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Message-Id: <9ea8e4b68d98e22e0e7e818e64bbc86f73d46c1e.1638962992.git.cdleonard@gmail.com>
Date: Wed, 8 Dec 2021 13:37:30 +0200
From: Leonard Crestez <cdleonard@...il.com>
To: David Ahern <dsahern@...nel.org>,
Dmitry Safonov <0x7f454c46@...il.com>,
Eric Dumazet <edumazet@...gle.com>
Cc: Francesco Ruggeri <fruggeri@...sta.com>,
Shuah Khan <shuah@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Herbert Xu <herbert@...dor.apana.org.au>,
Kuniyuki Iwashima <kuniyu@...zon.co.jp>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Jakub Kicinski <kuba@...nel.org>,
Yuchung Cheng <ycheng@...gle.com>,
Mat Martineau <mathew.j.martineau@...ux.intel.com>,
Christoph Paasch <cpaasch@...le.com>,
Ivan Delalande <colona@...sta.com>,
Priyaranjan Jha <priyarjha@...gle.com>, netdev@...r.kernel.org,
linux-crypto@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v3 15/18] tcp: authopt: Add prefixlen support
This allows making a key apply to an addr/prefix instead of just the
full addr. This is enabled through a custom flag, default behavior is
still full address match.
This is equivalent to TCP_MD5SIG_FLAG_PREFIX from TCP_MD5SIG and has
the same use-cases.
Signed-off-by: Leonard Crestez <cdleonard@...il.com>
---
include/net/tcp_authopt.h | 2 ++
include/uapi/linux/tcp.h | 10 ++++++
net/ipv4/tcp_authopt.c | 67 ++++++++++++++++++++++++++++++++++++---
3 files changed, 75 insertions(+), 4 deletions(-)
diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h
index e57bc732f737..6c50395c0412 100644
--- a/include/net/tcp_authopt.h
+++ b/include/net/tcp_authopt.h
@@ -41,10 +41,12 @@ struct tcp_authopt_key_info {
u8 keylen;
/** @key: Same as &tcp_authopt_key.key */
u8 key[TCP_AUTHOPT_MAXKEYLEN];
/** @l3index: Same as &tcp_authopt_key.ifindex */
int l3index;
+ /** @prefix: Length of addr match (default full) */
+ int prefixlen;
/** @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 ed27feb93b0e..b1063e1e1b9f 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -403,18 +403,21 @@ struct tcp_authopt {
* @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`
* @TCP_AUTHOPT_KEY_NOSEND: Key invalid for send (expired)
* @TCP_AUTHOPT_KEY_NORECV: Key invalid for recv (expired)
+ * @TCP_AUTHOPT_KEY_PREFIXLEN: Valid value in `tcp_authopt.prefixlen`, otherwise
+ * match full address length
*/
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),
TCP_AUTHOPT_KEY_NOSEND = (1 << 4),
TCP_AUTHOPT_KEY_NORECV = (1 << 5),
+ TCP_AUTHOPT_KEY_PREFIXLEN = (1 << 6),
};
/**
* enum tcp_authopt_alg - Algorithms for TCP Authentication Option
*/
@@ -465,10 +468,17 @@ struct tcp_authopt_key {
* connections through this interface. Interface must be an vrf master.
*
* This is similar to `tcp_msg5sig.tcpm_ifindex`
*/
int ifindex;
+ /**
+ * @prefixlen: length of prefix to match
+ *
+ * Without the TCP_AUTHOPT_KEY_PREFIXLEN flag this is ignored and a full
+ * address match is performed.
+ */
+ int prefixlen;
};
/* 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 946d598258b1..5069bb80054e 100644
--- a/net/ipv4/tcp_authopt.c
+++ b/net/ipv4/tcp_authopt.c
@@ -1,8 +1,13 @@
// SPDX-License-Identifier: GPL-2.0-or-later
+#include "linux/in6.h"
+#include "linux/inetdevice.h"
#include "linux/net.h"
+#include "linux/socket.h"
+#include "linux/tcp.h"
+#include "net/ipv6.h"
#include <linux/kernel.h>
#include <net/tcp.h>
#include <net/tcp_authopt.h>
#include <crypto/hash.h>
@@ -219,10 +224,14 @@ static bool tcp_authopt_key_match_exact(struct tcp_authopt_key_info *info,
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_PREFIXLEN) != (key->flags & TCP_AUTHOPT_KEY_PREFIXLEN))
+ return false;
+ if ((info->flags & TCP_AUTHOPT_KEY_PREFIXLEN) && info->prefixlen != key->prefixlen)
+ 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;
@@ -236,17 +245,20 @@ static bool tcp_authopt_key_match_skb_addr(struct tcp_authopt_key_info *key,
u16 keyaf = key->addr.ss_family;
struct iphdr *iph = (struct iphdr *)skb_network_header(skb);
if (keyaf == AF_INET && iph->version == 4) {
struct sockaddr_in *key_addr = (struct sockaddr_in *)&key->addr;
+ u32 mask = inet_make_mask(key->prefixlen);
- return iph->saddr == key_addr->sin_addr.s_addr;
+ return (iph->saddr & mask) == key_addr->sin_addr.s_addr;
} else if (keyaf == AF_INET6 && iph->version == 6) {
struct ipv6hdr *ip6h = (struct ipv6hdr *)skb_network_header(skb);
struct sockaddr_in6 *key_addr = (struct sockaddr_in6 *)&key->addr;
- return ipv6_addr_equal(&ip6h->saddr, &key_addr->sin6_addr);
+ return ipv6_prefix_equal(&ip6h->saddr,
+ &key_addr->sin6_addr,
+ key->prefixlen);
}
/* This actually happens with ipv6-mapped-ipv4-addresses
* IPv6 listen sockets will be asked to validate ipv4 packets.
*/
@@ -262,16 +274,19 @@ static bool tcp_authopt_key_match_sk_addr(struct tcp_authopt_key_info *key,
if (keyaf != addr_sk->sk_family)
return false;
if (keyaf == AF_INET) {
struct sockaddr_in *key_addr = (struct sockaddr_in *)&key->addr;
+ u32 mask = inet_make_mask(key->prefixlen);
- return addr_sk->sk_daddr == key_addr->sin_addr.s_addr;
+ return (addr_sk->sk_daddr & mask) == key_addr->sin_addr.s_addr;
} else if (keyaf == AF_INET6) {
struct sockaddr_in6 *key_addr = (struct sockaddr_in6 *)&key->addr;
- return ipv6_addr_equal(&addr_sk->sk_v6_daddr, &key_addr->sin6_addr);
+ return ipv6_prefix_equal(&addr_sk->sk_v6_daddr,
+ &key_addr->sin6_addr,
+ key->prefixlen);
}
return false;
}
@@ -296,10 +311,16 @@ static bool better_key_match(struct tcp_authopt_key_info *old, struct tcp_authop
/* l3index always overrides non-l3index */
if (old->l3index && new->l3index == 0)
return false;
if (old->l3index == 0 && new->l3index)
return true;
+ /* Full address match overrides match by prefixlen */
+ if (!(new->flags & TCP_AUTHOPT_KEY_PREFIXLEN) && (old->flags & TCP_AUTHOPT_KEY_PREFIXLEN))
+ return false;
+ /* Longer prefixes are better matches */
+ if (new->prefixlen > old->prefixlen)
+ return true;
return false;
}
static struct tcp_authopt_key_info *tcp_authopt_lookup_send(struct tcp_authopt_info *info,
@@ -596,20 +617,31 @@ 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_IFINDEX | \
+ TCP_AUTHOPT_KEY_PREFIXLEN | \
TCP_AUTHOPT_KEY_NOSEND | \
TCP_AUTHOPT_KEY_NORECV)
+static bool ipv6_addr_is_prefix(struct in6_addr *addr, int plen)
+{
+ struct in6_addr copy;
+
+ ipv6_addr_prefix_copy(©, addr, plen);
+
+ return !!memcmp(©, addr, sizeof(*addr));
+}
+
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 prefixlen;
int err;
sock_owned_by_me(sk);
err = check_sysctl_tcp_authopt();
if (err)
@@ -641,10 +673,36 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
if (opt.flags & TCP_AUTHOPT_KEY_ADDR_BIND) {
if (sk->sk_family != opt.addr.ss_family)
return -EINVAL;
}
+ /* check prefixlen */
+ if (opt.flags & TCP_AUTHOPT_KEY_PREFIXLEN) {
+ prefixlen = opt.prefixlen;
+ if (sk->sk_family == AF_INET) {
+ if (prefixlen < 0 || prefixlen > 32)
+ return -EINVAL;
+ if (((struct sockaddr_in *)&opt.addr)->sin_addr.s_addr &
+ ~inet_make_mask(prefixlen))
+ return -EINVAL;
+ }
+ if (sk->sk_family == AF_INET6) {
+ if (prefixlen < 0 || prefixlen > 128)
+ return -EINVAL;
+ if (!ipv6_addr_is_prefix(&((struct sockaddr_in6 *)&opt.addr)->sin6_addr,
+ prefixlen))
+ return -EINVAL;
+ }
+ } else {
+ if (sk->sk_family == AF_INET)
+ prefixlen = 32;
+ else if (sk->sk_family == AF_INET6)
+ prefixlen = 128;
+ else
+ return -EINVAL;
+ }
+
/* Initialize tcp_authopt_info if not already set */
info = __tcp_authopt_info_get_or_create(sk);
if (IS_ERR(info))
return PTR_ERR(info);
@@ -688,10 +746,11 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
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;
+ key_info->prefixlen = prefixlen;
hlist_add_head_rcu(&key_info->node, &info->head);
return 0;
}
--
2.25.1
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