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>
11 #include <net/secure_seq.h>
13 static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
15 static int __init net_secret_init(void)
17 get_random_bytes(net_secret, sizeof(net_secret));
20 late_initcall(net_secret_init);
23 static u32 seq_scale(u32 seq)
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)
35 return seq + (ktime_to_ns(ktime_get_real()) >> 6);
39 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
40 __u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr,
41 __be16 sport, __be16 dport)
43 u32 secret[MD5_MESSAGE_BYTES / 4];
44 u32 hash[MD5_DIGEST_WORDS];
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];
55 md5_transform(hash, secret);
57 return seq_scale(hash[0]);
59 EXPORT_SYMBOL(secure_tcpv6_sequence_number);
61 u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
64 u32 secret[MD5_MESSAGE_BYTES / 4];
65 u32 hash[MD5_DIGEST_WORDS];
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];
75 md5_transform(hash, secret);
83 __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
84 __be16 sport, __be16 dport)
86 u32 hash[MD5_DIGEST_WORDS];
88 hash[0] = (__force u32)saddr;
89 hash[1] = (__force u32)daddr;
90 hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
91 hash[3] = net_secret[15];
93 md5_transform(hash, net_secret);
95 return seq_scale(hash[0]);
98 u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
100 u32 hash[MD5_DIGEST_WORDS];
102 hash[0] = (__force u32)saddr;
103 hash[1] = (__force u32)daddr;
104 hash[2] = (__force u32)dport ^ net_secret[14];
105 hash[3] = net_secret[15];
107 md5_transform(hash, net_secret);
111 EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
114 #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
115 u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
116 __be16 sport, __be16 dport)
118 u32 hash[MD5_DIGEST_WORDS];
121 hash[0] = (__force u32)saddr;
122 hash[1] = (__force u32)daddr;
123 hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
124 hash[3] = net_secret[15];
126 md5_transform(hash, net_secret);
128 seq = hash[0] | (((u64)hash[1]) << 32);
129 seq += ktime_to_ns(ktime_get_real());
130 seq &= (1ull << 48) - 1;
134 EXPORT_SYMBOL(secure_dccp_sequence_number);
136 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
137 u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
138 __be16 sport, __be16 dport)
140 u32 secret[MD5_MESSAGE_BYTES / 4];
141 u32 hash[MD5_DIGEST_WORDS];
145 memcpy(hash, saddr, 16);
146 for (i = 0; i < 4; i++)
147 secret[i] = net_secret[i] + daddr[i];
148 secret[4] = net_secret[4] +
149 (((__force u16)sport << 16) + (__force u16)dport);
150 for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
151 secret[i] = net_secret[i];
153 md5_transform(hash, secret);
155 seq = hash[0] | (((u64)hash[1]) << 32);
156 seq += ktime_to_ns(ktime_get_real());
157 seq &= (1ull << 48) - 1;
161 EXPORT_SYMBOL(secure_dccpv6_sequence_number);