This commit adds support to add and remove keys but does not use them further.

Similar to tcp md5 a single pointer to a struct tcp_authopt_info* struct is added to struct tcp_sock, this avoids increasing memory usage. The data structures related to tcp_authopt are initialized on setsockopt and only freed on socket close.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/linux/tcp.h | 9 ++ include/net/tcp.h | 1 + include/net/tcp_authopt.h | 63 +++++++++ include/uapi/linux/tcp.h | 79 ++++++++++++ net/ipv4/Kconfig | 14 ++ net/ipv4/Makefile | 1 + net/ipv4/tcp.c | 30 +++++ net/ipv4/tcp_authopt.c | 260 ++++++++++++++++++++++++++++++++++++++ net/ipv4/tcp_ipv4.c | 2 + 9 files changed, 459 insertions(+) create mode 100644 include/net/tcp_authopt.h create mode 100644 net/ipv4/tcp_authopt.c

diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 48d8a363319e..50038f35ba51 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -140,10 +140,12 @@ struct tcp_request_sock { static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) { return (struct tcp_request_sock *)req; }

+struct tcp_authopt_info; + struct tcp_sock { /* inet_connection_sock has to be the first member of tcp_sock */ struct inet_connection_sock inet_conn; u16 tcp_header_len; /* Bytes of tcp header to send */ u16 gso_segs; /* Max number of segs per GSO packet */ @@ -403,10 +405,14 @@ struct tcp_sock {

/* TCP MD5 Signature Option information */ struct tcp_md5sig_info __rcu *md5sig_info; #endif

+#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_info __rcu *authopt_info; +#endif + /* TCP fastopen related information */ struct tcp_fastopen_request *fastopen_req; /* fastopen_rsk points to request_sock that resulted in this big * socket. Used to retransmit SYNACKs etc. */ @@ -453,10 +459,13 @@ struct tcp_timewait_sock { int tw_ts_recent_stamp; u32 tw_tx_delay; #ifdef CONFIG_TCP_MD5SIG struct tcp_md5sig_key *tw_md5_key; #endif +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_info *tw_authopt_info; +#endif };

static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) { return (struct tcp_timewait_sock *)sk; diff --git a/include/net/tcp.h b/include/net/tcp.h index 3166dc15d7d6..bb76554e8fe5 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -182,10 +182,11 @@ void tcp_time_wait(struct sock *sk, int state, int timeo); #define TCPOPT_WINDOW 3 /* Window scaling */ #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ #define TCPOPT_SACK 5 /* SACK Block */ #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ +#define TCPOPT_AUTHOPT 29 /* Auth Option (RFC5925) */ #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */ #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */ #define TCPOPT_EXP 254 /* Experimental */ /* Magic number to be after the option value for sharing TCP * experimental options. See draft-ietf-tcpm-experimental-options-00.txt diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h new file mode 100644 index 000000000000..19d304de18f8 --- /dev/null +++ b/include/net/tcp_authopt.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _LINUX_TCP_AUTHOPT_H +#define _LINUX_TCP_AUTHOPT_H + +#include <uapi/linux/tcp.h> + +/** + * struct tcp_authopt_key_info - Representation of a Master Key Tuple as per RFC5925 + * + * Key structure lifetime is only protected by RCU so readers needs to hold a + * single rcu_read_lock until they're done with the key. + */ +struct tcp_authopt_key_info { + struct hlist_node node; + struct rcu_head rcu; + u32 flags; + /* Wire identifiers */ + u8 send_id, recv_id; + u8 alg_id; + u8 keylen; + u8 key[TCP_AUTHOPT_MAXKEYLEN]; + struct sockaddr_storage addr; +}; + +/** + * struct tcp_authopt_info - Per-socket information regarding tcp_authopt + * + * This is lazy-initialized in order to avoid increasing memory usage for + * regular TCP sockets. Once created it is only destroyed on socket close. + */ +struct tcp_authopt_info { + /** @head: List of tcp_authopt_key_info */ + struct hlist_head head; + struct rcu_head rcu; + u32 flags; + u32 src_isn; + u32 dst_isn; +}; + +#ifdef CONFIG_TCP_AUTHOPT +void tcp_authopt_clear(struct sock *sk); +int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen); +int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *key); +int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen); +#else +static inline int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen) +{ + return -ENOPROTOOPT; +} +static inline int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *key) +{ + return -ENOPROTOOPT; +} +static inline void tcp_authopt_clear(struct sock *sk) +{ +} +static inline int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) +{ + return -ENOPROTOOPT; +} +#endif + +#endif /* _LINUX_TCP_AUTHOPT_H */ diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 8fc09e8638b3..c68ecd617774 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -126,10 +126,12 @@ enum { #define TCP_INQ 36 /* Notify bytes available to read as a cmsg on read */

#define TCP_CM_INQ TCP_INQ

#define TCP_TX_DELAY 37 /* delay outgoing packets by XX usec */ +#define TCP_AUTHOPT 38 /* TCP Authentication Option (RFC5925) */ +#define TCP_AUTHOPT_KEY 39 /* TCP Authentication Option Key (RFC5925) */

#define TCP_REPAIR_ON 1 #define TCP_REPAIR_OFF 0 #define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */ @@ -340,10 +342,87 @@ struct tcp_diag_md5sig { __u16 tcpm_keylen; __be32 tcpm_addr[4]; __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; };

+/** + * enum tcp_authopt_flag - flags for `tcp_authopt.flags` + */ +enum tcp_authopt_flag { + /** + * @TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED: + * Configure behavior of segments with TCP-AO coming from hosts for which no + * key is configured. The default recommended by RFC is to silently accept + * such connections. + */ + TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED = (1 << 2), +}; + +/** + * struct tcp_authopt - Per-socket options related to TCP Authentication Option + */ +struct tcp_authopt { + /** @flags: Combination of &enum tcp_authopt_flag */ + __u32 flags; +}; + +/** + * 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` + */ +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), +}; + +/** + * enum tcp_authopt_alg - Algorithms for TCP Authentication Option + */ +enum tcp_authopt_alg { + TCP_AUTHOPT_ALG_HMAC_SHA_1_96 = 1, + TCP_AUTHOPT_ALG_AES_128_CMAC_96 = 2, +}; + +/* for TCP_AUTHOPT_KEY socket option */ +#define TCP_AUTHOPT_MAXKEYLEN 80 + +/** + * struct tcp_authopt_key - TCP Authentication KEY + * + * Key are identified by the combination of: + * - send_id + * - recv_id + * - addr (iff TCP_AUTHOPT_KEY_ADDR_BIND) + * + * RFC5925 requires that key ids must not overlap for the same TCP connection. + * This is not enforced by linux. + */ +struct tcp_authopt_key { + /** @flags: Combination of &enum tcp_authopt_key_flag */ + __u32 flags; + /** @send_id: keyid value for send */ + __u8 send_id; + /** @recv_id: keyid value for receive */ + __u8 recv_id; + /** @alg: One of &enum tcp_authopt_alg */ + __u8 alg; + /** @keylen: Length of the key buffer */ + __u8 keylen; + /** @key: Secret key */ + __u8 key[TCP_AUTHOPT_MAXKEYLEN]; + /** + * @addr: Key is only valid for this address + * + * Ignored unless TCP_AUTHOPT_KEY_ADDR_BIND flag is set + */ + struct __kernel_sockaddr_storage addr; +}; + /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */

#define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1 struct tcp_zerocopy_receive { __u64 address; /* in: address of mapping */ diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 87983e70f03f..6459f4ea6f1d 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -740,5 +740,19 @@ config TCP_MD5SIG RFC2385 specifies a method of giving MD5 protection to TCP sessions. Its main (only?) use is to protect BGP sessions between core routers on the Internet.

If unsure, say N. + +config TCP_AUTHOPT + bool "TCP: Authentication Option support (RFC5925)" + select CRYPTO + select CRYPTO_SHA1 + select CRYPTO_HMAC + select CRYPTO_AES + select CRYPTO_CMAC + help + RFC5925 specifies a new method of giving protection to TCP sessions. + Its intended use is to protect BGP sessions between core routers + on the Internet. It obsoletes TCP MD5 (RFC2385) but is incompatible. + + If unsure, say N. diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index bbdd9c44f14e..d336f32ce177 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -59,10 +59,11 @@ obj-$(CONFIG_TCP_CONG_NV) += tcp_nv.o obj-$(CONFIG_TCP_CONG_VENO) += tcp_veno.o obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o +obj-$(CONFIG_TCP_AUTHOPT) += tcp_authopt.o obj-$(CONFIG_NET_SOCK_MSG) += tcp_bpf.o obj-$(CONFIG_BPF_SYSCALL) += udp_bpf.o obj-$(CONFIG_NETLABEL) += cipso_ipv4.o

obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index e8b48df73c85..9966acf259e2 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -271,10 +271,11 @@

#include <net/icmp.h> #include <net/inet_common.h> #include <net/tcp.h> #include <net/mptcp.h> +#include <net/tcp_authopt.h> #include <net/xfrm.h> #include <net/ip.h> #include <net/sock.h>

#include <linux/uaccess.h> @@ -3574,10 +3575,16 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname, case TCP_MD5SIG: case TCP_MD5SIG_EXT: err = tp->af_specific->md5_parse(sk, optname, optval, optlen); break; #endif + case TCP_AUTHOPT: + err = tcp_set_authopt(sk, optval, optlen); + break; + case TCP_AUTHOPT_KEY: + err = tcp_set_authopt_key(sk, optval, optlen); + break; case TCP_USER_TIMEOUT: /* Cap the max time in ms TCP will retry or probe the window * before giving up and aborting (ETIMEDOUT) a connection. */ if (val < 0) @@ -4220,10 +4227,33 @@ static int do_tcp_getsockopt(struct sock *sk, int level, if (!err && copy_to_user(optval, &zc, len)) err = -EFAULT; return err; } #endif +#ifdef CONFIG_TCP_AUTHOPT + case TCP_AUTHOPT: { + struct tcp_authopt info; + int err; + + if (get_user(len, optlen)) + return -EFAULT; + + lock_sock(sk); + err = tcp_get_authopt_val(sk, &info); + release_sock(sk); + + if (err) + return err; + len = min_t(unsigned int, len, sizeof(info)); + if (put_user(len, optlen)) + return -EFAULT; + if (copy_to_user(optval, &info, len)) + return -EFAULT; + return 0; + } +#endif + default: return -ENOPROTOOPT; }

if (put_user(len, optlen)) diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c new file mode 100644 index 000000000000..a771e5754c8a --- /dev/null +++ b/net/ipv4/tcp_authopt.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <linux/kernel.h> +#include <net/tcp.h> +#include <net/tcp_authopt.h> +#include <crypto/hash.h> + +/* checks that ipv4 or ipv6 addr matches. */ +static bool ipvx_addr_match(struct sockaddr_storage *a1, + struct sockaddr_storage *a2) +{ + if (a1->ss_family != a2->ss_family) + return false; + if (a1->ss_family == AF_INET && ( + ((struct sockaddr_in *)a1)->sin_addr.s_addr != + ((struct sockaddr_in *)a2)->sin_addr.s_addr)) + return false; + if (a1->ss_family == AF_INET6 && !ipv6_addr_equal( + &((struct sockaddr_in6 *)a1)->sin6_addr, + &((struct sockaddr_in6 *)a2)->sin6_addr)) + return false; + return true; +} + +static bool tcp_authopt_key_match_exact(struct tcp_authopt_key_info *info, + struct tcp_authopt_key *key) +{ + if (info->send_id != key->send_id) + return false; + if (info->recv_id != key->recv_id) + return false; + if ((info->flags & TCP_AUTHOPT_KEY_ADDR_BIND) != (key->recv_id & 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; + + return true; +} + +static struct tcp_authopt_key_info *tcp_authopt_key_lookup_exact(const struct sock *sk, + struct tcp_authopt_info *info, + struct tcp_authopt_key *ukey) +{ + struct tcp_authopt_key_info *key_info; + + hlist_for_each_entry_rcu(key_info, &info->head, node, lockdep_sock_is_held(sk)) + if (tcp_authopt_key_match_exact(key_info, ukey)) + return key_info; + + return NULL; +} + +static struct tcp_authopt_info *__tcp_authopt_info_get_or_create(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_authopt_info *info; + + info = rcu_dereference_check(tp->authopt_info, lockdep_sock_is_held(sk)); + if (info) + return info; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return ERR_PTR(-ENOMEM); + + sk_nocaps_add(sk, NETIF_F_GSO_MASK); + INIT_HLIST_HEAD(&info->head); + rcu_assign_pointer(tp->authopt_info, info); + + return info; +} + +#define TCP_AUTHOPT_KNOWN_FLAGS ( \ + TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED) + +/* Like copy_from_sockopt except tolerate different optlen for compatibility reasons + * + * If the src is shorter then it's from an old userspace and the rest of dst is + * filled with zeros. + * + * If the dst is shorter then src is from a newer userspace and we only accept + * if the rest of the option is all zeros. + * + * This allows sockopts to grow as long as for new fields zeros has no effect. + */ +static int _copy_from_sockptr_tolerant( + u8* dst, unsigned int dstlen, + sockptr_t src, unsigned int srclen) +{ + int err; + + /* If userspace optlen is too short fill the rest with zeros */ + if (srclen > dstlen) { + if (sockptr_is_kernel(src)) + return -EINVAL; + err = check_zeroed_user(src.user + dstlen, srclen - dstlen); + if (err < 0) + return err; + if (err == 0) + return -EINVAL; + } + err = copy_from_sockptr(dst, src, min(srclen, dstlen)); + if (err) + return err; + if (srclen < dstlen) + memset(dst + dstlen, 0, dstlen - srclen); + + return err; +} + +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); + + err = _copy_from_sockptr_tolerant((u8*)&opt, sizeof(opt), optval, optlen); + if (err) + return err; + + if (opt.flags & ~TCP_AUTHOPT_KNOWN_FLAGS) + return -EINVAL; + + info = __tcp_authopt_info_get_or_create(sk); + if (IS_ERR(info)) + return PTR_ERR(info); + + info->flags = opt.flags & TCP_AUTHOPT_KNOWN_FLAGS; + + return 0; +} + +int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *opt) +{ + struct tcp_sock *tp = tcp_sk(sk); + struct tcp_authopt_info *info; + + sock_owned_by_me(sk); + + 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; + + return 0; +} + +/* Free key nicely, for living sockets */ +static void tcp_authopt_key_del(struct sock *sk, + struct tcp_authopt_info *info, + struct tcp_authopt_key_info *key) +{ + sock_owned_by_me(sk); + hlist_del_rcu(&key->node); + atomic_sub(sizeof(*key), &sk->sk_omem_alloc); + kfree_rcu(key, rcu); +} + +/* Free info and keys. + * Don't touch tp->authopt_info, it might not even be assigned yes. + */ +void tcp_authopt_free(struct sock *sk, struct tcp_authopt_info *info) +{ + struct hlist_node *n; + struct tcp_authopt_key_info *key; + + hlist_for_each_entry_safe(key, n, &info->head, node) { + /* sk is NULL for timewait case + * struct timewait_sock doesn't track sk_omem_alloc + */ + if (sk) + atomic_sub(sizeof(*key), &sk->sk_omem_alloc); + hlist_del_rcu(&key->node); + kfree_rcu(key, rcu); + } + kfree_rcu(info, rcu); +} + +/* free everything and clear tcp_sock.authopt_info to NULL */ +void tcp_authopt_clear(struct sock *sk) +{ + struct tcp_authopt_info *info; + + info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + if (info) { + tcp_authopt_free(sk, info); + tcp_sk(sk)->authopt_info = NULL; + } +} + +#define TCP_AUTHOPT_KEY_KNOWN_FLAGS ( \ + TCP_AUTHOPT_KEY_DEL | \ + TCP_AUTHOPT_KEY_EXCLUDE_OPTS | \ + TCP_AUTHOPT_KEY_ADDR_BIND) + +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; + + sock_owned_by_me(sk); + + err = _copy_from_sockptr_tolerant((u8*)&opt, sizeof(opt), optval, optlen); + if (err) + return err; + + if (opt.flags & ~TCP_AUTHOPT_KEY_KNOWN_FLAGS) + return -EINVAL; + + if (opt.keylen > TCP_AUTHOPT_MAXKEYLEN) + return -EINVAL; + + /* Delete is a special case: */ + if (opt.flags & TCP_AUTHOPT_KEY_DEL) { + info = rcu_dereference_check(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + if (!info) + return -ENOENT; + key_info = tcp_authopt_key_lookup_exact(sk, info, &opt); + if (!key_info) + return -ENOENT; + tcp_authopt_key_del(sk, info, key_info); + return 0; + } + + /* check key family */ + if (opt.flags & TCP_AUTHOPT_KEY_ADDR_BIND) { + if (sk->sk_family != opt.addr.ss_family) + 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); + + 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. + */ + if ((old_key_info = tcp_authopt_key_lookup_exact(sk, info, &opt))) + tcp_authopt_key_del(sk, info, old_key_info); + key_info->flags = opt.flags & TCP_AUTHOPT_KEY_KNOWN_FLAGS; + key_info->send_id = opt.send_id; + key_info->recv_id = opt.recv_id; + key_info->alg_id = opt.alg; + key_info->keylen = opt.keylen; + memcpy(key_info->key, opt.key, opt.keylen); + memcpy(&key_info->addr, &opt.addr, sizeof(key_info->addr)); + hlist_add_head_rcu(&key_info->node, &info->head); + + return 0; +} diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 2e62e0d6373a..1348615c7576 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -60,10 +60,11 @@

#include <net/net_namespace.h> #include <net/icmp.h> #include <net/inet_hashtables.h> #include <net/tcp.h> +#include <net/tcp_authopt.h> #include <net/transp_v6.h> #include <net/ipv6.h> #include <net/inet_common.h> #include <net/timewait_sock.h> #include <net/xfrm.h> @@ -2256,10 +2257,11 @@ void tcp_v4_destroy_sock(struct sock *sk) tcp_clear_md5_list(sk); kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu); tp->md5sig_info = NULL; } #endif + tcp_authopt_clear(sk);

/* Clean up a referenced TCP bind bucket. */ if (inet_csk(sk)->icsk_bind_hash) inet_put_port(sk);

This test suite is written as a standalone python3 package using dependencies such as scapy.

The run.sh script wrapper called from kselftest infrastructure uses "tox" to generate an isolated virtual environment just for running these tests. The run.sh wrapper can be called from anywhere and does not rely on kselftest infrastructure.

The python3 and tox packages be installed manually but not any other dependencies

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- tools/testing/selftests/tcp_authopt/Makefile | 5 +++ .../testing/selftests/tcp_authopt/README.rst | 15 +++++++ tools/testing/selftests/tcp_authopt/config | 6 +++ .../selftests/tcp_authopt/requirements.txt | 40 +++++++++++++++++++ tools/testing/selftests/tcp_authopt/run.sh | 15 +++++++ tools/testing/selftests/tcp_authopt/setup.cfg | 17 ++++++++ tools/testing/selftests/tcp_authopt/setup.py | 5 +++ .../tcp_authopt/tcp_authopt_test/__init__.py | 0 8 files changed, 103 insertions(+) create mode 100644 tools/testing/selftests/tcp_authopt/Makefile create mode 100644 tools/testing/selftests/tcp_authopt/README.rst create mode 100644 tools/testing/selftests/tcp_authopt/config create mode 100644 tools/testing/selftests/tcp_authopt/requirements.txt create mode 100755 tools/testing/selftests/tcp_authopt/run.sh create mode 100644 tools/testing/selftests/tcp_authopt/setup.cfg create mode 100644 tools/testing/selftests/tcp_authopt/setup.py create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/__init__.py

diff --git a/tools/testing/selftests/tcp_authopt/Makefile b/tools/testing/selftests/tcp_authopt/Makefile new file mode 100644 index 000000000000..391412071875 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +include ../lib.mk + +TEST_PROGS += ./run.sh +TEST_FILES := setup.py setup.cfg tcp_authopt_test diff --git a/tools/testing/selftests/tcp_authopt/README.rst b/tools/testing/selftests/tcp_authopt/README.rst new file mode 100644 index 000000000000..e9e4acc0a22a --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/README.rst @@ -0,0 +1,15 @@ +========================================= +Tests for linux TCP Authentication Option +========================================= + +Test suite is written in python3 using pytest and scapy. The test suite is +mostly self-contained as a python package. + +The recommended way to run this is the included `run.sh` script as root, this +will automatically create a virtual environment with the correct dependencies +using `tox`. + +An old separate version can be found here: https://github.com/cdleonard/tcp-authopt-test + +Integration with kselftest infrastructure is minimal: when in doubt just run +this separately. diff --git a/tools/testing/selftests/tcp_authopt/config b/tools/testing/selftests/tcp_authopt/config new file mode 100644 index 000000000000..0d4e5d47fa72 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/config @@ -0,0 +1,6 @@ +# RFC5925 TCP Authentication Option and all algorithms +CONFIG_TCP_AUTHOPT=y +CONFIG_CRYPTO_SHA1=M +CONFIG_CRYPTO_HMAC=M +CONFIG_CRYPTO_AES=M +CONFIG_CRYPTO_CMAC=M diff --git a/tools/testing/selftests/tcp_authopt/requirements.txt b/tools/testing/selftests/tcp_authopt/requirements.txt new file mode 100644 index 000000000000..e30c8d12cf2e --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/requirements.txt @@ -0,0 +1,40 @@ +# +# This file is autogenerated by pip-compile with python 3.8 +# To update, run: +# +# pip-compile +# +argparse==1.4.0 + # via nsenter +attrs==21.2.0 + # via pytest +cffi==1.14.6 + # via cryptography +contextlib2==21.6.0 + # via nsenter +cryptography==3.4.8 + # via tcp-authopt-test (setup.py) +iniconfig==1.1.1 + # via pytest +nsenter==0.2 + # via tcp-authopt-test (setup.py) +packaging==21.0 + # via pytest +pathlib==1.0.1 + # via nsenter +pluggy==0.13.1 + # via pytest +py==1.10.0 + # via pytest +pycparser==2.20 + # via cffi +pyparsing==2.4.7 + # via packaging +pytest==6.2.4 + # via tcp-authopt-test (setup.py) +scapy==2.4.5 + # via tcp-authopt-test (setup.py) +toml==0.10.2 + # via pytest +waiting==1.4.1 + # via tcp-authopt-test (setup.py) diff --git a/tools/testing/selftests/tcp_authopt/run.sh b/tools/testing/selftests/tcp_authopt/run.sh new file mode 100755 index 000000000000..b3448d678aa2 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/run.sh @@ -0,0 +1,15 @@ +#! /bin/bash +# +# Create virtualenv using tox and run pytest +# Accepts all args that pytest does +# + +if ! command -v tox >/dev/null; then + echo >&2 "error: please install the python tox package" + exit 1 +fi +if [[ $(id -u) -ne 0 ]]; then + echo >&2 "warning: running as non-root user is unlikely to work" +fi +cd "$(dirname "${BASH_SOURCE[0]}")" +exec tox -- -s --log-cli-level=DEBUG "$@" diff --git a/tools/testing/selftests/tcp_authopt/setup.cfg b/tools/testing/selftests/tcp_authopt/setup.cfg new file mode 100644 index 000000000000..258dfffab9a3 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/setup.cfg @@ -0,0 +1,17 @@ +[options] +install_requires= + cryptography + nsenter + pytest + scapy + waiting + +[tox:tox] +envlist = py3 + +[testenv] +commands = pytest {posargs} + +[metadata] +name = tcp-authopt-test +version = 0.1 diff --git a/tools/testing/selftests/tcp_authopt/setup.py b/tools/testing/selftests/tcp_authopt/setup.py new file mode 100644 index 000000000000..d5e50aa1ca5e --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/setup.py @@ -0,0 +1,5 @@ +#! /usr/bin/env python3 + +from setuptools import setup + +setup() diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/__init__.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/__init__.py new file mode 100644 index 000000000000..e69de29bb2d1

The crypto_shash API is used in order to compute packet signatures. The API comes with several unfortunate limitations:

1) Allocating a crypto_shash can sleep and must be done in user context. 2) Packet signatures must be computed in softirq context 3) Packet signatures use dynamic "traffic keys" which require exclusive access to crypto_shash for crypto_setkey.

The solution is to allocate one crypto_shash for each possible cpu for each algorithm at setsockopt time. The per-cpu tfm is then borrowed from softirq context, signatures are computed and the tfm is returned.

The pool for each algorithm is allocated on first use.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/net/tcp_authopt.h | 15 ++++ net/ipv4/tcp_authopt.c | 167 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 182 insertions(+)

diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index 19d304de18f8..f6d7d6fa50c0 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -2,10 +2,24 @@ #ifndef _LINUX_TCP_AUTHOPT_H #define _LINUX_TCP_AUTHOPT_H

#include <uapi/linux/tcp.h>

+/* According to RFC5925 the length of the authentication option varies based on + * the signature algorithm. Linux only implements the algorithms defined in + * RFC5926 which have a constant length of 16. + * + * This is used in stack allocation of tcp option buffers for output. It is + * shorter than the length of the MD5 option. + * + * Input packets can have authentication options of different lengths but they + * will always be flagged as invalid (since no such algorithms are supported). + */ +#define TCPOLEN_AUTHOPT_OUTPUT 16 + +struct tcp_authopt_alg_imp; + /** * struct tcp_authopt_key_info - Representation of a Master Key Tuple as per RFC5925 * * Key structure lifetime is only protected by RCU so readers needs to hold a * single rcu_read_lock until they're done with the key. @@ -18,10 +32,11 @@ struct tcp_authopt_key_info { u8 send_id, recv_id; u8 alg_id; u8 keylen; u8 key[TCP_AUTHOPT_MAXKEYLEN]; struct sockaddr_storage addr; + struct tcp_authopt_alg_imp *alg; };

/** * struct tcp_authopt_info - Per-socket information regarding tcp_authopt * diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index a771e5754c8a..a682f88509aa 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -3,10 +3,164 @@ #include <linux/kernel.h> #include <net/tcp.h> #include <net/tcp_authopt.h> #include <crypto/hash.h>

+/* All current algorithms have a mac length of 12 but crypto API digestsize can be larger */ +#define TCP_AUTHOPT_MAXMACBUF 20 +#define TCP_AUTHOPT_MAX_TRAFFIC_KEY_LEN 20 +#define TCP_AUTHOPT_MACLEN 12 + +/* Constant data with per-algorithm information from RFC5926 + * The "KDF" and "MAC" happen to be the same for both algorithms. + */ +struct tcp_authopt_alg_imp { + /* Name of algorithm in crypto-api */ + const char *alg_name; + /* One of the TCP_AUTHOPT_ALG_* constants from uapi */ + u8 alg_id; + /* Length of traffic key */ + u8 traffic_key_len; + + /* shared crypto_shash */ + struct mutex init_mutex; + bool init_done; + struct crypto_shash * __percpu *tfms; +}; + +static struct tcp_authopt_alg_imp tcp_authopt_alg_list[] = { + { + .alg_id = TCP_AUTHOPT_ALG_HMAC_SHA_1_96, + .alg_name = "hmac(sha1)", + .traffic_key_len = 20, + .init_mutex = __MUTEX_INITIALIZER(tcp_authopt_alg_list[0].init_mutex), + }, + { + .alg_id = TCP_AUTHOPT_ALG_AES_128_CMAC_96, + .alg_name = "cmac(aes)", + .traffic_key_len = 16, + .init_mutex = __MUTEX_INITIALIZER(tcp_authopt_alg_list[1].init_mutex), + }, +}; + +/* get a pointer to the tcp_authopt_alg instance or NULL if id invalid */ +static inline struct tcp_authopt_alg_imp *tcp_authopt_alg_get(int alg_num) +{ + if (alg_num <= 0 || alg_num > 2) + return NULL; + return &tcp_authopt_alg_list[alg_num - 1]; +} + +static void __tcp_authopt_alg_free(struct tcp_authopt_alg_imp *alg) +{ + int cpu; + struct crypto_shash *tfm; + + if (!alg->tfms) + return; + for_each_possible_cpu(cpu) { + tfm = *per_cpu_ptr(alg->tfms, cpu); + if (tfm) { + crypto_free_shash(tfm); + *per_cpu_ptr(alg->tfms, cpu) = NULL; + } + } + free_percpu(alg->tfms); + alg->tfms = NULL; +} + +static int __tcp_authopt_alg_init(struct tcp_authopt_alg_imp *alg) +{ + struct crypto_shash *tfm; + int cpu; + int err; + + BUILD_BUG_ON(TCP_AUTHOPT_MAXMACBUF < TCPOLEN_AUTHOPT_OUTPUT); + if (WARN_ON_ONCE(alg->traffic_key_len > TCP_AUTHOPT_MAX_TRAFFIC_KEY_LEN)) + return -ENOBUFS; + + alg->tfms = alloc_percpu(struct crypto_shash*); + if (!alg->tfms) + return -ENOMEM; + for_each_possible_cpu(cpu) { + tfm = crypto_alloc_shash(alg->alg_name, 0, 0); + if (IS_ERR(tfm)) { + err = PTR_ERR(tfm); + goto out_err; + } + + /* sanity checks: */ + if (WARN_ON_ONCE(crypto_shash_digestsize(tfm) != alg->traffic_key_len)) { + err = -EINVAL; + goto out_err; + } + if (WARN_ON_ONCE(crypto_shash_digestsize(tfm) > TCP_AUTHOPT_MAXMACBUF)) { + err = -EINVAL; + goto out_err; + } + + *per_cpu_ptr(alg->tfms, cpu) = tfm; + } + return 0; + +out_err: + __tcp_authopt_alg_free(alg); + return err; +} + +static int tcp_authopt_alg_require(struct tcp_authopt_alg_imp *alg) +{ + int err = 0; + + mutex_lock(&alg->init_mutex); + if (alg->init_done) + goto out; + err = __tcp_authopt_alg_init(alg); + if (err) + goto out; + pr_info("initialized tcp-ao algorithm %s", alg->alg_name); + alg->init_done = true; + +out: + mutex_unlock(&alg->init_mutex); + return err; +} + +static struct crypto_shash *tcp_authopt_alg_get_tfm(struct tcp_authopt_alg_imp *alg) +{ + preempt_disable(); + return *this_cpu_ptr(alg->tfms); +} + +static void tcp_authopt_alg_put_tfm(struct tcp_authopt_alg_imp *alg, struct crypto_shash *tfm) +{ + WARN_ON(tfm != *this_cpu_ptr(alg->tfms)); + preempt_enable(); +} + +static struct crypto_shash *tcp_authopt_get_kdf_shash(struct tcp_authopt_key_info *key) +{ + return tcp_authopt_alg_get_tfm(key->alg); +} + +static void tcp_authopt_put_kdf_shash(struct tcp_authopt_key_info *key, + struct crypto_shash *tfm) +{ + return tcp_authopt_alg_put_tfm(key->alg, tfm); +} + +static struct crypto_shash *tcp_authopt_get_mac_shash(struct tcp_authopt_key_info *key) +{ + return tcp_authopt_alg_get_tfm(key->alg); +} + +static void tcp_authopt_put_mac_shash(struct tcp_authopt_key_info *key, + struct crypto_shash *tfm) +{ + return tcp_authopt_alg_put_tfm(key->alg, tfm); +} + /* checks that ipv4 or ipv6 addr matches. */ static bool ipvx_addr_match(struct sockaddr_storage *a1, struct sockaddr_storage *a2) { if (a1->ss_family != a2->ss_family) @@ -201,10 +355,12 @@ void tcp_authopt_clear(struct sock *sk) 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 err;

sock_owned_by_me(sk);

err = _copy_from_sockptr_tolerant((u8*)&opt, sizeof(opt), optval, optlen); if (err) @@ -237,10 +393,20 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) /* Initialize tcp_authopt_info if not already set */ info = __tcp_authopt_info_get_or_create(sk); if (IS_ERR(info)) return PTR_ERR(info);

+ /* check the algorithm */ + alg = tcp_authopt_alg_get(opt.alg); + if (!alg) + return -EINVAL; + if (WARN_ON_ONCE(alg->alg_id != opt.alg)) + return -EINVAL; + err = tcp_authopt_alg_require(alg); + if (err) + return err; + 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. @@ -249,10 +415,11 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) tcp_authopt_key_del(sk, info, old_key_info); key_info->flags = opt.flags & TCP_AUTHOPT_KEY_KNOWN_FLAGS; key_info->send_id = opt.send_id; key_info->recv_id = opt.recv_id; 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)); hlist_add_head_rcu(&key_info->node, &info->head);

The tcp_authopt features exposes a minimal interface to the rest of the TCP stack. Only a few functions are exposed and if the feature is disabled they return neutral values, avoiding ifdefs in the rest of the code.

Add calls into tcp authopt from send, receive and accept code.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/net/tcp_authopt.h | 103 +++++++++++++++ include/uapi/linux/snmp.h | 1 + net/ipv4/proc.c | 1 + net/ipv4/tcp_authopt.c | 263 ++++++++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 17 +++ net/ipv4/tcp_ipv4.c | 20 ++- net/ipv4/tcp_minisocks.c | 12 ++ net/ipv4/tcp_output.c | 80 +++++++++++- net/ipv6/tcp_ipv6.c | 21 ++- 9 files changed, 512 insertions(+), 6 deletions(-)

diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index f6d7d6fa50c0..263f98c3a1a8 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -51,28 +51,131 @@ struct tcp_authopt_info { u32 src_isn; u32 dst_isn; };

#ifdef CONFIG_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); int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *key); int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen); +struct tcp_authopt_key_info *__tcp_authopt_select_key( + const struct sock *sk, + struct tcp_authopt_info *info, + const struct sock *addr_sk, + u8 *rnextkeyid); +static inline struct tcp_authopt_key_info *tcp_authopt_select_key( + const struct sock *sk, + const struct sock *addr_sk, + u8 *rnextkeyid) +{ + if (static_branch_unlikely(&tcp_authopt_needed)) { + struct tcp_authopt_info *info = rcu_dereference(tcp_sk(sk)->authopt_info); + + if (info) + return __tcp_authopt_select_key(sk, info, addr_sk, rnextkeyid); + } + return NULL; +} +int tcp_authopt_hash( + char *hash_location, + struct tcp_authopt_key_info *key, + struct sock *sk, struct sk_buff *skb); +int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct request_sock *req); +static inline int tcp_authopt_openreq( + struct sock *newsk, + const struct sock *oldsk, + struct request_sock *req) +{ + if (!rcu_dereference(tcp_sk(oldsk)->authopt_info)) + return 0; + else + return __tcp_authopt_openreq(newsk, oldsk, req); +} +static inline void tcp_authopt_time_wait( + struct tcp_timewait_sock *tcptw, + struct tcp_sock *tp) +{ + if (static_branch_unlikely(&tcp_authopt_needed)) { + /* Transfer ownership of authopt_info to the twsk + * This requires no other users of the origin sock. + */ + sock_owned_by_me((struct sock *)tp); + tcptw->tw_authopt_info = tp->authopt_info; + tp->authopt_info = NULL; + } else { + tcptw->tw_authopt_info = NULL; + } +} +int __tcp_authopt_inbound_check( + struct sock *sk, + struct sk_buff *skb, + struct tcp_authopt_info *info); +/** tcp_authopt_inbound_check - check for valid TCP-AO signature. + * + * Return negative ERRNO on error, 0 if not present and 1 if present and valid + * If both TCP-AO and MD5 signatures are found this is reported as an error. + */ +static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb) +{ + if (static_branch_unlikely(&tcp_authopt_needed)) { + struct tcp_authopt_info *info = rcu_dereference(tcp_sk(sk)->authopt_info); + + if (info) + return __tcp_authopt_inbound_check(sk, skb, info); + } + + return 0; +} #else static inline int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen) { return -ENOPROTOOPT; } static inline int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *key) { return -ENOPROTOOPT; } +static inline void tcp_authopt_free(struct sock *sk, struct tcp_authopt_info *info) +{ +} static inline void tcp_authopt_clear(struct sock *sk) { } static inline int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) { return -ENOPROTOOPT; } +static inline struct tcp_authopt_key_info *tcp_authopt_select_key( + const struct sock *sk, + const struct sock *addr_sk, + u8 *rnextkeyid) +{ + return NULL; +} +static inline int tcp_authopt_hash( + char *hash_location, + struct tcp_authopt_key_info *key, + struct sock *sk, struct sk_buff *skb) +{ + return -EINVAL; +} +static inline int tcp_authopt_openreq(struct sock *newsk, + const struct sock *oldsk, + struct request_sock *req) +{ + return 0; +} +static inline void tcp_authopt_time_wait( + struct tcp_timewait_sock *tcptw, + struct tcp_sock *tp); +{ +} +static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb) +{ + return 0; +} #endif

#endif /* _LINUX_TCP_AUTHOPT_H */ diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h index 904909d020e2..1d96030889a1 100644 --- a/include/uapi/linux/snmp.h +++ b/include/uapi/linux/snmp.h @@ -290,10 +290,11 @@ enum LINUX_MIB_TCPDUPLICATEDATAREHASH, /* TCPDuplicateDataRehash */ LINUX_MIB_TCPDSACKRECVSEGS, /* TCPDSACKRecvSegs */ LINUX_MIB_TCPDSACKIGNOREDDUBIOUS, /* TCPDSACKIgnoredDubious */ LINUX_MIB_TCPMIGRATEREQSUCCESS, /* TCPMigrateReqSuccess */ LINUX_MIB_TCPMIGRATEREQFAILURE, /* TCPMigrateReqFailure */ + LINUX_MIB_TCPAUTHOPTFAILURE, /* TCPAuthOptFailure */ __LINUX_MIB_MAX };

/* linux Xfrm mib definitions */ enum diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index b0d3a09dc84e..61dd06f8389c 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -295,10 +295,11 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TcpDuplicateDataRehash", LINUX_MIB_TCPDUPLICATEDATAREHASH), SNMP_MIB_ITEM("TCPDSACKRecvSegs", LINUX_MIB_TCPDSACKRECVSEGS), SNMP_MIB_ITEM("TCPDSACKIgnoredDubious", LINUX_MIB_TCPDSACKIGNOREDDUBIOUS), SNMP_MIB_ITEM("TCPMigrateReqSuccess", LINUX_MIB_TCPMIGRATEREQSUCCESS), SNMP_MIB_ITEM("TCPMigrateReqFailure", LINUX_MIB_TCPMIGRATEREQFAILURE), + SNMP_MIB_ITEM("TCPAuthOptFailure", LINUX_MIB_TCPAUTHOPTFAILURE), SNMP_MIB_SENTINEL };

static void icmpmsg_put_line(struct seq_file *seq, unsigned long *vals, unsigned short *type, int count) diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index e2fd851b687b..0c32b8fb1d41 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 enabled when first struct tcp_authopt_info is allocated and never released */ +DEFINE_STATIC_KEY_FALSE(tcp_authopt_needed); +/* only for CONFIG_IPV6=m */ +EXPORT_SYMBOL(tcp_authopt_needed); + /* All current algorithms have a mac length of 12 but crypto API digestsize can be larger */ #define TCP_AUTHOPT_MAXMACBUF 20 #define TCP_AUTHOPT_MAX_TRAFFIC_KEY_LEN 20 #define TCP_AUTHOPT_MACLEN 12

@@ -190,10 +195,57 @@ static bool tcp_authopt_key_match_exact(struct tcp_authopt_key_info *info, return false;

return true; }

+static bool tcp_authopt_key_match_skb_addr( + struct tcp_authopt_key_info *key, + struct sk_buff *skb) +{ + 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; + + return iph->saddr == 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); + } else { + /* This actually happens with ipv6-mapped-ipv4-addresses + * IPv6 listen sockets will be asked to validate ipv4 packets. + */ + return false; + } +} + +static bool tcp_authopt_key_match_sk_addr( + struct tcp_authopt_key_info *key, + const struct sock *addr_sk) +{ + u16 keyaf = key->addr.ss_family; + + /* This probably can't happen even with ipv4-mapped-ipv6 */ + if (keyaf != addr_sk->sk_family) + return false; + + if (keyaf == AF_INET) { + struct sockaddr_in *key_addr = (struct sockaddr_in *)&key->addr; + + return addr_sk->sk_daddr == 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 false; +} + static struct tcp_authopt_key_info *tcp_authopt_key_lookup_exact(const struct sock *sk, struct tcp_authopt_info *info, struct tcp_authopt_key *ukey) { struct tcp_authopt_key_info *key_info; @@ -203,10 +255,49 @@ static struct tcp_authopt_key_info *tcp_authopt_key_lookup_exact(const struct so return key_info;

return NULL; }

+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; + + 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; + } + + return result; +} + +/** + * tcp_authopt_select_key - select key for sending + * + * addr_sk is the sock used for comparing daddr, it is only different from sk in + * the synack case. + * + * Result is protected by RCU and can't be stored, it may only be passed to + * tcp_authopt_hash and only under a single rcu_read_lock. + */ +struct tcp_authopt_key_info *__tcp_authopt_select_key( + const struct sock *sk, + struct tcp_authopt_info *info, + const struct sock *addr_sk, + u8 *rnextkeyid) +{ + return tcp_authopt_lookup_send(info, addr_sk, -1); +} + static struct tcp_authopt_info *__tcp_authopt_info_get_or_create(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); struct tcp_authopt_info *info;

@@ -216,10 +307,12 @@ static struct tcp_authopt_info *__tcp_authopt_info_get_or_create(struct sock *sk

info = kzalloc(sizeof(*info), GFP_KERNEL); if (!info) return ERR_PTR(-ENOMEM);

+ /* Never released: */ + static_branch_inc(&tcp_authopt_needed); sk_nocaps_add(sk, NETIF_F_GSO_MASK); INIT_HLIST_HEAD(&info->head); rcu_assign_pointer(tp->authopt_info, info);

return info; @@ -506,10 +599,65 @@ static int tcp_authopt_get_isn(struct sock *sk, } else { *sisn = htonl(authopt_info->src_isn); *disn = htonl(authopt_info->dst_isn); } rcu_read_unlock(); + + return 0; +} + +static int tcp_authopt_clone_keys(struct sock *newsk, + const struct sock *oldsk, + struct tcp_authopt_info *new_info, + struct tcp_authopt_info *old_info) +{ + struct tcp_authopt_key_info *old_key; + struct tcp_authopt_key_info *new_key; + + hlist_for_each_entry_rcu(old_key, &old_info->head, node, lockdep_sock_is_held(oldsk)) { + new_key = sock_kmalloc(newsk, sizeof(*new_key), GFP_ATOMIC); + if (!new_key) + return -ENOMEM; + memcpy(new_key, old_key, sizeof(*new_key)); + hlist_add_head_rcu(&new_key->node, &new_info->head); + } + + return 0; +} + +/** Called to create accepted sockets. + * + * Need to copy authopt info from listen socket. + */ +int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct request_sock *req) +{ + struct tcp_authopt_info *old_info; + struct tcp_authopt_info *new_info; + int err; + + old_info = rcu_dereference(tcp_sk(oldsk)->authopt_info); + if (!old_info) + return 0; + + /* Clear value copies from oldsk: */ + rcu_assign_pointer(tcp_sk(newsk)->authopt_info, NULL); + + new_info = kzalloc(sizeof(*new_info), GFP_ATOMIC); + if (!new_info) + return -ENOMEM; + + new_info->src_isn = tcp_rsk(req)->snt_isn; + new_info->dst_isn = tcp_rsk(req)->rcv_isn; + INIT_HLIST_HEAD(&new_info->head); + err = tcp_authopt_clone_keys(newsk, oldsk, new_info, old_info); + if (err) { + tcp_authopt_free(newsk, new_info); + return err; + } + sk_nocaps_add(newsk, NETIF_F_GSO_MASK); + rcu_assign_pointer(tcp_sk(newsk)->authopt_info, new_info); + return 0; }

/* feed traffic key into shash */ static int tcp_authopt_shash_traffic_key(struct shash_desc *desc, @@ -933,5 +1081,120 @@ static int __tcp_authopt_calc_mac(struct sock *sk,

out: tcp_authopt_put_mac_shash(key, mac_tfm); return err; } + +/** + * tcp_authopt_hash - fill in the mac + * + * The key must come from tcp_authopt_select_key. + */ +int tcp_authopt_hash(char *hash_location, + struct tcp_authopt_key_info *key, + struct sock *sk, + struct sk_buff *skb) +{ + /* MAC inside option is truncated to 12 bytes but crypto API needs output + * buffer to be large enough so we use a buffer on the stack. + */ + u8 macbuf[TCP_AUTHOPT_MAXMACBUF]; + int err; + + err = __tcp_authopt_calc_mac(sk, skb, key, false, macbuf); + if (err) { + /* If mac calculation fails and caller doesn't handle the error + * try to make it obvious inside the packet. + */ + memset(hash_location, 0, TCP_AUTHOPT_MACLEN); + return err; + } + memcpy(hash_location, macbuf, TCP_AUTHOPT_MACLEN); + + return 0; +} + +static struct tcp_authopt_key_info *tcp_authopt_lookup_recv(struct sock *sk, + struct sk_buff *skb, + struct tcp_authopt_info *info, + int recv_id) +{ + struct tcp_authopt_key_info *result = NULL; + struct tcp_authopt_key_info *key; + + /* 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; + } + + return result; +} + +int __tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb, struct tcp_authopt_info *info) +{ + struct tcphdr *th = (struct tcphdr *)skb_transport_header(skb); + struct tcphdr_authopt *opt; + struct tcp_authopt_key_info *key; + u8 macbuf[TCP_AUTHOPT_MAXMACBUF]; + int err; + + opt = (struct tcphdr_authopt *)tcp_authopt_find_option(th); + /* RFC5925 2.2: An endpoint MUST NOT use TCP-AO for the same connection + * in which TCP MD5 is used. When both options appear, TCP MUST silently + * discard the segment. + */ + if (tcp_parse_md5sig_option(th)) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + return -EINVAL; + } + key = tcp_authopt_lookup_recv(sk, skb, info, opt ? opt->keyid : -1); + + /* nothing found or expected */ + if (!opt && !key) + return 0; + if (!opt && key) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + net_info_ratelimited("TCP Authentication Missing\n"); + return -EINVAL; + } + if (opt && !key) { + /* RFC5925 Section 7.3: + * A TCP-AO implementation MUST allow for configuration of the behavior + * of segments with TCP-AO but that do not match an MKT. The initial + * default of this configuration SHOULD be to silently accept such + * connections. + */ + if (info->flags & TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + net_info_ratelimited("TCP Authentication Unexpected: Rejected\n"); + return -EINVAL; + } else { + net_info_ratelimited("TCP Authentication Unexpected: Accepted\n"); + return 0; + } + } + + /* bad inbound key len */ + if (TCPOLEN_AUTHOPT_OUTPUT != opt->len) + return -EINVAL; + + err = __tcp_authopt_calc_mac(sk, skb, key, true, macbuf); + if (err) + return err; + + if (memcmp(macbuf, opt->mac, TCP_AUTHOPT_MACLEN)) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + net_info_ratelimited("TCP Authentication Failed\n"); + return -EINVAL; + } + + return 1; +} +/* only for CONFIG_IPV6=m */ +EXPORT_SYMBOL(__tcp_authopt_inbound_check); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 141e85e6422b..7691eac93051 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -70,10 +70,11 @@ #include <linux/sysctl.h> #include <linux/kernel.h> #include <linux/prefetch.h> #include <net/dst.h> #include <net/tcp.h> +#include <net/tcp_authopt.h> #include <net/inet_common.h> #include <linux/ipsec.h> #include <asm/unaligned.h> #include <linux/errqueue.h> #include <trace/events/tcp.h> @@ -5967,18 +5968,34 @@ void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb) if (!icsk->icsk_ca_initialized) tcp_init_congestion_control(sk); tcp_init_buffer_space(sk); }

+static void tcp_authopt_finish_connect(struct sock *sk, struct sk_buff *skb) +{ +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_info *info; + + info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk)); + if (!info) + return; + + info->src_isn = ntohl(tcp_hdr(skb)->ack_seq) - 1; + info->dst_isn = ntohl(tcp_hdr(skb)->seq); +#endif +} + void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) { struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk);

tcp_set_state(sk, TCP_ESTABLISHED); icsk->icsk_ack.lrcvtime = tcp_jiffies32;

+ tcp_authopt_finish_connect(sk, skb); + if (skb) { icsk->icsk_af_ops->sk_rx_dst_set(sk, skb); security_inet_conn_established(sk, skb); sk_mark_napi_id(sk, skb); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 1348615c7576..e5c790795662 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1933,10 +1933,26 @@ static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph, TCP_SKB_CB(skb)->sacked = 0; TCP_SKB_CB(skb)->has_rxtstamp = skb->tstamp || skb_hwtstamps(skb)->hwtstamp; }

+static int tcp_v4_auth_inbound_check( + struct sock *sk, + struct sk_buff *skb, + int dif, int sdif) +{ + int aoret; + + aoret = tcp_authopt_inbound_check(sk, skb); + if (aoret < 0) + return aoret; + if (aoret > 0) + return 0; + + return tcp_v4_inbound_md5_hash(sk, skb, dif, sdif); +} + /* * From tcp_input.c */

int tcp_v4_rcv(struct sk_buff *skb) @@ -1991,11 +2007,11 @@ int tcp_v4_rcv(struct sk_buff *skb) struct request_sock *req = inet_reqsk(sk); bool req_stolen = false; struct sock *nsk;

sk = req->rsk_listener; - if (unlikely(tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))) { + if (unlikely(tcp_v4_auth_inbound_check(sk, skb, dif, sdif))) { sk_drops_add(sk, skb); reqsk_put(req); goto discard_it; } if (tcp_checksum_complete(skb)) { @@ -2057,11 +2073,11 @@ int tcp_v4_rcv(struct sk_buff *skb) }

if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse;

- if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif)) + if (tcp_v4_auth_inbound_check(sk, skb, dif, sdif)) goto discard_and_relse;

nf_reset_ct(skb);

if (tcp_filter(sk, skb)) diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index cf913a66df17..d4828cf3d6d1 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -18,10 +18,11 @@ * Arnt Gulbrandsen, agulbra@nvg.unit.no * Jorge Cwik, jorge@laser.satlink.net */

#include <net/tcp.h> +#include <net/tcp_authopt.h> #include <net/xfrm.h> #include <net/busy_poll.h>

static bool tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win) { @@ -300,10 +301,11 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) BUG_ON(tcptw->tw_md5_key && !tcp_alloc_md5sig_pool()); } } } while (0); #endif + tcp_authopt_time_wait(tcptw, tcp_sk(sk));

/* Get the TIME_WAIT timeout firing. */ if (timeo < rto) timeo = rto;

@@ -342,10 +344,19 @@ void tcp_twsk_destructor(struct sock *sk)

if (twsk->tw_md5_key) kfree_rcu(twsk->tw_md5_key, rcu); } #endif +#ifdef CONFIG_TCP_AUTHOPT + if (static_branch_unlikely(&tcp_authopt_needed)) { + struct tcp_timewait_sock *twsk = tcp_twsk(sk); + + /* twsk only contains sock_common so pass NULL as sk. */ + if (twsk->tw_authopt_info) + tcp_authopt_free(NULL, twsk->tw_authopt_info); + } +#endif } EXPORT_SYMBOL_GPL(tcp_twsk_destructor);

/* Warning : This function is called without sk_listener being locked. * Be sure to read socket fields once, as their value could change under us. @@ -532,10 +543,11 @@ struct sock *tcp_create_openreq_child(const struct sock *sk, #ifdef CONFIG_TCP_MD5SIG newtp->md5sig_info = NULL; /*XXX*/ if (newtp->af_specific->md5_lookup(sk, newsk)) newtp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED; #endif + tcp_authopt_openreq(newsk, sk, req); if (skb->len >= TCP_MSS_DEFAULT + newtp->tcp_header_len) newicsk->icsk_ack.last_seg_size = skb->len - newtp->tcp_header_len; newtp->rx_opt.mss_clamp = req->mss; tcp_ecn_openreq_child(newtp, req); newtp->fastopen_req = NULL; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 6d72f3ea48c4..fe5be506edb2 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -37,10 +37,11 @@

#define pr_fmt(fmt) "TCP: " fmt

#include <net/tcp.h> #include <net/mptcp.h> +#include <net/tcp_authopt.h>

#include <linux/compiler.h> #include <linux/gfp.h> #include <linux/module.h> #include <linux/static_key.h> @@ -411,10 +412,11 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp)

#define OPTION_SACK_ADVERTISE (1 << 0) #define OPTION_TS (1 << 1) #define OPTION_MD5 (1 << 2) #define OPTION_WSCALE (1 << 3) +#define OPTION_AUTHOPT (1 << 4) #define OPTION_FAST_OPEN_COOKIE (1 << 8) #define OPTION_SMC (1 << 9) #define OPTION_MPTCP (1 << 10)

static void smc_options_write(__be32 *ptr, u16 *options) @@ -435,16 +437,21 @@ static void smc_options_write(__be32 *ptr, u16 *options) struct tcp_out_options { u16 options; /* bit field of OPTION_* */ u16 mss; /* 0 to disable */ u8 ws; /* window scale, 0 to disable */ u8 num_sack_blocks; /* number of SACK blocks to include */ - u8 hash_size; /* bytes in hash_location */ u8 bpf_opt_len; /* length of BPF hdr option */ +#ifdef CONFIG_TCP_AUTHOPT + u8 authopt_rnextkeyid; /* rnextkey */ +#endif __u8 *hash_location; /* temporary pointer, overloaded */ __u32 tsval, tsecr; /* need to include OPTION_TS */ struct tcp_fastopen_cookie *fastopen_cookie; /* Fast open cookie */ struct mptcp_out_options mptcp; +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_key_info *authopt_key; +#endif };

static void mptcp_options_write(__be32 *ptr, const struct tcp_sock *tp, struct tcp_out_options *opts) { @@ -617,10 +624,25 @@ static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp, /* overload cookie hash location */ opts->hash_location = (__u8 *)ptr; ptr += 4; }

+#ifdef CONFIG_TCP_AUTHOPT + if (unlikely(OPTION_AUTHOPT & options)) { + struct tcp_authopt_key_info *key = opts->authopt_key; + + WARN_ON(!key); + *ptr = htonl((TCPOPT_AUTHOPT << 24) | + (TCPOLEN_AUTHOPT_OUTPUT << 16) | + (key->send_id << 8) | + opts->authopt_rnextkeyid); + /* overload cookie hash location */ + opts->hash_location = (__u8 *)(ptr + 1); + ptr += TCPOLEN_AUTHOPT_OUTPUT / 4; + } +#endif + if (unlikely(opts->mss)) { *ptr++ = htonl((TCPOPT_MSS << 24) | (TCPOLEN_MSS << 16) | opts->mss); } @@ -752,10 +774,28 @@ static void mptcp_set_option_cond(const struct request_sock *req, } } } }

+static int tcp_authopt_init_options(const struct sock *sk, + const struct sock *addr_sk, + struct tcp_out_options *opts) +{ +#ifdef CONFIG_TCP_AUTHOPT + struct tcp_authopt_key_info *key; + + key = tcp_authopt_select_key(sk, addr_sk, &opts->authopt_rnextkeyid); + if (key) { + opts->options |= OPTION_AUTHOPT; + opts->authopt_key = key; + return TCPOLEN_AUTHOPT_OUTPUT; + } +#endif + + return 0; +} + /* Compute TCP options for SYN packets. This is not the final * network wire format yet. */ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, struct tcp_out_options *opts, @@ -764,12 +804,15 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, struct tcp_sock *tp = tcp_sk(sk); unsigned int remaining = MAX_TCP_OPTION_SPACE; struct tcp_fastopen_request *fastopen = tp->fastopen_req;

*md5 = NULL; + + remaining -= tcp_authopt_init_options(sk, sk, opts); #ifdef CONFIG_TCP_MD5SIG if (static_branch_unlikely(&tcp_md5_needed) && + !(opts->options & OPTION_AUTHOPT) && rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { opts->options |= OPTION_MD5; remaining -= TCPOLEN_MD5SIG_ALIGNED; @@ -848,12 +891,13 @@ static unsigned int tcp_synack_options(const struct sock *sk, struct sk_buff *syn_skb) { struct inet_request_sock *ireq = inet_rsk(req); unsigned int remaining = MAX_TCP_OPTION_SPACE;

+ remaining -= tcp_authopt_init_options(sk, req_to_sk(req), opts); #ifdef CONFIG_TCP_MD5SIG - if (md5) { + if (md5 && !(opts->options & OPTION_AUTHOPT)) { opts->options |= OPTION_MD5; remaining -= TCPOLEN_MD5SIG_ALIGNED;

/* We can't fit any SACK blocks in a packet with MD5 + TS * options. There was discussion about disabling SACK @@ -919,13 +963,15 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb unsigned int size = 0; unsigned int eff_sacks;

opts->options = 0;

+ size += tcp_authopt_init_options(sk, sk, opts); *md5 = NULL; #ifdef CONFIG_TCP_MD5SIG if (static_branch_unlikely(&tcp_md5_needed) && + !(opts->options & OPTION_AUTHOPT) && rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { opts->options |= OPTION_MD5; size += TCPOLEN_MD5SIG_ALIGNED; @@ -1277,10 +1323,14 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,

inet = inet_sk(sk); tcb = TCP_SKB_CB(skb); memset(&opts, 0, sizeof(opts));

+#ifdef CONFIG_TCP_AUTHOPT + /* for tcp_authopt_init_options inside tcp_syn_options or tcp_established_options */ + rcu_read_lock(); +#endif if (unlikely(tcb->tcp_flags & TCPHDR_SYN)) { tcp_options_size = tcp_syn_options(sk, skb, &opts, &md5); } else { tcp_options_size = tcp_established_options(sk, skb, &opts, &md5); @@ -1365,10 +1415,17 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, sk_nocaps_add(sk, NETIF_F_GSO_MASK); tp->af_specific->calc_md5_hash(opts.hash_location, md5, sk, skb); } #endif +#ifdef CONFIG_TCP_AUTHOPT + if (opts.authopt_key) { + sk_nocaps_add(sk, NETIF_F_GSO_MASK); + tcp_authopt_hash(opts.hash_location, opts.authopt_key, sk, skb); + } + rcu_read_unlock(); +#endif

/* BPF prog is the last one writing header option */ bpf_skops_write_hdr_opt(sk, skb, NULL, NULL, 0, &opts);

INDIRECT_CALL_INET(icsk->icsk_af_ops->send_check, @@ -1836,12 +1893,21 @@ unsigned int tcp_current_mss(struct sock *sk) u32 mtu = dst_mtu(dst); if (mtu != inet_csk(sk)->icsk_pmtu_cookie) mss_now = tcp_sync_mss(sk, mtu); }

+#ifdef CONFIG_TCP_AUTHOPT + /* Even if the result is not used rcu_read_lock is required when scanning for + * tcp authentication keys. Otherwise lockdep will complain. + */ + rcu_read_lock(); +#endif header_len = tcp_established_options(sk, NULL, &opts, &md5) + sizeof(struct tcphdr); +#ifdef CONFIG_TCP_AUTHOPT + rcu_read_unlock(); +#endif /* The mss_cache is sized based on tp->tcp_header_len, which assumes * some common options. If this is an odd packet (because we have SACK * blocks etc) then our calculated header_len will be different, and * we have to adjust mss_now correspondingly */ if (header_len != tp->tcp_header_len) { @@ -3566,10 +3632,14 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, }

#ifdef CONFIG_TCP_MD5SIG rcu_read_lock(); md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, req_to_sk(req)); +#endif +#ifdef CONFIG_TCP_AUTHOPT + /* for tcp_authopt_init_options inside tcp_synack_options */ + rcu_read_lock(); #endif skb_set_hash(skb, tcp_rsk(req)->txhash, PKT_HASH_TYPE_L4); /* bpf program will be interested in the tcp_flags */ TCP_SKB_CB(skb)->tcp_flags = TCPHDR_SYN | TCPHDR_ACK; tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, md5, @@ -3603,10 +3673,16 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, if (md5) tcp_rsk(req)->af_specific->calc_md5_hash(opts.hash_location, md5, req_to_sk(req), skb); rcu_read_unlock(); #endif +#ifdef CONFIG_TCP_AUTHOPT + /* If signature fails we do nothing */ + if (opts.authopt_key) + tcp_authopt_hash(opts.hash_location, opts.authopt_key, req_to_sk(req), skb); + rcu_read_unlock(); +#endif

bpf_skops_write_hdr_opt((struct sock *)sk, skb, req, syn_skb, synack_type, &opts);

skb->skb_mstamp_ns = now; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 0ce52d46e4f8..724145ddf122 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -40,10 +40,11 @@ #include <linux/icmpv6.h> #include <linux/random.h> #include <linux/indirect_call_wrapper.h>

#include <net/tcp.h> +#include <net/tcp_authopt.h> #include <net/ndisc.h> #include <net/inet6_hashtables.h> #include <net/inet6_connection_sock.h> #include <net/ipv6.h> #include <net/transp_v6.h> @@ -1614,10 +1615,26 @@ static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr, TCP_SKB_CB(skb)->sacked = 0; TCP_SKB_CB(skb)->has_rxtstamp = skb->tstamp || skb_hwtstamps(skb)->hwtstamp; }

+static int tcp_v6_auth_inbound_check( + struct sock *sk, + struct sk_buff *skb, + int dif, int sdif) +{ + int aoret; + + aoret = tcp_authopt_inbound_check(sk, skb); + if (aoret < 0) + return aoret; + if (aoret > 0) + return 0; + + return tcp_v6_inbound_md5_hash(sk, skb, dif, sdif); +} + INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) { struct sk_buff *skb_to_free; int sdif = inet6_sdif(skb); int dif = inet6_iif(skb); @@ -1667,11 +1684,11 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) struct request_sock *req = inet_reqsk(sk); bool req_stolen = false; struct sock *nsk;

sk = req->rsk_listener; - if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif)) { + if (tcp_v6_auth_inbound_check(sk, skb, dif, sdif)) { sk_drops_add(sk, skb); reqsk_put(req); goto discard_it; } if (tcp_checksum_complete(skb)) { @@ -1730,11 +1747,11 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) }

if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) goto discard_and_relse;

- if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif)) + if (tcp_v6_auth_inbound_check(sk, skb, dif, sdif)) goto discard_and_relse;

if (tcp_filter(sk, skb)) goto discard_and_relse; th = (const struct tcphdr *)skb->data;

By default TCP-AO keys apply to all possible peers but it's possible to have different keys for different remote hosts.

This patch adds initial tests for the behavior behind the TCP_AUTHOPT_KEY_BIND_ADDR flag. Server rejection is tested via client timeout so this can be slightly slow.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- .../tcp_authopt_test/netns_fixture.py | 83 ++++++++++ .../tcp_authopt/tcp_authopt_test/server.py | 95 ++++++++++++ .../tcp_authopt/tcp_authopt_test/test_bind.py | 145 ++++++++++++++++++ .../tcp_authopt/tcp_authopt_test/utils.py | 102 ++++++++++++ 4 files changed, 425 insertions(+) create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/netns_fixture.py create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/server.py create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_bind.py create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/utils.py

diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/netns_fixture.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/netns_fixture.py new file mode 100644 index 000000000000..ca80f424dafd --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/netns_fixture.py @@ -0,0 +1,83 @@ +# SPDX-License-Identifier: GPL-2.0 +import subprocess +import socket +from ipaddress import IPv4Address +from ipaddress import IPv6Address + + +class NamespaceFixture: + """Create a pair of namespaces connected by one veth pair + + Each end of the pair has multiple addresses but everything is in the same subnet + """ + + server_netns_name = "tcp_authopt_test_server" + client_netns_name = "tcp_authopt_test_client" + + @classmethod + def get_ipv4_addr(cls, ns=1, index=1) -> IPv4Address: + return IPv4Address("10.10.0.0") + (ns << 8) + index + + @classmethod + def get_ipv6_addr(cls, ns=1, index=1) -> IPv6Address: + return IPv6Address("fd00::") + (ns << 16) + index + + @classmethod + def get_addr(cls, address_family=socket.AF_INET, ns=1, index=1): + if address_family == socket.AF_INET: + return cls.get_ipv4_addr(ns, index) + elif address_family == socket.AF_INET6: + return cls.get_ipv6_addr(ns, index) + else: + raise ValueError(f"Bad address_family={address_family}") + + # 02:* means "locally administered" + server_mac_addr = "02:00:00:00:00:01" + client_mac_addr = "02:00:00:00:00:02" + + ipv4_prefix_len = 16 + ipv6_prefix_len = 64 + + @classmethod + def get_prefix_length(cls, address_family) -> int: + return { + socket.AF_INET: cls.ipv4_prefix_len, + socket.AF_INET6: cls.ipv6_prefix_len, + }[address_family] + + def __init__(self, **kw): + for k, v in kw.items(): + setattr(self, k, v) + + def __enter__(self): + self._del_netns() + script = f""" +set -e +ip netns add {self.server_netns_name} +ip netns add {self.client_netns_name} +ip link add veth0 netns {self.server_netns_name} type veth peer name veth0 netns {self.client_netns_name} +ip netns exec {self.server_netns_name} ip link set veth0 up addr {self.server_mac_addr} +ip netns exec {self.client_netns_name} ip link set veth0 up addr {self.client_mac_addr} +""" + for index in [1, 2, 3]: + script += f"ip -n {self.server_netns_name} addr add {self.get_ipv4_addr(1, index)}/16 dev veth0\n" + script += f"ip -n {self.client_netns_name} addr add {self.get_ipv4_addr(2, index)}/16 dev veth0\n" + script += f"ip -n {self.server_netns_name} addr add {self.get_ipv6_addr(1, index)}/64 dev veth0 nodad\n" + script += f"ip -n {self.client_netns_name} addr add {self.get_ipv6_addr(2, index)}/64 dev veth0 nodad\n" + subprocess.run(script, shell=True, check=True) + return self + + def _del_netns(self): + script = f"""\ +set -e +if ip netns list | grep -q {self.server_netns_name}; then + ip netns del {self.server_netns_name} +fi +if ip netns list | grep -q {self.client_netns_name}; then + ip netns del {self.client_netns_name} +fi +""" + subprocess.run(script, shell=True, check=True) + + def __exit__(self, *a): + self._del_netns() diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/server.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/server.py new file mode 100644 index 000000000000..35e717fcf5f6 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/server.py @@ -0,0 +1,95 @@ +# SPDX-License-Identifier: GPL-2.0 +import logging +import os +import selectors +from contextlib import ExitStack +from threading import Thread + +logger = logging.getLogger(__name__) + + +class SimpleServerThread(Thread): + """Simple server thread for testing TCP sockets + + All data is read in 1000 bytes chunks and either echoed back or discarded. + + :ivar keep_half_open: do not close in response to remote close. + """ + + DEFAULT_BUFSIZE = 1000 + + def __init__(self, socket, mode="recv", bufsize=DEFAULT_BUFSIZE, keep_half_open=False): + self.listen_socket = socket + self.server_socket = [] + self.bufsize = bufsize + self.keep_half_open = keep_half_open + self.mode = mode + super().__init__() + + def _read(self, conn, events): + # logger.debug("events=%r", events) + try: + data = conn.recv(self.bufsize) + except ConnectionResetError: + # logger.info("reset %r", conn) + conn.close() + self.sel.unregister(conn) + return + # logger.debug("len(data)=%r", len(data)) + if len(data) == 0: + if not self.keep_half_open: + # logger.info("closing %r", conn) + conn.close() + self.sel.unregister(conn) + else: + if self.mode == "echo": + conn.sendall(data) + elif self.mode == "recv": + pass + else: + raise ValueError(f"Unknown mode {self.mode}") + + def _stop_pipe_read(self, conn, events): + self.should_loop = False + + def start(self) -> None: + self.exit_stack = ExitStack() + self._stop_pipe_rfd, self._stop_pipe_wfd = os.pipe() + self.exit_stack.callback(lambda: os.close(self._stop_pipe_rfd)) + self.exit_stack.callback(lambda: os.close(self._stop_pipe_wfd)) + return super().start() + + def _accept(self, conn, events): + assert conn == self.listen_socket + conn, _addr = self.listen_socket.accept() + conn = self.exit_stack.enter_context(conn) + conn.setblocking(False) + self.sel.register(conn, selectors.EVENT_READ, self._read) + self.server_socket.append(conn) + + def run(self): + self.should_loop = True + self.sel = self.exit_stack.enter_context(selectors.DefaultSelector()) + self.sel.register( + self._stop_pipe_rfd, selectors.EVENT_READ, self._stop_pipe_read + ) + self.sel.register(self.listen_socket, selectors.EVENT_READ, self._accept) + # logger.debug("loop init") + while self.should_loop: + for key, events in self.sel.select(timeout=1): + callback = key.data + callback(key.fileobj, events) + # logger.debug("loop done") + + def stop(self): + """Try to stop nicely""" + os.write(self._stop_pipe_wfd, b"Q") + self.join() + self.exit_stack.close() + + def __enter__(self): + self.start() + return self + + def __exit__(self, *args): + self.stop() diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_bind.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_bind.py new file mode 100644 index 000000000000..ecbaadcd6be8 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_bind.py @@ -0,0 +1,145 @@ +# SPDX-License-Identifier: GPL-2.0 +"""Test TCP-AO keys can be bound to specific remote addresses""" +from contextlib import ExitStack +import socket +import pytest +from .netns_fixture import NamespaceFixture +from .utils import create_listen_socket +from .server import SimpleServerThread +from .linux_tcp_authopt import ( + tcp_authopt, + TCP_AUTHOPT_FLAG, + TCP_AUTHOPT_KEY_FLAG, + TCP_AUTHOPT_ALG, + set_tcp_authopt, + set_tcp_authopt_key, + tcp_authopt_key, +) +from .utils import netns_context, DEFAULT_TCP_SERVER_PORT, check_socket_echo +from .conftest import skipif_missing_tcp_authopt + +pytestmark = skipif_missing_tcp_authopt + + +@pytest.mark.parametrize("address_family", [socket.AF_INET, socket.AF_INET6]) +def test_addr_server_bind(exit_stack: ExitStack, address_family): + """ "Server only accept client2, check client1 fails""" + nsfixture = exit_stack.enter_context(NamespaceFixture()) + server_addr = str(nsfixture.get_addr(address_family, 1, 1)) + client_addr = str(nsfixture.get_addr(address_family, 2, 1)) + client_addr2 = str(nsfixture.get_addr(address_family, 2, 2)) + + # create server: + listen_socket = exit_stack.push( + create_listen_socket(family=address_family, ns=nsfixture.server_netns_name) + ) + exit_stack.enter_context(SimpleServerThread(listen_socket, mode="echo")) + + # set keys: + server_key = tcp_authopt_key( + alg=TCP_AUTHOPT_ALG.HMAC_SHA_1_96, + key="hello", + flags=TCP_AUTHOPT_KEY_FLAG.BIND_ADDR, + addr=client_addr2, + ) + set_tcp_authopt( + listen_socket, + tcp_authopt(flags=TCP_AUTHOPT_FLAG.REJECT_UNEXPECTED), + ) + set_tcp_authopt_key(listen_socket, server_key) + + # create client socket: + def create_client_socket(): + with netns_context(nsfixture.client_netns_name): + client_socket = socket.socket(address_family, socket.SOCK_STREAM) + client_key = tcp_authopt_key( + alg=TCP_AUTHOPT_ALG.HMAC_SHA_1_96, + key="hello", + ) + set_tcp_authopt_key(client_socket, client_key) + return client_socket + + # addr match: + # with create_client_socket() as client_socket2: + # client_socket2.bind((client_addr2, 0)) + # client_socket2.settimeout(1.0) + # client_socket2.connect((server_addr, TCP_SERVER_PORT)) + + # addr mismatch: + with create_client_socket() as client_socket1: + client_socket1.bind((client_addr, 0)) + with pytest.raises(socket.timeout): + client_socket1.settimeout(1.0) + client_socket1.connect((server_addr, DEFAULT_TCP_SERVER_PORT)) + + +@pytest.mark.parametrize("address_family", [socket.AF_INET, socket.AF_INET6]) +def test_addr_client_bind(exit_stack: ExitStack, address_family): + """Client configures different keys with same id but different addresses""" + nsfixture = exit_stack.enter_context(NamespaceFixture()) + server_addr1 = str(nsfixture.get_addr(address_family, 1, 1)) + server_addr2 = str(nsfixture.get_addr(address_family, 1, 2)) + client_addr = str(nsfixture.get_addr(address_family, 2, 1)) + + # create servers: + listen_socket1 = exit_stack.enter_context( + create_listen_socket( + family=address_family, ns=nsfixture.server_netns_name, bind_addr=server_addr1 + ) + ) + listen_socket2 = exit_stack.enter_context( + create_listen_socket( + family=address_family, ns=nsfixture.server_netns_name, bind_addr=server_addr2 + ) + ) + exit_stack.enter_context(SimpleServerThread(listen_socket1, mode="echo")) + exit_stack.enter_context(SimpleServerThread(listen_socket2, mode="echo")) + + # set keys: + set_tcp_authopt_key( + listen_socket1, + tcp_authopt_key( + alg=TCP_AUTHOPT_ALG.HMAC_SHA_1_96, + key="11111", + ), + ) + set_tcp_authopt_key( + listen_socket2, + tcp_authopt_key( + alg=TCP_AUTHOPT_ALG.HMAC_SHA_1_96, + key="22222", + ), + ) + + # create client socket: + def create_client_socket(): + with netns_context(nsfixture.client_netns_name): + client_socket = socket.socket(address_family, socket.SOCK_STREAM) + set_tcp_authopt_key( + client_socket, + tcp_authopt_key( + alg=TCP_AUTHOPT_ALG.HMAC_SHA_1_96, + key="11111", + flags=TCP_AUTHOPT_KEY_FLAG.BIND_ADDR, + addr=server_addr1, + ), + ) + set_tcp_authopt_key( + client_socket, + tcp_authopt_key( + alg=TCP_AUTHOPT_ALG.HMAC_SHA_1_96, + key="22222", + flags=TCP_AUTHOPT_KEY_FLAG.BIND_ADDR, + addr=server_addr2, + ), + ) + client_socket.settimeout(1.0) + client_socket.bind((client_addr, 0)) + return client_socket + + with create_client_socket() as client_socket1: + client_socket1.connect((server_addr1, DEFAULT_TCP_SERVER_PORT)) + check_socket_echo(client_socket1) + with create_client_socket() as client_socket2: + client_socket2.connect((server_addr2, DEFAULT_TCP_SERVER_PORT)) + check_socket_echo(client_socket2) diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/utils.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/utils.py new file mode 100644 index 000000000000..acbd7307f712 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/utils.py @@ -0,0 +1,102 @@ +# SPDX-License-Identifier: GPL-2.0 +import json +import random +import subprocess +import socket +from contextlib import nullcontext + +from nsenter import Namespace + +# TCP port does not impact Authentication Option so define a single default +DEFAULT_TCP_SERVER_PORT = 17971 + + +def recvall(sock, todo): + """Receive exactly todo bytes unless EOF""" + data = bytes() + while True: + chunk = sock.recv(todo) + if not len(chunk): + return data + data += chunk + todo -= len(chunk) + if todo == 0: + return data + assert todo > 0 + + +def randbytes(count) -> bytes: + """Return a random byte array""" + return bytes([random.randint(0, 255) for index in range(count)]) + + +def check_socket_echo(sock: socket.socket, size=1000): + """Send random bytes and check they are received + + The default size is equal to `SimpleServerThread.DEFAULT_BUFSIZE` which + means that a single pair of packets will be sent at the TCP level. + """ + send_buf = randbytes(size) + sock.sendall(send_buf) + recv_buf = recvall(sock, size) + assert send_buf == recv_buf + + +def nstat_json(command_prefix: str = ""): + """Parse nstat output into a python dict""" + runres = subprocess.run( + f"{command_prefix}nstat -a --zeros --json", + shell=True, + check=True, + stdout=subprocess.PIPE, + encoding="utf-8", + ) + return json.loads(runres.stdout)["kernel"] + + +def netns_context(ns: str = ""): + """Create context manager for a certain optional netns + + If the ns argument is empty then just return a `nullcontext` + """ + if ns: + return Namespace("/var/run/netns/" + ns, "net") + else: + return nullcontext() + + +def create_listen_socket( + ns: str = "", + family=socket.AF_INET, + reuseaddr=True, + listen_depth=10, + bind_addr="", + bind_port=DEFAULT_TCP_SERVER_PORT, +): + with netns_context(ns): + listen_socket = socket.socket(family, socket.SOCK_STREAM) + if reuseaddr: + listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) + listen_socket.bind((str(bind_addr), bind_port)) + listen_socket.listen(listen_depth) + return listen_socket + + +def create_client_socket( + ns: str = "", family=socket.AF_INET, bind_addr="", bind_port=0, timeout=1.0 +): + with netns_context(ns): + client_socket = socket.socket(family, socket.SOCK_STREAM) + if bind_addr or bind_port: + client_socket.bind((str(bind_addr), bind_port)) + if timeout is not None: + client_socket.settimeout(timeout) + return client_socket + + +def socket_set_linger(sock, onoff, value): + import struct + + sock.setsockopt( + socket.SOL_SOCKET, socket.SO_LINGER, struct.pack("ii", int(onoff), int(value)) + )

This is required because tcp ipv4 sometimes sends replies without allocating a full skb that can be signed by tcp authopt.

Handle this with additional code in tcp authopt.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/net/tcp_authopt.h | 7 ++ net/ipv4/tcp_authopt.c | 147 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 154 insertions(+)

diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index 422f0034d32b..b012eaaf416f 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -81,10 +81,17 @@ static inline struct tcp_authopt_key_info *tcp_authopt_select_key( } int tcp_authopt_hash( char *hash_location, struct tcp_authopt_key_info *key, struct sock *sk, struct sk_buff *skb); +int tcp_v4_authopt_hash_reply( + char *hash_location, + struct tcp_authopt_info *info, + struct tcp_authopt_key_info *key, + __be32 saddr, + __be32 daddr, + struct tcphdr *th); int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct request_sock *req); static inline int tcp_authopt_openreq( struct sock *newsk, const struct sock *oldsk, struct request_sock *req) diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index 41f844d5d49a..756182401a3b 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -798,10 +798,74 @@ static int tcp_authopt_get_traffic_key(struct sock *sk, out: tcp_authopt_put_kdf_shash(key, kdf_tfm); return err; }

+struct tcp_v4_authopt_context_data { + __be32 saddr; + __be32 daddr; + __be16 sport; + __be16 dport; + __be32 sisn; + __be32 disn; + __be16 digestbits; +} __packed; + +static int tcp_v4_authopt_get_traffic_key_noskb( + struct tcp_authopt_key_info *key, + __be32 saddr, + __be32 daddr, + __be16 sport, + __be16 dport, + __be32 sisn, + __be32 disn, + u8 *traffic_key) +{ + int err; + struct crypto_shash *kdf_tfm; + SHASH_DESC_ON_STACK(desc, kdf_tfm); + struct tcp_v4_authopt_context_data data; + BUILD_BUG_ON(sizeof(data) != 22); + + kdf_tfm = tcp_authopt_get_kdf_shash(key); + if (IS_ERR(kdf_tfm)) + return PTR_ERR(kdf_tfm); + + err = tcp_authopt_setkey(kdf_tfm, key); + if (err) + goto out; + + desc->tfm = kdf_tfm; + err = crypto_shash_init(desc); + if (err) + goto out; + + // RFC5926 section 3.1.1.1 + // Separate to keep alignment semi-sane + err = crypto_shash_update(desc, "\x01TCP-AO", 7); + if (err) + return err; + data.saddr = saddr; + data.daddr = daddr; + data.sport = sport; + data.dport = dport; + data.sisn = sisn; + data.disn = disn; + data.digestbits = htons(crypto_shash_digestsize(desc->tfm) * 8); + + err = crypto_shash_update(desc, (u8*)&data, sizeof(data)); + if (err) + goto out; + err = crypto_shash_final(desc, traffic_key); + if (err) + goto out; + +out: + tcp_authopt_put_kdf_shash(key, kdf_tfm); + return err; +} + static int crypto_shash_update_zero(struct shash_desc *desc, int len) { u8 zero = 0; int i, err;

@@ -1122,10 +1186,93 @@ int tcp_authopt_hash(char *hash_location, memcpy(hash_location, macbuf, TCP_AUTHOPT_MACLEN);

return 0; }

+/** + * tcp_v4_authopt_hash_hdr - Hash tcp+ipv4 header without SKB + * + * The key must come from tcp_authopt_select_key. + */ +int tcp_v4_authopt_hash_reply(char *hash_location, + struct tcp_authopt_info *info, + struct tcp_authopt_key_info *key, + __be32 saddr, + __be32 daddr, + struct tcphdr *th) +{ + struct crypto_shash *mac_tfm; + u8 macbuf[TCP_AUTHOPT_MAXMACBUF]; + u8 traffic_key[TCP_AUTHOPT_MAX_TRAFFIC_KEY_LEN]; + SHASH_DESC_ON_STACK(desc, tfm); + __be32 sne = 0; + int err; + + /* Call special code path for computing traffic key without skb + * This can be called from tcp_v4_reqsk_send_ack so caching would be + * difficult here. + */ + err = tcp_v4_authopt_get_traffic_key_noskb( + key, + saddr, + daddr, + th->source, + th->dest, + htonl(info->src_isn), + htonl(info->dst_isn), + traffic_key); + if (err) + goto out_err_traffic_key; + + /* Init mac shash */ + mac_tfm = tcp_authopt_get_mac_shash(key); + if (IS_ERR(mac_tfm)) + return PTR_ERR(mac_tfm); + err = crypto_shash_setkey(mac_tfm, traffic_key, key->alg->traffic_key_len); + if (err) + goto out_err; + + desc->tfm = mac_tfm; + err = crypto_shash_init(desc); + if (err) + return err; + + err = crypto_shash_update(desc, (u8 *)&sne, 4); + if (err) + return err; + + err = tcp_authopt_hash_tcp4_pseudoheader(desc, saddr, daddr, th->doff * 4); + if (err) + return err; + + // TCP header with checksum set to zero. Caller ensures this. + if (WARN_ON_ONCE(th->check != 0)) + goto out_err; + err = crypto_shash_update(desc, (u8 *)th, sizeof(*th)); + if (err) + goto out_err; + + // TCP options + err = tcp_authopt_hash_opts(desc, th, !(key->flags & TCP_AUTHOPT_KEY_EXCLUDE_OPTS)); + if (err) + goto out_err; + + err = crypto_shash_final(desc, macbuf); + if (err) + goto out_err; + memcpy(hash_location, macbuf, TCP_AUTHOPT_MACLEN); + + tcp_authopt_put_mac_shash(key, mac_tfm); + return 0; + +out_err: + tcp_authopt_put_mac_shash(key, mac_tfm); +out_err_traffic_key: + memset(hash_location, 0, TCP_AUTHOPT_MACLEN); + return err; +} + static struct tcp_authopt_key_info *tcp_authopt_lookup_recv(struct sock *sk, struct sk_buff *skb, struct tcp_authopt_info *info, int recv_id) {

Tools like tcpdump and wireshark can parse the TCP Authentication Option but there is not yet support to verify correct signatures.

This patch implements TCP-AO signature verification using scapy and the python cryptography package.

The python code is verified itself with a subset of IETF test vectors from this page: https://datatracker.ietf.org/doc/html/draft-touch-tcpm-ao-test-vectors-02

The code in this commit is not specific to linux

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- .../tcp_authopt_test/scapy_tcp_authopt.py | 211 ++++++++++ .../tcp_authopt_test/scapy_utils.py | 176 +++++++++ .../tcp_authopt_test/test_vectors.py | 359 ++++++++++++++++++ .../tcp_authopt/tcp_authopt_test/validator.py | 127 +++++++ 4 files changed, 873 insertions(+) create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_tcp_authopt.py create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_utils.py create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_vectors.py create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/validator.py

diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_tcp_authopt.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_tcp_authopt.py new file mode 100644 index 000000000000..c32f9d931d2b --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_tcp_authopt.py @@ -0,0 +1,211 @@ +# SPDX-License-Identifier: GPL-2.0 +"""Packet-processing utilities implementing RFC5925 and RFC2926""" + +import logging +from scapy.layers.inet import TCP +from scapy.packet import Packet +from .scapy_utils import TCPOPT_AUTHOPT, IPvXAddress, get_packet_ipvx_src, get_packet_ipvx_dst, get_tcp_pseudoheader, get_tcp_doff +import struct +import hmac + +logger = logging.getLogger(__name__) + + +def _cmac_aes_digest(key: bytes, msg: bytes) -> bytes: + from cryptography.hazmat.primitives import cmac + from cryptography.hazmat.primitives.ciphers import algorithms + from cryptography.hazmat.backends import default_backend + + backend = default_backend() + c = cmac.CMAC(algorithms.AES(key), backend=backend) + c.update(bytes(msg)) + return c.finalize() + + +class TcpAuthOptAlg: + @classmethod + def kdf(cls, master_key: bytes, context: bytes) -> bytes: + raise NotImplementedError() + + @classmethod + def mac(cls, traffic_key: bytes, message: bytes) -> bytes: + raise NotImplementedError() + + maclen = -1 + + +class TcpAuthOptAlg_HMAC_SHA1(TcpAuthOptAlg): + @classmethod + def kdf(cls, master_key: bytes, context: bytes) -> bytes: + input = b"\x01" + b"TCP-AO" + context + b"\x00\xa0" + return hmac.digest(master_key, input, "SHA1") + + @classmethod + def mac(cls, traffic_key: bytes, message: bytes) -> bytes: + return hmac.digest(traffic_key, message, "SHA1")[:12] + + maclen = 12 + + +class TcpAuthOptAlg_CMAC_AES(TcpAuthOptAlg): + @classmethod + def kdf(self, master_key: bytes, context: bytes) -> bytes: + if len(master_key) == 16: + key = master_key + else: + key = _cmac_aes_digest(b"\x00" * 16, master_key) + return _cmac_aes_digest(key, b"\x01" + b"TCP-AO" + context + b"\x00\x80") + + @classmethod + def mac(self, traffic_key: bytes, message: bytes) -> bytes: + return _cmac_aes_digest(traffic_key, message)[:12] + + maclen = 12 + + +def get_alg(name: str) -> TcpAuthOptAlg: + if name.upper() == "HMAC-SHA-1-96": + return TcpAuthOptAlg_HMAC_SHA1() + elif name.upper() == "AES-128-CMAC-96": + return TcpAuthOptAlg_CMAC_AES() + else: + raise ValueError(f"Bad TCP AuthOpt algorithms {name}") + + +def build_context( + saddr: IPvXAddress, daddr: IPvXAddress, sport, dport, src_isn, dst_isn +) -> bytes: + """Build context bytes as specified by RFC5925 section 5.2""" + return ( + saddr.packed + + daddr.packed + + struct.pack( + "!HHII", + sport, + dport, + src_isn, + dst_isn, + ) + ) + + +def build_context_from_packet(p: Packet, src_isn: int, dst_isn: int) -> bytes: + """Build context based on a scapy Packet and src/dst initial-sequence numbers""" + return build_context( + get_packet_ipvx_src(p), + get_packet_ipvx_dst(p), + p[TCP].sport, + p[TCP].dport, + src_isn, + dst_isn, + ) + + +def build_message_from_packet(p: Packet, include_options=True, sne=0) -> bytearray: + """Build message bytes as described by RFC5925 section 5.1""" + result = bytearray() + result += struct.pack("!I", sne) + th = p[TCP] + + # ip pseudo-header: + result += get_tcp_pseudoheader(th) + + # tcp header with checksum set to zero + th_bytes = bytes(p[TCP]) + result += th_bytes[:16] + result += b"\x00\x00" + result += th_bytes[18:20] + + # Even if include_options=False the TCP-AO option itself is still included + # with the MAC set to all-zeros. This means we need to parse TCP options. + pos = 20 + tcphdr_optend = get_tcp_doff(th) * 4 + # logger.info("th_bytes: %s", th_bytes.hex(' ')) + assert len(th_bytes) >= tcphdr_optend + while pos < tcphdr_optend: + optnum = th_bytes[pos] + pos += 1 + if optnum == 0 or optnum == 1: + if include_options: + result += bytes([optnum]) + continue + + optlen = th_bytes[pos] + pos += 1 + if pos + optlen - 2 > tcphdr_optend: + logger.info( + "bad tcp option %d optlen %d beyond end-of-header", optnum, optlen + ) + break + if optlen < 2: + logger.info("bad tcp option %d optlen %d less than two", optnum, optlen) + break + if optnum == TCPOPT_AUTHOPT: + if optlen < 4: + logger.info("bad tcp option %d optlen %d", optnum, optlen) + break + result += bytes([optnum, optlen]) + result += th_bytes[pos : pos + 2] + result += (optlen - 4) * b"\x00" + elif include_options: + result += bytes([optnum, optlen]) + result += th_bytes[pos : pos + optlen - 2] + pos += optlen - 2 + result += bytes(p[TCP].payload) + return result + + +def check_tcp_authopt_signature( + p: Packet, alg: TcpAuthOptAlg, master_key, sisn, disn, include_options=True, sne=0 +): + from .scapy_utils import scapy_tcp_get_authopt_val + + ao = scapy_tcp_get_authopt_val(p[TCP]) + if ao is None: + return None + + context_bytes = build_context_from_packet(p, sisn, disn) + traffic_key = alg.kdf(master_key, context_bytes) + message_bytes = build_message_from_packet( + p, include_options=include_options, sne=sne + ) + mac = alg.mac(traffic_key, message_bytes) + return mac == ao.mac + + +def add_tcp_authopt_signature( + p: Packet, + alg: TcpAuthOptAlg, + master_key, + sisn, + disn, + keyid=0, + rnextkeyid=0, + include_options=True, + sne=0, +): + """Sign a packet""" + th = p[TCP] + keyids = struct.pack("BB", keyid, rnextkeyid) + th.options = th.options + [(TCPOPT_AUTHOPT, keyids + alg.maclen * b"\x00")] + + context_bytes = build_context_from_packet(p, sisn, disn) + traffic_key = alg.kdf(master_key, context_bytes) + message_bytes = build_message_from_packet( + p, include_options=include_options, sne=sne + ) + mac = alg.mac(traffic_key, message_bytes) + th.options[-1] = (TCPOPT_AUTHOPT, keyids + mac) + + +def break_tcp_authopt_signature(packet: Packet): + """Invalidate TCP-AO signature inside a packet + + The packet must already be signed and it gets modified in-place. + """ + opt = packet[TCP].options[-1] + if opt[0] != TCPOPT_AUTHOPT: + raise ValueError("TCP option list must end with TCP_AUTHOPT") + opt_mac = bytearray(opt[1]) + opt_mac[-1] ^= 0xFF + packet[TCP].options[-1] = (opt[0], bytes(opt_mac)) diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_utils.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_utils.py new file mode 100644 index 000000000000..5000b8fe9ada --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/scapy_utils.py @@ -0,0 +1,176 @@ +import typing +import struct +import socket +import threading +from dataclasses import dataclass +from ipaddress import IPv4Address, IPv6Address + +from scapy.packet import Packet +from scapy.layers.inet import IP, TCP +from scapy.layers.inet6 import IPv6 +from scapy.config import conf as scapy_conf +from scapy.sendrecv import AsyncSniffer + +from .utils import netns_context + +# TCPOPT numbers are apparently not available in scapy +TCPOPT_MD5SIG = 19 +TCPOPT_AUTHOPT = 29 + +# Easy generic handling of IPv4/IPv6Address +IPvXAddress = typing.Union[IPv4Address, IPv6Address] + + +def get_packet_ipvx_src(p: Packet) -> IPvXAddress: + if IP in p: + return IPv4Address(p[IP].src) + elif IPv6 in p: + return IPv6Address(p[IPv6].src) + else: + raise Exception("Neither IP nor IPv6 found on packet") + + +def get_packet_ipvx_dst(p: Packet) -> IPvXAddress: + if IP in p: + return IPv4Address(p[IP].dst) + elif IPv6 in p: + return IPv6Address(p[IPv6].dst) + else: + raise Exception("Neither IP nor IPv6 found on packet") + + +def get_tcp_doff(th: TCP): + """Get the TCP data offset, even if packet is not yet built""" + doff = th.dataofs + if doff is None: + opt_len = len(th.get_field("options").i2m(th, th.options)) + doff = 5 + ((opt_len + 3) // 4) + return doff + + +def get_tcp_v4_pseudoheader(tcp_packet: TCP) -> bytes: + iph = tcp_packet.underlayer + return struct.pack( + "!4s4sHH", + IPv4Address(iph.src).packed, + IPv4Address(iph.dst).packed, + socket.IPPROTO_TCP, + get_tcp_doff(tcp_packet) * 4 + len(tcp_packet.payload), + ) + + +def get_tcp_v6_pseudoheader(tcp_packet: TCP) -> bytes: + ipv6 = tcp_packet.underlayer + return struct.pack( + "!16s16sII", + IPv6Address(ipv6.src).packed, + IPv6Address(ipv6.dst).packed, + get_tcp_doff(tcp_packet) * 4 + len(tcp_packet.payload), + socket.IPPROTO_TCP, + ) + + +def get_tcp_pseudoheader(tcp_packet: TCP): + if isinstance(tcp_packet.underlayer, IP): + return get_tcp_v4_pseudoheader(tcp_packet) + if isinstance(tcp_packet.underlayer, IPv6): + return get_tcp_v6_pseudoheader(tcp_packet) + raise ValueError("TCP underlayer is neither IP nor IPv6") + + +def tcp_seq_wrap(seq): + return seq & 0xFFFFFFFF + + +@dataclass +class tcphdr_authopt: + """Representation of a TCP auth option as it appears in a TCP packet""" + + keyid: int + rnextkeyid: int + mac: bytes + + @classmethod + def unpack(cls, buf) -> "tcphdr_authopt": + return cls(buf[0], buf[1], buf[2:]) + + def __repr__(self): + return f"tcphdr_authopt({self.keyid}, {self.rnextkeyid}, bytes.fromhex({self.mac.hex(' ')!r})" + + +def scapy_tcp_get_authopt_val(tcp) -> typing.Optional[tcphdr_authopt]: + for optnum, optval in tcp.options: + if optnum == TCPOPT_AUTHOPT: + return tcphdr_authopt.unpack(optval) + return None + + +def scapy_tcp_get_md5_sig(tcp) -> typing.Optional[bytes]: + """Return the MD5 signature (as bytes) or None""" + for optnum, optval in tcp.options: + if optnum == TCPOPT_MD5SIG: + return optval + return None + + +def calc_tcp_md5_hash(p, key: bytes) -> bytes: + """Calculate TCP-MD5 hash from packet and return a 16-byte string""" + import hashlib + + h = hashlib.md5() + tp = p[TCP] + th_bytes = bytes(p[TCP]) + h.update(get_tcp_pseudoheader(tp)) + h.update(th_bytes[:16]) + h.update(b"\x00\x00") + h.update(th_bytes[18:20]) + h.update(bytes(tp.payload)) + h.update(key) + + return h.digest() + + +def create_l2socket(ns: str = "", **kw): + """Create a scapy L2socket inside a namespace""" + + with netns_context(ns): + return scapy_conf.L2socket(**kw) + + +def create_capture_socket(ns: str = "", **kw): + """Create a scapy L2listen socket inside a namespace""" + from scapy.config import conf as scapy_conf + + with netns_context(ns): + return scapy_conf.L2listen(**kw) + + +def scapy_sniffer_start_block(sniffer: AsyncSniffer, timeout=1): + """Like AsyncSniffer.start except block until sniffing starts + + This ensures no lost packets and no delays + """ + if sniffer.kwargs.get("started_callback"): + raise ValueError("sniffer must not already have a started_callback") + + e = threading.Event() + sniffer.kwargs["started_callback"] = e.set + sniffer.start() + e.wait(timeout=timeout) + if not e.is_set(): + raise TimeoutError("Timed out waiting for sniffer to start") + + +def scapy_sniffer_stop(sniffer: AsyncSniffer): + """Like AsyncSniffer.stop except no error is raising if not running""" + if sniffer is not None and sniffer.running: + sniffer.stop() + + +class AsyncSnifferContext(AsyncSniffer): + def __enter__(self): + scapy_sniffer_start_block(self) + return self + + def __exit__(self, *a): + scapy_sniffer_stop(self) diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_vectors.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_vectors.py new file mode 100644 index 000000000000..e918439ef9f4 --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_vectors.py @@ -0,0 +1,359 @@ +# SPDX-License-Identifier: GPL-2.0 +import logging +from ipaddress import IPv4Address, IPv6Address +from scapy.layers.inet import IP, TCP +from scapy.layers.inet6 import IPv6 +from .scapy_tcp_authopt import get_alg, build_context_from_packet, build_message_from_packet +from .scapy_utils import scapy_tcp_get_authopt_val +import socket + +logger = logging.getLogger(__name__) + + +class TestIETFVectors: + """Test python implementation of TCP-AO algorithms + + Data is a subset of IETF test vectors: + https://datatracker.ietf.org/doc/html/draft-touch-tcpm-ao-test-vectors-02 + """ + + master_key = b"testvector" + client_keyid = 61 + server_keyid = 84 + client_ipv4 = IPv4Address("10.11.12.13") + client_ipv6 = IPv6Address("FD00::1") + server_ipv4 = IPv4Address("172.27.28.29") + server_ipv6 = IPv6Address("FD00::2") + + client_isn_41x = 0xFBFBAB5A + server_isn_41x = 0x11C14261 + client_isn_42x = 0xCB0EFBEE + server_isn_42x = 0xACD5B5E1 + client_isn_61x = 0x176A833F + server_isn_61x = 0x3F51994B + client_isn_62x = 0x020C1E69 + server_isn_62x = 0xEBA3734D + + def check( + self, + packet_hex: str, + traffic_key_hex: str, + mac_hex: str, + src_isn, + dst_isn, + include_options=True, + alg_name="HMAC-SHA-1-96", + sne=0, + ): + packet_bytes = bytes.fromhex(packet_hex) + + # sanity check for ip version + ipv = packet_bytes[0] >> 4 + if ipv == 4: + p = IP(bytes.fromhex(packet_hex)) + assert p[IP].proto == socket.IPPROTO_TCP + elif ipv == 6: + p = IPv6(bytes.fromhex(packet_hex)) + assert p[IPv6].nh == socket.IPPROTO_TCP + else: + raise ValueError(f"bad ipv={ipv}") + + # sanity check for seq/ack in SYN/ACK packets + if p[TCP].flags.S and p[TCP].flags.A is False: + assert p[TCP].seq == src_isn + assert p[TCP].ack == 0 + if p[TCP].flags.S and p[TCP].flags.A: + assert p[TCP].seq == src_isn + assert p[TCP].ack == dst_isn + 1 + + # check traffic key + alg = get_alg(alg_name) + context_bytes = build_context_from_packet(p, src_isn, dst_isn) + traffic_key = alg.kdf(self.master_key, context_bytes) + assert traffic_key.hex(" ") == traffic_key_hex + + # check mac + message_bytes = build_message_from_packet( + p, include_options=include_options, sne=sne + ) + mac = alg.mac(traffic_key, message_bytes) + assert mac.hex(" ") == mac_hex + + # check option bytes in header + opt = scapy_tcp_get_authopt_val(p[TCP]) + assert opt is not None + assert opt.keyid in [self.client_keyid, self.server_keyid] + assert opt.rnextkeyid in [self.client_keyid, self.server_keyid] + assert opt.mac.hex(" ") == mac_hex + + def test_4_1_1(self): + self.check( + """ + 45 e0 00 4c dd 0f 40 00 ff 06 bf 6b 0a 0b 0c 0d + ac 1b 1c 1d e9 d7 00 b3 fb fb ab 5a 00 00 00 00 + e0 02 ff ff ca c4 00 00 02 04 05 b4 01 03 03 08 + 04 02 08 0a 00 15 5a b7 00 00 00 00 1d 10 3d 54 + 2e e4 37 c6 f8 ed e6 d7 c4 d6 02 e7 + """, + "6d 63 ef 1b 02 fe 15 09 d4 b1 40 27 07 fd 7b 04 16 ab b7 4f", + "2e e4 37 c6 f8 ed e6 d7 c4 d6 02 e7", + self.client_isn_41x, + 0, + ) + + def test_4_1_2(self): + self.check( + """ + 45 e0 00 4c 65 06 40 00 ff 06 37 75 ac 1b 1c 1d + 0a 0b 0c 0d 00 b3 e9 d7 11 c1 42 61 fb fb ab 5b + e0 12 ff ff 37 76 00 00 02 04 05 b4 01 03 03 08 + 04 02 08 0a 84 a5 0b eb 00 15 5a b7 1d 10 54 3d + ee ab 0f e2 4c 30 10 81 51 16 b3 be + """, + "d9 e2 17 e4 83 4a 80 ca 2f 3f d8 de 2e 41 b8 e6 79 7f ea 96", + "ee ab 0f e2 4c 30 10 81 51 16 b3 be", + self.server_isn_41x, + self.client_isn_41x, + ) + + def test_4_1_3(self): + self.check( + """ + 45 e0 00 87 36 a1 40 00 ff 06 65 9f 0a 0b 0c 0d + ac 1b 1c 1d e9 d7 00 b3 fb fb ab 5b 11 c1 42 62 + c0 18 01 04 a1 62 00 00 01 01 08 0a 00 15 5a c1 + 84 a5 0b eb 1d 10 3d 54 70 64 cf 99 8c c6 c3 15 + c2 c2 e2 bf ff ff ff ff ff ff ff ff ff ff ff ff + ff ff ff ff 00 43 01 04 da bf 00 b4 0a 0b 0c 0d + 26 02 06 01 04 00 01 00 01 02 02 80 00 02 02 02 + 00 02 02 42 00 02 06 41 04 00 00 da bf 02 08 40 + 06 00 64 00 01 01 00 + """, + "d2 e5 9c 65 ff c7 b1 a3 93 47 65 64 63 b7 0e dc 24 a1 3d 71", + "70 64 cf 99 8c c6 c3 15 c2 c2 e2 bf", + self.client_isn_41x, + self.server_isn_41x, + ) + + def test_4_1_4(self): + self.check( + """ + 45 e0 00 87 1f a9 40 00 ff 06 7c 97 ac 1b 1c 1d + 0a 0b 0c 0d 00 b3 e9 d7 11 c1 42 62 fb fb ab 9e + c0 18 01 00 40 0c 00 00 01 01 08 0a 84 a5 0b f5 + 00 15 5a c1 1d 10 54 3d a6 3f 0e cb bb 2e 63 5c + 95 4d ea c7 ff ff ff ff ff ff ff ff ff ff ff ff + ff ff ff ff 00 43 01 04 da c0 00 b4 ac 1b 1c 1d + 26 02 06 01 04 00 01 00 01 02 02 80 00 02 02 02 + 00 02 02 42 00 02 06 41 04 00 00 da c0 02 08 40 + 06 00 64 00 01 01 00 + """, + "d9 e2 17 e4 83 4a 80 ca 2f 3f d8 de 2e 41 b8 e6 79 7f ea 96", + "a6 3f 0e cb bb 2e 63 5c 95 4d ea c7", + self.server_isn_41x, + self.client_isn_41x, + ) + + def test_4_2_1(self): + self.check( + """ + 45 e0 00 4c 53 99 40 00 ff 06 48 e2 0a 0b 0c 0d + ac 1b 1c 1d ff 12 00 b3 cb 0e fb ee 00 00 00 00 + e0 02 ff ff 54 1f 00 00 02 04 05 b4 01 03 03 08 + 04 02 08 0a 00 02 4c ce 00 00 00 00 1d 10 3d 54 + 80 af 3c fe b8 53 68 93 7b 8f 9e c2 + """, + "30 ea a1 56 0c f0 be 57 da b5 c0 45 22 9f b1 0a 42 3c d7 ea", + "80 af 3c fe b8 53 68 93 7b 8f 9e c2", + self.client_isn_42x, + 0, + include_options=False, + ) + + def test_4_2_2(self): + self.check( + """ + 45 e0 00 4c 32 84 40 00 ff 06 69 f7 ac 1b 1c 1d + 0a 0b 0c 0d 00 b3 ff 12 ac d5 b5 e1 cb 0e fb ef + e0 12 ff ff 38 8e 00 00 02 04 05 b4 01 03 03 08 + 04 02 08 0a 57 67 72 f3 00 02 4c ce 1d 10 54 3d + 09 30 6f 9a ce a6 3a 8c 68 cb 9a 70 + """, + "b5 b2 89 6b b3 66 4e 81 76 b0 ed c6 e7 99 52 41 01 a8 30 7f", + "09 30 6f 9a ce a6 3a 8c 68 cb 9a 70", + self.server_isn_42x, + self.client_isn_42x, + include_options=False, + ) + + def test_4_2_3(self): + self.check( + """ + 45 e0 00 87 a8 f5 40 00 ff 06 f3 4a 0a 0b 0c 0d + ac 1b 1c 1d ff 12 00 b3 cb 0e fb ef ac d5 b5 e2 + c0 18 01 04 6c 45 00 00 01 01 08 0a 00 02 4c ce + 57 67 72 f3 1d 10 3d 54 71 06 08 cc 69 6c 03 a2 + 71 c9 3a a5 ff ff ff ff ff ff ff ff ff ff ff ff + ff ff ff ff 00 43 01 04 da bf 00 b4 0a 0b 0c 0d + 26 02 06 01 04 00 01 00 01 02 02 80 00 02 02 02 + 00 02 02 42 00 02 06 41 04 00 00 da bf 02 08 40 + 06 00 64 00 01 01 00 + """, + "f3 db 17 93 d7 91 0e cd 80 6c 34 f1 55 ea 1f 00 34 59 53 e3", + "71 06 08 cc 69 6c 03 a2 71 c9 3a a5", + self.client_isn_42x, + self.server_isn_42x, + include_options=False, + ) + + def test_4_2_4(self): + self.check( + """ + 45 e0 00 87 54 37 40 00 ff 06 48 09 ac 1b 1c 1d + 0a 0b 0c 0d 00 b3 ff 12 ac d5 b5 e2 cb 0e fc 32 + c0 18 01 00 46 b6 00 00 01 01 08 0a 57 67 72 f3 + 00 02 4c ce 1d 10 54 3d 97 76 6e 48 ac 26 2d e9 + ae 61 b4 f9 ff ff ff ff ff ff ff ff ff ff ff ff + ff ff ff ff 00 43 01 04 da c0 00 b4 ac 1b 1c 1d + 26 02 06 01 04 00 01 00 01 02 02 80 00 02 02 02 + 00 02 02 42 00 02 06 41 04 00 00 da c0 02 08 40 + 06 00 64 00 01 01 00 + """, + "b5 b2 89 6b b3 66 4e 81 76 b0 ed c6 e7 99 52 41 01 a8 30 7f", + "97 76 6e 48 ac 26 2d e9 ae 61 b4 f9", + self.server_isn_42x, + self.client_isn_42x, + include_options=False, + ) + + def test_5_1_1(self): + self.check( + """ + 45 e0 00 4c 7b 9f 40 00 ff 06 20 dc 0a 0b 0c 0d + ac 1b 1c 1d c4 fa 00 b3 78 7a 1d df 00 00 00 00 + e0 02 ff ff 5a 0f 00 00 02 04 05 b4 01 03 03 08 + 04 02 08 0a 00 01 7e d0 00 00 00 00 1d 10 3d 54 + e4 77 e9 9c 80 40 76 54 98 e5 50 91 + """, + "f5 b8 b3 d5 f3 4f db b6 eb 8d 4a b9 66 0e 60 e3", + "e4 77 e9 9c 80 40 76 54 98 e5 50 91", + 0x787A1DDF, + 0, + include_options=True, + alg_name="AES-128-CMAC-96", + ) + + def test_6_1_1(self): + self.check( + """ + 6e 08 91 dc 00 38 06 40 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 01 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 02 f7 e4 00 b3 17 6a 83 3f + 00 00 00 00 e0 02 ff ff 47 21 00 00 02 04 05 a0 + 01 03 03 08 04 02 08 0a 00 41 d0 87 00 00 00 00 + 1d 10 3d 54 90 33 ec 3d 73 34 b6 4c 5e dd 03 9f + """, + "62 5e c0 9d 57 58 36 ed c9 b6 42 84 18 bb f0 69 89 a3 61 bb", + "90 33 ec 3d 73 34 b6 4c 5e dd 03 9f", + self.client_isn_61x, + 0, + include_options=True, + ) + + def test_6_1_2(self): + self.check( + """ + 6e 01 00 9e 00 38 06 40 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 02 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 01 00 b3 f7 e4 3f 51 99 4b + 17 6a 83 40 e0 12 ff ff bf ec 00 00 02 04 05 a0 + 01 03 03 08 04 02 08 0a bd 33 12 9b 00 41 d0 87 + 1d 10 54 3d f1 cb a3 46 c3 52 61 63 f7 1f 1f 55 + """, + "e4 a3 7a da 2a 0a fc a8 71 14 34 91 3f e1 38 c7 71 eb cb 4a", + "f1 cb a3 46 c3 52 61 63 f7 1f 1f 55", + self.server_isn_61x, + self.client_isn_61x, + include_options=True, + ) + + def test_6_2_2(self): + self.check( + """ + 6e 0a 7e 1f 00 38 06 40 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 02 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 01 00 b3 c6 cd eb a3 73 4d + 02 0c 1e 6a e0 12 ff ff 77 4d 00 00 02 04 05 a0 + 01 03 03 08 04 02 08 0a 5e c9 9b 70 00 9d b9 5b + 1d 10 54 3d 3c 54 6b ad 97 43 f1 2d f8 b8 01 0d + """, + "40 51 08 94 7f 99 65 75 e7 bd bc 26 d4 02 16 a2 c7 fa 91 bd", + "3c 54 6b ad 97 43 f1 2d f8 b8 01 0d", + self.server_isn_62x, + self.client_isn_62x, + include_options=False, + ) + + def test_6_2_4(self): + self.check( + """ + 6e 0a 7e 1f 00 73 06 40 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 02 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 01 00 b3 c6 cd eb a3 73 4e + 02 0c 1e ad c0 18 01 00 71 6a 00 00 01 01 08 0a + 5e c9 9b 7a 00 9d b9 65 1d 10 54 3d 55 9a 81 94 + 45 b4 fd e9 8d 9e 13 17 ff ff ff ff ff ff ff ff + ff ff ff ff ff ff ff ff 00 43 01 04 fd e8 00 b4 + 01 01 01 7a 26 02 06 01 04 00 01 00 01 02 02 80 + 00 02 02 02 00 02 02 42 00 02 06 41 04 00 00 fd + e8 02 08 40 06 00 64 00 01 01 00 + """, + "40 51 08 94 7f 99 65 75 e7 bd bc 26 d4 02 16 a2 c7 fa 91 bd", + "55 9a 81 94 45 b4 fd e9 8d 9e 13 17", + self.server_isn_62x, + self.client_isn_62x, + include_options=False, + ) + + server_isn_71x = 0xA6744ECB + client_isn_71x = 0x193CCCEC + + def test_7_1_2(self): + self.check( + """ + 6e 06 15 20 00 38 06 40 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 02 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 01 00 b3 f8 5a a6 74 4e cb + 19 3c cc ed e0 12 ff ff ea bb 00 00 02 04 05 a0 + 01 03 03 08 04 02 08 0a 71 da ab c8 13 e4 ab 99 + 1d 10 54 3d dc 28 43 a8 4e 78 a6 bc fd c5 ed 80 + """, + "cf 1b 1e 22 5e 06 a6 36 16 76 4a 06 7b 46 f4 b1", + "dc 28 43 a8 4e 78 a6 bc fd c5 ed 80", + self.server_isn_71x, + self.client_isn_71x, + alg_name="AES-128-CMAC-96", + include_options=True, + ) + + def test_7_1_4(self): + self.check( + """ + 6e 06 15 20 00 73 06 40 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 02 fd 00 00 00 00 00 00 00 + 00 00 00 00 00 00 00 01 00 b3 f8 5a a6 74 4e cc + 19 3c cd 30 c0 18 01 00 52 f4 00 00 01 01 08 0a + 71 da ab d3 13 e4 ab a3 1d 10 54 3d c1 06 9b 7d + fd 3d 69 3a 6d f3 f2 89 ff ff ff ff ff ff ff ff + ff ff ff ff ff ff ff ff 00 43 01 04 fd e8 00 b4 + 01 01 01 7a 26 02 06 01 04 00 01 00 01 02 02 80 + 00 02 02 02 00 02 02 42 00 02 06 41 04 00 00 fd + e8 02 08 40 06 00 64 00 01 01 00 + """, + "cf 1b 1e 22 5e 06 a6 36 16 76 4a 06 7b 46 f4 b1", + "c1 06 9b 7d fd 3d 69 3a 6d f3 f2 89", + self.server_isn_71x, + self.client_isn_71x, + alg_name="AES-128-CMAC-96", + include_options=True, + ) diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/validator.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/validator.py new file mode 100644 index 000000000000..9becd39dc31e --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/validator.py @@ -0,0 +1,127 @@ +# SPDX-License-Identifier: GPL-2.0 +import logging +import typing +from dataclasses import dataclass + +from scapy.layers.inet import TCP +from scapy.packet import Packet + +from . import scapy_tcp_authopt +from .scapy_conntrack import TCPConnectionTracker, get_packet_tcp_connection_key +from .scapy_utils import scapy_tcp_get_authopt_val + +logger = logging.getLogger(__name__) + + +@dataclass +class TcpAuthValidatorKey: + """Representation of a TCP Authentication Option key for the validator + + The matching rules are independent. + """ + + key: bytes + alg_name: str + include_options: bool = True + keyid: typing.Optional[int] = None + sport: typing.Optional[int] = None + dport: typing.Optional[int] = None + + def match_packet(self, p: Packet) -> bool: + """Determine if this key matches a specific packet""" + if not TCP in p: + return False + authopt = scapy_tcp_get_authopt_val(p[TCP]) + if authopt is None: + return False + if self.keyid is not None and authopt.keyid != self.keyid: + return False + if self.sport is not None and p[TCP].sport != self.sport: + return False + if self.dport is not None and p[TCP].dport != self.dport: + return False + return True + + def get_alg_imp(self): + return scapy_tcp_authopt.get_alg(self.alg_name) + + +class TcpAuthValidator: + """Validate TCP Authentication Option signatures inside a capture + + This can track multiple connections, determine their initial sequence numbers + and verify their signatues independently. + + Keys are provided as a collection of `.TcpAuthValidatorKey` + """ + + keys: typing.List[TcpAuthValidatorKey] + tracker: TCPConnectionTracker + any_incomplete: bool = False + any_unsigned: bool = False + any_fail: bool = False + + def __init__(self, keys=None): + self.keys = keys or [] + self.tracker = TCPConnectionTracker() + self.conn_dict = {} + + def get_key_for_packet(self, p): + for k in self.keys: + if k.match_packet(p): + return k + return None + + def handle_packet(self, p: Packet): + if not TCP in p: + return + self.tracker.handle_packet(p) + authopt = scapy_tcp_get_authopt_val(p[TCP]) + if not authopt: + self.any_unsigned = True + logger.debug("skip packet without tcp authopt: %r", p) + return + key = self.get_key_for_packet(p) + if not key: + self.any_unsigned = True + logger.debug("skip packet not matching any known keys: %r", p) + return + tcp_track_key = get_packet_tcp_connection_key(p) + conn = self.tracker.get(tcp_track_key) + + if not conn.found_syn: + logger.warning("missing SYN for %s", p) + self.any_incomplete = True + return + if not conn.found_synack and not p[TCP].flags.S: + logger.warning("missing SYNACK for %s", p) + self.any_incomplete = True + return + + alg = key.get_alg_imp() + context_bytes = scapy_tcp_authopt.build_context_from_packet( + p, conn.sisn or 0, conn.disn or 0 + ) + traffic_key = alg.kdf(key.key, context_bytes) + message_bytes = scapy_tcp_authopt.build_message_from_packet( + p, include_options=key.include_options + ) + computed_mac = alg.mac(traffic_key, message_bytes) + captured_mac = authopt.mac + if computed_mac == captured_mac: + logger.debug("ok - mac %s", computed_mac.hex()) + else: + self.any_fail = True + logger.error( + "not ok - captured %s computed %s", + captured_mac.hex(), + computed_mac.hex(), + ) + + def raise_errors(self, allow_unsigned=False, allow_incomplete=False): + if self.any_fail: + raise Exception("Found failed signatures") + if self.any_incomplete and not allow_incomplete: + raise Exception("Incomplete capture missing SYN/ACK") + if self.any_unsigned and not allow_unsigned: + raise Exception("Found unsigned packets")

Add support for configuring TCP Authentication Option. Only a single key with default options.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- tools/testing/selftests/net/nettest.c | 34 ++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/nettest.c b/tools/testing/selftests/net/nettest.c index bd6288302094..f04c6af79129 100644 --- a/tools/testing/selftests/net/nettest.c +++ b/tools/testing/selftests/net/nettest.c @@ -100,10 +100,12 @@ struct sock_args { struct sockaddr_in v4; struct sockaddr_in6 v6; } md5_prefix; unsigned int prefix_len;

+ const char *authopt_password; + /* expected addresses and device index for connection */ const char *expected_dev; const char *expected_server_dev; int expected_ifindex;

@@ -250,10 +252,27 @@ static int switch_ns(const char *ns) close(fd);

return ret; }

+static int tcp_set_authopt(int sd, struct sock_args *args) +{ + struct tcp_authopt_key key; + int rc; + + memset(&key, 0, sizeof(key)); + strcpy((char *)key.key, args->authopt_password); + key.keylen = strlen(args->authopt_password); + key.alg = TCP_AUTHOPT_ALG_HMAC_SHA_1_96; + + rc = setsockopt(sd, IPPROTO_TCP, TCP_AUTHOPT_KEY, &key, sizeof(key)); + if (rc < 0) + log_err_errno("setsockopt(TCP_AUTHOPT_KEY)"); + + return rc; +} + static int tcp_md5sig(int sd, void *addr, socklen_t alen, struct sock_args *args) { int keylen = strlen(args->password); struct tcp_md5sig md5sig = {}; int opt = TCP_MD5SIG; @@ -1508,10 +1527,15 @@ static int do_server(struct sock_args *args, int ipc_fd) if (args->password && tcp_md5_remote(lsd, args)) { close(lsd); goto err_exit; }

+ if (args->authopt_password && tcp_set_authopt(lsd, args)) { + close(lsd); + goto err_exit; + } + ipc_write(ipc_fd, 1); while (1) { log_msg("waiting for client connection.\n"); FD_ZERO(&rfds); FD_SET(lsd, &rfds); @@ -1630,10 +1654,13 @@ static int connectsock(void *addr, socklen_t alen, struct sock_args *args) goto out;

if (args->password && tcp_md5sig(sd, addr, alen, args)) goto err;

+ if (args->authopt_password && tcp_set_authopt(sd, args)) + goto err; + if (args->bind_test_only) goto out;

if (connect(sd, addr, alen) < 0) { if (errno != EINPROGRESS) { @@ -1819,11 +1846,11 @@ static int ipc_parent(int cpid, int fd, struct sock_args *args)

wait(&status); return client_status; }

-#define GETOPT_STR "sr:l:c:p:t:g:P:DRn:M:X:m:d:I:BN:O:SCi6xL:0:1:2:3:Fbq" +#define GETOPT_STR "sr:l:c:p:t:g:P:DRn:M:X:m:A:d:I:BN:O:SCi6xL:0:1:2:3:Fbq"

static void print_usage(char *prog) { printf( "usage: %s OPTS\n" @@ -1856,10 +1883,12 @@ static void print_usage(char *prog) " -n num number of times to send message\n" "\n" " -M password use MD5 sum protection\n" " -X password MD5 password for client mode\n" " -m prefix/len prefix and length to use for MD5 key\n" + " -A password use RFC5925 TCP Authentication option\n" + "\n" " -g grp multicast group (e.g., 239.1.1.1)\n" " -i interactive mode (default is echo and terminate)\n" "\n" " -0 addr Expected local address\n" " -1 addr Expected remote address\n" @@ -1970,10 +1999,13 @@ int main(int argc, char *argv[]) args.client_pw = optarg; break; case 'm': args.md5_prefix_str = optarg; break; + case 'A': + args.authopt_password = optarg; + break; case 'S': args.use_setsockopt = 1; break; case 'C': args.use_cmsg = 1;

This script is otherwise very slow to run!

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- tools/testing/selftests/net/fcnal-test.sh | 12 ++++++++++++ 1 file changed, 12 insertions(+)

diff --git a/tools/testing/selftests/net/fcnal-test.sh b/tools/testing/selftests/net/fcnal-test.sh index 74a7580b6bde..484734db708f 100755 --- a/tools/testing/selftests/net/fcnal-test.sh +++ b/tools/testing/selftests/net/fcnal-test.sh @@ -1331,10 +1331,21 @@ ipv4_tcp() log_subsection "With VRF" setup "yes" ipv4_tcp_vrf }

+ +only_tcp_authopt() +{ + log_section "TCP Authentication" + setup + set_sysctl net.ipv4.tcp_l3mdev_accept=0 + log_subsection "IPv4 no VRF" + ipv4_tcp_authopt +} + + ################################################################################ # IPv4 UDP

ipv4_udp_novrf() { @@ -4021,10 +4032,11 @@ do ipv6_bind|bind6) ipv6_addr_bind;; ipv6_runtime) ipv6_runtime;; ipv6_netfilter) ipv6_netfilter;;

use_cases) use_cases;; + tcp_authopt) only_tcp_authopt;;

# setup namespaces and config, but do not run any tests setup) setup; exit 0;; vrf_setup) setup "yes"; exit 0;;

RFC5925 requires that the use can examine or control the keys being used. This is implemented in linux via fields on the TCP_AUTHOPT sockopt.

Add socket-level tests for the adjusting keyids on live connections and checking the they are reflected on the peer.

Also check smooth transitions via rnextkeyid.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- .../tcp_authopt_test/linux_tcp_authopt.py | 16 +- .../tcp_authopt_test/test_rollover.py | 180 ++++++++++++++++++ 2 files changed, 193 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_rollover.py

diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/linux_tcp_authopt.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/linux_tcp_authopt.py index 339298998ff9..1ba4358654be 100644 --- a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/linux_tcp_authopt.py +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/linux_tcp_authopt.py @@ -23,10 +23,12 @@ TCP_AUTHOPT_KEY = 39

TCP_AUTHOPT_MAXKEYLEN = 80

class TCP_AUTHOPT_FLAG(IntFlag): + LOCK_KEYID = BIT(0) + LOCK_RNEXTKEYID = BIT(1) REJECT_UNEXPECTED = BIT(2)

class TCP_AUTHOPT_KEY_FLAG(IntFlag): DEL = BIT(0) @@ -42,24 +44,32 @@ class TCP_AUTHOPT_ALG(IntEnum): @dataclass class tcp_authopt: """Like linux struct tcp_authopt"""

flags: int = 0 - sizeof = 4 + send_keyid: int = 0 + send_rnextkeyid: int = 0 + recv_keyid: int = 0 + recv_rnextkeyid: int = 0 + sizeof = 8

def pack(self) -> bytes: return struct.pack( - "I", + "IBBBB", self.flags, + self.send_keyid, + self.send_rnextkeyid, + self.recv_keyid, + self.recv_rnextkeyid, )

def __bytes__(self): return self.pack()

@classmethod def unpack(cls, b: bytes): - tup = struct.unpack("I", b) + tup = struct.unpack("IBBBB", b) return cls(*tup)

def set_tcp_authopt(sock, opt: tcp_authopt): return sock.setsockopt(socket.SOL_TCP, TCP_AUTHOPT, bytes(opt)) diff --git a/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_rollover.py b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_rollover.py new file mode 100644 index 000000000000..a348a7acfe0f --- /dev/null +++ b/tools/testing/selftests/tcp_authopt/tcp_authopt_test/test_rollover.py @@ -0,0 +1,180 @@ +# SPDX-License-Identifier: GPL-2.0 +import typing +import socket +from .server import SimpleServerThread +from .linux_tcp_authopt import ( + TCP_AUTHOPT_FLAG, + set_tcp_authopt_key, + tcp_authopt, + tcp_authopt_key, + set_tcp_authopt, + get_tcp_authopt, +) +from .utils import DEFAULT_TCP_SERVER_PORT, create_listen_socket, check_socket_echo +from contextlib import ExitStack, contextmanager +from .conftest import skipif_missing_tcp_authopt + +pytestmark = skipif_missing_tcp_authopt + + +@contextmanager +def make_tcp_authopt_socket_pair( + server_addr="127.0.0.1", + server_authopt: tcp_authopt = None, + server_key_list: typing.Iterable[tcp_authopt_key] = [], + client_authopt: tcp_authopt = None, + client_key_list: typing.Iterable[tcp_authopt_key] = [], +) -> typing.Tuple[socket.socket, socket.socket]: + """Make a pair for connected sockets for key switching tests + + Server runs in a background thread implementing echo protocol""" + with ExitStack() as exit_stack: + listen_socket = exit_stack.enter_context( + create_listen_socket(bind_addr=server_addr) + ) + server_thread = exit_stack.enter_context( + SimpleServerThread(listen_socket, mode="echo") + ) + client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + client_socket.settimeout(1.0) + + if server_authopt: + set_tcp_authopt(listen_socket, server_authopt) + for k in server_key_list: + set_tcp_authopt_key(listen_socket, k) + if client_authopt: + set_tcp_authopt(client_socket, client_authopt) + for k in client_key_list: + set_tcp_authopt_key(client_socket, k) + + client_socket.connect((server_addr, DEFAULT_TCP_SERVER_PORT)) + check_socket_echo(client_socket) + server_socket = server_thread.server_socket[0] + + yield client_socket, server_socket + + +def test_get_keyids(exit_stack: ExitStack): + """Check reading key ids""" + sk1 = tcp_authopt_key(send_id=11, recv_id=12, key="111") + sk2 = tcp_authopt_key(send_id=21, recv_id=22, key="222") + ck1 = tcp_authopt_key(send_id=12, recv_id=11, key="111") + client_socket, server_socket = exit_stack.enter_context( + make_tcp_authopt_socket_pair( + server_key_list=[sk1, sk2], + client_key_list=[ck1], + ) + ) + + check_socket_echo(client_socket) + client_tcp_authopt = get_tcp_authopt(client_socket) + server_tcp_authopt = get_tcp_authopt(server_socket) + assert server_tcp_authopt.send_keyid == 11 + assert server_tcp_authopt.send_rnextkeyid == 12 + assert server_tcp_authopt.recv_keyid == 12 + assert server_tcp_authopt.recv_rnextkeyid == 11 + assert client_tcp_authopt.send_keyid == 12 + assert client_tcp_authopt.send_rnextkeyid == 11 + assert client_tcp_authopt.recv_keyid == 11 + assert client_tcp_authopt.recv_rnextkeyid == 12 + + +def test_rollover_send_keyid(exit_stack: ExitStack): + """Check reading key ids""" + sk1 = tcp_authopt_key(send_id=11, recv_id=12, key="111") + sk2 = tcp_authopt_key(send_id=21, recv_id=22, key="222") + ck1 = tcp_authopt_key(send_id=12, recv_id=11, key="111") + ck2 = tcp_authopt_key(send_id=22, recv_id=21, key="222") + client_socket, server_socket = exit_stack.enter_context( + make_tcp_authopt_socket_pair( + server_key_list=[sk1, sk2], + client_key_list=[ck1, ck2], + client_authopt=tcp_authopt( + send_keyid=12, flags=TCP_AUTHOPT_FLAG.LOCK_KEYID + ), + ) + ) + + check_socket_echo(client_socket) + assert get_tcp_authopt(client_socket).recv_keyid == 11 + assert get_tcp_authopt(server_socket).recv_keyid == 12 + + # Explicit request for key2 + set_tcp_authopt( + client_socket, tcp_authopt(send_keyid=22, flags=TCP_AUTHOPT_FLAG.LOCK_KEYID) + ) + check_socket_echo(client_socket) + assert get_tcp_authopt(client_socket).recv_keyid == 21 + assert get_tcp_authopt(server_socket).recv_keyid == 22 + + +def test_rollover_rnextkeyid(exit_stack: ExitStack): + """Check reading key ids""" + sk1 = tcp_authopt_key(send_id=11, recv_id=12, key="111") + sk2 = tcp_authopt_key(send_id=21, recv_id=22, key="222") + ck1 = tcp_authopt_key(send_id=12, recv_id=11, key="111") + ck2 = tcp_authopt_key(send_id=22, recv_id=21, key="222") + client_socket, server_socket = exit_stack.enter_context( + make_tcp_authopt_socket_pair( + server_key_list=[sk1], + client_key_list=[ck1, ck2], + client_authopt=tcp_authopt( + send_keyid=12, flags=TCP_AUTHOPT_FLAG.LOCK_KEYID + ), + ) + ) + + check_socket_echo(client_socket) + assert get_tcp_authopt(server_socket).recv_rnextkeyid == 11 + + # request rnextkeyd=22 but server does not have it + set_tcp_authopt( + client_socket, + tcp_authopt(send_rnextkeyid=21, flags=TCP_AUTHOPT_FLAG.LOCK_RNEXTKEYID), + ) + check_socket_echo(client_socket) + check_socket_echo(client_socket) + assert get_tcp_authopt(server_socket).recv_rnextkeyid == 21 + assert get_tcp_authopt(server_socket).send_keyid == 11 + + # after adding k2 on server the key is switched + set_tcp_authopt_key(server_socket, sk2) + check_socket_echo(client_socket) + check_socket_echo(client_socket) + assert get_tcp_authopt(server_socket).send_keyid == 21 + + +def test_rollover_delkey(exit_stack: ExitStack): + sk1 = tcp_authopt_key(send_id=11, recv_id=12, key="111") + sk2 = tcp_authopt_key(send_id=21, recv_id=22, key="222") + ck1 = tcp_authopt_key(send_id=12, recv_id=11, key="111") + ck2 = tcp_authopt_key(send_id=22, recv_id=21, key="222") + client_socket, server_socket = exit_stack.enter_context( + make_tcp_authopt_socket_pair( + server_key_list=[sk1, sk2], + client_key_list=[ck1, ck2], + client_authopt=tcp_authopt( + send_keyid=12, flags=TCP_AUTHOPT_FLAG.LOCK_KEYID + ), + ) + ) + + check_socket_echo(client_socket) + assert get_tcp_authopt(server_socket).recv_keyid == 12 + + # invalid send_keyid is just ignored + set_tcp_authopt(client_socket, tcp_authopt(send_keyid=7)) + check_socket_echo(client_socket) + assert get_tcp_authopt(client_socket).send_keyid == 12 + assert get_tcp_authopt(server_socket).recv_keyid == 12 + assert get_tcp_authopt(client_socket).recv_keyid == 11 + + # If a key is removed it is replaced by anything that matches + ck1.delete_flag = True + set_tcp_authopt_key(client_socket, ck1) + check_socket_echo(client_socket) + check_socket_echo(client_socket) + assert get_tcp_authopt(client_socket).send_keyid == 22 + assert get_tcp_authopt(server_socket).send_keyid == 21 + assert get_tcp_authopt(server_socket).recv_keyid == 22 + assert get_tcp_authopt(client_socket).recv_keyid == 21