Commit | Line | Data |
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7cd23e53 JD |
1 | /* |
2 | * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. | |
3 | */ | |
4 | ||
6e5714ea DM |
5 | #include <linux/kernel.h> |
6 | #include <linux/init.h> | |
7 | #include <linux/cryptohash.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/cache.h> | |
10 | #include <linux/random.h> | |
11 | #include <linux/hrtimer.h> | |
12 | #include <linux/ktime.h> | |
13 | #include <linux/string.h> | |
e34c9a69 | 14 | #include <linux/net.h> |
7cd23e53 | 15 | #include <linux/siphash.h> |
6e5714ea DM |
16 | #include <net/secure_seq.h> |
17 | ||
cb03db9d | 18 | #if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET) |
7cd23e53 | 19 | #include <linux/in6.h> |
25429d7b | 20 | #include <net/tcp.h> |
6e5714ea | 21 | |
7cd23e53 | 22 | static siphash_key_t net_secret __read_mostly; |
28ee1b74 | 23 | static siphash_key_t ts_secret __read_mostly; |
9a3bab6b | 24 | |
34d92d53 | 25 | static __always_inline void net_secret_init(void) |
6e5714ea | 26 | { |
7cd23e53 | 27 | net_get_random_once(&net_secret, sizeof(net_secret)); |
6e5714ea | 28 | } |
84b114b9 ED |
29 | |
30 | static __always_inline void ts_secret_init(void) | |
31 | { | |
32 | net_get_random_once(&ts_secret, sizeof(ts_secret)); | |
33 | } | |
cb03db9d | 34 | #endif |
6e5714ea | 35 | |
68109090 | 36 | #ifdef CONFIG_INET |
6e5714ea DM |
37 | static u32 seq_scale(u32 seq) |
38 | { | |
39 | /* | |
40 | * As close as possible to RFC 793, which | |
41 | * suggests using a 250 kHz clock. | |
42 | * Further reading shows this assumes 2 Mb/s networks. | |
43 | * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. | |
44 | * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but | |
45 | * we also need to limit the resolution so that the u32 seq | |
46 | * overlaps less than one time per MSL (2 minutes). | |
47 | * Choosing a clock of 64 ns period is OK. (period of 274 s) | |
48 | */ | |
d2de875c | 49 | return seq + (ktime_get_real_ns() >> 6); |
6e5714ea | 50 | } |
68109090 | 51 | #endif |
6e5714ea | 52 | |
dfd56b8b | 53 | #if IS_ENABLED(CONFIG_IPV6) |
5d2ed052 ED |
54 | u32 secure_tcpv6_ts_off(const struct net *net, |
55 | const __be32 *saddr, const __be32 *daddr) | |
28ee1b74 FW |
56 | { |
57 | const struct { | |
58 | struct in6_addr saddr; | |
59 | struct in6_addr daddr; | |
60 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
61 | .saddr = *(struct in6_addr *)saddr, | |
62 | .daddr = *(struct in6_addr *)daddr, | |
63 | }; | |
64 | ||
5d2ed052 | 65 | if (net->ipv4.sysctl_tcp_timestamps != 1) |
28ee1b74 FW |
66 | return 0; |
67 | ||
84b114b9 | 68 | ts_secret_init(); |
28ee1b74 FW |
69 | return siphash(&combined, offsetofend(typeof(combined), daddr), |
70 | &ts_secret); | |
71 | } | |
84b114b9 | 72 | EXPORT_SYMBOL(secure_tcpv6_ts_off); |
28ee1b74 | 73 | |
84b114b9 ED |
74 | u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr, |
75 | __be16 sport, __be16 dport) | |
6e5714ea | 76 | { |
7cd23e53 JD |
77 | const struct { |
78 | struct in6_addr saddr; | |
79 | struct in6_addr daddr; | |
80 | __be16 sport; | |
81 | __be16 dport; | |
82 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
83 | .saddr = *(struct in6_addr *)saddr, | |
84 | .daddr = *(struct in6_addr *)daddr, | |
85 | .sport = sport, | |
86 | .dport = dport | |
87 | }; | |
84b114b9 ED |
88 | u32 hash; |
89 | ||
9a3bab6b | 90 | net_secret_init(); |
7cd23e53 JD |
91 | hash = siphash(&combined, offsetofend(typeof(combined), dport), |
92 | &net_secret); | |
7cd23e53 | 93 | return seq_scale(hash); |
6e5714ea | 94 | } |
84b114b9 | 95 | EXPORT_SYMBOL(secure_tcpv6_seq); |
6e5714ea DM |
96 | |
97 | u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, | |
98 | __be16 dport) | |
99 | { | |
7cd23e53 JD |
100 | const struct { |
101 | struct in6_addr saddr; | |
102 | struct in6_addr daddr; | |
103 | __be16 dport; | |
104 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
105 | .saddr = *(struct in6_addr *)saddr, | |
106 | .daddr = *(struct in6_addr *)daddr, | |
107 | .dport = dport | |
108 | }; | |
9a3bab6b | 109 | net_secret_init(); |
7cd23e53 JD |
110 | return siphash(&combined, offsetofend(typeof(combined), dport), |
111 | &net_secret); | |
6e5714ea | 112 | } |
58a317f1 | 113 | EXPORT_SYMBOL(secure_ipv6_port_ephemeral); |
6e5714ea DM |
114 | #endif |
115 | ||
116 | #ifdef CONFIG_INET | |
5d2ed052 | 117 | u32 secure_tcp_ts_off(const struct net *net, __be32 saddr, __be32 daddr) |
28ee1b74 | 118 | { |
5d2ed052 | 119 | if (net->ipv4.sysctl_tcp_timestamps != 1) |
28ee1b74 FW |
120 | return 0; |
121 | ||
84b114b9 | 122 | ts_secret_init(); |
28ee1b74 FW |
123 | return siphash_2u32((__force u32)saddr, (__force u32)daddr, |
124 | &ts_secret); | |
125 | } | |
6e5714ea | 126 | |
a30aad50 | 127 | /* secure_tcp_seq_and_tsoff(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d), |
7cd23e53 JD |
128 | * but fortunately, `sport' cannot be 0 in any circumstances. If this changes, |
129 | * it would be easy enough to have the former function use siphash_4u32, passing | |
130 | * the arguments as separate u32. | |
131 | */ | |
84b114b9 ED |
132 | u32 secure_tcp_seq(__be32 saddr, __be32 daddr, |
133 | __be16 sport, __be16 dport) | |
6e5714ea | 134 | { |
84b114b9 ED |
135 | u32 hash; |
136 | ||
9a3bab6b | 137 | net_secret_init(); |
7cd23e53 JD |
138 | hash = siphash_3u32((__force u32)saddr, (__force u32)daddr, |
139 | (__force u32)sport << 16 | (__force u32)dport, | |
140 | &net_secret); | |
7cd23e53 | 141 | return seq_scale(hash); |
6e5714ea DM |
142 | } |
143 | ||
144 | u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) | |
145 | { | |
9a3bab6b | 146 | net_secret_init(); |
7cd23e53 JD |
147 | return siphash_3u32((__force u32)saddr, (__force u32)daddr, |
148 | (__force u16)dport, &net_secret); | |
6e5714ea DM |
149 | } |
150 | EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); | |
151 | #endif | |
152 | ||
a3bf7ae9 | 153 | #if IS_ENABLED(CONFIG_IP_DCCP) |
6e5714ea DM |
154 | u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, |
155 | __be16 sport, __be16 dport) | |
156 | { | |
6e5714ea | 157 | u64 seq; |
9a3bab6b | 158 | net_secret_init(); |
c1ce1560 ED |
159 | seq = siphash_3u32((__force u32)saddr, (__force u32)daddr, |
160 | (__force u32)sport << 16 | (__force u32)dport, | |
161 | &net_secret); | |
d2de875c | 162 | seq += ktime_get_real_ns(); |
6e5714ea | 163 | seq &= (1ull << 48) - 1; |
6e5714ea DM |
164 | return seq; |
165 | } | |
166 | EXPORT_SYMBOL(secure_dccp_sequence_number); | |
167 | ||
dfd56b8b | 168 | #if IS_ENABLED(CONFIG_IPV6) |
6e5714ea DM |
169 | u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, |
170 | __be16 sport, __be16 dport) | |
171 | { | |
7cd23e53 JD |
172 | const struct { |
173 | struct in6_addr saddr; | |
174 | struct in6_addr daddr; | |
175 | __be16 sport; | |
176 | __be16 dport; | |
177 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
178 | .saddr = *(struct in6_addr *)saddr, | |
179 | .daddr = *(struct in6_addr *)daddr, | |
180 | .sport = sport, | |
181 | .dport = dport | |
182 | }; | |
6e5714ea | 183 | u64 seq; |
9a3bab6b | 184 | net_secret_init(); |
7cd23e53 JD |
185 | seq = siphash(&combined, offsetofend(typeof(combined), dport), |
186 | &net_secret); | |
d2de875c | 187 | seq += ktime_get_real_ns(); |
6e5714ea | 188 | seq &= (1ull << 48) - 1; |
6e5714ea DM |
189 | return seq; |
190 | } | |
191 | EXPORT_SYMBOL(secure_dccpv6_sequence_number); | |
192 | #endif | |
193 | #endif |