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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 | ||
22 | static u32 seq_scale(u32 seq) | |
23 | { | |
24 | /* | |
25 | * As close as possible to RFC 793, which | |
26 | * suggests using a 250 kHz clock. | |
27 | * Further reading shows this assumes 2 Mb/s networks. | |
28 | * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. | |
29 | * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but | |
30 | * we also need to limit the resolution so that the u32 seq | |
31 | * overlaps less than one time per MSL (2 minutes). | |
32 | * Choosing a clock of 64 ns period is OK. (period of 274 s) | |
33 | */ | |
34 | return seq + (ktime_to_ns(ktime_get_real()) >> 6); | |
35 | } | |
36 | ||
37 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
38 | __u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr, | |
39 | __be16 sport, __be16 dport) | |
40 | { | |
41 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
42 | u32 hash[MD5_DIGEST_WORDS]; | |
43 | u32 i; | |
44 | ||
45 | memcpy(hash, saddr, 16); | |
46 | for (i = 0; i < 4; i++) | |
47 | secret[i] = net_secret[i] + daddr[i]; | |
48 | secret[4] = net_secret[4] + | |
49 | (((__force u16)sport << 16) + (__force u16)dport); | |
50 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
51 | secret[i] = net_secret[i]; | |
52 | ||
53 | md5_transform(hash, secret); | |
54 | ||
55 | return seq_scale(hash[0]); | |
56 | } | |
57 | EXPORT_SYMBOL(secure_tcpv6_sequence_number); | |
58 | ||
59 | u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, | |
60 | __be16 dport) | |
61 | { | |
62 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
63 | u32 hash[MD5_DIGEST_WORDS]; | |
64 | u32 i; | |
65 | ||
66 | memcpy(hash, saddr, 16); | |
67 | for (i = 0; i < 4; i++) | |
68 | secret[i] = net_secret[i] + (__force u32) daddr[i]; | |
69 | secret[4] = net_secret[4] + (__force u32)dport; | |
70 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
71 | secret[i] = net_secret[i]; | |
72 | ||
73 | md5_transform(hash, secret); | |
74 | ||
75 | return hash[0]; | |
76 | } | |
77 | #endif | |
78 | ||
79 | #ifdef CONFIG_INET | |
80 | __u32 secure_ip_id(__be32 daddr) | |
81 | { | |
82 | u32 hash[MD5_DIGEST_WORDS]; | |
83 | ||
84 | hash[0] = (__force __u32) daddr; | |
85 | hash[1] = net_secret[13]; | |
86 | hash[2] = net_secret[14]; | |
87 | hash[3] = net_secret[15]; | |
88 | ||
89 | md5_transform(hash, net_secret); | |
90 | ||
91 | return hash[0]; | |
92 | } | |
93 | ||
94 | __u32 secure_ipv6_id(const __be32 daddr[4]) | |
95 | { | |
96 | __u32 hash[4]; | |
97 | ||
98 | memcpy(hash, daddr, 16); | |
99 | md5_transform(hash, net_secret); | |
100 | ||
101 | return hash[0]; | |
102 | } | |
103 | ||
104 | __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, | |
105 | __be16 sport, __be16 dport) | |
106 | { | |
107 | u32 hash[MD5_DIGEST_WORDS]; | |
108 | ||
109 | hash[0] = (__force u32)saddr; | |
110 | hash[1] = (__force u32)daddr; | |
111 | hash[2] = ((__force u16)sport << 16) + (__force u16)dport; | |
112 | hash[3] = net_secret[15]; | |
113 | ||
114 | md5_transform(hash, net_secret); | |
115 | ||
116 | return seq_scale(hash[0]); | |
117 | } | |
118 | ||
119 | u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) | |
120 | { | |
121 | u32 hash[MD5_DIGEST_WORDS]; | |
122 | ||
123 | hash[0] = (__force u32)saddr; | |
124 | hash[1] = (__force u32)daddr; | |
125 | hash[2] = (__force u32)dport ^ net_secret[14]; | |
126 | hash[3] = net_secret[15]; | |
127 | ||
128 | md5_transform(hash, net_secret); | |
129 | ||
130 | return hash[0]; | |
131 | } | |
132 | EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); | |
133 | #endif | |
134 | ||
135 | #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE) | |
136 | u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, | |
137 | __be16 sport, __be16 dport) | |
138 | { | |
139 | u32 hash[MD5_DIGEST_WORDS]; | |
140 | u64 seq; | |
141 | ||
142 | hash[0] = (__force u32)saddr; | |
143 | hash[1] = (__force u32)daddr; | |
144 | hash[2] = ((__force u16)sport << 16) + (__force u16)dport; | |
145 | hash[3] = net_secret[15]; | |
146 | ||
147 | md5_transform(hash, net_secret); | |
148 | ||
149 | seq = hash[0] | (((u64)hash[1]) << 32); | |
150 | seq += ktime_to_ns(ktime_get_real()); | |
151 | seq &= (1ull << 48) - 1; | |
152 | ||
153 | return seq; | |
154 | } | |
155 | EXPORT_SYMBOL(secure_dccp_sequence_number); | |
156 | ||
157 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
158 | u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, | |
159 | __be16 sport, __be16 dport) | |
160 | { | |
161 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
162 | u32 hash[MD5_DIGEST_WORDS]; | |
163 | u64 seq; | |
164 | u32 i; | |
165 | ||
166 | memcpy(hash, saddr, 16); | |
167 | for (i = 0; i < 4; i++) | |
168 | secret[i] = net_secret[i] + daddr[i]; | |
169 | secret[4] = net_secret[4] + | |
170 | (((__force u16)sport << 16) + (__force u16)dport); | |
171 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
172 | secret[i] = net_secret[i]; | |
173 | ||
174 | md5_transform(hash, secret); | |
175 | ||
176 | seq = hash[0] | (((u64)hash[1]) << 32); | |
177 | seq += ktime_to_ns(ktime_get_real()); | |
178 | seq &= (1ull << 48) - 1; | |
179 | ||
180 | return seq; | |
181 | } | |
182 | EXPORT_SYMBOL(secure_dccpv6_sequence_number); | |
183 | #endif | |
184 | #endif |