1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 #ifndef _TCP_AO_H 3 #define _TCP_AO_H 4 5 #include <crypto/sha2.h> /* for SHA256_DIGEST_SIZE */ 6 7 union tcp_ao_addr { 8 struct in_addr a4; 9 #if IS_ENABLED(CONFIG_IPV6) 10 struct in6_addr a6; 11 #endif 12 }; 13 14 struct tcp_ao_hdr { 15 u8 kind; 16 u8 length; 17 u8 keyid; 18 u8 rnext_keyid; 19 }; 20 21 static inline u8 tcp_ao_hdr_maclen(const struct tcp_ao_hdr *aoh) 22 { 23 return aoh->length - sizeof(struct tcp_ao_hdr); 24 } 25 26 struct tcp_ao_counters { 27 atomic64_t pkt_good; 28 atomic64_t pkt_bad; 29 atomic64_t key_not_found; 30 atomic64_t ao_required; 31 atomic64_t dropped_icmp; 32 }; 33 34 enum tcp_ao_algo_id { 35 TCP_AO_ALGO_HMAC_SHA1 = 1, /* specified by RFC 5926 */ 36 TCP_AO_ALGO_HMAC_SHA256, /* Linux extension */ 37 TCP_AO_ALGO_AES_128_CMAC, /* specified by RFC 5926 */ 38 }; 39 40 /* 41 * This is the maximum untruncated MAC length, in bytes. Note that the MACs 42 * actually get truncated to 20 or fewer bytes to fit in the TCP options space. 43 */ 44 #define TCP_AO_MAX_MAC_LEN SHA256_DIGEST_SIZE 45 46 #define TCP_AO_MAX_TRAFFIC_KEY_LEN SHA256_DIGEST_SIZE 47 48 struct tcp_ao_mac_ctx; 49 50 struct tcp_ao_key { 51 struct hlist_node node; 52 union tcp_ao_addr addr; 53 u8 key[TCP_AO_MAXKEYLEN]; 54 enum tcp_ao_algo_id algo; 55 unsigned int digest_size; 56 int l3index; 57 u8 prefixlen; 58 u8 family; 59 u8 keylen; 60 u8 keyflags; 61 u8 sndid; 62 u8 rcvid; 63 u8 maclen; 64 struct rcu_head rcu; 65 atomic64_t pkt_good; 66 atomic64_t pkt_bad; 67 u8 traffic_keys[]; 68 }; 69 70 static inline u8 *rcv_other_key(struct tcp_ao_key *key) 71 { 72 return key->traffic_keys; 73 } 74 75 static inline u8 *snd_other_key(struct tcp_ao_key *key) 76 { 77 return key->traffic_keys + key->digest_size; 78 } 79 80 static inline int tcp_ao_maclen(const struct tcp_ao_key *key) 81 { 82 return key->maclen; 83 } 84 85 /* Use tcp_ao_len_aligned() for TCP header calculations */ 86 static inline int tcp_ao_len(const struct tcp_ao_key *key) 87 { 88 return tcp_ao_maclen(key) + sizeof(struct tcp_ao_hdr); 89 } 90 91 static inline int tcp_ao_len_aligned(const struct tcp_ao_key *key) 92 { 93 return round_up(tcp_ao_len(key), 4); 94 } 95 96 static inline unsigned int tcp_ao_digest_size(struct tcp_ao_key *key) 97 { 98 return key->digest_size; 99 } 100 101 static inline int tcp_ao_sizeof_key(const struct tcp_ao_key *key) 102 { 103 return sizeof(struct tcp_ao_key) + (key->digest_size << 1); 104 } 105 106 struct tcp_ao_info { 107 /* List of tcp_ao_key's */ 108 struct hlist_head head; 109 /* current_key and rnext_key are maintained on sockets 110 * in TCP_AO_ESTABLISHED states. 111 * Their purpose is to cache keys on established connections, 112 * saving needless lookups. Never dereference any of them from 113 * listen sockets. 114 * ::current_key may change in RX to the key that was requested by 115 * the peer, please use READ_ONCE()/WRITE_ONCE() in order to avoid 116 * load/store tearing. 117 * Do the same for ::rnext_key, if you don't hold socket lock 118 * (it's changed only by userspace request in setsockopt()). 119 */ 120 struct tcp_ao_key *current_key; 121 struct tcp_ao_key *rnext_key; 122 struct tcp_ao_counters counters; 123 u32 ao_required :1, 124 accept_icmps :1, 125 __unused :30; 126 __be32 lisn; 127 __be32 risn; 128 /* Sequence Number Extension (SNE) are upper 4 bytes for SEQ, 129 * that protect TCP-AO connection from replayed old TCP segments. 130 * See RFC5925 (6.2). 131 * In order to get correct SNE, there's a helper tcp_ao_compute_sne(). 132 * It needs SEQ basis to understand whereabouts are lower SEQ numbers. 133 * According to that basis vector, it can provide incremented SNE 134 * when SEQ rolls over or provide decremented SNE when there's 135 * a retransmitted segment from before-rolling over. 136 * - for request sockets such basis is rcv_isn/snt_isn, which seems 137 * good enough as it's unexpected to receive 4 Gbytes on reqsk. 138 * - for full sockets the basis is rcv_nxt/snd_una. snd_una is 139 * taken instead of snd_nxt as currently it's easier to track 140 * in tcp_snd_una_update(), rather than updating SNE in all 141 * WRITE_ONCE(tp->snd_nxt, ...) 142 * - for time-wait sockets the basis is tw_rcv_nxt/tw_snd_nxt. 143 * tw_snd_nxt is not expected to change, while tw_rcv_nxt may. 144 */ 145 u32 snd_sne; 146 u32 rcv_sne; 147 refcount_t refcnt; /* Protects twsk destruction */ 148 struct rcu_head rcu; 149 }; 150 151 #ifdef CONFIG_TCP_MD5SIG 152 #include <linux/jump_label.h> 153 extern struct static_key_false_deferred tcp_md5_needed; 154 #define static_branch_tcp_md5() static_branch_unlikely(&tcp_md5_needed.key) 155 #else 156 #define static_branch_tcp_md5() false 157 #endif 158 #ifdef CONFIG_TCP_AO 159 /* TCP-AO structures and functions */ 160 #include <linux/jump_label.h> 161 extern struct static_key_false_deferred tcp_ao_needed; 162 #define static_branch_tcp_ao() static_branch_unlikely(&tcp_ao_needed.key) 163 #else 164 #define static_branch_tcp_ao() false 165 #endif 166 167 #ifdef CONFIG_TCP_AO 168 /* TCP-AO structures and functions */ 169 struct tcp4_ao_context { 170 __be32 saddr; 171 __be32 daddr; 172 __be16 sport; 173 __be16 dport; 174 __be32 sisn; 175 __be32 disn; 176 }; 177 178 struct tcp6_ao_context { 179 struct in6_addr saddr; 180 struct in6_addr daddr; 181 __be16 sport; 182 __be16 dport; 183 __be32 sisn; 184 __be32 disn; 185 }; 186 187 /* Established states are fast-path and there always is current_key/rnext_key */ 188 #define TCP_AO_ESTABLISHED (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | \ 189 TCPF_CLOSE_WAIT | TCPF_LAST_ACK | TCPF_CLOSING) 190 191 void tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb, 192 struct tcp_ao_key *key, struct tcphdr *th, 193 __u8 *hash_location); 194 void tcp_ao_mac_update(struct tcp_ao_mac_ctx *mac_ctx, const void *data, 195 size_t data_len); 196 int tcp_ao_hash_skb(unsigned short int family, 197 char *ao_hash, struct tcp_ao_key *key, 198 const struct sock *sk, const struct sk_buff *skb, 199 const u8 *tkey, int hash_offset, u32 sne); 200 int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family, 201 sockptr_t optval, int optlen); 202 struct tcp_ao_key *tcp_ao_established_key(const struct sock *sk, 203 struct tcp_ao_info *ao, 204 int sndid, int rcvid); 205 int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk, 206 struct request_sock *req, struct sk_buff *skb, 207 int family); 208 void tcp_ao_calc_traffic_key(const struct tcp_ao_key *mkt, u8 *traffic_key, 209 const void *input, unsigned int input_len); 210 void tcp_ao_destroy_sock(struct sock *sk, bool twsk); 211 void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp); 212 bool tcp_ao_ignore_icmp(const struct sock *sk, int family, int type, int code); 213 int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen); 214 int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen); 215 int tcp_ao_get_repair(struct sock *sk, sockptr_t optval, sockptr_t optlen); 216 int tcp_ao_set_repair(struct sock *sk, sockptr_t optval, unsigned int optlen); 217 enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk, 218 const struct sk_buff *skb, unsigned short int family, 219 const struct request_sock *req, int l3index, 220 const struct tcp_ao_hdr *aoh); 221 u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq); 222 struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, int l3index, 223 const union tcp_ao_addr *addr, 224 int family, int sndid, int rcvid); 225 int tcp_ao_hash_hdr(unsigned short family, char *ao_hash, 226 struct tcp_ao_key *key, const u8 *tkey, 227 const union tcp_ao_addr *daddr, 228 const union tcp_ao_addr *saddr, 229 const struct tcphdr *th, u32 sne); 230 int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, 231 const struct tcp_ao_hdr *aoh, int l3index, u32 seq, 232 struct tcp_ao_key **key, char **traffic_key, 233 bool *allocated_traffic_key, u8 *keyid, u32 *sne); 234 235 /* ipv4 specific functions */ 236 int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); 237 struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, 238 int sndid, int rcvid); 239 int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *mkt, 240 struct request_sock *req, const struct sk_buff *skb, 241 int hash_offset, u32 sne); 242 void tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, 243 const struct sock *sk, 244 __be32 sisn, __be32 disn, bool send); 245 void tcp_v4_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key, 246 struct request_sock *req); 247 struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk, 248 struct request_sock *req, 249 int sndid, int rcvid); 250 int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, 251 const struct sock *sk, const struct sk_buff *skb, 252 const u8 *tkey, int hash_offset, u32 sne); 253 /* ipv6 specific functions */ 254 void tcp_v6_ao_hash_pseudoheader(struct tcp_ao_mac_ctx *mac_ctx, 255 const struct in6_addr *daddr, 256 const struct in6_addr *saddr, int nbytes); 257 void tcp_v6_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key, 258 const struct sk_buff *skb, __be32 sisn, 259 __be32 disn); 260 void tcp_v6_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, 261 const struct sock *sk, __be32 sisn, 262 __be32 disn, bool send); 263 void tcp_v6_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key, 264 struct request_sock *req); 265 struct tcp_ao_key *tcp_v6_ao_lookup(const struct sock *sk, 266 struct sock *addr_sk, int sndid, int rcvid); 267 struct tcp_ao_key *tcp_v6_ao_lookup_rsk(const struct sock *sk, 268 struct request_sock *req, 269 int sndid, int rcvid); 270 int tcp_v6_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, 271 const struct sock *sk, const struct sk_buff *skb, 272 const u8 *tkey, int hash_offset, u32 sne); 273 int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); 274 int tcp_v6_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key, 275 struct request_sock *req, const struct sk_buff *skb, 276 int hash_offset, u32 sne); 277 void tcp_ao_established(struct sock *sk); 278 void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb); 279 void tcp_ao_connect_init(struct sock *sk); 280 void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, 281 struct request_sock *req, unsigned short int family); 282 #else /* CONFIG_TCP_AO */ 283 284 static inline void tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb, 285 struct tcp_ao_key *key, 286 struct tcphdr *th, __u8 *hash_location) 287 { 288 } 289 290 static inline void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, 291 struct request_sock *req, unsigned short int family) 292 { 293 } 294 295 static inline bool tcp_ao_ignore_icmp(const struct sock *sk, int family, 296 int type, int code) 297 { 298 return false; 299 } 300 301 static inline enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk, 302 const struct sk_buff *skb, unsigned short int family, 303 const struct request_sock *req, int l3index, 304 const struct tcp_ao_hdr *aoh) 305 { 306 return SKB_NOT_DROPPED_YET; 307 } 308 309 static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, 310 int l3index, const union tcp_ao_addr *addr, 311 int family, int sndid, int rcvid) 312 { 313 return NULL; 314 } 315 316 static inline void tcp_ao_destroy_sock(struct sock *sk, bool twsk) 317 { 318 } 319 320 static inline void tcp_ao_established(struct sock *sk) 321 { 322 } 323 324 static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb) 325 { 326 } 327 328 static inline void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, 329 struct tcp_sock *tp) 330 { 331 } 332 333 static inline void tcp_ao_connect_init(struct sock *sk) 334 { 335 } 336 337 static inline int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen) 338 { 339 return -ENOPROTOOPT; 340 } 341 342 static inline int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen) 343 { 344 return -ENOPROTOOPT; 345 } 346 347 static inline int tcp_ao_get_repair(struct sock *sk, 348 sockptr_t optval, sockptr_t optlen) 349 { 350 return -ENOPROTOOPT; 351 } 352 353 static inline int tcp_ao_set_repair(struct sock *sk, 354 sockptr_t optval, unsigned int optlen) 355 { 356 return -ENOPROTOOPT; 357 } 358 #endif 359 360 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 361 int tcp_do_parse_auth_options(const struct tcphdr *th, 362 const u8 **md5_hash, const u8 **ao_hash); 363 #else 364 static inline int tcp_do_parse_auth_options(const struct tcphdr *th, 365 const u8 **md5_hash, const u8 **ao_hash) 366 { 367 *md5_hash = NULL; 368 *ao_hash = NULL; 369 return 0; 370 } 371 #endif 372 373 #endif /* _TCP_AO_H */ 374