CVE-2011-3188: Other (NVD-CWE-Other)
value: The (1) IPv4 and (2) IPv6 implementations in the Linux kernel before 3.1 use a modified MD4 algorithm to generate sequence numbers and Fragment Identification values, which makes it easier for remote attackers to cause a denial of service (disrupted networking) or hijack network sessions by predicting these values and sending crafted packets.
CWE description: NVD is only using a subset of CWE for mapping instead of the entire CWE, and the weakness type is not covered by that subset.
CVSS v3 base score: 9.1
Published: 2012-05-24T23:55Z
Repository: https://github.com/torvalds/linux
Language: C
Files changed: drivers/char/random.c, include/linux/random.h, include/net/secure_seq.h, net/core/Makefile, net/core/secure_seq.c, net/dccp/ipv4.c, net/dccp/ipv6.c, net/ipv4/inet_hashtables.c, net/ipv4/inetpeer.c, net/ipv4/netfilter/nf_nat_proto_common.c, net/ipv4/route.c, net/ipv4/tcp_ipv4.c, net/ipv6/inet6_hashtables.c, net/ipv6/tcp_ipv6.c
Commit date: 2011-08-06 18:33:19 -0700
Commit message: net: Compute protocol sequence numbers and fragment IDs using MD5.

Computers have become a lot faster since we compromised on the
partial MD4 hash which we use currently for performance reasons.

MD5 is a much safer choice, and is inline with both RFC1948 and
other ISS generators (OpenBSD, Solaris, etc.)

Furthermore, only having 24-bits of the sequence number be truly
unpredictable is a very serious limitation.  So the periodic
regeneration and 8-bit counter have been removed.  We compute and
use a full 32-bit sequence number.

For ipv6, DCCP was found to use a 32-bit truncated initial sequence
number (it needs 43-bits) and that is fixed here as well.

Reported-by: Dan Kaminsky <dan@doxpara.com>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>

Diff: diff --git a/drivers/char/random.c b/drivers/char/random.c
index 729281961f22..c35a785005b0 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1298,367 +1298,34 @@ ctl_table random_table[] = {
 	},
 	{ }
 };
 #endif 	/* CONFIG_SYSCTL */
 
-/********************************************************************
- *
- * Random functions for networking
- *
- ********************************************************************/
-
-/*
- * TCP initial sequence number picking.  This uses the random number
- * generator to pick an initial secret value.  This value is hashed
- * along with the TCP endpoint information to provide a unique
- * starting point for each pair of TCP endpoints.  This defeats
- * attacks which rely on guessing the initial TCP sequence number.
- * This algorithm was suggested by Steve Bellovin.
- *
- * Using a very strong hash was taking an appreciable amount of the total
- * TCP connection establishment time, so this is a weaker hash,
- * compensated for by changing the secret periodically.
- */
-
-/* F, G and H are basic MD4 functions: selection, majority, parity */
-#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
-#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
-#define H(x, y, z) ((x) ^ (y) ^ (z))
-
-/*
- * The generic round function.  The application is so specific that
- * we don't bother protecting all the arguments with parens, as is generally
- * good macro practice, in favor of extra legibility.
- * Rotation is separate from addition to prevent recomputation
- */
-#define ROUND(f, a, b, c, d, x, s)	\
-	(a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s)))
-#define K1 0
-#define K2 013240474631UL
-#define K3 015666365641UL
-
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
-
-static __u32 twothirdsMD4Transform(__u32 const buf[4], __u32 const in[12])
-{
-	__u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
-
-	/* Round 1 */
-	ROUND(F, a, b, c, d, in[ 0] + K1,  3);
-	ROUND(F, d, a, b, c, in[ 1] + K1,  7);
-	ROUND(F, c, d, a, b, in[ 2] + K1, 11);
-	ROUND(F, b, c, d, a, in[ 3] + K1, 19);
-	ROUND(F, a, b, c, d, in[ 4] + K1,  3);
-	ROUND(F, d, a, b, c, in[ 5] + K1,  7);
-	ROUND(F, c, d, a, b, in[ 6] + K1, 11);
-	ROUND(F, b, c, d, a, in[ 7] + K1, 19);
-	ROUND(F, a, b, c, d, in[ 8] + K1,  3);
-	ROUND(F, d, a, b, c, in[ 9] + K1,  7);
-	ROUND(F, c, d, a, b, in[10] + K1, 11);
-	ROUND(F, b, c, d, a, in[11] + K1, 19);
-
-	/* Round 2 */
-	ROUND(G, a, b, c, d, in[ 1] + K2,  3);
-	ROUND(G, d, a, b, c, in[ 3] + K2,  5);
-	ROUND(G, c, d, a, b, in[ 5] + K2,  9);
-	ROUND(G, b, c, d, a, in[ 7] + K2, 13);
-	ROUND(G, a, b, c, d, in[ 9] + K2,  3);
-	ROUND(G, d, a, b, c, in[11] + K2,  5);
-	ROUND(G, c, d, a, b, in[ 0] + K2,  9);
-	ROUND(G, b, c, d, a, in[ 2] + K2, 13);
-	ROUND(G, a, b, c, d, in[ 4] + K2,  3);
-	ROUND(G, d, a, b, c, in[ 6] + K2,  5);
-	ROUND(G, c, d, a, b, in[ 8] + K2,  9);
-	ROUND(G, b, c, d, a, in[10] + K2, 13);
-
-	/* Round 3 */
-	ROUND(H, a, b, c, d, in[ 3] + K3,  3);
-	ROUND(H, d, a, b, c, in[ 7] + K3,  9);
-	ROUND(H, c, d, a, b, in[11] + K3, 11);
-	ROUND(H, b, c, d, a, in[ 2] + K3, 15);
-	ROUND(H, a, b, c, d, in[ 6] + K3,  3);
-	ROUND(H, d, a, b, c, in[10] + K3,  9);
-	ROUND(H, c, d, a, b, in[ 1] + K3, 11);
-	ROUND(H, b, c, d, a, in[ 5] + K3, 15);
-	ROUND(H, a, b, c, d, in[ 9] + K3,  3);
-	ROUND(H, d, a, b, c, in[ 0] + K3,  9);
-	ROUND(H, c, d, a, b, in[ 4] + K3, 11);
-	ROUND(H, b, c, d, a, in[ 8] + K3, 15);
-
-	return buf[1] + b; /* "most hashed" word */
-	/* Alternative: return sum of all words? */
-}
-#endif
-
-#undef ROUND
-#undef F
-#undef G
-#undef H
-#undef K1
-#undef K2
-#undef K3
-
-/* This should not be decreased so low that ISNs wrap too fast. */
-#define REKEY_INTERVAL (300 * HZ)
-/*
- * Bit layout of the tcp sequence numbers (before adding current time):
- * bit 24-31: increased after every key exchange
- * bit 0-23: hash(source,dest)
- *
- * The implementation is similar to the algorithm described
- * in the Appendix of RFC 1185, except that
- * - it uses a 1 MHz clock instead of a 250 kHz clock
- * - it performs a rekey every 5 minutes, which is equivalent
- * 	to a (source,dest) tulple dependent forward jump of the
- * 	clock by 0..2^(HASH_BITS+1)
- *
- * Thus the average ISN wraparound time is 68 minutes instead of
- * 4.55 hours.
- *
- * SMP cleanup and lock avoidance with poor man's RCU.
- * 			Manfred Spraul <manfred@colorfullife.com>
- *
- */
-#define COUNT_BITS 8
-#define COUNT_MASK ((1 << COUNT_BITS) - 1)
-#define HASH_BITS 24
-#define HASH_MASK ((1 << HASH_BITS) - 1)
+static u32 random_int_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
 
-static struct keydata {
-	__u32 count; /* already shifted to the final position */
-	__u32 secret[12];
-} ____cacheline_aligned ip_keydata[2];
-
-static unsigned int ip_cnt;
-
-static void rekey_seq_generator(struct work_struct *work);
-
-static DECLARE_DELAYED_WORK(rekey_work, rekey_seq_generator);
-
-/*
- * Lock avoidance:
- * The ISN generation runs lockless - it's just a hash over random data.
- * State changes happen every 5 minutes when the random key is replaced.
- * Synchronization is performed by having two copies of the hash function
- * state and rekey_seq_generator always updates the inactive copy.
- * The copy is then activated by updating ip_cnt.
- * The implementation breaks down if someone blocks the thread
- * that processes SYN requests for more than 5 minutes. Should never
- * happen, and even if that happens only a not perfectly compliant
- * ISN is generated, nothing fatal.
- */
-static void rekey_seq_generator(struct work_struct *work)
+static int __init random_int_secret_init(void)
 {
-	struct keydata *keyptr = &ip_keydata[1 ^ (ip_cnt & 1)];
-
-	get_random_bytes(keyptr->secret, sizeof(keyptr->secret));
-	keyptr->count = (ip_cnt & COUNT_MASK) << HASH_BITS;
-	smp_wmb();
-	ip_cnt++;
-	schedule_delayed_work(&rekey_work,
-			      round_jiffies_relative(REKEY_INTERVAL));
-}
-
-static inline struct keydata *get_keyptr(void)
-{
-	struct keydata *keyptr = &ip_keydata[ip_cnt & 1];
-
-	smp_rmb();
-
-	return keyptr;
-}
-
-static __init int seqgen_init(void)
-{
-	rekey_seq_generator(NULL);
+	get_random_bytes(random_int_secret, sizeof(random_int_secret));
 	return 0;
 }
-late_initcall(seqgen_init);
-
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
-__u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
-				   __be16 sport, __be16 dport)
-{
-	__u32 seq;
-	__u32 hash[12];
-	struct keydata *keyptr = get_keyptr();
-
-	/* The procedure is the same as for IPv4, but addresses are longer.
-	 * Thus we must use twothirdsMD4Transform.
-	 */
-
-	memcpy(hash, saddr, 16);
-	hash[4] = ((__force u16)sport << 16) + (__force u16)dport;
-	memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7);
-
-	seq = twothirdsMD4Transform((const __u32 *)daddr, hash) & HASH_MASK;
-	seq += keyptr->count;
-
-	seq += ktime_to_ns(ktime_get_real());
-
-	return seq;
-}
-EXPORT_SYMBOL(secure_tcpv6_sequence_number);
-#endif
-
-/*  The code below is shamelessly stolen from secure_tcp_sequence_number().
- *  All blames to Andrey V. Savochkin <saw@msu.ru>.
- */
-__u32 secure_ip_id(__be32 daddr)
-{
-	struct keydata *keyptr;
-	__u32 hash[4];
-
-	keyptr = get_keyptr();
-
-	/*
-	 *  Pick a unique starting offset for each IP destination.
-	 *  The dest ip address is placed in the starting vector,
-	 *  which is then hashed with random data.
-	 */
-	hash[0] = (__force __u32)daddr;
-	hash[1] = keyptr->secret[9];
-	hash[2] = keyptr->secret[10];
-	hash[3] = keyptr->secret[11];
-
-	return half_md4_transform(hash, keyptr->secret);
-}
-
-__u32 secure_ipv6_id(const __be32 daddr[4])
-{
-	const struct keydata *keyptr;
-	__u32 hash[4];
-
-	keyptr = get_keyptr();
-
-	hash[0] = (__force __u32)daddr[0];
-	hash[1] = (__force __u32)daddr[1];
-	hash[2] = (__force __u32)daddr[2];
-	hash[3] = (__force __u32)daddr[3];
-
-	return half_md4_transform(hash, keyptr->secret);
-}
-
-#ifdef CONFIG_INET
-
-__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
-				 __be16 sport, __be16 dport)
-{
-	__u32 seq;
-	__u32 hash[4];
-	struct keydata *keyptr = get_keyptr();
-
-	/*
-	 *  Pick a unique starting offset for each TCP connection endpoints
-	 *  (saddr, daddr, sport, dport).
-	 *  Note that the words are placed into the starting vector, which is
-	 *  then mixed with a partial MD4 over random data.
-	 */
-	hash[0] = (__force u32)saddr;
-	hash[1] = (__force u32)daddr;
-	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
-	hash[3] = keyptr->secret[11];
-
-	seq = half_md4_transform(hash, keyptr->secret) & HASH_MASK;
-	seq += keyptr->count;
-	/*
-	 *	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)
-	 */
-	seq += ktime_to_ns(ktime_get_real()) >> 6;
-
-	return seq;
-}
-
-/* Generate secure starting point for ephemeral IPV4 transport port search */
-u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
-{
-	struct keydata *keyptr = get_keyptr();
-	u32 hash[4];
-
-	/*
-	 *  Pick a unique starting offset for each ephemeral port search
-	 *  (saddr, daddr, dport) and 48bits of random data.
-	 */
-	hash[0] = (__force u32)saddr;
-	hash[1] = (__force u32)daddr;
-	hash[2] = (__force u32)dport ^ keyptr->secret[10];
-	hash[3] = keyptr->secret[11];
-
-	return half_md4_transform(hash, keyptr->secret);
-}
-EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
-
-#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
-u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
-			       __be16 dport)
-{
-	struct keydata *keyptr = get_keyptr();
-	u32 hash[12];
-
-	memcpy(hash, saddr, 16);
-	hash[4] = (__force u32)dport;
-	memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7);
-
-	return twothirdsMD4Transform((const __u32 *)daddr, hash);
-}
-#endif
-
-#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
-/* Similar to secure_tcp_sequence_number but generate a 48 bit value
- * bit's 32-47 increase every key exchange
- *       0-31  hash(source, dest)
- */
-u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
-				__be16 sport, __be16 dport)
-{
-	u64 seq;
-	__u32 hash[4];
-	struct keydata *keyptr = get_keyptr();
-
-	hash[0] = (__force u32)saddr;
-	hash[1] = (__force u32)daddr;
-	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
-	hash[3] = keyptr->secret[11];
-
-	seq = half_md4_transform(hash, keyptr->secret);
-	seq |= ((u64)keyptr->count) << (32 - HASH_BITS);
-
-	seq += ktime_to_ns(ktime_get_real());
-	seq &= (1ull << 48) - 1;
-
-	return seq;
-}
-EXPORT_SYMBOL(secure_dccp_sequence_number);
-#endif
-
-#endif /* CONFIG_INET */
-
+late_initcall(random_int_secret_init);
 
 /*
  * Get a random word for internal kernel use only. Similar to urandom but
  * with the goal of minimal entropy pool depletion. As a result, the random
  * value is not cryptographically secure but for several uses the cost of
  * depleting entropy is too high
  */
-DEFINE_PER_CPU(__u32 [4], get_random_int_hash);
+DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
 unsigned int get_random_int(void)
 {
-	struct keydata *keyptr;
 	__u32 *hash = get_cpu_var(get_random_int_hash);
-	int ret;
+	unsigned int ret;
 
-	keyptr = get_keyptr();
 	hash[0] += current->pid + jiffies + get_cycles();
-
-	ret = half_md4_transform(hash, keyptr->secret);
+	md5_transform(hash, random_int_secret);
+	ret = hash[0];
 	put_cpu_var(get_random_int_hash);
 
 	return ret;
 }
 
diff --git a/include/linux/random.h b/include/linux/random.h
index ce29a040c8dc..d13059f3ea32 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -55,22 +55,10 @@ extern void add_input_randomness(unsigned int type, unsigned int code,
 extern void add_interrupt_randomness(int irq);
 
 extern void get_random_bytes(void *buf, int nbytes);
 void generate_random_uuid(unsigned char uuid_out[16]);
 
-extern __u32 secure_ip_id(__be32 daddr);
-extern __u32 secure_ipv6_id(const __be32 daddr[4]);
-extern u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
-extern u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
-				      __be16 dport);
-extern __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
-					__be16 sport, __be16 dport);
-extern __u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
-					  __be16 sport, __be16 dport);
-extern u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
-				       __be16 sport, __be16 dport);
-
 #ifndef MODULE
 extern const struct file_operations random_fops, urandom_fops;
 #endif
 
 unsigned int get_random_int(void);
diff --git a/include/net/secure_seq.h b/include/net/secure_seq.h
new file mode 100644
index 000000000000..d97f6892c019
--- /dev/null
+++ b/include/net/secure_seq.h
@@ -0,0 +1,20 @@
+#ifndef _NET_SECURE_SEQ
+#define _NET_SECURE_SEQ
+
+#include <linux/types.h>
+
+extern __u32 secure_ip_id(__be32 daddr);
+extern __u32 secure_ipv6_id(const __be32 daddr[4]);
+extern u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
+extern u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
+				      __be16 dport);
+extern __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
+					__be16 sport, __be16 dport);
+extern __u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
+					  __be16 sport, __be16 dport);
+extern u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
+				       __be16 sport, __be16 dport);
+extern u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
+					 __be16 sport, __be16 dport);
+
+#endif /* _NET_SECURE_SEQ */
diff --git a/net/core/Makefile b/net/core/Makefile
index 8a04dd22cf77..0d357b1c4e57 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile
@@ -1,11 +1,11 @@
 #
 # Makefile for the Linux networking core.
 #
 
 obj-y := sock.o request_sock.o skbuff.o iovec.o datagram.o stream.o scm.o \
-	 gen_stats.o gen_estimator.o net_namespace.o
+	 gen_stats.o gen_estimator.o net_namespace.o secure_seq.o
 
 obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
 
 obj-y		     += dev.o ethtool.o dev_addr_lists.o dst.o netevent.o \
 			neighbour.o rtnetlink.o utils.o link_watch.o filter.o
diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
new file mode 100644
index 000000000000..45329d7c9dd9
--- /dev/null
+++ b/net/core/secure_seq.c
@@ -0,0 +1,184 @@
+#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 <net/secure_seq.h>
+
+static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
+
+static int __init net_secret_init(void)
+{
+	get_random_bytes(net_secret, sizeof(net_secret));
+	return 0;
+}
+late_initcall(net_secret_init);
+
+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_to_ns(ktime_get_real()) >> 6);
+}
+
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+__u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
+				   __be16 sport, __be16 dport)
+{
+	u32 secret[MD5_MESSAGE_BYTES / 4];
+	u32 hash[MD5_DIGEST_WORDS];
+	u32 i;
+
+	memcpy(hash, saddr, 16);
+	for (i = 0; i < 4; i++)
+		secret[i] = net_secret[i] + daddr[i];
+	secret[4] = net_secret[4] +
+		(((__force u16)sport << 16) + (__force u16)dport);
+	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
+		secret[i] = net_secret[i];
+
+	md5_transform(hash, secret);
+
+	return seq_scale(hash[0]);
+}
+EXPORT_SYMBOL(secure_tcpv6_sequence_number);
+
+u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
+			       __be16 dport)
+{
+	u32 secret[MD5_MESSAGE_BYTES / 4];
+	u32 hash[MD5_DIGEST_WORDS];
+	u32 i;
+
+	memcpy(hash, saddr, 16);
+	for (i = 0; i < 4; i++)
+		secret[i] = net_secret[i] + (__force u32) daddr[i];
+	secret[4] = net_secret[4] + (__force u32)dport;
+	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
+		secret[i] = net_secret[i];
+
+	md5_transform(hash, secret);
+
+	return hash[0];
+}
+#endif
+
+#ifdef CONFIG_INET
+__u32 secure_ip_id(__be32 daddr)
+{
+	u32 hash[MD5_DIGEST_WORDS];
+
+	hash[0] = (__force __u32) daddr;
+	hash[1] = net_secret[13];
+	hash[2] = net_secret[14];
+	hash[3] = net_secret[15];
+
+	md5_transform(hash, net_secret);
+
+	return hash[0];
+}
+
+__u32 secure_ipv6_id(const __be32 daddr[4])
+{
+	__u32 hash[4];
+
+	memcpy(hash, daddr, 16);
+	md5_transform(hash, net_secret);
+
+	return hash[0];
+}
+
+__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
+				 __be16 sport, __be16 dport)
+{
+	u32 hash[MD5_DIGEST_WORDS];
+
+	hash[0] = (__force u32)saddr;
+	hash[1] = (__force u32)daddr;
+	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
+	hash[3] = net_secret[15];
+
+	md5_transform(hash, net_secret);
+
+	return seq_scale(hash[0]);
+}
+
+u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
+{
+	u32 hash[MD5_DIGEST_WORDS];
+
+	hash[0] = (__force u32)saddr;
+	hash[1] = (__force u32)daddr;
+	hash[2] = (__force u32)dport ^ net_secret[14];
+	hash[3] = net_secret[15];
+
+	md5_transform(hash, net_secret);
+
+	return hash[0];
+}
+EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
+#endif
+
+#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
+u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
+				__be16 sport, __be16 dport)
+{
+	u32 hash[MD5_DIGEST_WORDS];
+	u64 seq;
+
+	hash[0] = (__force u32)saddr;
+	hash[1] = (__force u32)daddr;
+	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
+	hash[3] = net_secret[15];
+
+	md5_transform(hash, net_secret);
+
+	seq = hash[0] | (((u64)hash[1]) << 32);
+	seq += ktime_to_ns(ktime_get_real());
+	seq &= (1ull << 48) - 1;
+
+	return seq;
+}
+EXPORT_SYMBOL(secure_dccp_sequence_number);
+
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
+				  __be16 sport, __be16 dport)
+{
+	u32 secret[MD5_MESSAGE_BYTES / 4];
+	u32 hash[MD5_DIGEST_WORDS];
+	u64 seq;
+	u32 i;
+
+	memcpy(hash, saddr, 16);
+	for (i = 0; i < 4; i++)
+		secret[i] = net_secret[i] + daddr[i];
+	secret[4] = net_secret[4] +
+		(((__force u16)sport << 16) + (__force u16)dport);
+	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
+		secret[i] = net_secret[i];
+
+	md5_transform(hash, secret);
+
+	seq = hash[0] | (((u64)hash[1]) << 32);
+	seq += ktime_to_ns(ktime_get_real());
+	seq &= (1ull << 48) - 1;
+
+	return seq;
+}
+EXPORT_SYMBOL(secure_dccpv6_sequence_number);
+#endif
+#endif
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 8c36adfd1919..332639b56f4d 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -24,10 +24,11 @@
 #include <net/protocol.h>
 #include <net/sock.h>
 #include <net/timewait_sock.h>
 #include <net/tcp_states.h>
 #include <net/xfrm.h>
+#include <net/secure_seq.h>
 
 #include "ackvec.h"
 #include "ccid.h"
 #include "dccp.h"
 #include "feat.h"
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 8dc4348774a5..b74f76117dcf 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -27,10 +27,11 @@
 #include <net/ipv6.h>
 #include <net/protocol.h>
 #include <net/transp_v6.h>
 #include <net/ip6_checksum.h>
 #include <net/xfrm.h>
+#include <net/secure_seq.h>
 
 #include "dccp.h"
 #include "ipv6.h"
 #include "feat.h"
 
@@ -67,17 +68,11 @@ static inline void dccp_v6_send_check(struct sock *sk, struct sk_buff *skb)
 
 	dccp_csum_outgoing(skb);
 	dh->dccph_checksum = dccp_v6_csum_finish(skb, &np->saddr, &np->daddr);
 }
 
-static inline __u32 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
-						  __be16 sport, __be16 dport   )
-{
-	return secure_tcpv6_sequence_number(saddr, daddr, sport, dport);
-}
-
-static inline __u32 dccp_v6_init_sequence(struct sk_buff *skb)
+static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
 {
 	return secure_dccpv6_sequence_number(ipv6_hdr(skb)->daddr.s6_addr32,
 					     ipv6_hdr(skb)->saddr.s6_addr32,
 					     dccp_hdr(skb)->dccph_dport,
 					     dccp_hdr(skb)->dccph_sport     );
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 3c0369a3a663..984ec656b03b 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -19,10 +19,11 @@
 #include <linux/slab.h>
 #include <linux/wait.h>
 
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
+#include <net/secure_seq.h>
 #include <net/ip.h>
 
 /*
  * Allocate and initialize a new local port bind bucket.
  * The bindhash mutex for snum's hash chain must be held here.
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index e38213817d0a..86f13c67ea85 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -17,10 +17,11 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/net.h>
 #include <net/ip.h>
 #include <net/inetpeer.h>
+#include <net/secure_seq.h>
 
 /*
  *  Theory of operations.
  *  We keep one entry for each peer IP address.  The nodes contains long-living
  *  information about the peer which doesn't depend on routes.
diff --git a/net/ipv4/netfilter/nf_nat_proto_common.c b/net/ipv4/netfilter/nf_nat_proto_common.c
index 3e61faf23a9a..f52d41ea0690 100644
--- a/net/ipv4/netfilter/nf_nat_proto_common.c
+++ b/net/ipv4/netfilter/nf_nat_proto_common.c
@@ -10,10 +10,11 @@
 #include <linux/types.h>
 #include <linux/random.h>
 #include <linux/ip.h>
 
 #include <linux/netfilter.h>
+#include <net/secure_seq.h>
 #include <net/netfilter/nf_nat.h>
 #include <net/netfilter/nf_nat_core.h>
 #include <net/netfilter/nf_nat_rule.h>
 #include <net/netfilter/nf_nat_protocol.h>
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 6afc4eb50591..e3dec1c9f09d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -107,10 +107,11 @@
 #include <net/rtnetlink.h>
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
 #endif
 #include <net/atmclip.h>
+#include <net/secure_seq.h>
 
 #define RT_FL_TOS(oldflp4) \
     ((u32)(oldflp4->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
 
 #define IP_MAX_MTU	0xFFF0
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 955b8e65b69e..1c12b8ec849d 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -70,10 +70,11 @@
 #include <net/ipv6.h>
 #include <net/inet_common.h>
 #include <net/timewait_sock.h>
 #include <net/xfrm.h>
 #include <net/netdma.h>
+#include <net/secure_seq.h>
 
 #include <linux/inet.h>
 #include <linux/ipv6.h>
 #include <linux/stddef.h>
 #include <linux/proc_fs.h>
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index b53197233709..73f1a00a96af 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -18,10 +18,11 @@
 #include <linux/random.h>
 
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
 #include <net/inet6_hashtables.h>
+#include <net/secure_seq.h>
 #include <net/ip.h>
 
 int __inet6_hash(struct sock *sk, struct inet_timewait_sock *tw)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 78aa53492b3e..d1fb63f4aeb7 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -59,10 +59,11 @@
 #include <net/snmp.h>
 #include <net/dsfield.h>
 #include <net/timewait_sock.h>
 #include <net/netdma.h>
 #include <net/inet_common.h>
+#include <net/secure_seq.h>
 
 #include <asm/uaccess.h>
 
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>

Vulnerable code: /********************************************************************
 *
 * Random functions for networking
 *
 ********************************************************************/

/*
 * TCP initial sequence number picking.  This uses the random number
 * generator to pick an initial secret value.  This value is hashed
 * along with the TCP endpoint information to provide a unique
 * starting point for each pair of TCP endpoints.  This defeats
 * attacks which rely on guessing the initial TCP sequence number.
 * This algorithm was suggested by Steve Bellovin.
 *
 * Using a very strong hash was taking an appreciable amount of the total
 * TCP connection establishment time, so this is a weaker hash,
 * compensated for by changing the secret periodically.
 */

/* F, G and H are basic MD4 functions: selection, majority, parity */
#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))

/*
 * The generic round function.  The application is so specific that
 * we don't bother protecting all the arguments with parens, as is generally
 * good macro practice, in favor of extra legibility.
 * Rotation is separate from addition to prevent recomputation
 */
#define ROUND(f, a, b, c, d, x, s)	\
	(a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s)))
#define K1 0
#define K2 013240474631UL
#define K3 015666365641UL

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)

static __u32 twothirdsMD4Transform(__u32 const buf[4], __u32 const in[12])
{
	__u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];

	/* Round 1 */
	ROUND(F, a, b, c, d, in[ 0] + K1,  3);
	ROUND(F, d, a, b, c, in[ 1] + K1,  7);
	ROUND(F, c, d, a, b, in[ 2] + K1, 11);
	ROUND(F, b, c, d, a, in[ 3] + K1, 19);
	ROUND(F, a, b, c, d, in[ 4] + K1,  3);
	ROUND(F, d, a, b, c, in[ 5] + K1,  7);
	ROUND(F, c, d, a, b, in[ 6] + K1, 11);
	ROUND(F, b, c, d, a, in[ 7] + K1, 19);
	ROUND(F, a, b, c, d, in[ 8] + K1,  3);
	ROUND(F, d, a, b, c, in[ 9] + K1,  7);
	ROUND(F, c, d, a, b, in[10] + K1, 11);
	ROUND(F, b, c, d, a, in[11] + K1, 19);

	/* Round 2 */
	ROUND(G, a, b, c, d, in[ 1] + K2,  3);
	ROUND(G, d, a, b, c, in[ 3] + K2,  5);
	ROUND(G, c, d, a, b, in[ 5] + K2,  9);
	ROUND(G, b, c, d, a, in[ 7] + K2, 13);
	ROUND(G, a, b, c, d, in[ 9] + K2,  3);
	ROUND(G, d, a, b, c, in[11] + K2,  5);
	ROUND(G, c, d, a, b, in[ 0] + K2,  9);
	ROUND(G, b, c, d, a, in[ 2] + K2, 13);
	ROUND(G, a, b, c, d, in[ 4] + K2,  3);
	ROUND(G, d, a, b, c, in[ 6] + K2,  5);
	ROUND(G, c, d, a, b, in[ 8] + K2,  9);
	ROUND(G, b, c, d, a, in[10] + K2, 13);

	/* Round 3 */
	ROUND(H, a, b, c, d, in[ 3] + K3,  3);
	ROUND(H, d, a, b, c, in[ 7] + K3,  9);
	ROUND(H, c, d, a, b, in[11] + K3, 11);
	ROUND(H, b, c, d, a, in[ 2] + K3, 15);
	ROUND(H, a, b, c, d, in[ 6] + K3,  3);
	ROUND(H, d, a, b, c, in[10] + K3,  9);
	ROUND(H, c, d, a, b, in[ 1] + K3, 11);
	ROUND(H, b, c, d, a, in[ 5] + K3, 15);
	ROUND(H, a, b, c, d, in[ 9] + K3,  3);
	ROUND(H, d, a, b, c, in[ 0] + K3,  9);
	ROUND(H, c, d, a, b, in[ 4] + K3, 11);
	ROUND(H, b, c, d, a, in[ 8] + K3, 15);

	return buf[1] + b; /* "most hashed" word */
	/* Alternative: return sum of all words? */
}
#endif

#undef ROUND
#undef F
#undef G
#undef H
#undef K1
#undef K2
#undef K3

/* This should not be decreased so low that ISNs wrap too fast. */
#define REKEY_INTERVAL (300 * HZ)
/*
 * Bit layout of the tcp sequence numbers (before adding current time):
 * bit 24-31: increased after every key exchange
 * bit 0-23: hash(source,dest)
 *
 * The implementation is similar to the algorithm described
 * in the Appendix of RFC 1185, except that
 * - it uses a 1 MHz clock instead of a 250 kHz clock
 * - it performs a rekey every 5 minutes, which is equivalent
 * 	to a (source,dest) tulple dependent forward jump of the
 * 	clock by 0..2^(HASH_BITS+1)
 *
 * Thus the average ISN wraparound time is 68 minutes instead of
 * 4.55 hours.
 *
 * SMP cleanup and lock avoidance with poor man's RCU.
 * 			Manfred Spraul <manfred@colorfullife.com>
 *
 */
#define COUNT_BITS 8
#define COUNT_MASK ((1 << COUNT_BITS) - 1)
#define HASH_BITS 24
#define HASH_MASK ((1 << HASH_BITS) - 1)
static struct keydata {
	__u32 count; /* already shifted to the final position */
	__u32 secret[12];
} ____cacheline_aligned ip_keydata[2];

static unsigned int ip_cnt;

static void rekey_seq_generator(struct work_struct *work);

static DECLARE_DELAYED_WORK(rekey_work, rekey_seq_generator);

/*
 * Lock avoidance:
 * The ISN generation runs lockless - it's just a hash over random data.
 * State changes happen every 5 minutes when the random key is replaced.
 * Synchronization is performed by having two copies of the hash function
 * state and rekey_seq_generator always updates the inactive copy.
 * The copy is then activated by updating ip_cnt.
 * The implementation breaks down if someone blocks the thread
 * that processes SYN requests for more than 5 minutes. Should never
 * happen, and even if that happens only a not perfectly compliant
 * ISN is generated, nothing fatal.
 */
static void rekey_seq_generator(struct work_struct *work)
	struct keydata *keyptr = &ip_keydata[1 ^ (ip_cnt & 1)];

	get_random_bytes(keyptr->secret, sizeof(keyptr->secret));
	keyptr->count = (ip_cnt & COUNT_MASK) << HASH_BITS;
	smp_wmb();
	ip_cnt++;
	schedule_delayed_work(&rekey_work,
			      round_jiffies_relative(REKEY_INTERVAL));
}

static inline struct keydata *get_keyptr(void)
{
	struct keydata *keyptr = &ip_keydata[ip_cnt & 1];

	smp_rmb();

	return keyptr;
}

static __init int seqgen_init(void)
{
	rekey_seq_generator(NULL);
late_initcall(seqgen_init);

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
__u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
				   __be16 sport, __be16 dport)
{
	__u32 seq;
	__u32 hash[12];
	struct keydata *keyptr = get_keyptr();

	/* The procedure is the same as for IPv4, but addresses are longer.
	 * Thus we must use twothirdsMD4Transform.
	 */

	memcpy(hash, saddr, 16);
	hash[4] = ((__force u16)sport << 16) + (__force u16)dport;
	memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7);

	seq = twothirdsMD4Transform((const __u32 *)daddr, hash) & HASH_MASK;
	seq += keyptr->count;

	seq += ktime_to_ns(ktime_get_real());

	return seq;
}
EXPORT_SYMBOL(secure_tcpv6_sequence_number);
#endif

/*  The code below is shamelessly stolen from secure_tcp_sequence_number().
 *  All blames to Andrey V. Savochkin <saw@msu.ru>.
 */
__u32 secure_ip_id(__be32 daddr)
{
	struct keydata *keyptr;
	__u32 hash[4];

	keyptr = get_keyptr();

	/*
	 *  Pick a unique starting offset for each IP destination.
	 *  The dest ip address is placed in the starting vector,
	 *  which is then hashed with random data.
	 */
	hash[0] = (__force __u32)daddr;
	hash[1] = keyptr->secret[9];
	hash[2] = keyptr->secret[10];
	hash[3] = keyptr->secret[11];

	return half_md4_transform(hash, keyptr->secret);
}

__u32 secure_ipv6_id(const __be32 daddr[4])
{
	const struct keydata *keyptr;
	__u32 hash[4];

	keyptr = get_keyptr();

	hash[0] = (__force __u32)daddr[0];
	hash[1] = (__force __u32)daddr[1];
	hash[2] = (__force __u32)daddr[2];
	hash[3] = (__force __u32)daddr[3];

	return half_md4_transform(hash, keyptr->secret);
}

#ifdef CONFIG_INET

__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
				 __be16 sport, __be16 dport)
{
	__u32 seq;
	__u32 hash[4];
	struct keydata *keyptr = get_keyptr();

	/*
	 *  Pick a unique starting offset for each TCP connection endpoints
	 *  (saddr, daddr, sport, dport).
	 *  Note that the words are placed into the starting vector, which is
	 *  then mixed with a partial MD4 over random data.
	 */
	hash[0] = (__force u32)saddr;
	hash[1] = (__force u32)daddr;
	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
	hash[3] = keyptr->secret[11];

	seq = half_md4_transform(hash, keyptr->secret) & HASH_MASK;
	seq += keyptr->count;
	/*
	 *	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)
	 */
	seq += ktime_to_ns(ktime_get_real()) >> 6;

	return seq;
}

/* Generate secure starting point for ephemeral IPV4 transport port search */
u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
{
	struct keydata *keyptr = get_keyptr();
	u32 hash[4];

	/*
	 *  Pick a unique starting offset for each ephemeral port search
	 *  (saddr, daddr, dport) and 48bits of random data.
	 */
	hash[0] = (__force u32)saddr;
	hash[1] = (__force u32)daddr;
	hash[2] = (__force u32)dport ^ keyptr->secret[10];
	hash[3] = keyptr->secret[11];

	return half_md4_transform(hash, keyptr->secret);
}
EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
			       __be16 dport)
{
	struct keydata *keyptr = get_keyptr();
	u32 hash[12];

	memcpy(hash, saddr, 16);
	hash[4] = (__force u32)dport;
	memcpy(&hash[5], keyptr->secret, sizeof(__u32) * 7);

	return twothirdsMD4Transform((const __u32 *)daddr, hash);
}
#endif

#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
/* Similar to secure_tcp_sequence_number but generate a 48 bit value
 * bit's 32-47 increase every key exchange
 *       0-31  hash(source, dest)
 */
u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
				__be16 sport, __be16 dport)
{
	u64 seq;
	__u32 hash[4];
	struct keydata *keyptr = get_keyptr();

	hash[0] = (__force u32)saddr;
	hash[1] = (__force u32)daddr;
	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
	hash[3] = keyptr->secret[11];

	seq = half_md4_transform(hash, keyptr->secret);
	seq |= ((u64)keyptr->count) << (32 - HASH_BITS);

	seq += ktime_to_ns(ktime_get_real());
	seq &= (1ull << 48) - 1;

	return seq;
}
EXPORT_SYMBOL(secure_dccp_sequence_number);
#endif

#endif /* CONFIG_INET */

DEFINE_PER_CPU(__u32 [4], get_random_int_hash);
	struct keydata *keyptr;
	int ret;
	keyptr = get_keyptr();

	ret = half_md4_transform(hash, keyptr->secret);
extern __u32 secure_ip_id(__be32 daddr);
extern __u32 secure_ipv6_id(const __be32 daddr[4]);
extern u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
extern u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
				      __be16 dport);
extern __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
					__be16 sport, __be16 dport);
extern __u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
					  __be16 sport, __be16 dport);
extern u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
				       __be16 sport, __be16 dport);

	 gen_stats.o gen_estimator.o net_namespace.o
static inline __u32 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
						  __be16 sport, __be16 dport   )
{
	return secure_tcpv6_sequence_number(saddr, daddr, sport, dport);
}

static inline __u32 dccp_v6_init_sequence(struct sk_buff *skb)
Fixed code: static u32 random_int_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;
static int __init random_int_secret_init(void)
	get_random_bytes(random_int_secret, sizeof(random_int_secret));
late_initcall(random_int_secret_init);
DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
	unsigned int ret;
	md5_transform(hash, random_int_secret);
	ret = hash[0];
#ifndef _NET_SECURE_SEQ
#define _NET_SECURE_SEQ

#include <linux/types.h>

extern __u32 secure_ip_id(__be32 daddr);
extern __u32 secure_ipv6_id(const __be32 daddr[4]);
extern u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport);
extern u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
				      __be16 dport);
extern __u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
					__be16 sport, __be16 dport);
extern __u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
					  __be16 sport, __be16 dport);
extern u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
				       __be16 sport, __be16 dport);
extern u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
					 __be16 sport, __be16 dport);

#endif /* _NET_SECURE_SEQ */
	 gen_stats.o gen_estimator.o net_namespace.o secure_seq.o
#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 <net/secure_seq.h>

static u32 net_secret[MD5_MESSAGE_BYTES / 4] ____cacheline_aligned;

static int __init net_secret_init(void)
{
	get_random_bytes(net_secret, sizeof(net_secret));
	return 0;
}
late_initcall(net_secret_init);

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_to_ns(ktime_get_real()) >> 6);
}

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
__u32 secure_tcpv6_sequence_number(__be32 *saddr, __be32 *daddr,
				   __be16 sport, __be16 dport)
{
	u32 secret[MD5_MESSAGE_BYTES / 4];
	u32 hash[MD5_DIGEST_WORDS];
	u32 i;

	memcpy(hash, saddr, 16);
	for (i = 0; i < 4; i++)
		secret[i] = net_secret[i] + daddr[i];
	secret[4] = net_secret[4] +
		(((__force u16)sport << 16) + (__force u16)dport);
	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
		secret[i] = net_secret[i];

	md5_transform(hash, secret);

	return seq_scale(hash[0]);
}
EXPORT_SYMBOL(secure_tcpv6_sequence_number);

u32 secure_ipv6_port_ephemeral(const __be32 *saddr, const __be32 *daddr,
			       __be16 dport)
{
	u32 secret[MD5_MESSAGE_BYTES / 4];
	u32 hash[MD5_DIGEST_WORDS];
	u32 i;

	memcpy(hash, saddr, 16);
	for (i = 0; i < 4; i++)
		secret[i] = net_secret[i] + (__force u32) daddr[i];
	secret[4] = net_secret[4] + (__force u32)dport;
	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
		secret[i] = net_secret[i];

	md5_transform(hash, secret);

	return hash[0];
}
#endif

#ifdef CONFIG_INET
__u32 secure_ip_id(__be32 daddr)
{
	u32 hash[MD5_DIGEST_WORDS];

	hash[0] = (__force __u32) daddr;
	hash[1] = net_secret[13];
	hash[2] = net_secret[14];
	hash[3] = net_secret[15];

	md5_transform(hash, net_secret);

	return hash[0];
}

__u32 secure_ipv6_id(const __be32 daddr[4])
{
	__u32 hash[4];

	memcpy(hash, daddr, 16);
	md5_transform(hash, net_secret);

	return hash[0];
}

__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
				 __be16 sport, __be16 dport)
{
	u32 hash[MD5_DIGEST_WORDS];

	hash[0] = (__force u32)saddr;
	hash[1] = (__force u32)daddr;
	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
	hash[3] = net_secret[15];

	md5_transform(hash, net_secret);

	return seq_scale(hash[0]);
}

u32 secure_ipv4_port_ephemeral(__be32 saddr, __be32 daddr, __be16 dport)
{
	u32 hash[MD5_DIGEST_WORDS];

	hash[0] = (__force u32)saddr;
	hash[1] = (__force u32)daddr;
	hash[2] = (__force u32)dport ^ net_secret[14];
	hash[3] = net_secret[15];

	md5_transform(hash, net_secret);

	return hash[0];
}
EXPORT_SYMBOL_GPL(secure_ipv4_port_ephemeral);
#endif

#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
				__be16 sport, __be16 dport)
{
	u32 hash[MD5_DIGEST_WORDS];
	u64 seq;

	hash[0] = (__force u32)saddr;
	hash[1] = (__force u32)daddr;
	hash[2] = ((__force u16)sport << 16) + (__force u16)dport;
	hash[3] = net_secret[15];

	md5_transform(hash, net_secret);

	seq = hash[0] | (((u64)hash[1]) << 32);
	seq += ktime_to_ns(ktime_get_real());
	seq &= (1ull << 48) - 1;

	return seq;
}
EXPORT_SYMBOL(secure_dccp_sequence_number);

#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
u64 secure_dccpv6_sequence_number(__be32 *saddr, __be32 *daddr,
				  __be16 sport, __be16 dport)
{
	u32 secret[MD5_MESSAGE_BYTES / 4];
	u32 hash[MD5_DIGEST_WORDS];
	u64 seq;
	u32 i;

	memcpy(hash, saddr, 16);
	for (i = 0; i < 4; i++)
		secret[i] = net_secret[i] + daddr[i];
	secret[4] = net_secret[4] +
		(((__force u16)sport << 16) + (__force u16)dport);
	for (i = 5; i < MD5_MESSAGE_BYTES / 4; i++)
		secret[i] = net_secret[i];

	md5_transform(hash, secret);

	seq = hash[0] | (((u64)hash[1]) << 32);
	seq += ktime_to_ns(ktime_get_real());
	seq &= (1ull << 48) - 1;

	return seq;
}
EXPORT_SYMBOL(secure_dccpv6_sequence_number);
#endif
#endif
#include <net/secure_seq.h>
#include <net/secure_seq.h>
static inline __u64 dccp_v6_init_sequence(struct sk_buff *skb)
#include <net/secure_seq.h>
#include <net/secure_seq.h>
#include <net/secure_seq.h>
#include <net/secure_seq.h>
#include <net/secure_seq.h>
#include <net/secure_seq.h>
#include <net/secure_seq.h>