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 }; 149 150 #ifdef CONFIG_TCP_MD5SIG 151 #include <linux/jump_label.h> 152 extern struct static_key_false_deferred tcp_md5_needed; 153 #define static_branch_tcp_md5() static_branch_unlikely(&tcp_md5_needed.key) 154 #else 155 #define static_branch_tcp_md5() false 156 #endif 157 #ifdef CONFIG_TCP_AO 158 /* TCP-AO structures and functions */ 159 #include <linux/jump_label.h> 160 extern struct static_key_false_deferred tcp_ao_needed; 161 #define static_branch_tcp_ao() static_branch_unlikely(&tcp_ao_needed.key) 162 #else 163 #define static_branch_tcp_ao() false 164 #endif 165 166 #ifdef CONFIG_TCP_AO 167 /* TCP-AO structures and functions */ 168 struct tcp4_ao_context { 169 __be32 saddr; 170 __be32 daddr; 171 __be16 sport; 172 __be16 dport; 173 __be32 sisn; 174 __be32 disn; 175 }; 176 177 struct tcp6_ao_context { 178 struct in6_addr saddr; 179 struct in6_addr daddr; 180 __be16 sport; 181 __be16 dport; 182 __be32 sisn; 183 __be32 disn; 184 }; 185 186 /* Established states are fast-path and there always is current_key/rnext_key */ 187 #define TCP_AO_ESTABLISHED (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | \ 188 TCPF_CLOSE_WAIT | TCPF_LAST_ACK | TCPF_CLOSING) 189 190 void tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb, 191 struct tcp_ao_key *key, struct tcphdr *th, 192 __u8 *hash_location); 193 void tcp_ao_mac_update(struct tcp_ao_mac_ctx *mac_ctx, const void *data, 194 size_t data_len); 195 int tcp_ao_hash_skb(unsigned short int family, 196 char *ao_hash, struct tcp_ao_key *key, 197 const struct sock *sk, const struct sk_buff *skb, 198 const u8 *tkey, int hash_offset, u32 sne); 199 int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family, 200 sockptr_t optval, int optlen); 201 struct tcp_ao_key *tcp_ao_established_key(const struct sock *sk, 202 struct tcp_ao_info *ao, 203 int sndid, int rcvid); 204 int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk, 205 struct request_sock *req, struct sk_buff *skb, 206 int family); 207 void tcp_ao_calc_traffic_key(const struct tcp_ao_key *mkt, u8 *traffic_key, 208 const void *input, unsigned int input_len); 209 void tcp_ao_destroy_sock(struct sock *sk, bool twsk); 210 void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp); 211 bool tcp_ao_ignore_icmp(const struct sock *sk, int family, int type, int code); 212 int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen); 213 int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen); 214 int tcp_ao_get_repair(struct sock *sk, sockptr_t optval, sockptr_t optlen); 215 int tcp_ao_set_repair(struct sock *sk, sockptr_t optval, unsigned int optlen); 216 enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk, 217 const struct sk_buff *skb, unsigned short int family, 218 const struct request_sock *req, int l3index, 219 const struct tcp_ao_hdr *aoh); 220 u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq); 221 struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, int l3index, 222 const union tcp_ao_addr *addr, 223 int family, int sndid, int rcvid); 224 int tcp_ao_hash_hdr(unsigned short family, char *ao_hash, 225 struct tcp_ao_key *key, const u8 *tkey, 226 const union tcp_ao_addr *daddr, 227 const union tcp_ao_addr *saddr, 228 const struct tcphdr *th, u32 sne); 229 int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, 230 const struct tcp_ao_hdr *aoh, int l3index, u32 seq, 231 struct tcp_ao_key **key, char **traffic_key, 232 bool *allocated_traffic_key, u8 *keyid, u32 *sne); 233 234 /* ipv4 specific functions */ 235 int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); 236 struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, 237 int sndid, int rcvid); 238 int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *mkt, 239 struct request_sock *req, const struct sk_buff *skb, 240 int hash_offset, u32 sne); 241 void tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, 242 const struct sock *sk, 243 __be32 sisn, __be32 disn, bool send); 244 void tcp_v4_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key, 245 struct request_sock *req); 246 struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk, 247 struct request_sock *req, 248 int sndid, int rcvid); 249 int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, 250 const struct sock *sk, const struct sk_buff *skb, 251 const u8 *tkey, int hash_offset, u32 sne); 252 /* ipv6 specific functions */ 253 void tcp_v6_ao_hash_pseudoheader(struct tcp_ao_mac_ctx *mac_ctx, 254 const struct in6_addr *daddr, 255 const struct in6_addr *saddr, int nbytes); 256 void tcp_v6_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key, 257 const struct sk_buff *skb, __be32 sisn, 258 __be32 disn); 259 void tcp_v6_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, 260 const struct sock *sk, __be32 sisn, 261 __be32 disn, bool send); 262 void tcp_v6_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key, 263 struct request_sock *req); 264 struct tcp_ao_key *tcp_v6_ao_lookup(const struct sock *sk, 265 struct sock *addr_sk, int sndid, int rcvid); 266 struct tcp_ao_key *tcp_v6_ao_lookup_rsk(const struct sock *sk, 267 struct request_sock *req, 268 int sndid, int rcvid); 269 int tcp_v6_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, 270 const struct sock *sk, const struct sk_buff *skb, 271 const u8 *tkey, int hash_offset, u32 sne); 272 int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); 273 int tcp_v6_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key, 274 struct request_sock *req, const struct sk_buff *skb, 275 int hash_offset, u32 sne); 276 void tcp_ao_established(struct sock *sk); 277 void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb); 278 void tcp_ao_connect_init(struct sock *sk); 279 void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, 280 struct request_sock *req, unsigned short int family); 281 #else /* CONFIG_TCP_AO */ 282 283 static inline void tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb, 284 struct tcp_ao_key *key, 285 struct tcphdr *th, __u8 *hash_location) 286 { 287 } 288 289 static inline void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, 290 struct request_sock *req, unsigned short int family) 291 { 292 } 293 294 static inline bool tcp_ao_ignore_icmp(const struct sock *sk, int family, 295 int type, int code) 296 { 297 return false; 298 } 299 300 static inline enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk, 301 const struct sk_buff *skb, unsigned short int family, 302 const struct request_sock *req, int l3index, 303 const struct tcp_ao_hdr *aoh) 304 { 305 return SKB_NOT_DROPPED_YET; 306 } 307 308 static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, 309 int l3index, const union tcp_ao_addr *addr, 310 int family, int sndid, int rcvid) 311 { 312 return NULL; 313 } 314 315 static inline void tcp_ao_destroy_sock(struct sock *sk, bool twsk) 316 { 317 } 318 319 static inline void tcp_ao_established(struct sock *sk) 320 { 321 } 322 323 static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb) 324 { 325 } 326 327 static inline void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, 328 struct tcp_sock *tp) 329 { 330 } 331 332 static inline void tcp_ao_connect_init(struct sock *sk) 333 { 334 } 335 336 static inline int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen) 337 { 338 return -ENOPROTOOPT; 339 } 340 341 static inline int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen) 342 { 343 return -ENOPROTOOPT; 344 } 345 346 static inline int tcp_ao_get_repair(struct sock *sk, 347 sockptr_t optval, sockptr_t optlen) 348 { 349 return -ENOPROTOOPT; 350 } 351 352 static inline int tcp_ao_set_repair(struct sock *sk, 353 sockptr_t optval, unsigned int optlen) 354 { 355 return -ENOPROTOOPT; 356 } 357 #endif 358 359 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) 360 int tcp_do_parse_auth_options(const struct tcphdr *th, 361 const u8 **md5_hash, const u8 **ao_hash); 362 #else 363 static inline int tcp_do_parse_auth_options(const struct tcphdr *th, 364 const u8 **md5_hash, const u8 **ao_hash) 365 { 366 *md5_hash = NULL; 367 *ao_hash = NULL; 368 return 0; 369 } 370 #endif 371 372 #endif /* _TCP_AO_H */ 373