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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
7cd23e53 JD |
2 | /* |
3 | * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. | |
4 | */ | |
5 | ||
6e5714ea DM |
6 | #include <linux/kernel.h> |
7 | #include <linux/init.h> | |
6e5714ea DM |
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 | |
49ecc2e9 ED |
22 | static siphash_aligned_key_t net_secret; |
23 | static siphash_aligned_key_t ts_secret; | |
9a3bab6b | 24 | |
4dfa9b43 ED |
25 | #define EPHEMERAL_PORT_SHUFFLE_PERIOD (10 * HZ) |
26 | ||
34d92d53 | 27 | static __always_inline void net_secret_init(void) |
6e5714ea | 28 | { |
7cd23e53 | 29 | net_get_random_once(&net_secret, sizeof(net_secret)); |
6e5714ea | 30 | } |
84b114b9 ED |
31 | |
32 | static __always_inline void ts_secret_init(void) | |
33 | { | |
34 | net_get_random_once(&ts_secret, sizeof(ts_secret)); | |
35 | } | |
cb03db9d | 36 | #endif |
6e5714ea | 37 | |
68109090 | 38 | #ifdef CONFIG_INET |
6e5714ea DM |
39 | static u32 seq_scale(u32 seq) |
40 | { | |
41 | /* | |
42 | * As close as possible to RFC 793, which | |
43 | * suggests using a 250 kHz clock. | |
44 | * Further reading shows this assumes 2 Mb/s networks. | |
45 | * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. | |
46 | * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but | |
47 | * we also need to limit the resolution so that the u32 seq | |
48 | * overlaps less than one time per MSL (2 minutes). | |
49 | * Choosing a clock of 64 ns period is OK. (period of 274 s) | |
50 | */ | |
d2de875c | 51 | return seq + (ktime_get_real_ns() >> 6); |
6e5714ea | 52 | } |
68109090 | 53 | #endif |
6e5714ea | 54 | |
dfd56b8b | 55 | #if IS_ENABLED(CONFIG_IPV6) |
5d2ed052 ED |
56 | u32 secure_tcpv6_ts_off(const struct net *net, |
57 | const __be32 *saddr, const __be32 *daddr) | |
28ee1b74 FW |
58 | { |
59 | const struct { | |
60 | struct in6_addr saddr; | |
61 | struct in6_addr daddr; | |
62 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
63 | .saddr = *(struct in6_addr *)saddr, | |
64 | .daddr = *(struct in6_addr *)daddr, | |
65 | }; | |
66 | ||
3666f666 | 67 | if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1) |
28ee1b74 FW |
68 | return 0; |
69 | ||
84b114b9 | 70 | ts_secret_init(); |
28ee1b74 FW |
71 | return siphash(&combined, offsetofend(typeof(combined), daddr), |
72 | &ts_secret); | |
73 | } | |
84b114b9 | 74 | EXPORT_SYMBOL(secure_tcpv6_ts_off); |
28ee1b74 | 75 | |
84b114b9 ED |
76 | u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr, |
77 | __be16 sport, __be16 dport) | |
6e5714ea | 78 | { |
7cd23e53 JD |
79 | const struct { |
80 | struct in6_addr saddr; | |
81 | struct in6_addr daddr; | |
82 | __be16 sport; | |
83 | __be16 dport; | |
84 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
85 | .saddr = *(struct in6_addr *)saddr, | |
86 | .daddr = *(struct in6_addr *)daddr, | |
87 | .sport = sport, | |
88 | .dport = dport | |
89 | }; | |
84b114b9 ED |
90 | u32 hash; |
91 | ||
9a3bab6b | 92 | net_secret_init(); |
7cd23e53 JD |
93 | hash = siphash(&combined, offsetofend(typeof(combined), dport), |
94 | &net_secret); | |
7cd23e53 | 95 | return seq_scale(hash); |
6e5714ea | 96 | } |
84b114b9 | 97 | EXPORT_SYMBOL(secure_tcpv6_seq); |
6e5714ea | 98 | |
b2d05756 | 99 | u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, |
6e5714ea DM |
100 | __be16 dport) |
101 | { | |
7cd23e53 JD |
102 | const struct { |
103 | struct in6_addr saddr; | |
104 | struct in6_addr daddr; | |
4dfa9b43 | 105 | unsigned int timeseed; |
7cd23e53 JD |
106 | __be16 dport; |
107 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
108 | .saddr = *(struct in6_addr *)saddr, | |
109 | .daddr = *(struct in6_addr *)daddr, | |
4dfa9b43 ED |
110 | .timeseed = jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD, |
111 | .dport = dport, | |
7cd23e53 | 112 | }; |
9a3bab6b | 113 | net_secret_init(); |
7cd23e53 JD |
114 | return siphash(&combined, offsetofend(typeof(combined), dport), |
115 | &net_secret); | |
6e5714ea | 116 | } |
58a317f1 | 117 | EXPORT_SYMBOL(secure_ipv6_port_ephemeral); |
6e5714ea DM |
118 | #endif |
119 | ||
120 | #ifdef CONFIG_INET | |
5d2ed052 | 121 | u32 secure_tcp_ts_off(const struct net *net, __be32 saddr, __be32 daddr) |
28ee1b74 | 122 | { |
3666f666 | 123 | if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1) |
28ee1b74 FW |
124 | return 0; |
125 | ||
84b114b9 | 126 | ts_secret_init(); |
28ee1b74 FW |
127 | return siphash_2u32((__force u32)saddr, (__force u32)daddr, |
128 | &ts_secret); | |
129 | } | |
6e5714ea | 130 | |
a30aad50 | 131 | /* secure_tcp_seq_and_tsoff(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d), |
7cd23e53 JD |
132 | * but fortunately, `sport' cannot be 0 in any circumstances. If this changes, |
133 | * it would be easy enough to have the former function use siphash_4u32, passing | |
134 | * the arguments as separate u32. | |
135 | */ | |
84b114b9 ED |
136 | u32 secure_tcp_seq(__be32 saddr, __be32 daddr, |
137 | __be16 sport, __be16 dport) | |
6e5714ea | 138 | { |
84b114b9 ED |
139 | u32 hash; |
140 | ||
9a3bab6b | 141 | net_secret_init(); |
7cd23e53 JD |
142 | hash = siphash_3u32((__force u32)saddr, (__force u32)daddr, |
143 | (__force u32)sport << 16 | (__force u32)dport, | |
144 | &net_secret); | |
7cd23e53 | 145 | return seq_scale(hash); |
6e5714ea | 146 | } |
07f3355d | 147 | EXPORT_SYMBOL_GPL(secure_tcp_seq); |
6e5714ea | 148 | |
b2d05756 | 149 | u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) |
6e5714ea | 150 | { |
9a3bab6b | 151 | net_secret_init(); |
4dfa9b43 ED |
152 | return siphash_4u32((__force u32)saddr, (__force u32)daddr, |
153 | (__force u16)dport, | |
154 | jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD, | |
155 | &net_secret); | |
6e5714ea DM |
156 | } |
157 | EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); | |
158 | #endif | |
159 | ||
a3bf7ae9 | 160 | #if IS_ENABLED(CONFIG_IP_DCCP) |
6e5714ea DM |
161 | u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, |
162 | __be16 sport, __be16 dport) | |
163 | { | |
6e5714ea | 164 | u64 seq; |
9a3bab6b | 165 | net_secret_init(); |
c1ce1560 ED |
166 | seq = siphash_3u32((__force u32)saddr, (__force u32)daddr, |
167 | (__force u32)sport << 16 | (__force u32)dport, | |
168 | &net_secret); | |
d2de875c | 169 | seq += ktime_get_real_ns(); |
6e5714ea | 170 | seq &= (1ull << 48) - 1; |
6e5714ea DM |
171 | return seq; |
172 | } | |
173 | EXPORT_SYMBOL(secure_dccp_sequence_number); | |
174 | ||
dfd56b8b | 175 | #if IS_ENABLED(CONFIG_IPV6) |
6e5714ea DM |
176 | u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, |
177 | __be16 sport, __be16 dport) | |
178 | { | |
7cd23e53 JD |
179 | const struct { |
180 | struct in6_addr saddr; | |
181 | struct in6_addr daddr; | |
182 | __be16 sport; | |
183 | __be16 dport; | |
184 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
185 | .saddr = *(struct in6_addr *)saddr, | |
186 | .daddr = *(struct in6_addr *)daddr, | |
187 | .sport = sport, | |
188 | .dport = dport | |
189 | }; | |
6e5714ea | 190 | u64 seq; |
9a3bab6b | 191 | net_secret_init(); |
7cd23e53 JD |
192 | seq = siphash(&combined, offsetofend(typeof(combined), dport), |
193 | &net_secret); | |
d2de875c | 194 | seq += ktime_get_real_ns(); |
6e5714ea | 195 | seq &= (1ull << 48) - 1; |
6e5714ea DM |
196 | return seq; |
197 | } | |
198 | EXPORT_SYMBOL(secure_dccpv6_sequence_number); | |
199 | #endif | |
200 | #endif |