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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 | ||
9a3bab6b | 13 | #define NET_SECRET_SIZE (MD5_MESSAGE_BYTES / 4) |
6e5714ea | 14 | |
9a3bab6b ED |
15 | static u32 net_secret[NET_SECRET_SIZE] ____cacheline_aligned; |
16 | ||
17 | static void net_secret_init(void) | |
6e5714ea | 18 | { |
9a3bab6b ED |
19 | u32 tmp; |
20 | int i; | |
21 | ||
22 | if (likely(net_secret[0])) | |
23 | return; | |
24 | ||
25 | for (i = NET_SECRET_SIZE; i > 0;) { | |
26 | do { | |
27 | get_random_bytes(&tmp, sizeof(tmp)); | |
28 | } while (!tmp); | |
29 | cmpxchg(&net_secret[--i], 0, tmp); | |
30 | } | |
6e5714ea | 31 | } |
6e5714ea | 32 | |
68109090 | 33 | #ifdef CONFIG_INET |
6e5714ea DM |
34 | static u32 seq_scale(u32 seq) |
35 | { | |
36 | /* | |
37 | * As close as possible to RFC 793, which | |
38 | * suggests using a 250 kHz clock. | |
39 | * Further reading shows this assumes 2 Mb/s networks. | |
40 | * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate. | |
41 | * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but | |
42 | * we also need to limit the resolution so that the u32 seq | |
43 | * overlaps less than one time per MSL (2 minutes). | |
44 | * Choosing a clock of 64 ns period is OK. (period of 274 s) | |
45 | */ | |
46 | return seq + (ktime_to_ns(ktime_get_real()) >> 6); | |
47 | } | |
68109090 | 48 | #endif |
6e5714ea | 49 | |
dfd56b8b | 50 | #if IS_ENABLED(CONFIG_IPV6) |
cf533ea5 | 51 | __u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr, |
6e5714ea DM |
52 | __be16 sport, __be16 dport) |
53 | { | |
54 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
55 | u32 hash[MD5_DIGEST_WORDS]; | |
56 | u32 i; | |
57 | ||
9a3bab6b | 58 | net_secret_init(); |
6e5714ea DM |
59 | memcpy(hash, saddr, 16); |
60 | for (i = 0; i < 4; i++) | |
747465ef | 61 | secret[i] = net_secret[i] + (__force u32)daddr[i]; |
6e5714ea DM |
62 | secret[4] = net_secret[4] + |
63 | (((__force u16)sport << 16) + (__force u16)dport); | |
64 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
65 | secret[i] = net_secret[i]; | |
66 | ||
67 | md5_transform(hash, secret); | |
68 | ||
69 | return seq_scale(hash[0]); | |
70 | } | |
71 | EXPORT_SYMBOL(secure_tcpv6_sequence_number); | |
72 | ||
73 | u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr, | |
74 | __be16 dport) | |
75 | { | |
76 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
77 | u32 hash[MD5_DIGEST_WORDS]; | |
78 | u32 i; | |
79 | ||
9a3bab6b | 80 | net_secret_init(); |
6e5714ea DM |
81 | memcpy(hash, saddr, 16); |
82 | for (i = 0; i < 4; i++) | |
83 | secret[i] = net_secret[i] + (__force u32) daddr[i]; | |
84 | secret[4] = net_secret[4] + (__force u32)dport; | |
85 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
86 | secret[i] = net_secret[i]; | |
87 | ||
88 | md5_transform(hash, secret); | |
89 | ||
90 | return hash[0]; | |
91 | } | |
58a317f1 | 92 | EXPORT_SYMBOL(secure_ipv6_port_ephemeral); |
6e5714ea DM |
93 | #endif |
94 | ||
95 | #ifdef CONFIG_INET | |
96 | __u32 secure_ip_id(__be32 daddr) | |
97 | { | |
98 | u32 hash[MD5_DIGEST_WORDS]; | |
99 | ||
9a3bab6b | 100 | net_secret_init(); |
6e5714ea DM |
101 | hash[0] = (__force __u32) daddr; |
102 | hash[1] = net_secret[13]; | |
103 | hash[2] = net_secret[14]; | |
104 | hash[3] = net_secret[15]; | |
105 | ||
106 | md5_transform(hash, net_secret); | |
107 | ||
108 | return hash[0]; | |
109 | } | |
110 | ||
111 | __u32 secure_ipv6_id(const __be32 daddr[4]) | |
112 | { | |
113 | __u32 hash[4]; | |
114 | ||
9a3bab6b | 115 | net_secret_init(); |
6e5714ea DM |
116 | memcpy(hash, daddr, 16); |
117 | md5_transform(hash, net_secret); | |
118 | ||
119 | return hash[0]; | |
120 | } | |
121 | ||
122 | __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr, | |
123 | __be16 sport, __be16 dport) | |
124 | { | |
125 | u32 hash[MD5_DIGEST_WORDS]; | |
126 | ||
9a3bab6b | 127 | net_secret_init(); |
6e5714ea DM |
128 | hash[0] = (__force u32)saddr; |
129 | hash[1] = (__force u32)daddr; | |
130 | hash[2] = ((__force u16)sport << 16) + (__force u16)dport; | |
131 | hash[3] = net_secret[15]; | |
132 | ||
133 | md5_transform(hash, net_secret); | |
134 | ||
135 | return seq_scale(hash[0]); | |
136 | } | |
137 | ||
138 | u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport) | |
139 | { | |
140 | u32 hash[MD5_DIGEST_WORDS]; | |
141 | ||
9a3bab6b | 142 | net_secret_init(); |
6e5714ea DM |
143 | hash[0] = (__force u32)saddr; |
144 | hash[1] = (__force u32)daddr; | |
145 | hash[2] = (__force u32)dport ^ net_secret[14]; | |
146 | hash[3] = net_secret[15]; | |
147 | ||
148 | md5_transform(hash, net_secret); | |
149 | ||
150 | return hash[0]; | |
151 | } | |
152 | EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral); | |
153 | #endif | |
154 | ||
a3bf7ae9 | 155 | #if IS_ENABLED(CONFIG_IP_DCCP) |
6e5714ea DM |
156 | u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr, |
157 | __be16 sport, __be16 dport) | |
158 | { | |
159 | u32 hash[MD5_DIGEST_WORDS]; | |
160 | u64 seq; | |
161 | ||
9a3bab6b | 162 | net_secret_init(); |
6e5714ea DM |
163 | hash[0] = (__force u32)saddr; |
164 | hash[1] = (__force u32)daddr; | |
165 | hash[2] = ((__force u16)sport << 16) + (__force u16)dport; | |
166 | hash[3] = net_secret[15]; | |
167 | ||
168 | md5_transform(hash, net_secret); | |
169 | ||
170 | seq = hash[0] | (((u64)hash[1]) << 32); | |
171 | seq += ktime_to_ns(ktime_get_real()); | |
172 | seq &= (1ull << 48) - 1; | |
173 | ||
174 | return seq; | |
175 | } | |
176 | EXPORT_SYMBOL(secure_dccp_sequence_number); | |
177 | ||
dfd56b8b | 178 | #if IS_ENABLED(CONFIG_IPV6) |
6e5714ea DM |
179 | u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr, |
180 | __be16 sport, __be16 dport) | |
181 | { | |
182 | u32 secret[MD5_MESSAGE_BYTES / 4]; | |
183 | u32 hash[MD5_DIGEST_WORDS]; | |
184 | u64 seq; | |
185 | u32 i; | |
186 | ||
9a3bab6b | 187 | net_secret_init(); |
6e5714ea DM |
188 | memcpy(hash, saddr, 16); |
189 | for (i = 0; i < 4; i++) | |
190 | secret[i] = net_secret[i] + daddr[i]; | |
191 | secret[4] = net_secret[4] + | |
192 | (((__force u16)sport << 16) + (__force u16)dport); | |
193 | for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++) | |
194 | secret[i] = net_secret[i]; | |
195 | ||
196 | md5_transform(hash, secret); | |
197 | ||
198 | seq = hash[0] | (((u64)hash[1]) << 32); | |
199 | seq += ktime_to_ns(ktime_get_real()); | |
200 | seq &= (1ull << 48) - 1; | |
201 | ||
202 | return seq; | |
203 | } | |
204 | EXPORT_SYMBOL(secure_dccpv6_sequence_number); | |
205 | #endif | |
206 | #endif |