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
tcp_ao_hdr_maclen(const struct tcp_ao_hdr * aoh)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
rcv_other_key(struct tcp_ao_key * key)70 static inline u8 *rcv_other_key(struct tcp_ao_key *key)
71 {
72 return key->traffic_keys;
73 }
74
snd_other_key(struct tcp_ao_key * key)75 static inline u8 *snd_other_key(struct tcp_ao_key *key)
76 {
77 return key->traffic_keys + key->digest_size;
78 }
79
tcp_ao_maclen(const struct tcp_ao_key * key)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 */
tcp_ao_len(const struct tcp_ao_key * key)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
tcp_ao_len_aligned(const struct tcp_ao_key * key)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
tcp_ao_digest_size(struct tcp_ao_key * key)96 static inline unsigned int tcp_ao_digest_size(struct tcp_ao_key *key)
97 {
98 return key->digest_size;
99 }
100
tcp_ao_sizeof_key(const struct tcp_ao_key * key)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
tcp_ao_transmit_skb(struct sock * sk,struct sk_buff * skb,struct tcp_ao_key * key,struct tcphdr * th,__u8 * hash_location)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
tcp_ao_syncookie(struct sock * sk,const struct sk_buff * skb,struct request_sock * req,unsigned short int family)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
tcp_ao_ignore_icmp(const struct sock * sk,int family,int type,int code)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
tcp_inbound_ao_hash(struct sock * sk,const struct sk_buff * skb,unsigned short int family,const struct request_sock * req,int l3index,const struct tcp_ao_hdr * aoh)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
tcp_ao_do_lookup(const struct sock * sk,int l3index,const union tcp_ao_addr * addr,int family,int sndid,int rcvid)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
tcp_ao_destroy_sock(struct sock * sk,bool twsk)316 static inline void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
317 {
318 }
319
tcp_ao_established(struct sock * sk)320 static inline void tcp_ao_established(struct sock *sk)
321 {
322 }
323
tcp_ao_finish_connect(struct sock * sk,struct sk_buff * skb)324 static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb)
325 {
326 }
327
tcp_ao_time_wait(struct tcp_timewait_sock * tcptw,struct tcp_sock * tp)328 static inline void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw,
329 struct tcp_sock *tp)
330 {
331 }
332
tcp_ao_connect_init(struct sock * sk)333 static inline void tcp_ao_connect_init(struct sock *sk)
334 {
335 }
336
tcp_ao_get_mkts(struct sock * sk,sockptr_t optval,sockptr_t optlen)337 static inline int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen)
338 {
339 return -ENOPROTOOPT;
340 }
341
tcp_ao_get_sock_info(struct sock * sk,sockptr_t optval,sockptr_t optlen)342 static inline int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen)
343 {
344 return -ENOPROTOOPT;
345 }
346
tcp_ao_get_repair(struct sock * sk,sockptr_t optval,sockptr_t optlen)347 static inline int tcp_ao_get_repair(struct sock *sk,
348 sockptr_t optval, sockptr_t optlen)
349 {
350 return -ENOPROTOOPT;
351 }
352
tcp_ao_set_repair(struct sock * sk,sockptr_t optval,unsigned int optlen)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
tcp_do_parse_auth_options(const struct tcphdr * th,const u8 ** md5_hash,const u8 ** ao_hash)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