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Message-Id: <20170607005414.25361-1-colona@arista.com>
Date: Tue, 6 Jun 2017 17:54:13 -0700
From: Ivan Delalande <colona@...sta.com>
To: David Miller <davem@...emloft.net>
Cc: Eric Dumazet <eric.dumazet@...il.com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, Ivan Delalande <colona@...sta.com>
Subject: [PATCH 1/2] tcp: md5: add an address prefix for key lookup
This allows the keys used for TCP MD5 signature to be used for whole
range of addresses, specified with a prefix length, instead of only one
address as it currently is.
Signed-off-by: Bob Gilligan <gilligan@...sta.com>
Signed-off-by: Eric Mowat <mowat@...sta.com>
Signed-off-by: Ivan Delalande <colona@...sta.com>
---
include/net/tcp.h | 6 +++--
net/ipv4/tcp_ipv4.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++-------
net/ipv6/tcp_ipv6.c | 12 ++++++----
3 files changed, 70 insertions(+), 16 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 38a7427ae902..2b68023ab095 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1395,6 +1395,7 @@ struct tcp_md5sig_key {
u8 keylen;
u8 family; /* AF_INET or AF_INET6 */
union tcp_md5_addr addr;
+ u8 prefixlen;
u8 key[TCP_MD5SIG_MAXKEYLEN];
struct rcu_head rcu;
};
@@ -1438,9 +1439,10 @@ 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, const u8 *newkey, u8 newkeylen, gfp_t gfp);
+ int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
+ gfp_t gfp);
int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr,
- int family);
+ int family, u8 prefixlen);
struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
const struct sock *addr_sk);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5ab2aac5ca19..51ca3bd5a8a3 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -80,6 +80,7 @@
#include <linux/stddef.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <linux/inetdevice.h>
#include <crypto/hash.h>
#include <linux/scatterlist.h>
@@ -906,6 +907,9 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
struct tcp_md5sig_key *key;
unsigned int size = sizeof(struct in_addr);
const struct tcp_md5sig_info *md5sig;
+ __be32 mask;
+ struct tcp_md5sig_key *best_match = NULL;
+ bool match;
/* caller either holds rcu_read_lock() or socket lock */
md5sig = rcu_dereference_check(tp->md5sig_info,
@@ -919,12 +923,55 @@ struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk,
hlist_for_each_entry_rcu(key, &md5sig->head, node) {
if (key->family != family)
continue;
- if (!memcmp(&key->addr, addr, size))
+
+ if (family == AF_INET) {
+ mask = inet_make_mask(key->prefixlen);
+ match = (key->addr.a4.s_addr & mask) ==
+ (addr->a4.s_addr & mask);
+#if IS_ENABLED(CONFIG_IPV6)
+ } else if (family == AF_INET6) {
+ match = ipv6_prefix_equal(&key->addr.a6, &addr->a6,
+ key->prefixlen);
+#endif
+ } else {
+ match = false;
+ }
+
+ if (match && (!best_match ||
+ key->prefixlen > best_match->prefixlen))
+ best_match = key;
+ }
+ return best_match;
+}
+EXPORT_SYMBOL(tcp_md5_do_lookup);
+
+struct tcp_md5sig_key *tcp_md5_do_lookup_exact(const struct sock *sk,
+ const union tcp_md5_addr *addr,
+ int family, u8 prefixlen)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+ struct tcp_md5sig_key *key;
+ unsigned int size = sizeof(struct in_addr);
+ const struct tcp_md5sig_info *md5sig;
+
+ /* caller either holds rcu_read_lock() or socket lock */
+ md5sig = rcu_dereference_check(tp->md5sig_info,
+ lockdep_sock_is_held(sk));
+ if (!md5sig)
+ return NULL;
+#if IS_ENABLED(CONFIG_IPV6)
+ if (family == AF_INET6)
+ size = sizeof(struct in6_addr);
+#endif
+ hlist_for_each_entry_rcu(key, &md5sig->head, node) {
+ if (key->family != family)
+ continue;
+ if (!memcmp(&key->addr, addr, size) &&
+ key->prefixlen == prefixlen)
return key;
}
return NULL;
}
-EXPORT_SYMBOL(tcp_md5_do_lookup);
struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk,
const struct sock *addr_sk)
@@ -938,14 +985,15 @@ EXPORT_SYMBOL(tcp_v4_md5_lookup);
/* This can be called on a newly created socket, from other files */
int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
- int family, const u8 *newkey, u8 newkeylen, gfp_t gfp)
+ int family, u8 prefixlen, const u8 *newkey, u8 newkeylen,
+ gfp_t gfp)
{
/* Add Key to the list */
struct tcp_md5sig_key *key;
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_md5sig_info *md5sig;
- key = tcp_md5_do_lookup(sk, addr, family);
+ key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
if (key) {
/* Pre-existing entry - just update that one. */
memcpy(key->key, newkey, newkeylen);
@@ -976,6 +1024,7 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
memcpy(key->key, newkey, newkeylen);
key->keylen = newkeylen;
key->family = family;
+ key->prefixlen = prefixlen;
memcpy(&key->addr, addr,
(family == AF_INET6) ? sizeof(struct in6_addr) :
sizeof(struct in_addr));
@@ -984,11 +1033,12 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr,
}
EXPORT_SYMBOL(tcp_md5_do_add);
-int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family)
+int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family,
+ u8 prefixlen)
{
struct tcp_md5sig_key *key;
- key = tcp_md5_do_lookup(sk, addr, family);
+ key = tcp_md5_do_lookup_exact(sk, addr, family, prefixlen);
if (!key)
return -ENOENT;
hlist_del_rcu(&key->node);
@@ -1031,13 +1081,13 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval,
if (!cmd.tcpm_keylen)
return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
- AF_INET);
+ AF_INET, 32);
if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
return -EINVAL;
return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr,
- AF_INET, cmd.tcpm_key, cmd.tcpm_keylen,
+ AF_INET, 32, cmd.tcpm_key, cmd.tcpm_keylen,
GFP_KERNEL);
}
@@ -1340,7 +1390,7 @@ struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
* across. Shucks.
*/
tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr,
- AF_INET, key->key, key->keylen, GFP_ATOMIC);
+ AF_INET, 32, key->key, key->keylen, GFP_ATOMIC);
sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
}
#endif
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7a8237acd210..5cf19dab60aa 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -532,9 +532,9 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
if (!cmd.tcpm_keylen) {
if (ipv6_addr_v4mapped(&sin6->sin6_addr))
return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
- AF_INET);
+ AF_INET, 32);
return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
- AF_INET6);
+ AF_INET6, 128);
}
if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
@@ -542,10 +542,12 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval,
if (ipv6_addr_v4mapped(&sin6->sin6_addr))
return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3],
- AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
+ AF_INET, 32, cmd.tcpm_key,
+ cmd.tcpm_keylen, GFP_KERNEL);
return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr,
- AF_INET6, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL);
+ AF_INET6, 128, cmd.tcpm_key, cmd.tcpm_keylen,
+ GFP_KERNEL);
}
static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp,
@@ -1183,7 +1185,7 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
* across. Shucks.
*/
tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr,
- AF_INET6, key->key, key->keylen,
+ AF_INET6, 128, key->key, key->keylen,
sk_gfp_mask(sk, GFP_ATOMIC));
}
#endif
--
2.13.0
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