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6e5714ea DM |
1 | #include <linux/kernel.h> |
2 | #include <linux/init.h> | |
3 | #include <linux/cryptohash.h> | |
4 | #include <linux/module.h> | |
5 | #include <linux/cache.h> | |
6 | #include <linux/random.h> | |
7 | #include <linux/hrtimer.h> | |
8 | #include <linux/ktime.h> | |
9 | #include <linux/string.h> | |
10 | ||
11 | #include <net/secure_seq.h> | |
12 | ||
13 | static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned; | |
14 | ||
15 | static int __init net_secret_init(void) | |
16 | { | |
17 | get_random_bytes(net_secret, sizeof(net_secret)); | |
18 | return 0; | |
19 | } | |
20 | late_initcall(net_secret_init); | |
21 | ||
68109090 | 22 | #ifdef CONFIG_INET |
6e5714ea DM |
23 | static u32 seq_scale(u32 seq) |
24 | { | |
25 | /* | |
26 | * As close as possible to RFC 793, which | |
27 | * suggests using a 250 kHz clock. | |
28 | * Further reading shows this assumes 2 Mb/s networks. | |
29 | * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. | |
30 | * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but | |
31 | * we also need to limit the resolution so that the u32 seq | |
32 | * overlaps less than one time per MSL (2 minutes). | |
33 | * Choosing a clock of 64 ns period is OK. (period of 274 s) | |
34 | */ | |
35 | return seq + (ktime_to_ns(ktime_get_real()) >> 6); | |
36 | } | |
68109090 | 37 | #endif |
6e5714ea | 38 | |
dfd56b8b | 39 | #if IS_ENABLED(CONFIG_IPV6) |
cf533ea5 | 40 | __u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr, |
6e5714ea DM |
41 | __be16 sport, __be16 dport) |
42 | { | |
43 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
44 | u32 hash[MD5_DIGEST_WORDS]; | |
45 | u32 i; | |
46 | ||
47 | memcpy(hash, saddr, 16); | |
48 | for (i = 0; i < 4; i++) | |
49 | secret[i] = net_secret[i] + daddr[i]; | |
50 | secret[4] = net_secret[4] + | |
51 | (((__force u16)sport << 16) + (__force u16)dport); | |
52 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
53 | secret[i] = net_secret[i]; | |
54 | ||
55 | md5_transform(hash, secret); | |
56 | ||
57 | return seq_scale(hash[0]); | |
58 | } | |
59 | EXPORT_SYMBOL(secure_tcpv6_sequence_number); | |
60 | ||
61 | u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, | |
62 | __be16 dport) | |
63 | { | |
64 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
65 | u32 hash[MD5_DIGEST_WORDS]; | |
66 | u32 i; | |
67 | ||
68 | memcpy(hash, saddr, 16); | |
69 | for (i = 0; i < 4; i++) | |
70 | secret[i] = net_secret[i] + (__force u32) daddr[i]; | |
71 | secret[4] = net_secret[4] + (__force u32)dport; | |
72 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
73 | secret[i] = net_secret[i]; | |
74 | ||
75 | md5_transform(hash, secret); | |
76 | ||
77 | return hash[0]; | |
78 | } | |
79 | #endif | |
80 | ||
81 | #ifdef CONFIG_INET | |
82 | __u32 secure_ip_id(__be32 daddr) | |
83 | { | |
84 | u32 hash[MD5_DIGEST_WORDS]; | |
85 | ||
86 | hash[0] = (__force __u32) daddr; | |
87 | hash[1] = net_secret[13]; | |
88 | hash[2] = net_secret[14]; | |
89 | hash[3] = net_secret[15]; | |
90 | ||
91 | md5_transform(hash, net_secret); | |
92 | ||
93 | return hash[0]; | |
94 | } | |
95 | ||
96 | __u32 secure_ipv6_id(const __be32 daddr[4]) | |
97 | { | |
98 | __u32 hash[4]; | |
99 | ||
100 | memcpy(hash, daddr, 16); | |
101 | md5_transform(hash, net_secret); | |
102 | ||
103 | return hash[0]; | |
104 | } | |
105 | ||
106 | __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, | |
107 | __be16 sport, __be16 dport) | |
108 | { | |
109 | u32 hash[MD5_DIGEST_WORDS]; | |
110 | ||
111 | hash[0] = (__force u32)saddr; | |
112 | hash[1] = (__force u32)daddr; | |
113 | hash[2] = ((__force u16)sport << 16) + (__force u16)dport; | |
114 | hash[3] = net_secret[15]; | |
115 | ||
116 | md5_transform(hash, net_secret); | |
117 | ||
118 | return seq_scale(hash[0]); | |
119 | } | |
120 | ||
121 | u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) | |
122 | { | |
123 | u32 hash[MD5_DIGEST_WORDS]; | |
124 | ||
125 | hash[0] = (__force u32)saddr; | |
126 | hash[1] = (__force u32)daddr; | |
127 | hash[2] = (__force u32)dport ^ net_secret[14]; | |
128 | hash[3] = net_secret[15]; | |
129 | ||
130 | md5_transform(hash, net_secret); | |
131 | ||
132 | return hash[0]; | |
133 | } | |
134 | EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); | |
135 | #endif | |
136 | ||
137 | #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE) | |
138 | u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, | |
139 | __be16 sport, __be16 dport) | |
140 | { | |
141 | u32 hash[MD5_DIGEST_WORDS]; | |
142 | u64 seq; | |
143 | ||
144 | hash[0] = (__force u32)saddr; | |
145 | hash[1] = (__force u32)daddr; | |
146 | hash[2] = ((__force u16)sport << 16) + (__force u16)dport; | |
147 | hash[3] = net_secret[15]; | |
148 | ||
149 | md5_transform(hash, net_secret); | |
150 | ||
151 | seq = hash[0] | (((u64)hash[1]) << 32); | |
152 | seq += ktime_to_ns(ktime_get_real()); | |
153 | seq &= (1ull << 48) - 1; | |
154 | ||
155 | return seq; | |
156 | } | |
157 | EXPORT_SYMBOL(secure_dccp_sequence_number); | |
158 | ||
dfd56b8b | 159 | #if IS_ENABLED(CONFIG_IPV6) |
6e5714ea DM |
160 | u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, |
161 | __be16 sport, __be16 dport) | |
162 | { | |
163 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
164 | u32 hash[MD5_DIGEST_WORDS]; | |
165 | u64 seq; | |
166 | u32 i; | |
167 | ||
168 | memcpy(hash, saddr, 16); | |
169 | for (i = 0; i < 4; i++) | |
170 | secret[i] = net_secret[i] + daddr[i]; | |
171 | secret[4] = net_secret[4] + | |
172 | (((__force u16)sport << 16) + (__force u16)dport); | |
173 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
174 | secret[i] = net_secret[i]; | |
175 | ||
176 | md5_transform(hash, secret); | |
177 | ||
178 | seq = hash[0] | (((u64)hash[1]) << 32); | |
179 | seq += ktime_to_ns(ktime_get_real()); | |
180 | seq &= (1ull << 48) - 1; | |
181 | ||
182 | return seq; | |
183 | } | |
184 | EXPORT_SYMBOL(secure_dccpv6_sequence_number); | |
185 | #endif | |
186 | #endif |