[mirror_ubuntu-artful-kernel.git] / net / core / secure_seq.c

/*
 * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/cryptohash.h>
#include <linux/module.h>
#include <linux/cache.h>
#include <linux/random.h>
#include <linux/hrtimer.h>
#include <linux/ktime.h>
#include <linux/string.h>
#include <linux/net.h>
#include <linux/siphash.h>
#include <net/secure_seq.h>

#if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET)
#include <linux/in6.h>
#include <net/tcp.h>

static siphash_key_t net_secret __read_mostly;
static siphash_key_t ts_secret __read_mostly;

static __always_inline void net_secret_init(void)
{
	net_get_random_once(&net_secret, sizeof(net_secret));
}

static __always_inline void ts_secret_init(void)
{
	net_get_random_once(&ts_secret, sizeof(ts_secret));
}
#endif

#ifdef CONFIG_INET
static u32 seq_scale(u32 seq)
{
	/*
	 *	As close as possible to RFC 793, which
	 *	suggests using a 250 kHz clock.
	 *	Further reading shows this assumes 2 Mb/s networks.
	 *	For 10 Mb/s Ethernet, a 1 MHz clock is appropriate.
	 *	For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but
	 *	we also need to limit the resolution so that the u32 seq
	 *	overlaps less than one time per MSL (2 minutes).
	 *	Choosing a clock of 64 ns period is OK. (period of 274 s)
	 */
	return seq + (ktime_get_real_ns() >> 6);
}
#endif

#if IS_ENABLED(CONFIG_IPV6)
u32 secure_tcpv6_ts_off(const __be32 *saddr, const __be32 *daddr)
{
	const struct {
		struct in6_addr saddr;
		struct in6_addr daddr;
	} __aligned(SIPHASH_ALIGNMENT) combined = {
		.saddr = *(struct in6_addr *)saddr,
		.daddr = *(struct in6_addr *)daddr,
	};

	if (sysctl_tcp_timestamps != 1)
		return 0;

	ts_secret_init();
	return siphash(&combined, offsetofend(typeof(combined), daddr),
		       &ts_secret);
}
EXPORT_SYMBOL(secure_tcpv6_ts_off);

u32 secure_tcpv6_seq(const __be32 *saddr, const __be32 *daddr,
		     __be16 sport, __be16 dport)
{
	const struct {
		struct in6_addr saddr;
		struct in6_addr daddr;
		__be16 sport;
		__be16 dport;
	} __aligned(SIPHASH_ALIGNMENT) combined = {
		.saddr = *(struct in6_addr *)saddr,
		.daddr = *(struct in6_addr *)daddr,
		.sport = sport,
		.dport = dport
	};
	u32 hash;

	net_secret_init();
	hash = siphash(&combined, offsetofend(typeof(combined), dport),
		       &net_secret);
	return seq_scale(hash);
}
EXPORT_SYMBOL(secure_tcpv6_seq);

u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
			       __be16 dport)
{
	const struct {
		struct in6_addr saddr;
		struct in6_addr daddr;
		__be16 dport;
	} __aligned(SIPHASH_ALIGNMENT) combined = {
		.saddr = *(struct in6_addr *)saddr,
		.daddr = *(struct in6_addr *)daddr,
		.dport = dport
	};
	net_secret_init();
	return siphash(&combined, offsetofend(typeof(combined), dport),
		       &net_secret);
}
EXPORT_SYMBOL(secure_ipv6_port_ephemeral);
#endif

#ifdef CONFIG_INET
u32 secure_tcp_ts_off(__be32 saddr, __be32 daddr)
{
	if (sysctl_tcp_timestamps != 1)
		return 0;

	ts_secret_init();
	return siphash_2u32((__force u32)saddr, (__force u32)daddr,
			    &ts_secret);
}

/* secure_tcp_seq_and_tsoff(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d),
 * but fortunately, `sport' cannot be 0 in any circumstances. If this changes,
 * it would be easy enough to have the former function use siphash_4u32, passing
 * the arguments as separate u32.
 */
u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
		   __be16 sport, __be16 dport)
{
	u32 hash;

	net_secret_init();
	hash = siphash_3u32((__force u32)saddr, (__force u32)daddr,
			    (__force u32)sport << 16 | (__force u32)dport,
			    &net_secret);
	return seq_scale(hash);
}

u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
{
	net_secret_init();
	return siphash_3u32((__force u32)saddr, (__force u32)daddr,
			    (__force u16)dport, &net_secret);
}
EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
#endif

#if IS_ENABLED(CONFIG_IP_DCCP)
u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
				__be16 sport, __be16 dport)
{
	u64 seq;
	net_secret_init();
	seq = siphash_3u32((__force u32)saddr, (__force u32)daddr,
			   (__force u32)sport << 16 | (__force u32)dport,
			   &net_secret);
	seq += ktime_get_real_ns();
	seq &= (1ull << 48) - 1;
	return seq;
}
EXPORT_SYMBOL(secure_dccp_sequence_number);

#if IS_ENABLED(CONFIG_IPV6)
u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
				  __be16 sport, __be16 dport)
{
	const struct {
		struct in6_addr saddr;
		struct in6_addr daddr;
		__be16 sport;
		__be16 dport;
	} __aligned(SIPHASH_ALIGNMENT) combined = {
		.saddr = *(struct in6_addr *)saddr,
		.daddr = *(struct in6_addr *)daddr,
		.sport = sport,
		.dport = dport
	};
	u64 seq;
	net_secret_init();
	seq = siphash(&combined, offsetofend(typeof(combined), dport),
		      &net_secret);
	seq += ktime_get_real_ns();
	seq &= (1ull << 48) - 1;
	return seq;
}
EXPORT_SYMBOL(secure_dccpv6_sequence_number);
#endif
#endif
Commit	Line	Data
7cd23e53 JD	1	/*
	2	* Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
	3	*/
	4
6e5714ea DM	5	#include <linux/kernel.h>
	6	#include <linux/init.h>
	7	#include <linux/cryptohash.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>
e34c9a69	14	#include <linux/net.h>
7cd23e53	15	#include <linux/siphash.h>
6e5714ea DM	16	#include <net/secure_seq.h>
6e5714ea DM	17
cb03db9d	18	#if IS_ENABLED(CONFIG_IPV6) \|\| IS_ENABLED(CONFIG_INET)
7cd23e53	19	#include <linux/in6.h>
25429d7b	20	#include <net/tcp.h>
6e5714ea	21
7cd23e53	22	static siphash_key_t net_secret __read_mostly;
28ee1b74	23	static siphash_key_t ts_secret __read_mostly;
9a3bab6b	24
34d92d53	25	static __always_inline void net_secret_init(void)
6e5714ea	26	{
7cd23e53	27	net_get_random_once(&net_secret, sizeof(net_secret));
6e5714ea	28	}
84b114b9 ED	29
	30	static __always_inline void ts_secret_init(void)
	31	{
	32	net_get_random_once(&ts_secret, sizeof(ts_secret));
	33	}
cb03db9d	34	#endif
6e5714ea	35
68109090	36	#ifdef CONFIG_INET
6e5714ea DM	37	static u32 seq_scale(u32 seq)
	38	{
	39	/*
	40	* As close as possible to RFC 793, which
	41	* suggests using a 250 kHz clock.
	42	* Further reading shows this assumes 2 Mb/s networks.
	43	* For 10 Mb/s Ethernet, a 1 MHz clock is appropriate.
	44	* For 10 Gb/s Ethernet, a 1 GHz clock should be ok, but
	45	* we also need to limit the resolution so that the u32 seq
	46	* overlaps less than one time per MSL (2 minutes).
	47	* Choosing a clock of 64 ns period is OK. (period of 274 s)
	48	*/
d2de875c	49	return seq + (ktime_get_real_ns() >> 6);
6e5714ea	50	}
68109090	51	#endif
6e5714ea	52
dfd56b8b	53	#if IS_ENABLED(CONFIG_IPV6)
84b114b9	54	u32 secure_tcpv6_ts_off(const __be32 saddr, const __be32 daddr)
28ee1b74 FW	55	{
	56	const struct {
	57	struct in6_addr saddr;
	58	struct in6_addr daddr;
	59	} __aligned(SIPHASH_ALIGNMENT) combined = {
	60	.saddr = (struct in6_addr )saddr,
	61	.daddr = (struct in6_addr )daddr,
	62	};
	63
	64	if (sysctl_tcp_timestamps != 1)
	65	return 0;
	66
84b114b9	67	ts_secret_init();
28ee1b74 FW	68	return siphash(&combined, offsetofend(typeof(combined), daddr),
	69	&ts_secret);
	70	}
84b114b9	71	EXPORT_SYMBOL(secure_tcpv6_ts_off);
28ee1b74	72
84b114b9 ED	73	u32 secure_tcpv6_seq(const __be32 saddr, const __be32 daddr,
84b114b9 ED	74	__be16 sport, __be16 dport)
6e5714ea	75	{
7cd23e53 JD	76	const struct {
	77	struct in6_addr saddr;
	78	struct in6_addr daddr;
	79	__be16 sport;
	80	__be16 dport;
	81	} __aligned(SIPHASH_ALIGNMENT) combined = {
	82	.saddr = (struct in6_addr )saddr,
	83	.daddr = (struct in6_addr )daddr,
	84	.sport = sport,
	85	.dport = dport
	86	};
84b114b9 ED	87	u32 hash;
84b114b9 ED	88
9a3bab6b	89	net_secret_init();
7cd23e53 JD	90	hash = siphash(&combined, offsetofend(typeof(combined), dport),
7cd23e53 JD	91	&net_secret);
7cd23e53	92	return seq_scale(hash);
6e5714ea	93	}
84b114b9	94	EXPORT_SYMBOL(secure_tcpv6_seq);
6e5714ea DM	95
	96	u32 secure_ipv6_port_ephemeral(const __be32 saddr, const __be32 daddr,
	97	__be16 dport)
	98	{
7cd23e53 JD	99	const struct {
	100	struct in6_addr saddr;
	101	struct in6_addr daddr;
	102	__be16 dport;
	103	} __aligned(SIPHASH_ALIGNMENT) combined = {
	104	.saddr = (struct in6_addr )saddr,
	105	.daddr = (struct in6_addr )daddr,
	106	.dport = dport
	107	};
9a3bab6b	108	net_secret_init();
7cd23e53 JD	109	return siphash(&combined, offsetofend(typeof(combined), dport),
7cd23e53 JD	110	&net_secret);
6e5714ea	111	}
58a317f1	112	EXPORT_SYMBOL(secure_ipv6_port_ephemeral);
6e5714ea DM	113	#endif
	114
	115	#ifdef CONFIG_INET
84b114b9	116	u32 secure_tcp_ts_off(__be32 saddr, __be32 daddr)
28ee1b74 FW	117	{
	118	if (sysctl_tcp_timestamps != 1)
	119	return 0;
	120
84b114b9	121	ts_secret_init();
28ee1b74 FW	122	return siphash_2u32((__force u32)saddr, (__force u32)daddr,
	123	&ts_secret);
	124	}
6e5714ea	125
a30aad50	126	/* secure_tcp_seq_and_tsoff(a, b, 0, d) == secure_ipv4_port_ephemeral(a, b, d),
7cd23e53 JD	127	* but fortunately, `sport' cannot be 0 in any circumstances. If this changes,
	128	* it would be easy enough to have the former function use siphash_4u32, passing
	129	* the arguments as separate u32.
	130	*/
84b114b9 ED	131	u32 secure_tcp_seq(__be32 saddr, __be32 daddr,
84b114b9 ED	132	__be16 sport, __be16 dport)
6e5714ea	133	{
84b114b9 ED	134	u32 hash;
84b114b9 ED	135
9a3bab6b	136	net_secret_init();
7cd23e53 JD	137	hash = siphash_3u32((__force u32)saddr, (__force u32)daddr,
	138	(__force u32)sport << 16 \| (__force u32)dport,
	139	&net_secret);
7cd23e53	140	return seq_scale(hash);
6e5714ea DM	141	}
	142
	143	u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
	144	{
9a3bab6b	145	net_secret_init();
7cd23e53 JD	146	return siphash_3u32((__force u32)saddr, (__force u32)daddr,
7cd23e53 JD	147	(__force u16)dport, &net_secret);
6e5714ea DM	148	}
	149	EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
	150	#endif
	151
a3bf7ae9	152	#if IS_ENABLED(CONFIG_IP_DCCP)
6e5714ea DM	153	u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
	154	__be16 sport, __be16 dport)
	155	{
6e5714ea	156	u64 seq;
9a3bab6b	157	net_secret_init();
c1ce1560 ED	158	seq = siphash_3u32((__force u32)saddr, (__force u32)daddr,
	159	(__force u32)sport << 16 \| (__force u32)dport,
	160	&net_secret);
d2de875c	161	seq += ktime_get_real_ns();
6e5714ea	162	seq &= (1ull << 48) - 1;
6e5714ea DM	163	return seq;
	164	}
	165	EXPORT_SYMBOL(secure_dccp_sequence_number);
	166
dfd56b8b	167	#if IS_ENABLED(CONFIG_IPV6)
6e5714ea DM	168	u64 secure_dccpv6_sequence_number(__be32 saddr, __be32 daddr,
	169	__be16 sport, __be16 dport)
	170	{
7cd23e53 JD	171	const struct {
	172	struct in6_addr saddr;
	173	struct in6_addr daddr;
	174	__be16 sport;
	175	__be16 dport;
	176	} __aligned(SIPHASH_ALIGNMENT) combined = {
	177	.saddr = (struct in6_addr )saddr,
	178	.daddr = (struct in6_addr )daddr,
	179	.sport = sport,
	180	.dport = dport
	181	};
6e5714ea	182	u64 seq;
9a3bab6b	183	net_secret_init();
7cd23e53 JD	184	seq = siphash(&combined, offsetofend(typeof(combined), dport),
7cd23e53 JD	185	&net_secret);
d2de875c	186	seq += ktime_get_real_ns();
6e5714ea	187	seq &= (1ull << 48) - 1;
6e5714ea DM	188	return seq;
	189	}
	190	EXPORT_SYMBOL(secure_dccpv6_sequence_number);
	191	#endif
	192	#endif