct tcp_ao_key *key) +{ + return key->maclen; +} + +static inline int tcp_ao_len(const struct tcp_ao_key *key) +{ + return tcp_ao_maclen(key) + sizeof(struct tcp_ao_hdr); +} + +static inline unsigned int tcp_ao_digest_size(struct tcp_ao_key *key) +{ + return key->digest_size; +} + +static inline int tcp_ao_sizeof_key(const struct tcp_ao_key *key) +{ + return sizeof(struct tcp_ao_key) + (key->digest_size << 1); +} + +struct tcp_ao_info { + /* List of tcp_ao_key's */ + struct hlist_head head; + /* current_key and rnext_key aren't maintained on listen sockets. + * Their purpose is to cache keys on established connections, + * saving needless lookups. Never dereference any of them from + * listen sockets. + * ::current_key may change in RX to the key that was requested by + * the peer, please use READ_ONCE()/WRITE_ONCE() in order to avoid + * load/store tearing. + * Do the same for ::rnext_key, if you don't hold socket lock + * (it's changed only by userspace request in setsockopt()). + */ + struct tcp_ao_key *current_key; + struct tcp_ao_key *rnext_key; + u32 flags; + __be32 lisn; + __be32 risn; + struct rcu_head rcu; +}; + +#endif /* _TCP_AO_H */ diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 8aa3916e14f6..74a1267baac5 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -361,6 +361,8 @@ struct tcp_diag_md5sig { __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; }; +#define TCP_AO_MAXKEYLEN 80 + /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */ #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1 diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 89e2ab023272..8e94ed7c56a0 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -744,6 +744,19 @@ config DEFAULT_TCP_CONG config TCP_SIGPOOL tristate +config TCP_AO + bool "TCP: Authentication Option (RFC5925)" + select CRYPTO + select TCP_SIGPOOL + depends on 64BIT && IPV6 != m # seq-number extension needs WRITE_ONCE(u64) + help + TCP-AO specifies the use of stronger Message Authentication Codes (MACs), + protects against replays for long-lived TCP connections, and + provides more details on the association of security with TCP + connections than TCP MD5 (See RFC5925) + + If unsure, say N. + config TCP_MD5SIG bool "TCP: MD5 Signature Option support (RFC2385)" select CRYPTO