include/net/tcp_ao.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 #ifndef _TCP_AO_H
   3 #define _TCP_AO_H
   4
   5 #define TCP_AO_KEY_ALIGN        1
   6 #define __tcp_ao_key_align __aligned(TCP_AO_KEY_ALIGN)
   7
   8 union tcp_ao_addr {
   9         struct in_addr  a4;
  10 #if IS_ENABLED(CONFIG_IPV6)
  11         struct in6_addr a6;
  12 #endif
  13 };
  14
  15 struct tcp_ao_hdr {
  16         u8      kind;
  17         u8      length;
  18         u8      keyid;
  19         u8      rnext_keyid;
  20 };
  21
  22 struct tcp_ao_counters {
  23         atomic64_t      pkt_good;
  24         atomic64_t      pkt_bad;
  25         atomic64_t      key_not_found;
  26         atomic64_t      ao_required;
  27         atomic64_t      dropped_icmp;
  28 };
  29
  30 struct tcp_ao_key {
  31         struct hlist_node       node;
  32         union tcp_ao_addr       addr;
  33         u8                      key[TCP_AO_MAXKEYLEN] __tcp_ao_key_align;
  34         unsigned int            tcp_sigpool_id;
  35         unsigned int            digest_size;
  36         int                     l3index;
  37         u8                      prefixlen;
  38         u8                      family;
  39         u8                      keylen;
  40         u8                      keyflags;
  41         u8                      sndid;
  42         u8                      rcvid;
  43         u8                      maclen;
  44         struct rcu_head         rcu;
  45         atomic64_t              pkt_good;
  46         atomic64_t              pkt_bad;
  47         u8                      traffic_keys[];
  48 };
  49
  50 static inline u8 *rcv_other_key(struct tcp_ao_key *key)
  51 {
  52         return key->traffic_keys;
  53 }
  54
  55 static inline u8 *snd_other_key(struct tcp_ao_key *key)
  56 {
  57         return key->traffic_keys + key->digest_size;
  58 }
  59
  60 static inline int tcp_ao_maclen(const struct tcp_ao_key *key)
  61 {
  62         return key->maclen;
  63 }
  64
  65 /* Use tcp_ao_len_aligned() for TCP header calculations */
  66 static inline int tcp_ao_len(const struct tcp_ao_key *key)
  67 {
  68         return tcp_ao_maclen(key) + sizeof(struct tcp_ao_hdr);
  69 }
  70
  71 static inline int tcp_ao_len_aligned(const struct tcp_ao_key *key)
  72 {
  73         return round_up(tcp_ao_len(key), 4);
  74 }
  75
  76 static inline unsigned int tcp_ao_digest_size(struct tcp_ao_key *key)
  77 {
  78         return key->digest_size;
  79 }
  80
  81 static inline int tcp_ao_sizeof_key(const struct tcp_ao_key *key)
  82 {
  83         return sizeof(struct tcp_ao_key) + (key->digest_size << 1);
  84 }
  85
  86 struct tcp_ao_info {
  87         /* List of tcp_ao_key's */
  88         struct hlist_head       head;
  89         /* current_key and rnext_key aren't maintained on listen sockets.
  90          * Their purpose is to cache keys on established connections,
  91          * saving needless lookups. Never dereference any of them from
  92          * listen sockets.
  93          * ::current_key may change in RX to the key that was requested by
  94          * the peer, please use READ_ONCE()/WRITE_ONCE() in order to avoid
  95          * load/store tearing.
  96          * Do the same for ::rnext_key, if you don't hold socket lock
  97          * (it's changed only by userspace request in setsockopt()).
  98          */
  99         struct tcp_ao_key       *current_key;
 100         struct tcp_ao_key       *rnext_key;
 101         struct tcp_ao_counters  counters;
 102         u32                     ao_required     :1,
 103                                 accept_icmps    :1,
 104                                 __unused        :30;
 105         __be32                  lisn;
 106         __be32                  risn;
 107         /* Sequence Number Extension (SNE) are upper 4 bytes for SEQ,
 108          * that protect TCP-AO connection from replayed old TCP segments.
 109          * See RFC5925 (6.2).
 110          * In order to get correct SNE, there's a helper tcp_ao_compute_sne().
 111          * It needs SEQ basis to understand whereabouts are lower SEQ numbers.
 112          * According to that basis vector, it can provide incremented SNE
 113          * when SEQ rolls over or provide decremented SNE when there's
 114          * a retransmitted segment from before-rolling over.
 115          * - for request sockets such basis is rcv_isn/snt_isn, which seems
 116          *   good enough as it's unexpected to receive 4 Gbytes on reqsk.
 117          * - for full sockets the basis is rcv_nxt/snd_una. snd_una is
 118          *   taken instead of snd_nxt as currently it's easier to track
 119          *   in tcp_snd_una_update(), rather than updating SNE in all
 120          *   WRITE_ONCE(tp->snd_nxt, ...)
 121          * - for time-wait sockets the basis is tw_rcv_nxt/tw_snd_nxt.
 122          *   tw_snd_nxt is not expected to change, while tw_rcv_nxt may.
 123          */
 124         u32                     snd_sne;
 125         u32                     rcv_sne;
 126         refcount_t              refcnt;         /* Protects twsk destruction */
 127         struct rcu_head         rcu;
 128 };
 129
 130 #ifdef CONFIG_TCP_MD5SIG
 131 #include <linux/jump_label.h>
 132 extern struct static_key_false_deferred tcp_md5_needed;
 133 #define static_branch_tcp_md5() static_branch_unlikely(&tcp_md5_needed.key)
 134 #else
 135 #define static_branch_tcp_md5() false
 136 #endif
 137 #ifdef CONFIG_TCP_AO
 138 /* TCP-AO structures and functions */
 139 #include <linux/jump_label.h>
 140 extern struct static_key_false_deferred tcp_ao_needed;
 141 #define static_branch_tcp_ao()  static_branch_unlikely(&tcp_ao_needed.key)
 142 #else
 143 #define static_branch_tcp_ao()  false
 144 #endif
 145
 146 static inline bool tcp_hash_should_produce_warnings(void)
 147 {
 148         return static_branch_tcp_md5() || static_branch_tcp_ao();
 149 }
 150
 151 #define tcp_hash_fail(msg, family, skb, fmt, ...)                       \
 152 do {                                                                    \
 153         const struct tcphdr *th = tcp_hdr(skb);                         \
 154         char hdr_flags[6];                                              \
 155         char *f = hdr_flags;                                            \
 156                                                                         \
 157         if (!tcp_hash_should_produce_warnings())                        \
 158                 break;                                                  \
 159         if (th->fin)                                                    \
 160                 *f++ = 'F';                                             \
 161         if (th->syn)                                                    \
 162                 *f++ = 'S';                                             \
 163         if (th->rst)                                                    \
 164                 *f++ = 'R';                                             \
 165         if (th->psh)                                                    \
 166                 *f++ = 'P';                                             \
 167         if (th->ack)                                                    \
 168                 *f++ = '.';                                             \
 169         *f = 0;                                                         \
 170         if ((family) == AF_INET) {                                      \
 171                 net_info_ratelimited("%s for %pI4.%d->%pI4.%d [%s] " fmt "\n", \
 172                                 msg, &ip_hdr(skb)->saddr, ntohs(th->source), \
 173                                 &ip_hdr(skb)->daddr, ntohs(th->dest),   \
 174                                 hdr_flags, ##__VA_ARGS__);              \
 175         } else {                                                        \
 176                 net_info_ratelimited("%s for [%pI6c].%d->[%pI6c].%d [%s]" fmt "\n", \
 177                                 msg, &ipv6_hdr(skb)->saddr, ntohs(th->source), \
 178                                 &ipv6_hdr(skb)->daddr, ntohs(th->dest), \
 179                                 hdr_flags, ##__VA_ARGS__);              \
 180         }                                                               \
 181 } while (0)
 182
 183 #ifdef CONFIG_TCP_AO
 184 /* TCP-AO structures and functions */
 185 struct tcp4_ao_context {
 186         __be32          saddr;
 187         __be32          daddr;
 188         __be16          sport;
 189         __be16          dport;
 190         __be32          sisn;
 191         __be32          disn;
 192 };
 193
 194 struct tcp6_ao_context {
 195         struct in6_addr saddr;
 196         struct in6_addr daddr;
 197         __be16          sport;
 198         __be16          dport;
 199         __be32          sisn;
 200         __be32          disn;
 201 };
 202
 203 struct tcp_sigpool;
 204 #define TCP_AO_ESTABLISHED (TCPF_ESTABLISHED | TCPF_FIN_WAIT1 | TCPF_FIN_WAIT2 | \
 205                             TCPF_CLOSE | TCPF_CLOSE_WAIT | \
 206                             TCPF_LAST_ACK | TCPF_CLOSING)
 207
 208 int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
 209                         struct tcp_ao_key *key, struct tcphdr *th,
 210                         __u8 *hash_location);
 211 int tcp_ao_hash_skb(unsigned short int family,
 212                     char *ao_hash, struct tcp_ao_key *key,
 213                     const struct sock *sk, const struct sk_buff *skb,
 214                     const u8 *tkey, int hash_offset, u32 sne);
 215 int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family,
 216                  sockptr_t optval, int optlen);
 217 struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao,
 218                                           int sndid, int rcvid);
 219 int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk,
 220                              struct request_sock *req, struct sk_buff *skb,
 221                              int family);
 222 int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx,
 223                             unsigned int len, struct tcp_sigpool *hp);
 224 void tcp_ao_destroy_sock(struct sock *sk, bool twsk);
 225 void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp);
 226 bool tcp_ao_ignore_icmp(const struct sock *sk, int family, int type, int code);
 227 int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen);
 228 int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen);
 229 int tcp_ao_get_repair(struct sock *sk, sockptr_t optval, sockptr_t optlen);
 230 int tcp_ao_set_repair(struct sock *sk, sockptr_t optval, unsigned int optlen);
 231 enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk,
 232                         const struct sk_buff *skb, unsigned short int family,
 233                         const struct request_sock *req, int l3index,
 234                         const struct tcp_ao_hdr *aoh);
 235 u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq);
 236 struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, int l3index,
 237                                     const union tcp_ao_addr *addr,
 238                                     int family, int sndid, int rcvid);
 239 int tcp_ao_hash_hdr(unsigned short family, char *ao_hash,
 240                     struct tcp_ao_key *key, const u8 *tkey,
 241                     const union tcp_ao_addr *daddr,
 242                     const union tcp_ao_addr *saddr,
 243                     const struct tcphdr *th, u32 sne);
 244 int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
 245                          const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
 246                          struct tcp_ao_key **key, char **traffic_key,
 247                          bool *allocated_traffic_key, u8 *keyid, u32 *sne);
 248
 249 /* ipv4 specific functions */
 250 int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen);
 251 struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk,
 252                                     int sndid, int rcvid);
 253 int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *mkt,
 254                           struct request_sock *req, const struct sk_buff *skb,
 255                           int hash_offset, u32 sne);
 256 int tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
 257                           const struct sock *sk,
 258                           __be32 sisn, __be32 disn, bool send);
 259 int tcp_v4_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key,
 260                            struct request_sock *req);
 261 struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk,
 262                                         struct request_sock *req,
 263                                         int sndid, int rcvid);
 264 int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key,
 265                        const struct sock *sk, const struct sk_buff *skb,
 266                        const u8 *tkey, int hash_offset, u32 sne);
 267 /* ipv6 specific functions */
 268 int tcp_v6_ao_hash_pseudoheader(struct tcp_sigpool *hp,
 269                                 const struct in6_addr *daddr,
 270                                 const struct in6_addr *saddr, int nbytes);
 271 int tcp_v6_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key,
 272                            const struct sk_buff *skb, __be32 sisn, __be32 disn);
 273 int tcp_v6_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
 274                           const struct sock *sk, __be32 sisn,
 275                           __be32 disn, bool send);
 276 int tcp_v6_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key,
 277                            struct request_sock *req);
 278 struct tcp_ao_key *tcp_v6_ao_lookup(const struct sock *sk,
 279                                     struct sock *addr_sk, int sndid, int rcvid);
 280 struct tcp_ao_key *tcp_v6_ao_lookup_rsk(const struct sock *sk,
 281                                         struct request_sock *req,
 282                                         int sndid, int rcvid);
 283 int tcp_v6_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key,
 284                        const struct sock *sk, const struct sk_buff *skb,
 285                        const u8 *tkey, int hash_offset, u32 sne);
 286 int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen);
 287 int tcp_v6_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key,
 288                           struct request_sock *req, const struct sk_buff *skb,
 289                           int hash_offset, u32 sne);
 290 void tcp_ao_established(struct sock *sk);
 291 void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb);
 292 void tcp_ao_connect_init(struct sock *sk);
 293 void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
 294                       struct request_sock *req, unsigned short int family);
 295 #else /* CONFIG_TCP_AO */
 296
 297 static inline int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
 298                                       struct tcp_ao_key *key, struct tcphdr *th,
 299                                       __u8 *hash_location)
 300 {
 301         return 0;
 302 }
 303
 304 static inline void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
 305                                     struct request_sock *req, unsigned short int family)
 306 {
 307 }
 308
 309 static inline bool tcp_ao_ignore_icmp(const struct sock *sk, int family,
 310                                       int type, int code)
 311 {
 312         return false;
 313 }
 314
 315 static inline enum skb_drop_reason tcp_inbound_ao_hash(struct sock *sk,
 316                 const struct sk_buff *skb, unsigned short int family,
 317                 const struct request_sock *req, int l3index,
 318                 const struct tcp_ao_hdr *aoh)
 319 {
 320         return SKB_NOT_DROPPED_YET;
 321 }
 322
 323 static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk,
 324                 int l3index, const union tcp_ao_addr *addr,
 325                 int family, int sndid, int rcvid)
 326 {
 327         return NULL;
 328 }
 329
 330 static inline void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
 331 {
 332 }
 333
 334 static inline void tcp_ao_established(struct sock *sk)
 335 {
 336 }
 337
 338 static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb)
 339 {
 340 }
 341
 342 static inline void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw,
 343                                     struct tcp_sock *tp)
 344 {
 345 }
 346
 347 static inline void tcp_ao_connect_init(struct sock *sk)
 348 {
 349 }
 350
 351 static inline int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen)
 352 {
 353         return -ENOPROTOOPT;
 354 }
 355
 356 static inline int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen)
 357 {
 358         return -ENOPROTOOPT;
 359 }
 360
 361 static inline int tcp_ao_get_repair(struct sock *sk,
 362                                     sockptr_t optval, sockptr_t optlen)
 363 {
 364         return -ENOPROTOOPT;
 365 }
 366
 367 static inline int tcp_ao_set_repair(struct sock *sk,
 368                                     sockptr_t optval, unsigned int optlen)
 369 {
 370         return -ENOPROTOOPT;
 371 }
 372 #endif
 373
 374 #if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
 375 int tcp_do_parse_auth_options(const struct tcphdr *th,
 376                               const u8 **md5_hash, const u8 **ao_hash);
 377 #else
 378 static inline int tcp_do_parse_auth_options(const struct tcphdr *th,
 379                 const u8 **md5_hash, const u8 **ao_hash)
 380 {
 381         *md5_hash = NULL;
 382         *ao_hash = NULL;
 383         return 0;
 384 }
 385 #endif
 386
 387 #endif /* _TCP_AO_H */