Initial import

1 files changed, 273 insertions, 0 deletions

diff --git a/net/core/secure_seq.c b/net/core/secure_seq.c
new file mode 100644
index 000000000..d0c430921
--- /dev/null
+++ b/net/core/secure_seq.c
@@ -0,0 +1,273 @@
+#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/socket.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+
+#include <net/tcp.h>
+#include <net/secure_seq.h>
+
+#if IS_ENABLED(CONFIG_IPV6) || IS_ENABLED(CONFIG_INET)
+#define NET_SECRET_SIZE (MD5_MESSAGE_BYTES / 4)
+
+static u32 net_secret[NET_SECRET_SIZE] ____cacheline_aligned;
+
+static __always_inline void net_secret_init(void)
+{
+	net_get_random_once(net_secret, sizeof(net_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
+
+#ifdef CONFIG_TCP_STEALTH
+u32 tcp_stealth_sequence_number(struct sock *sk, __be32 *daddr,
+				u32 daddr_size, __be16 dport)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct tcp_md5sig_key *md5;
+
+	__u32 sec[MD5_MESSAGE_BYTES / sizeof(__u32)];
+	__u32 i;
+	__u32 tsval = 0;
+
+	__be32 iv[MD5_DIGEST_WORDS] = { 0 };
+	__be32 isn;
+
+	memcpy(iv, daddr, (daddr_size > sizeof(iv)) ? sizeof(iv) : daddr_size);
+
+#ifdef CONFIG_TCP_MD5SIG
+	md5 = tp->af_specific->md5_lookup(sk, sk);
+#else
+	md5 = NULL;
+#endif
+	if (likely(sysctl_tcp_timestamps && !md5) || tp->stealth.saw_tsval)
+		tsval = tp->stealth.mstamp.stamp_jiffies;
+
+	((__be16 *)iv)[2] ^= cpu_to_be16(tp->stealth.integrity_hash);
+	iv[2] ^= cpu_to_be32(tsval);
+	((__be16 *)iv)[6] ^= dport;
+
+	for (i = 0; i < MD5_DIGEST_WORDS; i++)
+		iv[i] = le32_to_cpu(iv[i]);
+	for (i = 0; i < MD5_MESSAGE_BYTES / sizeof(__le32); i++)
+		sec[i] = le32_to_cpu(((__le32 *)tp->stealth.secret)[i]);
+
+	md5_transform(iv, sec);
+
+	isn = cpu_to_be32(iv[0]) ^ cpu_to_be32(iv[1]) ^
+	      cpu_to_be32(iv[2]) ^ cpu_to_be32(iv[3]);
+
+	if (tp->stealth.mode & TCP_STEALTH_MODE_INTEGRITY)
+		be32_isn_to_be16_ih(isn) =
+			cpu_to_be16(tp->stealth.integrity_hash);
+
+	return be32_to_cpu(isn);
+}
+EXPORT_SYMBOL(tcp_stealth_sequence_number);
+
+u32 tcp_stealth_do_auth(struct sock *sk, struct sk_buff *skb)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct tcphdr *th = tcp_hdr(skb);
+	__be32 isn = th->seq;
+	__be32 hash;
+	__be32 *daddr;
+	u32 daddr_size;
+
+	tp->stealth.saw_tsval =
+		tcp_parse_tsval_option(&tp->stealth.mstamp.stamp_jiffies, th);
+
+	if (tp->stealth.mode & TCP_STEALTH_MODE_INTEGRITY_LEN)
+		tp->stealth.integrity_hash =
+			be16_to_cpu(be32_isn_to_be16_ih(isn));
+
+	switch (tp->inet_conn.icsk_inet.sk.sk_family) {
+#if IS_ENABLED(CONFIG_IPV6)
+	case PF_INET6:
+		daddr_size = sizeof(ipv6_hdr(skb)->daddr.s6_addr32);
+		daddr = ipv6_hdr(skb)->daddr.s6_addr32;
+	break;
+#endif
+	case PF_INET:
+		daddr_size = sizeof(ip_hdr(skb)->daddr);
+		daddr = &ip_hdr(skb)->daddr;
+	break;
+	default:
+		pr_err("TCP Stealth: Unknown network layer protocol, stop!\n");
+		return 1;
+	}
+
+	hash = tcp_stealth_sequence_number(sk, daddr, daddr_size, th->dest);
+	cpu_to_be32s(&hash);
+
+	if (tp->stealth.mode & TCP_STEALTH_MODE_AUTH &&
+	    tp->stealth.mode & TCP_STEALTH_MODE_INTEGRITY_LEN &&
+	    be32_isn_to_be16_av(isn) == be32_isn_to_be16_av(hash))
+		return 0;
+
+	if (tp->stealth.mode & TCP_STEALTH_MODE_AUTH &&
+	    !(tp->stealth.mode & TCP_STEALTH_MODE_INTEGRITY_LEN) &&
+	    isn == hash)
+		return 0;
+
+	return 1;
+}
+EXPORT_SYMBOL(tcp_stealth_do_auth);
+#endif
+
+#if IS_ENABLED(CONFIG_IPV6)
+__u32 secure_tcpv6_sequence_number(const __be32 *saddr, const __be32 *daddr,
+				   __be16 sport, __be16 dport)
+{
+	u32 secret[MD5_MESSAGE_BYTES / 4];
+	u32 hash[MD5_DIGEST_WORDS];
+	u32 i;
+
+	net_secret_init();
+	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 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;
+
+	net_secret_init();
+	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];
+}
+EXPORT_SYMBOL(secure_ipv6_port_ephemeral);
+#endif
+
+#ifdef CONFIG_INET
+
+__u32 secure_tcp_sequence_number(__be32 saddr, __be32 daddr,
+				 __be16 sport, __be16 dport)
+{
+	u32 hash[MD5_DIGEST_WORDS];
+
+	net_secret_init();
+	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];
+
+	net_secret_init();
+	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 IS_ENABLED(CONFIG_IP_DCCP)
+u64 secure_dccp_sequence_number(__be32 saddr, __be32 daddr,
+				__be16 sport, __be16 dport)
+{
+	u32 hash[MD5_DIGEST_WORDS];
+	u64 seq;
+
+	net_secret_init();
+	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_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)
+{
+	u32 secret[MD5_MESSAGE_BYTES / 4];
+	u32 hash[MD5_DIGEST_WORDS];
+	u64 seq;
+	u32 i;
+
+	net_secret_init();
+	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_get_real_ns();
+	seq &= (1ull << 48) - 1;
+
+	return seq;
+}
+EXPORT_SYMBOL(secure_dccpv6_sequence_number);
+#endif
+#endif