This is similar to TCP MD5 in functionality but it's sufficiently different that userspace interface and wire formats are incompatible. Compared to TCP-MD5 more algorithms are supported and multiple keys can be used on the same connection but there is still no negotiation mechanism. Expected use-case is protecting long-duration BGP/LDP connections between routers using pre-shared keys. This is an early version which focuses on getting the correct signature bits on the wire in a way that can interoperate with other implementations. Major issues still need to be solved: * Lockdep warnings (incorrect context for initializing shash) * Support for aes-128-cmac-96 * Binding keys to addresses and/or interfaces similar to md5 * Sequence Number Extension A small test suite is here: https://github.com/cdleonard/tcp-authopt-test The tests work by establishing loopback TCP connections, capturing packets with scapy and validating signatures. Changes for yabgp are here: https://github.com/cdleonard/yabgp/commits/tcp_authopt The patched version of yabgp can establish a BGP session protected by TCP Authentication Option with a Cisco IOS-XR router. I'm especially interested in feedback regarding ABI and testing. Signed-off-by: Leonard Crestez <cdleonard@xxxxxxxxx> --- Allocating shash requires user context but holding a struct tfm in tcp_authopt_key_info allocated by tcp_set_authopt_key doesn't work because when a server handshake is succesful the server socket needs to copy the keys of the listen socket in softirq context. Sharing the crypto_shash tfm between listen and server sockets doesn't work well either because keys for each connection (and each syn packet) are different and the hmac or cmac key is per-tfm rather than per shash_desc. The server sockets would need locking to access their shared tfm. Simplest solution would be to allocate one shash for each CPU and borrow it for each hashing operation. TCP-MD5 allocates one ahash globally but that can't work for hmac/cmac because of setkey. Signed-off-by: Leonard Crestez <cdleonard@xxxxxxxxx> --- include/linux/tcp.h | 6 + include/net/tcp.h | 1 + include/net/tcp_authopt.h | 103 ++++++ include/uapi/linux/snmp.h | 1 + include/uapi/linux/tcp.h | 40 +++ net/ipv4/Kconfig | 14 + net/ipv4/Makefile | 1 + net/ipv4/proc.c | 1 + net/ipv4/tcp.c | 7 + net/ipv4/tcp_authopt.c | 718 ++++++++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 17 + net/ipv4/tcp_ipv4.c | 5 + net/ipv4/tcp_minisocks.c | 2 + net/ipv4/tcp_output.c | 65 +++- 14 files changed, 980 insertions(+), 1 deletion(-) create mode 100644 include/net/tcp_authopt.h create mode 100644 net/ipv4/tcp_authopt.c diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 48d8a363319e..cfddfc720b00 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -140,10 +140,12 @@ struct tcp_request_sock { static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) { return (struct tcp_request_sock *)req; } +struct tcp_authopt_info; + struct tcp_sock { /* inet_connection_sock has to be the first member of tcp_sock */ struct inet_connection_sock inet_conn; u16 tcp_header_len; /* Bytes of tcp header to send */ u16 gso_segs; /* Max number of segs per GSO packet */ @@ -403,10 +405,14 @@ struct tcp_sock { /* TCP MD5 Signature Option information */ struct tcp_md5sig_info __rcu *md5sig_info; #endif +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_info __rcu *authopt_info; +#endif + /* TCP fastopen related information */ struct tcp_fastopen_request *fastopen_req; /* fastopen_rsk points to request_sock that resulted in this big * socket. Used to retransmit SYNACKs etc. */ diff --git a/include/net/tcp.h b/include/net/tcp.h index 17df9b047ee4..767611fd5ec3 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -182,10 +182,11 @@ void tcp_time_wait(struct sock *sk, int state, int timeo); #define TCPOPT_WINDOW 3 /* Window scaling */ #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ #define TCPOPT_SACK 5 /* SACK Block */ #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ +#define TCPOPT_AUTHOPT 29 /* Auth Option (RFC5925) */ #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ #define TCPOPT_EXP 254 /* Experimental */ /* Magic number to be after the option value for sharing TCP * experimental options. See draft-ietf-tcpm-experimental-options-00.txt diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h new file mode 100644 index 000000000000..aaab5c955984 --- /dev/null +++ b/include/net/tcp_authopt.h @@ -0,0 +1,103 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _LINUX_TCP_AUTHOPT_H +#define _LINUX_TCP_AUTHOPT_H + +#include <uapi/linux/tcp.h> + +/* Representation of a Master Key Tuple as per RFC5925 */ +struct tcp_authopt_key_info { + struct hlist_node node; + /* Local identifier */ + u32 local_id; + u32 flags; + /* Wire identifiers */ + u8 send_id, recv_id; + u8 alg; + u8 keylen; + u8 key[TCP_AUTHOPT_MAXKEYLEN]; + u8 maclen; + u8 traffic_key_len; + struct rcu_head rcu; +}; + +/* Per-socket information regarding tcp_authopt */ +struct tcp_authopt_info { + struct hlist_head head; + u32 local_send_id; + u32 src_isn; + u32 dst_isn; + u8 rnextkeyid; + struct rcu_head rcu; +}; + +#ifdef CONFIG_TCP_AUTHOPT +struct tcp_authopt_key_info *tcp_authopt_key_info_lookup(struct sock *sk, int key_id); +void tcp_authopt_clear(struct sock *sk); +int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen); +int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen); +int tcp_authopt_hash( + char *hash_location, + struct tcp_authopt_key_info *key, + struct sock *sk, struct sk_buff *skb); +int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct request_sock *req); +static inline int tcp_authopt_openreq( + struct sock *newsk, + const struct sock *oldsk, + struct request_sock *req) +{ + if (!rcu_dereference(tcp_sk(oldsk)->authopt_info)) + return 0; + else + return __tcp_authopt_openreq(newsk, oldsk, req); +} +int __tcp_authopt_inbound_check( + struct sock *sk, + struct sk_buff *skb, + struct tcp_authopt_info *info); +static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_authopt_info *info = rcu_dereference(tcp_sk(sk)->authopt_info); + + if (info) + return __tcp_authopt_inbound_check(sk, skb, info); + else + return 0; +} +#else +static inline struct tcp_authopt_key_info *tcp_authopt_key_info_lookup( + struct sock *sk, + int key_id) +{ + return NULL; +} +static inline int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen) +{ + return -ENOPROTOOPT; +} +static inline void tcp_authopt_clear(struct sock *sk) +{ +} +static inline int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) +{ + return -ENOPROTOOPT; +} +static inline int tcp_authopt_hash( + char *hash_location, + struct tcp_authopt_key_info *key, + struct sock *sk, struct sk_buff *skb) +{ + return -EINVAL; +} +static inline int tcp_authopt_openreq(struct sock *newsk, + const struct sock *oldsk, + struct request_sock *req) +{ + return 0; +} +static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb) +{ + return 0; +} +#endif + +#endif /* _LINUX_TCP_AUTHOPT_H */ diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index 904909d020e2..1d96030889a1 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -290,10 +290,11 @@ enum LINUX_MIB_TCPDUPLICATEDATAREHASH, /* TCPDuplicateDataRehash */ LINUX_MIB_TCPDSACKRECVSEGS, /* TCPDSACKRecvSegs */ LINUX_MIB_TCPDSACKIGNOREDDUBIOUS, /* TCPDSACKIgnoredDubious */ LINUX_MIB_TCPMIGRATEREQSUCCESS, /* TCPMigrateReqSuccess */ LINUX_MIB_TCPMIGRATEREQFAILURE, /* TCPMigrateReqFailure */ + LINUX_MIB_TCPAUTHOPTFAILURE, /* TCPAuthOptFailure */ __LINUX_MIB_MAX }; /* linux Xfrm mib definitions */ enum diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 8fc09e8638b3..30b8ad769871 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -126,10 +126,12 @@ enum { #define TCP_INQ 36 /* Notify bytes available to read as a cmsg on read */ #define TCP_CM_INQ TCP_INQ #define TCP_TX_DELAY 37 /* delay outgoing packets by XX usec */ +#define TCP_AUTHOPT 38 /* TCP Authentication Option (RFC2385) */ +#define TCP_AUTHOPT_KEY 39 /* TCP Authentication Option update key (RFC2385) */ #define TCP_REPAIR_ON 1 #define TCP_REPAIR_OFF 0 #define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */ @@ -340,10 +342,48 @@ struct tcp_diag_md5sig { __u16 tcpm_keylen; __be32 tcpm_addr[4]; __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; }; +/* for TCP_AUTHOPT socket option */ +#define TCP_AUTHOPT_MAXKEYLEN 80 + +#define TCP_AUTHOPT_ALG_HMAC_SHA_1_96 1 +#define TCP_AUTHOPT_ALG_AES_128_CMAC_96 2 + +/* Per-socket options */ +struct tcp_authopt { + /* No flags currently defined */ + __u32 flags; + /* local_id of preferred output key */ + __u32 local_send_id; +}; + +/* Delete the key by local_id and ignore all fields */ +#define TCP_AUTHOPT_KEY_DEL (1 << 0) +/* Exclude TCP options from signature */ +#define TCP_AUTHOPT_KEY_EXCLUDE_OPTS (1 << 1) + +/* Per-key options + * Each key is identified by a non-zero local_id which is managed by the application. + */ +struct tcp_authopt_key { + /* Mix of TCP_AUTHOPT_KEY_ flags */ + __u32 flags; + /* Local identifier */ + __u32 local_id; + /* SendID on the network */ + __u8 send_id; + /* RecvID on the network */ + __u8 recv_id; + /* One of the TCP_AUTHOPT_ALG_* constant */ + __u8 alg; + /* Length of the key buffer */ + __u8 keylen; + __u8 key[TCP_AUTHOPT_MAXKEYLEN]; +}; + /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */ #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1 struct tcp_zerocopy_receive { __u64 address; /* in: address of mapping */ diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 87983e70f03f..6459f4ea6f1d 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -740,5 +740,19 @@ config TCP_MD5SIG RFC2385 specifies a method of giving MD5 protection to TCP sessions. Its main (only?) use is to protect BGP sessions between core routers on the Internet. If unsure, say N. + +config TCP_AUTHOPT + bool "TCP: Authentication Option support (RFC5925)" + select CRYPTO + select CRYPTO_SHA1 + select CRYPTO_HMAC + select CRYPTO_AES + select CRYPTO_CMAC + help + RFC5925 specifies a new method of giving protection to TCP sessions. + Its intended use is to protect BGP sessions between core routers + on the Internet. It obsoletes TCP MD5 (RFC2385) but is incompatible. + + If unsure, say N. diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index bbdd9c44f14e..d336f32ce177 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -59,10 +59,11 @@ obj-$(CONFIG_TCP_CONG_NV) += tcp_nv.o obj-$(CONFIG_TCP_CONG_VENO) += tcp_veno.o obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o +obj-$(CONFIG_TCP_AUTHOPT) += tcp_authopt.o obj-$(CONFIG_NET_SOCK_MSG) += tcp_bpf.o obj-$(CONFIG_BPF_SYSCALL) += udp_bpf.o obj-$(CONFIG_NETLABEL) += cipso_ipv4.o obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \ diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index b0d3a09dc84e..61dd06f8389c 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -295,10 +295,11 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TcpDuplicateDataRehash", LINUX_MIB_TCPDUPLICATEDATAREHASH), SNMP_MIB_ITEM("TCPDSACKRecvSegs", LINUX_MIB_TCPDSACKRECVSEGS), SNMP_MIB_ITEM("TCPDSACKIgnoredDubious", LINUX_MIB_TCPDSACKIGNOREDDUBIOUS), SNMP_MIB_ITEM("TCPMigrateReqSuccess", LINUX_MIB_TCPMIGRATEREQSUCCESS), SNMP_MIB_ITEM("TCPMigrateReqFailure", LINUX_MIB_TCPMIGRATEREQFAILURE), + SNMP_MIB_ITEM("TCPAuthOptFailure", LINUX_MIB_TCPAUTHOPTFAILURE), SNMP_MIB_SENTINEL }; static void icmpmsg_put_line(struct seq_file *seq, unsigned long *vals, unsigned short *type, int count) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 8cb44040ec68..3c29bb579d27 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -271,10 +271,11 @@ #include <net/icmp.h> #include <net/inet_common.h> #include <net/tcp.h> #include <net/mptcp.h> +#include <net/tcp_authopt.h> #include <net/xfrm.h> #include <net/ip.h> #include <net/sock.h> #include <linux/uaccess.h> @@ -3573,10 +3574,16 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname, case TCP_MD5SIG: case TCP_MD5SIG_EXT: err = tp->af_specific->md5_parse(sk, optname, optval, optlen); break; #endif + case TCP_AUTHOPT: + err = tcp_set_authopt(sk, optval, optlen); + break; + case TCP_AUTHOPT_KEY: + err = tcp_set_authopt_key(sk, optval, optlen); + break; case TCP_USER_TIMEOUT: /* Cap the max time in ms TCP will retry or probe the window * before giving up and aborting (ETIMEDOUT) a connection. */ if (val < 0) diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c new file mode 100644 index 000000000000..40ee83fc0afe --- /dev/null +++ b/net/ipv4/tcp_authopt.c @@ -0,0 +1,718 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <linux/kernel.h> +#include <net/tcp.h> +#include <net/tcp_authopt.h> +#include <crypto/hash.h> +#include <trace/events/tcp.h> + +/* All current algorithms have a mac length of 12 but crypto API digestsize can be larger */ +#define TCP_AUTHOPT_MAXMACBUF 20 +#define TCP_AUTHOPT_MAX_TRAFFIC_KEY_LEN 20 + +struct tcp_authopt_key_info *__tcp_authopt_key_info_lookup(struct sock *sk, + struct tcp_authopt_info *info, + int key_id) +{ + struct tcp_authopt_key_info *key; + + hlist_for_each_entry_rcu(key, &info->head, node, lockdep_sock_is_held(sk)) + if (key->local_id == key_id) + return key; + + return NULL; +} + +struct tcp_authopt_key_info *tcp_authopt_key_info_lookup(struct sock *sk, int key_id) +{ + struct tcp_authopt_info *info; + struct tcp_authopt_key_info *key; + + info = rcu_dereference_check(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + if (!info) + return NULL; + + hlist_for_each_entry_rcu(key, &info->head, node, lockdep_sock_is_held(sk)) + if (key->local_id == key_id) + return key; + + return NULL; +} + +int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_authopt opt; + struct tcp_authopt_info *info; + + if (optlen < sizeof(opt)) + return -EINVAL; + + WARN_ON(!lockdep_sock_is_held(sk)); + if (copy_from_sockptr(&opt, optval, sizeof(opt))) + return -EFAULT; + + info = rcu_dereference_check(tp->authopt_info, lockdep_sock_is_held(sk)); + if (!info) { + info = kmalloc(sizeof(*info), GFP_KERNEL | __GFP_ZERO); + if (!info) + return -ENOMEM; + + sk_nocaps_add(sk, NETIF_F_GSO_MASK); + INIT_HLIST_HEAD(&info->head); + rcu_assign_pointer(tp->authopt_info, info); + } + info->local_send_id = opt.local_send_id; + + return 0; +} + +static void tcp_authopt_key_del(struct sock *sk, struct tcp_authopt_key_info *key) +{ + hlist_del_rcu(&key->node); + atomic_sub(sizeof(*key), &sk->sk_omem_alloc); + kfree_rcu(key, rcu); +} + +/* free info and keys but don't touch tp->authopt_info */ +void __tcp_authopt_info_free(struct sock *sk, struct tcp_authopt_info *info) +{ + struct hlist_node *n; + struct tcp_authopt_key_info *key; + + hlist_for_each_entry_safe(key, n, &info->head, node) + tcp_authopt_key_del(sk, key); + kfree_rcu(info, rcu); +} + +/* free everything and clear tcp_sock.authopt_info to NULL */ +void tcp_authopt_clear(struct sock *sk) +{ + struct tcp_authopt_info *info; + + info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + if (info) { + __tcp_authopt_info_free(sk, info); + tcp_sk(sk)->authopt_info = NULL; + } +} + +int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) +{ + struct tcp_authopt_key opt; + struct tcp_authopt_info *info; + struct tcp_authopt_key_info *key_info; + u8 traffic_key_len, maclen; + + if (optlen < sizeof(opt)) + return -EINVAL; + + if (copy_from_sockptr(&opt, optval, sizeof(opt))) + return -EFAULT; + + if (opt.keylen > TCP_AUTHOPT_MAXKEYLEN) + return -EINVAL; + + if (opt.local_id == 0) + return -EINVAL; + + /* must set authopt before setting keys */ + info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + if (!info) + return -EINVAL; + + if (opt.flags & TCP_AUTHOPT_KEY_DEL) { + key_info = __tcp_authopt_key_info_lookup(sk, info, opt.local_id); + if (!key_info) + return -ENOENT; + tcp_authopt_key_del(sk, key_info); + return 0; + } + + /* check the algorithm */ + if (opt.alg == TCP_AUTHOPT_ALG_HMAC_SHA_1_96) { + traffic_key_len = 20; + maclen = 12; + } else if (opt.alg == TCP_AUTHOPT_ALG_AES_128_CMAC_96) { + traffic_key_len = 16; + maclen = 12; + } else { + return -EINVAL; + } + + /* If an old value exists for same local_id it is deleted */ + key_info = __tcp_authopt_key_info_lookup(sk, info, opt.local_id); + if (key_info) + tcp_authopt_key_del(sk, key_info); + key_info = sock_kmalloc(sk, sizeof(*key_info), GFP_KERNEL | __GFP_ZERO); + if (!key_info) + return -ENOMEM; + key_info->local_id = opt.local_id; + key_info->flags = opt.flags & TCP_AUTHOPT_KEY_EXCLUDE_OPTS; + key_info->send_id = opt.send_id; + key_info->recv_id = opt.recv_id; + key_info->alg = opt.alg; + key_info->keylen = opt.keylen; + memcpy(key_info->key, opt.key, opt.keylen); + key_info->maclen = maclen; + key_info->traffic_key_len = traffic_key_len; + hlist_add_head_rcu(&key_info->node, &info->head); + + return 0; +} + +static int tcp_authopt_clone_keys(struct sock *newsk, + const struct sock *oldsk, + struct tcp_authopt_info *new_info, + struct tcp_authopt_info *old_info) +{ + struct tcp_authopt_key_info *old_key; + struct tcp_authopt_key_info *new_key; + + hlist_for_each_entry_rcu(old_key, &old_info->head, node, lockdep_sock_is_held(sk)) { + new_key = sock_kmalloc(newsk, sizeof(*new_key), GFP_KERNEL); + if (!new_key) + return -ENOMEM; + memcpy(new_key, old_key, sizeof(*new_key)); + hlist_add_head_rcu(&new_key->node, &new_info->head); + } + + return 0; +} + +/** Called to create accepted sockets. + * + * Need to copy authopt info from listen socket. + */ +int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct request_sock *req) +{ + struct tcp_authopt_info *old_info; + struct tcp_authopt_info *new_info; + int err; + + old_info = rcu_dereference(tcp_sk(oldsk)->authopt_info); + if (!old_info) + return 0; + + new_info = kmalloc(sizeof(*new_info), GFP_KERNEL | __GFP_ZERO); + if (!new_info) + return -ENOMEM; + + sk_nocaps_add(newsk, NETIF_F_GSO_MASK); + new_info->src_isn = tcp_rsk(req)->snt_isn; + new_info->dst_isn = tcp_rsk(req)->rcv_isn; + new_info->local_send_id = old_info->local_send_id; + INIT_HLIST_HEAD(&new_info->head); + err = tcp_authopt_clone_keys(newsk, oldsk, new_info, old_info); + if (err) { + __tcp_authopt_info_free(newsk, new_info); + return err; + } + rcu_assign_pointer(tcp_sk(newsk)->authopt_info, new_info); + + return 0; +} + +/* feed traffic key into shash */ +static int tcp_authopt_shash_traffic_key(struct shash_desc *desc, + struct sock *sk, + struct sk_buff *skb, + bool input, + bool ipv6) +{ + struct tcphdr *th = tcp_hdr(skb); + int err; + __be32 sisn, disn; + + // RFC5926 section 3.1.1.1 + err = crypto_shash_update(desc, "\x01TCP-AO", 7); + if (err) + return err; + + /* Addresses from packet on input and from socket on output + * This is because on output MAC is computed before prepending IP header + */ + if (input) { + if (ipv6) + err = crypto_shash_update(desc, (u8 *)&ipv6_hdr(skb)->saddr, 32); + else + err = crypto_shash_update(desc, (u8 *)&ip_hdr(skb)->saddr, 8); + if (err) + return err; + } else { + if (ipv6) { + struct in6_addr *saddr; + struct in6_addr *daddr; + + saddr = &sk->sk_v6_rcv_saddr; + daddr = &sk->sk_v6_daddr; + err = crypto_shash_update(desc, (u8 *)&sk->sk_v6_rcv_saddr, 16); + if (err) + return err; + err = crypto_shash_update(desc, (u8 *)&sk->sk_v6_daddr, 16); + if (err) + return err; + } else { + err = crypto_shash_update(desc, (u8 *)&sk->sk_rcv_saddr, 4); + if (err) + return err; + err = crypto_shash_update(desc, (u8 *)&sk->sk_daddr, 4); + if (err) + return err; + } + } + + /* TCP ports from header */ + err = crypto_shash_update(desc, (u8 *)&th->source, 4); + if (err) + return err; + + /* special cases for SYN and SYN/ACK */ + if (th->syn && !th->ack) { + sisn = th->seq; + disn = 0; + } else if (th->syn && th->ack) { + sisn = th->seq; + disn = htonl(ntohl(th->ack_seq) - 1); + } else { + struct tcp_authopt_info *authopt_info = rcu_dereference(tcp_sk(sk)->authopt_info); + /* authopt was removed from under us, maybe socket deleted? */ + /* should pass this as an argument instead */ + if (!authopt_info) + return -EINVAL; + /* Initial sequence numbers for ESTABLISHED connections from info */ + if (input) { + sisn = htonl(authopt_info->dst_isn); + disn = htonl(authopt_info->src_isn); + } else { + sisn = htonl(authopt_info->src_isn); + disn = htonl(authopt_info->dst_isn); + } + } + + err = crypto_shash_update(desc, (u8 *)&sisn, 4); + if (err) + return err; + err = crypto_shash_update(desc, (u8 *)&disn, 4); + if (err) + return err; + + /* This hardcodes sha1 digestsize in bits: */ + err = crypto_shash_update(desc, "\x00\xa0", 2); + if (err) + return err; + + return 0; +} + +static int tcp_authopt_get_traffic_key(struct sock *sk, + struct sk_buff *skb, + struct tcp_authopt_key_info *key, + bool input, + bool ipv6, + u8 *traffic_key) +{ + SHASH_DESC_ON_STACK(desc, kdf_tfm); + struct crypto_shash *kdf_tfm; + int err; + + if (key->alg == TCP_AUTHOPT_ALG_HMAC_SHA_1_96) + kdf_tfm = crypto_alloc_shash("hmac(sha1)", 0, 0); + else + return -EINVAL; + if (IS_ERR(kdf_tfm)) + return PTR_ERR(kdf_tfm); + if (WARN_ON(crypto_shash_digestsize(kdf_tfm) != key->traffic_key_len)) { + err = -ENOBUFS; + goto out; + } + + err = crypto_shash_setkey(kdf_tfm, key->key, key->keylen); + if (err) + goto out; + + desc->tfm = kdf_tfm; + err = crypto_shash_init(desc); + if (err) + goto out; + + err = tcp_authopt_shash_traffic_key(desc, sk, skb, input, ipv6); + if (err) + goto out; + + err = crypto_shash_final(desc, traffic_key); + if (err) + goto out; + //printk("traffic_key: %*phN\n", 20, traffic_key); + +out: + crypto_free_shash(kdf_tfm); + return err; +} + +static int crypto_shash_update_zero(struct shash_desc *desc, int len) +{ + u8 zero = 0; + int i, err; + + for (i = 0; i < len; ++i) { + err = crypto_shash_update(desc, &zero, 1); + if (err) + return err; + } + + return 0; +} + +static int tcp_authopt_hash_tcp4_pseudoheader(struct shash_desc *desc, + __be32 saddr, + __be32 daddr, + int nbytes) +{ + struct tcp4_pseudohdr phdr = { + .saddr = saddr, + .daddr = daddr, + .pad = 0, + .protocol = IPPROTO_TCP, + .len = htons(nbytes) + }; + return crypto_shash_update(desc, (u8 *)&phdr, sizeof(phdr)); +} + +static int tcp_authopt_hash_tcp6_pseudoheader(struct shash_desc *desc, + struct in6_addr *saddr, + struct in6_addr *daddr, + u32 plen) +{ + int err; + u32 buf[2]; + + buf[0] = htonl(plen); + buf[1] = htonl(IPPROTO_TCP); + + err = crypto_shash_update(desc, (u8 *)saddr, sizeof(*saddr)); + if (err) + return err; + err = crypto_shash_update(desc, (u8 *)daddr, sizeof(*daddr)); + if (err) + return err; + return crypto_shash_update(desc, (u8 *)&buf, sizeof(buf)); +} + +/* TCP authopt as found in header */ +struct tcphdr_authopt { + u8 num; + u8 len; + u8 keyid; + u8 rnextkeyid; + u8 mac[0]; +}; + +/* Find TCP_AUTHOPT in header. + * + * Returns pointer to TCP_AUTHOPT or NULL if not found. + */ +static u8 *tcp_authopt_find_option(struct tcphdr *th) +{ + int length = (th->doff << 2) - sizeof(*th); + u8 *ptr = (u8 *)(th + 1); + + while (length >= 2) { + int opcode = *ptr++; + int opsize; + + switch (opcode) { + case TCPOPT_EOL: + return NULL; + case TCPOPT_NOP: + length--; + continue; + default: + if (length < 2) + return NULL; + opsize = *ptr++; + if (opsize < 2) + return NULL; + if (opsize > length) + return NULL; + if (opcode == TCPOPT_AUTHOPT) + return ptr - 2; + } + ptr += opsize - 2; + length -= opsize; + } + return NULL; +} + +/** Hash tcphdr options. + * If include_options is false then only the TCPOPT_AUTHOPT option itself is hashed + * Maybe we could skip option parsing by assuming the AUTHOPT header is at hash_location-4? + */ +static int tcp_authopt_hash_opts(struct shash_desc *desc, + struct tcphdr *th, + bool include_options) +{ + int err; + /* start of options */ + u8 *tcp_opts = (u8 *)(th + 1); + /* end of options */ + u8 *tcp_data = ((u8 *)th) + th->doff * 4; + /* pointer to TCPOPT_AUTHOPT */ + u8 *authopt_ptr = tcp_authopt_find_option(th); + u8 authopt_len; + + if (!authopt_ptr) + return -EINVAL; + authopt_len = *(authopt_ptr + 1); + + if (include_options) { + err = crypto_shash_update(desc, tcp_opts, authopt_ptr - tcp_opts + 4); + if (err) + return err; + err = crypto_shash_update_zero(desc, authopt_len - 4); + if (err) + return err; + err = crypto_shash_update(desc, + authopt_ptr + authopt_len, + tcp_data - (authopt_ptr + authopt_len)); + if (err) + return err; + } else { + err = crypto_shash_update(desc, authopt_ptr, 4); + if (err) + return err; + err = crypto_shash_update_zero(desc, authopt_len - 4); + if (err) + return err; + } + + return 0; +} + +static int skb_shash_frags(struct shash_desc *desc, + struct sk_buff *skb) +{ + struct sk_buff *frag_iter; + int err, i; + + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + skb_frag_t *f = &skb_shinfo(skb)->frags[i]; + u32 p_off, p_len, copied; + struct page *p; + u8 *vaddr; + + skb_frag_foreach_page(f, skb_frag_off(f), skb_frag_size(f), + p, p_off, p_len, copied) { + vaddr = kmap_atomic(p); + err = crypto_shash_update(desc, vaddr + p_off, p_len); + kunmap_atomic(vaddr); + if (err) + return err; + } + } + + skb_walk_frags(skb, frag_iter) { + err = skb_shash_frags(desc, frag_iter); + if (err) + return err; + } + + return 0; +} + +static int tcp_authopt_hash_packet(struct crypto_shash *tfm, + struct sock *sk, + struct sk_buff *skb, + bool input, + bool ipv6, + bool include_options, + u8 *macbuf) +{ + struct tcphdr *th = tcp_hdr(skb); + SHASH_DESC_ON_STACK(desc, tfm); + int err; + + /* NOTE: SNE unimplemented */ + __be32 sne = 0; + + desc->tfm = tfm; + err = crypto_shash_init(desc); + if (err) + return err; + + err = crypto_shash_update(desc, (u8 *)&sne, 4); + if (err) + return err; + + if (ipv6) { + struct in6_addr *saddr; + struct in6_addr *daddr; + + if (input) { + saddr = &ipv6_hdr(skb)->saddr; + daddr = &ipv6_hdr(skb)->daddr; + } else { + saddr = &sk->sk_v6_rcv_saddr; + daddr = &sk->sk_v6_daddr; + } + err = tcp_authopt_hash_tcp6_pseudoheader(desc, saddr, daddr, skb->len); + if (err) + return err; + } else { + __be32 saddr; + __be32 daddr; + + if (input) { + saddr = ip_hdr(skb)->saddr; + daddr = ip_hdr(skb)->daddr; + } else { + saddr = sk->sk_rcv_saddr; + daddr = sk->sk_daddr; + } + err = tcp_authopt_hash_tcp4_pseudoheader(desc, saddr, daddr, skb->len); + if (err) + return err; + } + + // TCP header with checksum set to zero + { + struct tcphdr hashed_th = *th; + + hashed_th.check = 0; + err = crypto_shash_update(desc, (u8 *)&hashed_th, sizeof(hashed_th)); + if (err) + return err; + } + + // TCP options + err = tcp_authopt_hash_opts(desc, th, include_options); + if (err) + return err; + + // Rest of SKB->data + err = crypto_shash_update(desc, (u8 *)th + th->doff * 4, skb_headlen(skb) - th->doff * 4); + if (err) + return err; + + err = skb_shash_frags(desc, skb); + if (err) + return err; + + return crypto_shash_final(desc, macbuf); +} + +int __tcp_authopt_calc_mac(struct sock *sk, + struct sk_buff *skb, + struct tcp_authopt_key_info *key, + bool input, + char *macbuf) +{ + struct crypto_shash *mac_tfm; + u8 traffic_key[TCP_AUTHOPT_MAX_TRAFFIC_KEY_LEN]; + int err; + bool ipv6 = (sk->sk_family != AF_INET); + + if (sk->sk_family != AF_INET && sk->sk_family != AF_INET6) + return -EINVAL; + if (WARN_ON(key->traffic_key_len > sizeof(traffic_key))) + return -ENOBUFS; + + err = tcp_authopt_get_traffic_key(sk, skb, key, input, ipv6, traffic_key); + if (err) + return err; + + if (key->alg == TCP_AUTHOPT_ALG_HMAC_SHA_1_96) + mac_tfm = crypto_alloc_shash("hmac(sha1)", 0, 0); + else + return -EINVAL; + if (IS_ERR(mac_tfm)) + return PTR_ERR(mac_tfm); + if (crypto_shash_digestsize(mac_tfm) > TCP_AUTHOPT_MAXMACBUF) { + err = -EINVAL; + goto out; + } + err = crypto_shash_setkey(mac_tfm, traffic_key, key->traffic_key_len); + if (err) + goto out; + + err = tcp_authopt_hash_packet(mac_tfm, + sk, + skb, + input, + ipv6, + !(key->flags & TCP_AUTHOPT_KEY_EXCLUDE_OPTS), + macbuf); + //printk("mac: %*phN\n", key->maclen, macbuf); + +out: + crypto_free_shash(mac_tfm); + return err; +} + +int tcp_authopt_hash(char *hash_location, + struct tcp_authopt_key_info *key, + struct sock *sk, + struct sk_buff *skb) +{ + /* MAC inside option is truncated to 12 bytes but crypto API needs output + * buffer to be large enough so we use a buffer on the stack. + */ + u8 macbuf[TCP_AUTHOPT_MAXMACBUF]; + int err; + + if (WARN_ON(key->maclen > sizeof(macbuf))) + return -ENOBUFS; + + err = __tcp_authopt_calc_mac(sk, skb, key, false, macbuf); + if (err) { + memset(hash_location, 0, key->maclen); + return err; + } + memcpy(hash_location, macbuf, key->maclen); + + return 0; +} + +static struct tcp_authopt_key_info *tcp_authopt_inbound_key_lookup(struct sock *sk, + struct tcp_authopt_info *info, + u8 recv_id) +{ + struct tcp_authopt_key_info *key; + + /* multiple matches will cause occasional failures */ + hlist_for_each_entry_rcu(key, &info->head, node, 0) + if (key->recv_id == recv_id) + return key; + + return NULL; +} + +int __tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb, struct tcp_authopt_info *info) +{ + struct tcphdr *th = (struct tcphdr *)skb_transport_header(skb); + struct tcphdr_authopt *opt = (struct tcphdr_authopt *)tcp_authopt_find_option(th); + struct tcp_authopt_key_info *key; + u8 macbuf[16]; + int err; + + /* wrong, should reject if missing key: */ + if (!opt) + return 0; + + key = tcp_authopt_inbound_key_lookup(sk, info, opt->keyid); + /* bad inbound key len */ + if (key->maclen + 4 != opt->len) + return -EINVAL; + + err = __tcp_authopt_calc_mac(sk, skb, key, true, macbuf); + if (err) + return err; + + if (memcmp(macbuf, opt->mac, key->maclen)) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + net_info_ratelimited("TCP Authentication Failed\n"); + return -EINVAL; + } + + return 0; +} diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 149ceb5c94ff..9cd540c42d3f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -70,10 +70,11 @@ #include <linux/sysctl.h> #include <linux/kernel.h> #include <linux/prefetch.h> #include <net/dst.h> #include <net/tcp.h> +#include <net/tcp_authopt.h> #include <net/inet_common.h> #include <linux/ipsec.h> #include <asm/unaligned.h> #include <linux/errqueue.h> #include <trace/events/tcp.h> @@ -5935,18 +5936,34 @@ void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb) if (!icsk->icsk_ca_initialized) tcp_init_congestion_control(sk); tcp_init_buffer_space(sk); } +static void tcp_authopt_finish_connect(struct sock *sk, struct sk_buff *skb) +{ +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_info *info; + + info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + if (!info) + return; + + info->src_isn = ntohl(tcp_hdr(skb)->ack_seq) - 1; + info->dst_isn = ntohl(tcp_hdr(skb)->seq); +#endif +} + void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); tcp_set_state(sk, TCP_ESTABLISHED); icsk->icsk_ack.lrcvtime = tcp_jiffies32; + tcp_authopt_finish_connect(sk, skb); + if (skb) { icsk->icsk_af_ops->sk_rx_dst_set(sk, skb); security_inet_conn_established(sk, skb); sk_mark_napi_id(sk, skb); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index b9dc2d6197be..b0e25c6d40eb 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -60,10 +60,11 @@ #include <net/net_namespace.h> #include <net/icmp.h> #include <net/inet_hashtables.h> #include <net/tcp.h> +#include <net/tcp_authopt.h> #include <net/transp_v6.h> #include <net/ipv6.h> #include <net/inet_common.h> #include <net/timewait_sock.h> #include <net/xfrm.h> @@ -2059,10 +2060,13 @@ int tcp_v4_rcv(struct sk_buff *skb) goto discard_and_relse; if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif)) goto discard_and_relse; + if (tcp_authopt_inbound_check(sk, skb)) + goto discard_and_relse; + nf_reset_ct(skb); if (tcp_filter(sk, skb)) goto discard_and_relse; th = (const struct tcphdr *)skb->data; @@ -2256,10 +2260,11 @@ void tcp_v4_destroy_sock(struct sock *sk) tcp_clear_md5_list(sk); kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu); tp->md5sig_info = NULL; } #endif + tcp_authopt_clear(sk); /* Clean up a referenced TCP bind bucket. */ if (inet_csk(sk)->icsk_bind_hash) inet_put_port(sk); diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 0a4f3f16140a..4d7d86547b0e 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -24,10 +24,11 @@ #include <linux/slab.h> #include <linux/sysctl.h> #include <linux/workqueue.h> #include <linux/static_key.h> #include <net/tcp.h> +#include <net/tcp_authopt.h> #include <net/inet_common.h> #include <net/xfrm.h> #include <net/busy_poll.h> static bool tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win) @@ -539,10 +540,11 @@ struct sock *tcp_create_openreq_child(const struct sock *sk, #ifdef CONFIG_TCP_MD5SIG newtp->md5sig_info = NULL; /*XXX*/ if (newtp->af_specific->md5_lookup(sk, newsk)) newtp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED; #endif + tcp_authopt_openreq(newsk, sk, req); if (skb->len >= TCP_MSS_DEFAULT + newtp->tcp_header_len) newicsk->icsk_ack.last_seg_size = skb->len - newtp->tcp_header_len; newtp->rx_opt.mss_clamp = req->mss; tcp_ecn_openreq_child(newtp, req); newtp->fastopen_req = NULL; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 29553fce8502..2a680acca73d 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -37,10 +37,11 @@ #define pr_fmt(fmt) "TCP: " fmt #include <net/tcp.h> #include <net/mptcp.h> +#include <net/tcp_authopt.h> #include <linux/compiler.h> #include <linux/gfp.h> #include <linux/module.h> #include <linux/static_key.h> @@ -411,10 +412,11 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp) #define OPTION_SACK_ADVERTISE (1 << 0) #define OPTION_TS (1 << 1) #define OPTION_MD5 (1 << 2) #define OPTION_WSCALE (1 << 3) +#define OPTION_AUTHOPT (1 << 4) #define OPTION_FAST_OPEN_COOKIE (1 << 8) #define OPTION_SMC (1 << 9) #define OPTION_MPTCP (1 << 10) static void smc_options_write(__be32 *ptr, u16 *options) @@ -435,16 +437,21 @@ static void smc_options_write(__be32 *ptr, u16 *options) struct tcp_out_options { u16 options; /* bit field of OPTION_* */ u16 mss; /* 0 to disable */ u8 ws; /* window scale, 0 to disable */ u8 num_sack_blocks; /* number of SACK blocks to include */ - u8 hash_size; /* bytes in hash_location */ u8 bpf_opt_len; /* length of BPF hdr option */ +#ifdef CONFIG_TCP_AUTHOPT + u8 authopt_rnextkeyid; +#endif __u8 *hash_location; /* temporary pointer, overloaded */ __u32 tsval, tsecr; /* need to include OPTION_TS */ struct tcp_fastopen_cookie *fastopen_cookie; /* Fast open cookie */ struct mptcp_out_options mptcp; +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_key_info *authopt_key; +#endif }; static void mptcp_options_write(__be32 *ptr, const struct tcp_sock *tp, struct tcp_out_options *opts) { @@ -617,10 +624,24 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp, /* overload cookie hash location */ opts->hash_location = (__u8 *)ptr; ptr += 4; } +#ifdef CONFIG_TCP_AUTHOPT + if (unlikely(OPTION_AUTHOPT & options)) { + struct tcp_authopt_key_info *key = opts->authopt_key; + + WARN_ON(!key); + *ptr++ = htonl((TCPOPT_AUTHOPT << 24) | ((4 + key->maclen) << 16) | + (key->send_id << 8) | opts->authopt_rnextkeyid); + /* overload cookie hash location */ + opts->hash_location = (__u8 *)ptr; + /* maclen is currently always 12 but try to align nicely anyway. */ + ptr += (key->maclen + 3) / 4; + } +#endif + if (unlikely(opts->mss)) { *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | opts->mss); } @@ -752,10 +773,37 @@ static void mptcp_set_option_cond(const struct request_sock *req, } } } } +static int tcp_authopt_init_options(const struct sock *sk, + struct tcp_out_options *opts) +{ +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_info *info; + struct tcp_authopt_key_info *key; + + info = rcu_dereference_check(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + + if (!info) + return 0; + + if (!info->local_send_id) + return 0; + + key = tcp_authopt_key_info_lookup((struct sock *)sk, info->local_send_id); + if (key) { + opts->options |= OPTION_AUTHOPT; + opts->authopt_key = key; + opts->authopt_rnextkeyid = info->rnextkeyid; + return 4 + key->maclen; + } +#endif + + return 0; +} + /* Compute TCP options for SYN packets. This is not the final * network wire format yet. */ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, struct tcp_out_options *opts, @@ -774,10 +822,11 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, opts->options |= OPTION_MD5; remaining -= TCPOLEN_MD5SIG_ALIGNED; } } #endif + remaining -= tcp_authopt_init_options(sk, opts); /* We always get an MSS option. The option bytes which will be seen in * normal data packets should timestamps be used, must be in the MSS * advertised. But we subtract them from tp->mss_cache so that * calculations in tcp_sendmsg are simpler etc. So account for this @@ -862,10 +911,11 @@ static unsigned int tcp_synack_options(const struct sock *sk, */ if (synack_type != TCP_SYNACK_COOKIE) ireq->tstamp_ok &= !ireq->sack_ok; } #endif + remaining -= tcp_authopt_init_options(sk, opts); /* We always send an MSS option. */ opts->mss = mss; remaining -= TCPOLEN_MSS_ALIGNED; @@ -930,10 +980,11 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb opts->options |= OPTION_MD5; size += TCPOLEN_MD5SIG_ALIGNED; } } #endif + size += tcp_authopt_init_options(sk, opts); if (likely(tp->rx_opt.tstamp_ok)) { opts->options |= OPTION_TS; opts->tsval = skb ? tcp_skb_timestamp(skb) + tp->tsoffset : 0; opts->tsecr = tp->rx_opt.ts_recent; @@ -1365,10 +1416,17 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, sk_nocaps_add(sk, NETIF_F_GSO_MASK); tp->af_specific->calc_md5_hash(opts.hash_location, md5, sk, skb); } #endif +#ifdef CONFIG_TCP_AUTHOPT + if (opts.authopt_key) { + sk_nocaps_add(sk, NETIF_F_GSO_MASK); + err = tcp_authopt_hash(opts.hash_location, opts.authopt_key, sk, skb); + WARN_ON(err); // FIXME + } +#endif /* BPF prog is the last one writing header option */ bpf_skops_write_hdr_opt(sk, skb, NULL, NULL, 0, &opts); INDIRECT_CALL_INET(icsk->icsk_af_ops->send_check, @@ -3602,10 +3660,15 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, if (md5) tcp_rsk(req)->af_specific->calc_md5_hash(opts.hash_location, md5, req_to_sk(req), skb); rcu_read_unlock(); #endif +#ifdef CONFIG_TCP_AUTHOPT + /* If signature fails we do nothing */ + if (opts.authopt_key) + tcp_authopt_hash(opts.hash_location, opts.authopt_key, req_to_sk(req), skb); +#endif bpf_skops_write_hdr_opt((struct sock *)sk, skb, req, syn_skb, synack_type, &opts); skb->skb_mstamp_ns = now; base-commit: 0d6835ffe50c9c1f098b5704394331710b67af48 -- 2.25.1
