[PATCH v2 21/25] tcp: authopt: Add initial l3index support
From: Leonard Crestez
Date: Mon Nov 01 2021 - 12:37:15 EST
This is a parallel feature to tcp_md5sig.tcpm_ifindex support and allows
applications to server multiple VRFs with a single socket.
The ifindex argument must be the ifindex of a VRF device and must match
exactly, keys with ifindex == 0 (outside of VRF) will not match for
connections inside a VRF.
Keys without the TCP_AUTHOPT_KEY_IFINDEX will ignore ifindex and match
both inside and outside VRF.
Signed-off-by: Leonard Crestez <cdleonard@xxxxxxxxx>
---
include/net/tcp_authopt.h | 2 ++
include/uapi/linux/tcp.h | 11 ++++++
net/ipv4/tcp_authopt.c | 76 +++++++++++++++++++++++++++++++++++----
3 files changed, 82 insertions(+), 7 deletions(-)
diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h
index 9341e10ef542..072d5383f14b 100644
--- a/include/net/tcp_authopt.h
+++ b/include/net/tcp_authopt.h
@@ -39,10 +39,12 @@ struct tcp_authopt_key_info {
u8 alg_id;
/** @keylen: Same as &tcp_authopt_key.keylen */
u8 keylen;
/** @key: Same as &tcp_authopt_key.key */
u8 key[TCP_AUTHOPT_MAXKEYLEN];
+ /** @l3index: Same as &tcp_authopt_key.ifindex */
+ int l3index;
/** @addr: Same as &tcp_authopt_key.addr */
struct sockaddr_storage addr;
/** @alg: Algorithm implementation matching alg_id */
struct tcp_authopt_alg_imp *alg;
};
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index e02176390519..a7f5f918ed5a 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -400,15 +400,17 @@ struct tcp_authopt {
* enum tcp_authopt_key_flag - flags for `tcp_authopt.flags`
*
* @TCP_AUTHOPT_KEY_DEL: Delete the key and ignore non-id fields
* @TCP_AUTHOPT_KEY_EXCLUDE_OPTS: Exclude TCP options from signature
* @TCP_AUTHOPT_KEY_ADDR_BIND: Key only valid for `tcp_authopt.addr`
+ * @TCP_AUTHOPT_KEY_IFINDEX: Key only valid for `tcp_authopt.ifindex`
*/
enum tcp_authopt_key_flag {
TCP_AUTHOPT_KEY_DEL = (1 << 0),
TCP_AUTHOPT_KEY_EXCLUDE_OPTS = (1 << 1),
TCP_AUTHOPT_KEY_ADDR_BIND = (1 << 2),
+ TCP_AUTHOPT_KEY_IFINDEX = (1 << 3),
};
/**
* enum tcp_authopt_alg - Algorithms for TCP Authentication Option
*/
@@ -450,10 +452,19 @@ struct tcp_authopt_key {
* @addr: Key is only valid for this address
*
* Ignored unless TCP_AUTHOPT_KEY_ADDR_BIND flag is set
*/
struct __kernel_sockaddr_storage addr;
+ /**
+ * @ifindex: ifindex of vrf (l3mdev_master) interface
+ *
+ * If the TCP_AUTHOPT_KEY_IFINDEX flag is set then key only applies for
+ * connections through this interface. Interface must be an vrf master.
+ *
+ * This is similar to `tcp_msg5sig.tcpm_ifindex`
+ */
+ int ifindex;
};
/* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
#define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c
index a02fe0d14b63..f497537ce16c 100644
--- a/net/ipv4/tcp_authopt.c
+++ b/net/ipv4/tcp_authopt.c
@@ -1,7 +1,8 @@
// SPDX-License-Identifier: GPL-2.0-or-later
+#include "linux/net.h"
#include <linux/kernel.h>
#include <net/tcp.h>
#include <net/tcp_authopt.h>
#include <crypto/hash.h>
@@ -190,10 +191,14 @@ static bool tcp_authopt_key_match_exact(struct tcp_authopt_key_info *info,
{
if (info->send_id != key->send_id)
return false;
if (info->recv_id != key->recv_id)
return false;
+ if ((info->flags & TCP_AUTHOPT_KEY_IFINDEX) != (key->flags & TCP_AUTHOPT_KEY_IFINDEX))
+ return false;
+ if ((info->flags & TCP_AUTHOPT_KEY_IFINDEX) && info->l3index != key->ifindex)
+ return false;
if ((info->flags & TCP_AUTHOPT_KEY_ADDR_BIND) != (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND))
return false;
if (info->flags & TCP_AUTHOPT_KEY_ADDR_BIND)
if (!ipvx_addr_match(&info->addr, &key->addr))
return false;
@@ -257,26 +262,49 @@ static struct tcp_authopt_key_info *tcp_authopt_key_lookup_exact(const struct so
return key_info;
return NULL;
}
+static bool better_key_match(struct tcp_authopt_key_info *old, struct tcp_authopt_key_info *new)
+{
+ if (!old)
+ return true;
+
+ /* l3index always overrides non-l3index */
+ if (old->l3index && new->l3index == 0)
+ return false;
+ if (old->l3index == 0 && new->l3index)
+ return true;
+
+ return false;
+}
+
static struct tcp_authopt_key_info *tcp_authopt_lookup_send(struct tcp_authopt_info *info,
const struct sock *addr_sk,
int send_id)
{
struct tcp_authopt_key_info *result = NULL;
struct tcp_authopt_key_info *key;
+ int l3index = -1;
hlist_for_each_entry_rcu(key, &info->head, node, 0) {
if (send_id >= 0 && key->send_id != send_id)
continue;
if (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND)
if (!tcp_authopt_key_match_sk_addr(key, addr_sk))
continue;
- if (result && net_ratelimit())
- pr_warn("ambiguous tcp authentication keys configured for send\n");
- result = key;
+ if (key->flags & TCP_AUTHOPT_KEY_IFINDEX) {
+ if (l3index < 0)
+ l3index = l3mdev_master_ifindex_by_index(sock_net(addr_sk),
+ addr_sk->sk_bound_dev_if);
+ if (l3index != key->l3index)
+ continue;
+ }
+ if (better_key_match(result, key))
+ result = key;
+ else if (result)
+ net_warn_ratelimited("ambiguous tcp authentication keys configured for send\n");
}
return result;
}
@@ -527,18 +555,20 @@ void tcp_authopt_clear(struct sock *sk)
}
#define TCP_AUTHOPT_KEY_KNOWN_FLAGS ( \
TCP_AUTHOPT_KEY_DEL | \
TCP_AUTHOPT_KEY_EXCLUDE_OPTS | \
- TCP_AUTHOPT_KEY_ADDR_BIND)
+ TCP_AUTHOPT_KEY_ADDR_BIND | \
+ TCP_AUTHOPT_KEY_IFINDEX)
int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
{
struct tcp_authopt_key opt;
struct tcp_authopt_info *info;
struct tcp_authopt_key_info *key_info, *old_key_info;
struct tcp_authopt_alg_imp *alg;
+ int l3index = 0;
int err;
sock_owned_by_me(sk);
if (!sysctl_tcp_authopt)
return -EPERM;
@@ -584,10 +614,24 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
return -EINVAL;
err = tcp_authopt_alg_require(alg);
if (err)
return err;
+ /* check ifindex is valid (zero is always valid) */
+ if (opt.flags & TCP_AUTHOPT_KEY_IFINDEX && opt.ifindex) {
+ struct net_device *dev;
+
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(sock_net(sk), opt.ifindex);
+ if (dev && netif_is_l3_master(dev))
+ l3index = dev->ifindex;
+ rcu_read_unlock();
+
+ if (!l3index)
+ return -EINVAL;
+ }
+
key_info = sock_kmalloc(sk, sizeof(*key_info), GFP_KERNEL | __GFP_ZERO);
if (!key_info)
return -ENOMEM;
/* If an old key exists with exact ID then remove and replace.
* RCU-protected readers might observe both and pick any.
@@ -601,10 +645,11 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
key_info->alg_id = opt.alg;
key_info->alg = alg;
key_info->keylen = opt.keylen;
memcpy(key_info->key, opt.key, opt.keylen);
memcpy(&key_info->addr, &opt.addr, sizeof(key_info->addr));
+ key_info->l3index = l3index;
hlist_add_head_rcu(&key_info->node, &info->head);
return 0;
}
@@ -1436,21 +1481,38 @@ static struct tcp_authopt_key_info *tcp_authopt_lookup_recv(struct sock *sk,
struct tcp_authopt_info *info,
int recv_id)
{
struct tcp_authopt_key_info *result = NULL;
struct tcp_authopt_key_info *key;
+ int l3index = -1;
/* multiple matches will cause occasional failures */
hlist_for_each_entry_rcu(key, &info->head, node, 0) {
if (recv_id >= 0 && key->recv_id != recv_id)
continue;
if (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND &&
!tcp_authopt_key_match_skb_addr(key, skb))
continue;
- if (result && net_ratelimit())
- pr_warn("ambiguous tcp authentication keys configured for receive\n");
- result = key;
+ if (key->flags & TCP_AUTHOPT_KEY_IFINDEX) {
+ if (l3index < 0) {
+ if (skb->protocol == htons(ETH_P_IP)) {
+ l3index = inet_sdif(skb) ? inet_iif(skb) : 0;
+ } else if (skb->protocol == htons(ETH_P_IPV6)) {
+ l3index = inet6_sdif(skb) ? inet6_iif(skb) : 0;
+ } else {
+ WARN_ONCE(1, "unexpected skb->protocol=%x", skb->protocol);
+ continue;
+ }
+ }
+
+ if (l3index != key->l3index)
+ continue;
+ }
+ if (better_key_match(result, key))
+ result = key;
+ else if (result)
+ net_warn_ratelimited("ambiguous tcp authentication keys configured for send\n");
}
return result;
}
--
2.25.1