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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
13static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
14
15static int __init net_secret_init(void)
16{
17 get_random_bytes(net_secret, sizeof(net_secret));
18 return 0;
19}
20late_initcall(net_secret_init);
21
22static 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}
57EXPORT_SYMBOL(secure_tcpv6_sequence_number);
58
59u32 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
119u32 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}
132EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
133#endif
134
135#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
136u64 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}
155EXPORT_SYMBOL(secure_dccp_sequence_number);
156
157#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
158u64 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}
182EXPORT_SYMBOL(secure_dccpv6_sequence_number);
183#endif
184#endif
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
13static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
14
15static int __init net_secret_init(void)
16{
17 get_random_bytes(net_secret, sizeof(net_secret));
18 return 0;
19}
20late_initcall(net_secret_init);
21
22#ifdef CONFIG_INET
23static 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}
37#endif
38
39#if IS_ENABLED(CONFIG_IPV6)
40__u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr,
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] + (__force u32)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}
59EXPORT_SYMBOL(secure_tcpv6_sequence_number);
60
61u32 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
121u32 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}
134EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
135#endif
136
137#if IS_ENABLED(CONFIG_IP_DCCP)
138u64 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}
157EXPORT_SYMBOL(secure_dccp_sequence_number);
158
159#if IS_ENABLED(CONFIG_IPV6)
160u64 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}
184EXPORT_SYMBOL(secure_dccpv6_sequence_number);
185#endif
186#endif