Merge branch 'tcp-Add-support-for-L3-domains-to-MD5-auth'

David Ahern says:

====================
tcp: Add support for L3 domains to MD5 auth

With VRF, the scope of network addresses is limited to the L3 domain
the device is associated. MD5 keys are based on addresses, so proper
VRF support requires an L3 domain to be considered for the lookups.

Leverage the new TCP_MD5SIG_EXT option to add support for a device index
to MD5 keys. The __tcpm_pad entry in tcp_md5sig is renamed to tcpm_ifindex
and a new flag, TCP_MD5SIG_FLAG_IFINDEX, in tcpm_flags determines if the
entry is examined. This follows what was done for MD5 and prefixes with
commits
   8917a777be3b ("tcp: md5: add TCP_MD5SIG_EXT socket option to set a key address prefix")
   6797318e623d ("tcp: md5: add an address prefix for key lookup")

Handling both a device AND L3 domain is much more complicated for the
response paths. This set focuses only on L3 support - requiring the
device index to be an l3mdev (ie, VRF). Support for slave devices can
be added later if desired, much like the progression of support for
sockets bound to a VRF and then bound to a device in a VRF. Kernel
code is setup to explicitly call out that current lookup is for an L3
index, while the uapi just references a device index allowing its
meaning to include other devices in the future.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 14 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e460ea7f767b..7df37e2fddca 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1532,8 +1532,9 @@ struct tcp_md5sig_key {
 	struct hlist_node	node;
 	u8			keylen;
 	u8			family; /* AF_INET or AF_INET6 */
-	union tcp_md5_addr	addr;
 	u8			prefixlen;
+	union tcp_md5_addr	addr;
+	int			l3index; /* set if key added with L3 scope */
 	u8			key[TCP_MD5SIG_MAXKEYLEN];
 	struct rcu_head		rcu;
 };
@@ -1577,34 +1578,33 @@ struct tcp_md5sig_pool {
 int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key,
 			const struct sock *sk, const struct sk_buff *skb);
 int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
-		   int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
-		   gfp_t gfp);
+		   int family, u8 prefixlen, int l3index,
+		   const u8 *newkey, u8 newkeylen, gfp_t gfp);
 int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
-		   int family, u8 prefixlen);
+		   int family, u8 prefixlen, int l3index);
 struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
 					 const struct sock *addr_sk);
 
 #ifdef CONFIG_TCP_MD5SIG
 #include <linux/jump_label.h>
 extern struct static_key_false tcp_md5_needed;
-struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk,
+struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index,
 					   const union tcp_md5_addr *addr,
 					   int family);
 static inline struct tcp_md5sig_key *
-tcp_md5_do_lookup(const struct sock *sk,
-		  const union tcp_md5_addr *addr,
-		  int family)
+tcp_md5_do_lookup(const struct sock *sk, int l3index,
+		  const union tcp_md5_addr *addr, int family)
 {
 	if (!static_branch_unlikely(&tcp_md5_needed))
 		return NULL;
-	return __tcp_md5_do_lookup(sk, addr, family);
+	return __tcp_md5_do_lookup(sk, l3index, addr, family);
 }
 
 #define tcp_twsk_md5_key(twsk)	((twsk)->tw_md5_key)
 #else
-static inline struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
-					 const union tcp_md5_addr *addr,
-					 int family)
+static inline struct tcp_md5sig_key *
+tcp_md5_do_lookup(const struct sock *sk, int l3index,
+		  const union tcp_md5_addr *addr, int family)
 {
 	return NULL;
 }
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index 74af1f759cee..d87184e673ca 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -317,14 +317,15 @@ enum {
 #define TCP_MD5SIG_MAXKEYLEN	80
 
 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
-#define TCP_MD5SIG_FLAG_PREFIX		1	/* address prefix length */
+#define TCP_MD5SIG_FLAG_PREFIX		0x1	/* address prefix length */
+#define TCP_MD5SIG_FLAG_IFINDEX		0x2	/* ifindex set */
 
 struct tcp_md5sig {
 	struct __kernel_sockaddr_storage tcpm_addr;	/* address associated */
 	__u8	tcpm_flags;				/* extension flags */
 	__u8	tcpm_prefixlen;				/* address prefix */
 	__u16	tcpm_keylen;				/* key length */
-	__u32	__tcpm_pad;				/* zero */
+	int	tcpm_ifindex;				/* device index for scope */
 	__u8	tcpm_key[TCP_MD5SIG_MAXKEYLEN];		/* key (binary) */
 };