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