Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
4 */
5
6#include <linux/kernel.h>
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/cache.h>
10#include <linux/random.h>
11#include <linux/hrtimer.h>
12#include <linux/ktime.h>
13#include <linux/string.h>
14#include <linux/net.h>
15#include <linux/siphash.h>
16#include <net/secure_seq.h>
17
18#if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET)
19#include <linux/in6.h>
20#include <net/tcp.h>
21
22static siphash_aligned_key_t net_secret;
23static siphash_aligned_key_t ts_secret;
24
25#define EPHEMERAL_PORT_SHUFFLE_PERIOD (10 * HZ)
26
27static __always_inline void net_secret_init(void)
28{
29 net_get_random_once(&net_secret, sizeof(net_secret));
30}
31
32static __always_inline void ts_secret_init(void)
33{
34 net_get_random_once(&ts_secret, sizeof(ts_secret));
35}
36#endif
37
38#ifdef CONFIG_INET
39static u32 seq_scale(u32 seq)
40{
41 /*
42 * As close as possible to RFC 793, which
43 * suggests using a 250 kHz clock.
44 * Further reading shows this assumes 2 Mb/s networks.
45 * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate.
46 * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but
47 * we also need to limit the resolution so that the u32 seq
48 * overlaps less than one time per MSL (2 minutes).
49 * Choosing a clock of 64 ns period is OK. (period of 274 s)
50 */
51 return seq + (ktime_get_real_ns() >> 6);
52}
53#endif
54
55#if IS_ENABLED(CONFIG_IPV6)
56u32 secure_tcpv6_ts_off(const struct net *net,
57 const __be32 *saddr, const __be32 *daddr)
58{
59 const struct {
60 struct in6_addr saddr;
61 struct in6_addr daddr;
62 } __aligned(SIPHASH_ALIGNMENT) combined = {
63 .saddr = *(struct in6_addr *)saddr,
64 .daddr = *(struct in6_addr *)daddr,
65 };
66
67 if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1)
68 return 0;
69
70 ts_secret_init();
71 return siphash(&combined, offsetofend(typeof(combined), daddr),
72 &ts_secret);
73}
74EXPORT_SYMBOL(secure_tcpv6_ts_off);
75
76u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr,
77 __be16 sport, __be16 dport)
78{
79 const struct {
80 struct in6_addr saddr;
81 struct in6_addr daddr;
82 __be16 sport;
83 __be16 dport;
84 } __aligned(SIPHASH_ALIGNMENT) combined = {
85 .saddr = *(struct in6_addr *)saddr,
86 .daddr = *(struct in6_addr *)daddr,
87 .sport = sport,
88 .dport = dport
89 };
90 u32 hash;
91
92 net_secret_init();
93 hash = siphash(&combined, offsetofend(typeof(combined), dport),
94 &net_secret);
95 return seq_scale(hash);
96}
97EXPORT_SYMBOL(secure_tcpv6_seq);
98
99u64 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
100 __be16 dport)
101{
102 const struct {
103 struct in6_addr saddr;
104 struct in6_addr daddr;
105 unsigned int timeseed;
106 __be16 dport;
107 } __aligned(SIPHASH_ALIGNMENT) combined = {
108 .saddr = *(struct in6_addr *)saddr,
109 .daddr = *(struct in6_addr *)daddr,
110 .timeseed = jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD,
111 .dport = dport,
112 };
113 net_secret_init();
114 return siphash(&combined, offsetofend(typeof(combined), dport),
115 &net_secret);
116}
117EXPORT_SYMBOL(secure_ipv6_port_ephemeral);
118#endif
119
120#ifdef CONFIG_INET
121u32 secure_tcp_ts_off(const struct net *net, __be32 saddr, __be32 daddr)
122{
123 if (READ_ONCE(net->ipv4.sysctl_tcp_timestamps) != 1)
124 return 0;
125
126 ts_secret_init();
127 return siphash_2u32((__force u32)saddr, (__force u32)daddr,
128 &ts_secret);
129}
130
131/* secure_tcp_seq_and_tsoff(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d),
132 * but fortunately, `sport' cannot be 0 in any circumstances. If this changes,
133 * it would be easy enough to have the former function use siphash_4u32, passing
134 * the arguments as separate u32.
135 */
136u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
137 __be16 sport, __be16 dport)
138{
139 u32 hash;
140
141 net_secret_init();
142 hash = siphash_3u32((__force u32)saddr, (__force u32)daddr,
143 (__force u32)sport << 16 | (__force u32)dport,
144 &net_secret);
145 return seq_scale(hash);
146}
147EXPORT_SYMBOL_GPL(secure_tcp_seq);
148
149u64 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
150{
151 net_secret_init();
152 return siphash_4u32((__force u32)saddr, (__force u32)daddr,
153 (__force u16)dport,
154 jiffies / EPHEMERAL_PORT_SHUFFLE_PERIOD,
155 &net_secret);
156}
157EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
158#endif
159
160#if IS_ENABLED(CONFIG_IP_DCCP)
161u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
162 __be16 sport, __be16 dport)
163{
164 u64 seq;
165 net_secret_init();
166 seq = siphash_3u32((__force u32)saddr, (__force u32)daddr,
167 (__force u32)sport << 16 | (__force u32)dport,
168 &net_secret);
169 seq += ktime_get_real_ns();
170 seq &= (1ull << 48) - 1;
171 return seq;
172}
173EXPORT_SYMBOL(secure_dccp_sequence_number);
174
175#if IS_ENABLED(CONFIG_IPV6)
176u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
177 __be16 sport, __be16 dport)
178{
179 const struct {
180 struct in6_addr saddr;
181 struct in6_addr daddr;
182 __be16 sport;
183 __be16 dport;
184 } __aligned(SIPHASH_ALIGNMENT) combined = {
185 .saddr = *(struct in6_addr *)saddr,
186 .daddr = *(struct in6_addr *)daddr,
187 .sport = sport,
188 .dport = dport
189 };
190 u64 seq;
191 net_secret_init();
192 seq = siphash(&combined, offsetofend(typeof(combined), dport),
193 &net_secret);
194 seq += ktime_get_real_ns();
195 seq &= (1ull << 48) - 1;
196 return seq;
197}
198EXPORT_SYMBOL(secure_dccpv6_sequence_number);
199#endif
200#endif
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
4 */
5
6#include <linux/kernel.h>
7#include <linux/init.h>
8#include <linux/cryptohash.h>
9#include <linux/module.h>
10#include <linux/cache.h>
11#include <linux/random.h>
12#include <linux/hrtimer.h>
13#include <linux/ktime.h>
14#include <linux/string.h>
15#include <linux/net.h>
16#include <linux/siphash.h>
17#include <net/secure_seq.h>
18
19#if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET)
20#include <linux/in6.h>
21#include <net/tcp.h>
22
23static siphash_key_t net_secret __read_mostly;
24static siphash_key_t ts_secret __read_mostly;
25
26static __always_inline void net_secret_init(void)
27{
28 net_get_random_once(&net_secret, sizeof(net_secret));
29}
30
31static __always_inline void ts_secret_init(void)
32{
33 net_get_random_once(&ts_secret, sizeof(ts_secret));
34}
35#endif
36
37#ifdef CONFIG_INET
38static u32 seq_scale(u32 seq)
39{
40 /*
41 * As close as possible to RFC 793, which
42 * suggests using a 250 kHz clock.
43 * Further reading shows this assumes 2 Mb/s networks.
44 * For 10 Mb/s Ethernet, a 1 MHz clock is appropriate.
45 * For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but
46 * we also need to limit the resolution so that the u32 seq
47 * overlaps less than one time per MSL (2 minutes).
48 * Choosing a clock of 64 ns period is OK. (period of 274 s)
49 */
50 return seq + (ktime_get_real_ns() >> 6);
51}
52#endif
53
54#if IS_ENABLED(CONFIG_IPV6)
55u32 secure_tcpv6_ts_off(const struct net *net,
56 const __be32 *saddr, const __be32 *daddr)
57{
58 const struct {
59 struct in6_addr saddr;
60 struct in6_addr daddr;
61 } __aligned(SIPHASH_ALIGNMENT) combined = {
62 .saddr = *(struct in6_addr *)saddr,
63 .daddr = *(struct in6_addr *)daddr,
64 };
65
66 if (net->ipv4.sysctl_tcp_timestamps != 1)
67 return 0;
68
69 ts_secret_init();
70 return siphash(&combined, offsetofend(typeof(combined), daddr),
71 &ts_secret);
72}
73EXPORT_SYMBOL(secure_tcpv6_ts_off);
74
75u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr,
76 __be16 sport, __be16 dport)
77{
78 const struct {
79 struct in6_addr saddr;
80 struct in6_addr daddr;
81 __be16 sport;
82 __be16 dport;
83 } __aligned(SIPHASH_ALIGNMENT) combined = {
84 .saddr = *(struct in6_addr *)saddr,
85 .daddr = *(struct in6_addr *)daddr,
86 .sport = sport,
87 .dport = dport
88 };
89 u32 hash;
90
91 net_secret_init();
92 hash = siphash(&combined, offsetofend(typeof(combined), dport),
93 &net_secret);
94 return seq_scale(hash);
95}
96EXPORT_SYMBOL(secure_tcpv6_seq);
97
98u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
99 __be16 dport)
100{
101 const struct {
102 struct in6_addr saddr;
103 struct in6_addr daddr;
104 __be16 dport;
105 } __aligned(SIPHASH_ALIGNMENT) combined = {
106 .saddr = *(struct in6_addr *)saddr,
107 .daddr = *(struct in6_addr *)daddr,
108 .dport = dport
109 };
110 net_secret_init();
111 return siphash(&combined, offsetofend(typeof(combined), dport),
112 &net_secret);
113}
114EXPORT_SYMBOL(secure_ipv6_port_ephemeral);
115#endif
116
117#ifdef CONFIG_INET
118u32 secure_tcp_ts_off(const struct net *net, __be32 saddr, __be32 daddr)
119{
120 if (net->ipv4.sysctl_tcp_timestamps != 1)
121 return 0;
122
123 ts_secret_init();
124 return siphash_2u32((__force u32)saddr, (__force u32)daddr,
125 &ts_secret);
126}
127
128/* secure_tcp_seq_and_tsoff(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d),
129 * but fortunately, `sport' cannot be 0 in any circumstances. If this changes,
130 * it would be easy enough to have the former function use siphash_4u32, passing
131 * the arguments as separate u32.
132 */
133u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
134 __be16 sport, __be16 dport)
135{
136 u32 hash;
137
138 net_secret_init();
139 hash = siphash_3u32((__force u32)saddr, (__force u32)daddr,
140 (__force u32)sport << 16 | (__force u32)dport,
141 &net_secret);
142 return seq_scale(hash);
143}
144EXPORT_SYMBOL_GPL(secure_tcp_seq);
145
146u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
147{
148 net_secret_init();
149 return siphash_3u32((__force u32)saddr, (__force u32)daddr,
150 (__force u16)dport, &net_secret);
151}
152EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
153#endif
154
155#if IS_ENABLED(CONFIG_IP_DCCP)
156u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
157 __be16 sport, __be16 dport)
158{
159 u64 seq;
160 net_secret_init();
161 seq = siphash_3u32((__force u32)saddr, (__force u32)daddr,
162 (__force u32)sport << 16 | (__force u32)dport,
163 &net_secret);
164 seq += ktime_get_real_ns();
165 seq &= (1ull << 48) - 1;
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 const struct {
175 struct in6_addr saddr;
176 struct in6_addr daddr;
177 __be16 sport;
178 __be16 dport;
179 } __aligned(SIPHASH_ALIGNMENT) combined = {
180 .saddr = *(struct in6_addr *)saddr,
181 .daddr = *(struct in6_addr *)daddr,
182 .sport = sport,
183 .dport = dport
184 };
185 u64 seq;
186 net_secret_init();
187 seq = siphash(&combined, offsetofend(typeof(combined), dport),
188 &net_secret);
189 seq += ktime_get_real_ns();
190 seq &= (1ull << 48) - 1;
191 return seq;
192}
193EXPORT_SYMBOL(secure_dccpv6_sequence_number);
194#endif
195#endif