From: Leonard Crestez <cdleonard@gmail.com>
To: David Ahern <dsahern@kernel.org>, Shuah Khan <shuah@kernel.org>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Herbert Xu <herbert@gondor.apana.org.au>,
Kuniyuki Iwashima <kuniyu@amazon.co.jp>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Jakub Kicinski <kuba@kernel.org>,
Yuchung Cheng <ycheng@google.com>,
Francesco Ruggeri <fruggeri@arista.com>,
Mat Martineau <mathew.j.martineau@linux.intel.com>,
Christoph Paasch <cpaasch@apple.com>,
Ivan Delalande <colona@arista.com>,
Priyaranjan Jha <priyarjha@google.com>,
netdev@vger.kernel.org, linux-crypto@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 09/25] tcp: authopt: Disable via sysctl by default
Date: Mon, 1 Nov 2021 18:34:44 +0200 [thread overview]
Message-ID: <137399b962131c278acbfa5446a3b6d59aa0547b.1635784253.git.cdleonard@gmail.com> (raw)
In-Reply-To: <cover.1635784253.git.cdleonard@gmail.com>
This is mainly intended to protect against local privilege escalations
through a rarely used feature so it is deliberately not namespaced.
Enforcement is only at the setsockopt level, this should be enough to
ensure that the tcp_authopt_needed static key never turns on.
No effort is made to handle disabling when the feature is already in
use.
Signed-off-by: Leonard Crestez <cdleonard@gmail.com>
---
Documentation/networking/ip-sysctl.rst | 6 ++++++
include/net/tcp_authopt.h | 1 +
net/ipv4/sysctl_net_ipv4.c | 10 ++++++++++
net/ipv4/tcp_authopt.c | 13 ++++++++++++-
4 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 16b8bf72feaf..3f00681f73d7 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -987,10 +987,16 @@ tcp_limit_output_bytes - INTEGER
tcp_challenge_ack_limit - INTEGER
Limits number of Challenge ACK sent per second, as recommended
in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks)
Default: 1000
+tcp_authopt - BOOLEAN
+ Enable the TCP Authentication Option (RFC5925), a replacement for TCP
+ MD5 Signatures (RFC2835).
+
+ Default: 0
+
UDP variables
=============
udp_l3mdev_accept - BOOLEAN
Enabling this option allows a "global" bound socket to work
diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h
index 8bb76128ed11..a505db1dd67b 100644
--- a/include/net/tcp_authopt.h
+++ b/include/net/tcp_authopt.h
@@ -65,10 +65,11 @@ struct tcp_authopt_info {
/** @dst_isn: Remote Initial Sequence Number */
u32 dst_isn;
};
#ifdef CONFIG_TCP_AUTHOPT
+extern int sysctl_tcp_authopt;
DECLARE_STATIC_KEY_FALSE(tcp_authopt_needed);
void tcp_authopt_free(struct sock *sk, struct tcp_authopt_info *info);
void tcp_authopt_clear(struct sock *sk);
int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 97eb54774924..cc34de6e4817 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -17,10 +17,11 @@
#include <net/udp.h>
#include <net/cipso_ipv4.h>
#include <net/ping.h>
#include <net/protocol.h>
#include <net/netevent.h>
+#include <net/tcp_authopt.h>
static int two = 2;
static int three __maybe_unused = 3;
static int four = 4;
static int thousand = 1000;
@@ -583,10 +584,19 @@ static struct ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = proc_douintvec_minmax,
.extra1 = &sysctl_fib_sync_mem_min,
.extra2 = &sysctl_fib_sync_mem_max,
},
+#ifdef CONFIG_TCP_AUTHOPT
+ {
+ .procname = "tcp_authopt",
+ .data = &sysctl_tcp_authopt,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+#endif
{ }
};
static struct ctl_table ipv4_net_table[] = {
{
diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c
index 5e80e5e5e36e..7c49dcce7d24 100644
--- a/net/ipv4/tcp_authopt.c
+++ b/net/ipv4/tcp_authopt.c
@@ -3,10 +3,15 @@
#include <linux/kernel.h>
#include <net/tcp.h>
#include <net/tcp_authopt.h>
#include <crypto/hash.h>
+/* This is mainly intended to protect against local privilege escalations through
+ * a rarely used feature so it is deliberately not namespaced.
+ */
+int sysctl_tcp_authopt;
+
/* This is enabled when first struct tcp_authopt_info is allocated and never released */
DEFINE_STATIC_KEY_FALSE(tcp_authopt_needed);
EXPORT_SYMBOL(tcp_authopt_needed);
/* All current algorithms have a mac length of 12 but crypto API digestsize can be larger */
@@ -360,10 +365,12 @@ int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen)
struct tcp_authopt opt;
struct tcp_authopt_info *info;
int err;
sock_owned_by_me(sk);
+ if (!sysctl_tcp_authopt)
+ return -EPERM;
err = _copy_from_sockptr_tolerant((u8 *)&opt, sizeof(opt), optval, optlen);
if (err)
return err;
@@ -382,13 +389,15 @@ int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen)
int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *opt)
{
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_authopt_info *info;
+ memset(opt, 0, sizeof(*opt));
sock_owned_by_me(sk);
+ if (!sysctl_tcp_authopt)
+ return -EPERM;
- memset(opt, 0, sizeof(*opt));
info = rcu_dereference_check(tp->authopt_info, lockdep_sock_is_held(sk));
if (!info)
return -ENOENT;
opt->flags = info->flags & TCP_AUTHOPT_KNOWN_FLAGS;
@@ -451,10 +460,12 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
struct tcp_authopt_key_info *key_info, *old_key_info;
struct tcp_authopt_alg_imp *alg;
int err;
sock_owned_by_me(sk);
+ if (!sysctl_tcp_authopt)
+ return -EPERM;
err = _copy_from_sockptr_tolerant((u8 *)&opt, sizeof(opt), optval, optlen);
if (err)
return err;
--
2.25.1
next prev parent reply other threads:[~2021-11-01 16:35 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 16:34 [PATCH v2] tcp: Initial support for RFC5925 auth option Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 01/25] tcp: authopt: Initial support and key management Leonard Crestez
2021-11-03 2:29 ` David Ahern
2021-11-05 12:10 ` Leonard Crestez
2021-11-05 1:22 ` Dmitry Safonov
2021-11-05 7:04 ` Leonard Crestez
2021-11-05 14:50 ` Dmitry Safonov
2021-11-05 18:00 ` Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 02/25] docs: Add user documentation for tcp_authopt Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 03/25] selftests: Initial tcp_authopt test module Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 04/25] selftests: tcp_authopt: Initial sockopt manipulation Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 05/25] tcp: authopt: Add crypto initialization Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 06/25] tcp: authopt: Compute packet signatures Leonard Crestez
2021-11-05 1:53 ` Dmitry Safonov
2021-11-05 6:39 ` Leonard Crestez
2021-11-05 2:08 ` Dmitry Safonov
2021-11-05 6:09 ` Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 07/25] tcp: Use BIT() for OPTION_* constants Leonard Crestez
2021-11-03 2:31 ` David Ahern
2021-11-03 22:19 ` Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 08/25] tcp: authopt: Hook into tcp core Leonard Crestez
2021-11-01 16:34 ` Leonard Crestez [this message]
2021-11-03 2:39 ` [PATCH v2 09/25] tcp: authopt: Disable via sysctl by default David Ahern
2021-11-05 8:50 ` Leonard Crestez
2021-11-05 1:46 ` Dmitry Safonov
2021-11-01 16:34 ` [PATCH v2 10/25] selftests: tcp_authopt: Test key address binding Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 11/25] tcp: authopt: Implement Sequence Number Extension Leonard Crestez
2021-11-01 19:22 ` Francesco Ruggeri
2021-11-02 10:03 ` Leonard Crestez
2021-11-02 19:21 ` Francesco Ruggeri
2021-11-03 22:01 ` Leonard Crestez
2021-11-01 20:54 ` Eric Dumazet
2021-11-02 9:50 ` Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 12/25] tcp: ipv6: Add AO signing for tcp_v6_send_response Leonard Crestez
2021-11-03 2:44 ` David Ahern
2021-11-03 22:09 ` Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 13/25] tcp: authopt: Add support for signing skb-less replies Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 14/25] tcp: ipv4: Add AO signing for " Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 15/25] selftests: tcp_authopt: Implement SNE in python Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 16/25] selftests: tcp_authopt: Add scapy-based packet signing code Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 17/25] selftests: tcp_authopt: Add packet-level tests Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 18/25] selftests: tcp_authopt: Initial sne test Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 19/25] tcp: authopt: Add key selection controls Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 20/25] selftests: tcp_authopt: Add tests for rollover Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 21/25] tcp: authopt: Add initial l3index support Leonard Crestez
2021-11-03 3:06 ` David Ahern
2021-11-05 12:26 ` Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 22/25] selftests: tcp_authopt: Initial tests for l3mdev handling Leonard Crestez
2021-11-01 16:34 ` [PATCH v2 23/25] selftests: nettest: Rename md5_prefix to key_addr_prefix Leonard Crestez
2021-11-03 3:08 ` David Ahern
2021-11-01 16:34 ` [PATCH v2 24/25] selftests: nettest: Initial tcp_authopt support Leonard Crestez
2021-11-03 3:09 ` David Ahern
2021-11-01 16:35 ` [PATCH v2 25/25] selftests: net/fcnal: " Leonard Crestez
2021-11-03 3:18 ` [PATCH v2] tcp: Initial support for RFC5925 auth option David Ahern
2021-11-03 22:22 ` Leonard Crestez
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