Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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_to_ns(ktime_get_real()) >> 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__u32 secure_ip_id(__be32 daddr)
89{
90 u32 hash[MD5_DIGEST_WORDS];
91
92 net_secret_init();
93 hash[0] = (__force __u32) daddr;
94 hash[1] = net_secret[13];
95 hash[2] = net_secret[14];
96 hash[3] = net_secret[15];
97
98 md5_transform(hash, net_secret);
99
100 return hash[0];
101}
102
103__u32 secure_ipv6_id(const __be32 daddr[4])
104{
105 __u32 hash[4];
106
107 net_secret_init();
108 memcpy(hash, daddr, 16);
109 md5_transform(hash, net_secret);
110
111 return hash[0];
112}
113
114__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
115 __be16 sport, __be16 dport)
116{
117 u32 hash[MD5_DIGEST_WORDS];
118
119 net_secret_init();
120 hash[0] = (__force u32)saddr;
121 hash[1] = (__force u32)daddr;
122 hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
123 hash[3] = net_secret[15];
124
125 md5_transform(hash, net_secret);
126
127 return seq_scale(hash[0]);
128}
129
130u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
131{
132 u32 hash[MD5_DIGEST_WORDS];
133
134 net_secret_init();
135 hash[0] = (__force u32)saddr;
136 hash[1] = (__force u32)daddr;
137 hash[2] = (__force u32)dport ^ net_secret[14];
138 hash[3] = net_secret[15];
139
140 md5_transform(hash, net_secret);
141
142 return hash[0];
143}
144EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
145#endif
146
147#if IS_ENABLED(CONFIG_IP_DCCP)
148u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
149 __be16 sport, __be16 dport)
150{
151 u32 hash[MD5_DIGEST_WORDS];
152 u64 seq;
153
154 net_secret_init();
155 hash[0] = (__force u32)saddr;
156 hash[1] = (__force u32)daddr;
157 hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
158 hash[3] = net_secret[15];
159
160 md5_transform(hash, net_secret);
161
162 seq = hash[0] | (((u64)hash[1]) << 32);
163 seq += ktime_to_ns(ktime_get_real());
164 seq &= (1ull << 48) - 1;
165
166 return seq;
167}
168EXPORT_SYMBOL(secure_dccp_sequence_number);
169
170#if IS_ENABLED(CONFIG_IPV6)
171u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
172 __be16 sport, __be16 dport)
173{
174 u32 secret[MD5_MESSAGE_BYTES / 4];
175 u32 hash[MD5_DIGEST_WORDS];
176 u64 seq;
177 u32 i;
178
179 net_secret_init();
180 memcpy(hash, saddr, 16);
181 for (i = 0; i < 4; i++)
182 secret[i] = net_secret[i] + daddr[i];
183 secret[4] = net_secret[4] +
184 (((__force u16)sport << 16) + (__force u16)dport);
185 for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
186 secret[i] = net_secret[i];
187
188 md5_transform(hash, secret);
189
190 seq = hash[0] | (((u64)hash[1]) << 32);
191 seq += ktime_to_ns(ktime_get_real());
192 seq &= (1ull << 48) - 1;
193
194 return seq;
195}
196EXPORT_SYMBOL(secure_dccpv6_sequence_number);
197#endif
198#endif