]>
Commit | Line | Data |
---|---|---|
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 | { |
28ee1b74 | 27 | net_get_random_once(&ts_secret, sizeof(ts_secret)); |
7cd23e53 | 28 | net_get_random_once(&net_secret, sizeof(net_secret)); |
6e5714ea | 29 | } |
cb03db9d | 30 | #endif |
6e5714ea | 31 | |
68109090 | 32 | #ifdef CONFIG_INET |
6e5714ea DM |
33 | static u32 seq_scale(u32 seq) |
34 | { | |
35 | /* | |
36 | * As close as possible to RFC 793, which | |
37 | * suggests using a 250 kHz clock. | |
38 | * Further reading shows this assumes 2 Mb/s networks. | |
39 | * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. | |
40 | * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but | |
41 | * we also need to limit the resolution so that the u32 seq | |
42 | * overlaps less than one time per MSL (2 minutes). | |
43 | * Choosing a clock of 64 ns period is OK. (period of 274 s) | |
44 | */ | |
d2de875c | 45 | return seq + (ktime_get_real_ns() >> 6); |
6e5714ea | 46 | } |
68109090 | 47 | #endif |
6e5714ea | 48 | |
dfd56b8b | 49 | #if IS_ENABLED(CONFIG_IPV6) |
28ee1b74 FW |
50 | static u32 secure_tcpv6_ts_off(const __be32 *saddr, const __be32 *daddr) |
51 | { | |
52 | const struct { | |
53 | struct in6_addr saddr; | |
54 | struct in6_addr daddr; | |
55 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
56 | .saddr = *(struct in6_addr *)saddr, | |
57 | .daddr = *(struct in6_addr *)daddr, | |
58 | }; | |
59 | ||
60 | if (sysctl_tcp_timestamps != 1) | |
61 | return 0; | |
62 | ||
63 | return siphash(&combined, offsetofend(typeof(combined), daddr), | |
64 | &ts_secret); | |
65 | } | |
66 | ||
95a22cae FW |
67 | u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr, |
68 | __be16 sport, __be16 dport, u32 *tsoff) | |
6e5714ea | 69 | { |
7cd23e53 JD |
70 | const struct { |
71 | struct in6_addr saddr; | |
72 | struct in6_addr daddr; | |
73 | __be16 sport; | |
74 | __be16 dport; | |
75 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
76 | .saddr = *(struct in6_addr *)saddr, | |
77 | .daddr = *(struct in6_addr *)daddr, | |
78 | .sport = sport, | |
79 | .dport = dport | |
80 | }; | |
81 | u64 hash; | |
9a3bab6b | 82 | net_secret_init(); |
7cd23e53 JD |
83 | hash = siphash(&combined, offsetofend(typeof(combined), dport), |
84 | &net_secret); | |
28ee1b74 | 85 | *tsoff = secure_tcpv6_ts_off(saddr, daddr); |
7cd23e53 | 86 | return seq_scale(hash); |
6e5714ea DM |
87 | } |
88 | EXPORT_SYMBOL(secure_tcpv6_sequence_number); | |
89 | ||
90 | u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, | |
91 | __be16 dport) | |
92 | { | |
7cd23e53 JD |
93 | const struct { |
94 | struct in6_addr saddr; | |
95 | struct in6_addr daddr; | |
96 | __be16 dport; | |
97 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
98 | .saddr = *(struct in6_addr *)saddr, | |
99 | .daddr = *(struct in6_addr *)daddr, | |
100 | .dport = dport | |
101 | }; | |
9a3bab6b | 102 | net_secret_init(); |
7cd23e53 JD |
103 | return siphash(&combined, offsetofend(typeof(combined), dport), |
104 | &net_secret); | |
6e5714ea | 105 | } |
58a317f1 | 106 | EXPORT_SYMBOL(secure_ipv6_port_ephemeral); |
6e5714ea DM |
107 | #endif |
108 | ||
109 | #ifdef CONFIG_INET | |
28ee1b74 FW |
110 | static u32 secure_tcp_ts_off(__be32 saddr, __be32 daddr) |
111 | { | |
112 | if (sysctl_tcp_timestamps != 1) | |
113 | return 0; | |
114 | ||
115 | return siphash_2u32((__force u32)saddr, (__force u32)daddr, | |
116 | &ts_secret); | |
117 | } | |
6e5714ea | 118 | |
7cd23e53 JD |
119 | /* secure_tcp_sequence_number(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d), |
120 | * but fortunately, `sport' cannot be 0 in any circumstances. If this changes, | |
121 | * it would be easy enough to have the former function use siphash_4u32, passing | |
122 | * the arguments as separate u32. | |
123 | */ | |
124 | ||
95a22cae FW |
125 | u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, |
126 | __be16 sport, __be16 dport, u32 *tsoff) | |
6e5714ea | 127 | { |
7cd23e53 | 128 | u64 hash; |
9a3bab6b | 129 | net_secret_init(); |
7cd23e53 JD |
130 | hash = siphash_3u32((__force u32)saddr, (__force u32)daddr, |
131 | (__force u32)sport << 16 | (__force u32)dport, | |
132 | &net_secret); | |
28ee1b74 | 133 | *tsoff = secure_tcp_ts_off(saddr, daddr); |
7cd23e53 | 134 | return seq_scale(hash); |
6e5714ea DM |
135 | } |
136 | ||
137 | u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) | |
138 | { | |
9a3bab6b | 139 | net_secret_init(); |
7cd23e53 JD |
140 | return siphash_3u32((__force u32)saddr, (__force u32)daddr, |
141 | (__force u16)dport, &net_secret); | |
6e5714ea DM |
142 | } |
143 | EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); | |
144 | #endif | |
145 | ||
a3bf7ae9 | 146 | #if IS_ENABLED(CONFIG_IP_DCCP) |
6e5714ea DM |
147 | u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, |
148 | __be16 sport, __be16 dport) | |
149 | { | |
6e5714ea | 150 | u64 seq; |
9a3bab6b | 151 | net_secret_init(); |
c1ce1560 ED |
152 | seq = siphash_3u32((__force u32)saddr, (__force u32)daddr, |
153 | (__force u32)sport << 16 | (__force u32)dport, | |
154 | &net_secret); | |
d2de875c | 155 | seq += ktime_get_real_ns(); |
6e5714ea | 156 | seq &= (1ull << 48) - 1; |
6e5714ea DM |
157 | return seq; |
158 | } | |
159 | EXPORT_SYMBOL(secure_dccp_sequence_number); | |
160 | ||
dfd56b8b | 161 | #if IS_ENABLED(CONFIG_IPV6) |
6e5714ea DM |
162 | u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, |
163 | __be16 sport, __be16 dport) | |
164 | { | |
7cd23e53 JD |
165 | const struct { |
166 | struct in6_addr saddr; | |
167 | struct in6_addr daddr; | |
168 | __be16 sport; | |
169 | __be16 dport; | |
170 | } __aligned(SIPHASH_ALIGNMENT) combined = { | |
171 | .saddr = *(struct in6_addr *)saddr, | |
172 | .daddr = *(struct in6_addr *)daddr, | |
173 | .sport = sport, | |
174 | .dport = dport | |
175 | }; | |
6e5714ea | 176 | u64 seq; |
9a3bab6b | 177 | net_secret_init(); |
7cd23e53 JD |
178 | seq = siphash(&combined, offsetofend(typeof(combined), dport), |
179 | &net_secret); | |
d2de875c | 180 | seq += ktime_get_real_ns(); |
6e5714ea | 181 | seq &= (1ull << 48) - 1; |
6e5714ea DM |
182 | return seq; |
183 | } | |
184 | EXPORT_SYMBOL(secure_dccpv6_sequence_number); | |
185 | #endif | |
186 | #endif |