The .rst documentation contains a brief description of the user interface and includes kernel-doc generated from uapi header.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- Documentation/networking/index.rst | 1 + Documentation/networking/tcp_authopt.rst | 44 ++++++++++++++++++++++++ 2 files changed, 45 insertions(+) create mode 100644 Documentation/networking/tcp_authopt.rst

diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index 58bc8cd367c6..f5c324a060d8 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -100,10 +100,11 @@ Contents: strparser switchdev sysfs-tagging tc-actions-env-rules tcp-thin + tcp_authopt team timestamping tipc tproxy tuntap diff --git a/Documentation/networking/tcp_authopt.rst b/Documentation/networking/tcp_authopt.rst new file mode 100644 index 000000000000..484f66f41ad5 --- /dev/null +++ b/Documentation/networking/tcp_authopt.rst @@ -0,0 +1,44 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================= +TCP Authentication Option +========================= + +The TCP Authentication option specified by RFC5925 replaces the TCP MD5 +Signature option. It similar in goals but not compatible in either wire formats +or ABI. + +Interface +========= + +Individual keys can be added to or removed from a TCP socket by using +TCP_AUTHOPT_KEY setsockopt and a ``struct tcp_authopt_key``. There is no +support for reading back keys and updates always replace the old key. These +structures represent "Master Key Tuples (MKTs)" as described by the RFC. + +Per-socket options can set or read using the TCP_AUTHOPT sockopt and a ``struct +tcp_authopt``. This is optional: doing setsockopt TCP_AUTHOPT_KEY is +sufficient to enable the feature. + +Configuration associated with TCP Authentication is indepedently attached to +each TCP socket. After listen and accept the newly returned socket gets an +independent copy of relevant settings from the listen socket. + +Key binding +----------- + +Keys can be bound to remote addresses in a way that is similar to TCP_MD5. + + * The full address must match (/32 or /128) + * Ports are ignored + * Address binding is optional, by default keys match all addresses + +RFC5925 requires that key ids do not overlap when tcp identifiers (addr/port) +overlap. This is not enforced by linux, configuring ambiguous keys will result +in packet drops and lost connections. + +ABI Reference +============= + +.. kernel-doc:: include/uapi/linux/tcp.h + :identifiers: tcp_authopt tcp_authopt_flag tcp_authopt_key tcp_authopt_key_flag tcp_authopt_alg

This chunk of code is identical between the implementation of TCP-MD5 and TCP-AO so rename and refactor

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/net/tcp.h | 2 +- net/ipv4/tcp.c | 38 ++++++++++++++++++++------------------ net/ipv4/tcp_ipv4.c | 2 +- net/ipv6/tcp_ipv6.c | 2 +- 4 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h index 6cc2eeb45deb..1a0513b0ead0 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1688,11 +1688,11 @@ struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); static inline void tcp_put_md5sig_pool(void) { local_bh_enable(); }

-int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, const struct sk_buff *, +int tcp_sig_hash_skb_data(struct ahash_request *, const struct sk_buff *, unsigned int header_len); int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key);

/* From tcp_fastopen.c */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 022811dd705d..8e6cbb5a1da7 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4400,16 +4400,31 @@ struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) local_bh_enable(); return NULL; } EXPORT_SYMBOL(tcp_get_md5sig_pool);

-int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, +int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) +{ + u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */ + struct scatterlist sg; + + sg_init_one(&sg, key->key, keylen); + ahash_request_set_crypt(hp->md5_req, &sg, NULL, keylen); + + /* We use data_race() because tcp_md5_do_add() might change key->key under us */ + return data_race(crypto_ahash_update(hp->md5_req)); +} +EXPORT_SYMBOL(tcp_md5_hash_key); +#endif /* CONFIG_TCP_MD5SIG */ + +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AUTHOPT) + +int tcp_sig_hash_skb_data(struct ahash_request *req, const struct sk_buff *skb, unsigned int header_len) { struct scatterlist sg; const struct tcphdr *tp = tcp_hdr(skb); - struct ahash_request *req = hp->md5_req; unsigned int i; const unsigned int head_data_len = skb_headlen(skb) > header_len ? skb_headlen(skb) - header_len : 0; const struct skb_shared_info *shi = skb_shinfo(skb); struct sk_buff *frag_iter; @@ -4432,31 +4447,18 @@ int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, if (crypto_ahash_update(req)) return 1; }

skb_walk_frags(skb, frag_iter) - if (tcp_md5_hash_skb_data(hp, frag_iter, 0)) + if (tcp_sig_hash_skb_data(req, frag_iter, 0)) return 1;

return 0; } -EXPORT_SYMBOL(tcp_md5_hash_skb_data); +EXPORT_SYMBOL(tcp_sig_hash_skb_data);

-int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key) -{ - u8 keylen = READ_ONCE(key->keylen); /* paired with WRITE_ONCE() in tcp_md5_do_add */ - struct scatterlist sg; - - sg_init_one(&sg, key->key, keylen); - ahash_request_set_crypt(hp->md5_req, &sg, NULL, keylen); - - /* We use data_race() because tcp_md5_do_add() might change key->key under us */ - return data_race(crypto_ahash_update(hp->md5_req)); -} -EXPORT_SYMBOL(tcp_md5_hash_key); - -#endif +#endif /* defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AUTHOPT) */

void tcp_done(struct sock *sk) { struct request_sock *req;

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 0aa5122b29e0..91cad11db32e 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1381,11 +1381,11 @@ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, if (crypto_ahash_init(req)) goto clear_hash;

if (tcp_v4_md5_hash_headers(hp, daddr, saddr, th, skb->len)) goto clear_hash; - if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) + if (tcp_sig_hash_skb_data(hp->md5_req, skb, th->doff << 2)) goto clear_hash; if (tcp_md5_hash_key(hp, key)) goto clear_hash; ahash_request_set_crypt(req, NULL, md5_hash, 0); if (crypto_ahash_final(req)) diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 3b7d6ede1364..e98fc6f12c61 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -750,11 +750,11 @@ static int tcp_v6_md5_hash_skb(char *md5_hash, if (crypto_ahash_init(req)) goto clear_hash;

if (tcp_v6_md5_hash_headers(hp, daddr, saddr, th, skb->len)) goto clear_hash; - if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) + if (tcp_sig_hash_skb_data(hp->md5_req, skb, th->doff << 2)) goto clear_hash; if (tcp_md5_hash_key(hp, key)) goto clear_hash; ahash_request_set_crypt(req, NULL, md5_hash, 0); if (crypto_ahash_final(req))

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. This approach is different from MD5.

There very few interactions with MD5 but tcp_parse_md5sig_option was modifed to parse AO and MD5 simultaneously. If both are present the packet is droppped as required by RFC5925.

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

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/net/tcp.h | 24 +++- include/net/tcp_authopt.h | 135 ++++++++++++++++++ include/uapi/linux/snmp.h | 1 + net/ipv4/proc.c | 1 + net/ipv4/tcp_authopt.c | 293 ++++++++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 40 ++++-- net/ipv4/tcp_ipv4.c | 50 ++++++- net/ipv4/tcp_minisocks.c | 12 ++ net/ipv4/tcp_output.c | 85 ++++++++++- net/ipv6/tcp_ipv6.c | 49 ++++++- 10 files changed, 665 insertions(+), 25 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h index 1a0513b0ead0..eed4bbfdca78 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -422,11 +422,33 @@ int tcp_mmap(struct file *file, struct socket *sock, struct vm_area_struct *vma); #endif void tcp_parse_options(const struct net *net, const struct sk_buff *skb, struct tcp_options_received *opt_rx, int estab, struct tcp_fastopen_cookie *foc); -const u8 *tcp_parse_md5sig_option(const struct tcphdr *th); +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AUTHOPT) +int tcp_parse_sig_options(const struct tcphdr *th, + const u8 **md5ptr, + const u8 **aoptr); +#else +static inline int tcp_parse_sig_options(const struct tcphdr *th, + const u8 **md5ptr, + const u8 **aoptr) +{ + aoptr = NULL; + md5ptr = NULL; + return 0; +} +#endif +static inline const u8 *tcp_parse_md5sig_option(const struct tcphdr *th) +{ + const u8 *md5, *ao; + int ret; + + ret = tcp_parse_sig_options(th, &md5, &ao); + + return (md5 && !ao && !ret) ? md5 : NULL; +}

/* * BPF SKB-less helpers */ u16 tcp_v4_get_syncookie(struct sock *sk, struct iphdr *iph, diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index ce005f7ce797..fb07394de261 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -74,28 +74,163 @@ struct tcphdr_authopt { u8 rnextkeyid; u8 mac[0]; };

#ifdef CONFIG_TCP_AUTHOPT +DECLARE_STATIC_KEY_FALSE(tcp_authopt_needed_key); +#define tcp_authopt_needed (static_branch_unlikely(&tcp_authopt_needed_key)) + +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, + struct tcp_authopt_info **info, + u8 *rnextkeyid) +{ + if (tcp_authopt_needed) { + *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 tcp_authopt_info *info, + 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); +} +void __tcp_authopt_finish_connect(struct sock *sk, struct sk_buff *skb, + struct tcp_authopt_info *info); +static inline void tcp_authopt_finish_connect(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_authopt_info *info; + + if (tcp_authopt_needed) { + info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, + lockdep_sock_is_held(sk)); + + if (info) + __tcp_authopt_finish_connect(sk, skb, info); + } +} +static inline void tcp_authopt_time_wait( + struct tcp_timewait_sock *tcptw, + struct tcp_sock *tp) +{ + if (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; + } +} +/** 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 the AO signature is present and valid then caller skips MD5 check. + */ +int __tcp_authopt_inbound_check( + struct sock *sk, + struct sk_buff *skb, + struct tcp_authopt_info *info, + const u8 *opt); +static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb, const u8 *opt) +{ + if (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, opt); + } + return 0; +} +static inline int tcp_authopt_inbound_check_req(struct request_sock *req, struct sk_buff *skb, + const u8 *opt) +{ + if (tcp_authopt_needed) { + struct sock *lsk = req->rsk_listener; + struct tcp_authopt_info *info = rcu_dereference(tcp_sk(lsk)->authopt_info); + + if (info) + return __tcp_authopt_inbound_check((struct sock *)req, skb, info, opt); + } + 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 int tcp_authopt_hash( + char *hash_location, + struct tcp_authopt_key_info *key, + struct tcp_authopt_key *info, + 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_finish_connect(struct sock *sk, struct sk_buff *skb) +{ +} +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, const u8 *opt) +{ + return 0; +} +static inline int tcp_authopt_inbound_check_req(struct request_sock *sk, struct sk_buff *skb, + const u8 *opt) +{ + 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 f30273afb539..70f7a8a47045 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 29524ed56733..dd9b89b1f137 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -3,10 +3,14 @@ #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_key); +EXPORT_SYMBOL(tcp_authopt_needed_key); + /* 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

@@ -214,10 +218,55 @@ 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); + } + + /* 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; @@ -227,10 +276,50 @@ 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 + * + * @sk: socket + * @info: socket's tcp_authopt_info + * @addr_sk: socket used for address lookup. Same as sk except for synack case + * @rnextkeyid: value of rnextkeyid caller should write in packet + * + * 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;

@@ -240,10 +329,12 @@ 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_key); sk_gso_disable(sk); INIT_HLIST_HEAD(&info->head); rcu_assign_pointer(tp->authopt_info, info);

return info; @@ -528,10 +619,71 @@ static int crypto_ahash_buf(struct ahash_request *req, u8 *buf, uint len) ahash_request_set_crypt(req, &sg, NULL, len);

return crypto_ahash_update(req); }

+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_gso_disable(newsk); + rcu_assign_pointer(tcp_sk(newsk)->authopt_info, new_info); + + return 0; +} + +void __tcp_authopt_finish_connect(struct sock *sk, struct sk_buff *skb, + struct tcp_authopt_info *info) +{ + info->src_isn = ntohl(tcp_hdr(skb)->ack_seq) - 1; + info->dst_isn = ntohl(tcp_hdr(skb)->seq); +} + /* feed traffic key into ahash */ static int tcp_authopt_ahash_traffic_key(struct tcp_authopt_alg_pool *pool, struct sock *sk, struct sk_buff *skb, struct tcp_authopt_info *info, @@ -768,10 +920,11 @@ static int tcp_authopt_hash_opts(struct tcp_authopt_alg_pool *pool,

static int tcp_authopt_hash_packet(struct tcp_authopt_alg_pool *pool, struct sock *sk, struct sk_buff *skb, struct tcphdr_authopt *aoptr, + struct tcp_authopt_info *info, bool input, bool ipv6, bool include_options, u8 *macbuf) { @@ -881,14 +1034,154 @@ static int __tcp_authopt_calc_mac(struct sock *sk,

err = tcp_authopt_hash_packet(mac_pool, sk, skb, aoptr, + info, input, ipv6, !(key->flags & TCP_AUTHOPT_KEY_EXCLUDE_OPTS), macbuf);

out: tcp_authopt_put_mac_pool(key, mac_pool); 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 tcp_authopt_info *info, + 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; + struct tcphdr_authopt *aoptr = (struct tcphdr_authopt *)(hash_location - 4); + + err = __tcp_authopt_calc_mac(sk, skb, aoptr, key, info, false, macbuf); + if (err) + goto fail; + memcpy(hash_location, macbuf, TCP_AUTHOPT_MACLEN); + + return 0; + +fail: + /* 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; +} + +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, + bool *anykey) +{ + struct tcp_authopt_key_info *result = NULL; + struct tcp_authopt_key_info *key; + + *anykey = false; + /* multiple matches will cause occasional failures */ + hlist_for_each_entry_rcu(key, &info->head, node, 0) { + if (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND && + !tcp_authopt_key_match_skb_addr(key, skb)) + continue; + *anykey = true; + if (recv_id >= 0 && key->recv_id != recv_id) + continue; + if (!result) + result = key; + else if (result) + net_warn_ratelimited("ambiguous tcp authentication keys configured for recv\n"); + } + + return result; +} + +/* Show a rate-limited message for authentication fail */ +static void print_tcpao_notice(const char *msg, struct sk_buff *skb) +{ + struct iphdr *iph = (struct iphdr *)skb_network_header(skb); + struct tcphdr *th = (struct tcphdr *)skb_transport_header(skb); + + if (iph->version == 4) { + net_info_ratelimited("%s (%pI4, %d)->(%pI4, %d)\n", msg, + &iph->saddr, ntohs(th->source), + &iph->daddr, ntohs(th->dest)); + } else if (iph->version == 6) { + struct ipv6hdr *ip6h = (struct ipv6hdr *)skb_network_header(skb); + + net_info_ratelimited("%s (%pI6, %d)->(%pI6, %d)\n", msg, + &ip6h->saddr, ntohs(th->source), + &ip6h->daddr, ntohs(th->dest)); + } else { + WARN_ONCE(1, "%s unknown IP version\n", msg); + } +} + +int __tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb, + struct tcp_authopt_info *info, const u8 *_opt) +{ + struct tcphdr_authopt *opt = (struct tcphdr_authopt *)_opt; + struct tcp_authopt_key_info *key; + bool anykey; + u8 macbuf[TCP_AUTHOPT_MAXMACBUF]; + int err; + + key = tcp_authopt_lookup_recv(sk, skb, info, opt ? opt->keyid : -1, &anykey); + + /* nothing found or expected */ + if (!opt && !key) + return 0; + if (!opt && key) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + print_tcpao_notice("TCP Authentication Missing", skb); + return -EINVAL; + } + if (opt && !anykey) { + /* 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); + print_tcpao_notice("TCP Authentication Unexpected: Rejected", skb); + return -EINVAL; + } + print_tcpao_notice("TCP Authentication Unexpected: Accepted", skb); + return 0; + } + if (opt && !key) { + /* Keys are configured for peer but with different keyid than packet */ + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + print_tcpao_notice("TCP Authentication Failed", skb); + return -EINVAL; + } + + /* bad inbound key len */ + if (opt->len != TCPOLEN_AUTHOPT_OUTPUT) + return -EINVAL; + + err = __tcp_authopt_calc_mac(sk, skb, opt, key, info, true, macbuf); + if (err) + return err; + + if (memcmp(macbuf, opt->mac, TCP_AUTHOPT_MACLEN)) { + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); + print_tcpao_notice("TCP Authentication Failed", skb); + return -EINVAL; + } + + return 1; +} +EXPORT_SYMBOL(__tcp_authopt_inbound_check); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 3658b9c3dd2b..4c9e403971fb 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> @@ -4173,43 +4174,60 @@ static bool tcp_fast_parse_options(const struct net *net, tp->rx_opt.rcv_tsecr -= tp->tsoffset;

return true; }

-#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AUTHOPT) /* - * Parse MD5 Signature option + * Parse MD5 and AO options + * + * md5ptr: pointer to content of MD5 option (16-byte hash) + * aoptr: pointer to start of AO option (variable length) */ -const u8 *tcp_parse_md5sig_option(const struct tcphdr *th) +int tcp_parse_sig_options(const struct tcphdr *th, const u8 **md5ptr, const u8 **aoptr) { int length = (th->doff << 2) - sizeof(*th); const u8 *ptr = (const u8 *)(th + 1);

+ *md5ptr = NULL; + *aoptr = NULL; + /* If not enough data remaining, we can short cut */ - while (length >= TCPOLEN_MD5SIG) { + while (length >= 4) { int opcode = *ptr++; int opsize;

switch (opcode) { case TCPOPT_EOL: - return NULL; + goto out; case TCPOPT_NOP: length--; continue; default: opsize = *ptr++; if (opsize < 2 || opsize > length) - return NULL; - if (opcode == TCPOPT_MD5SIG) - return opsize == TCPOLEN_MD5SIG ? ptr : NULL; + goto out; + if (opcode == TCPOPT_MD5SIG && opsize == TCPOLEN_MD5SIG) + *md5ptr = ptr; + if (opcode == TCPOPT_AUTHOPT) + *aoptr = ptr - 2; } ptr += opsize - 2; length -= opsize; } - return NULL; + +out: + /* 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 (*md5ptr && *aoptr) + return -EINVAL; + + return 0; } -EXPORT_SYMBOL(tcp_parse_md5sig_option); +EXPORT_SYMBOL(tcp_parse_sig_options); #endif

/* Sorry, PAWS as specified is broken wrt. pure-ACKs -DaveM * * It is not fatal. If this ACK does _not_ change critical state (seqs, window) @@ -5992,10 +6010,12 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) 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 91cad11db32e..b16f263c3121 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1405,22 +1405,20 @@ EXPORT_SYMBOL(tcp_v4_md5_hash_skb); #endif

/* Called with rcu_read_lock() */ static bool tcp_v4_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, - int dif, int sdif) + int dif, int sdif, + const u8 *hash_location) { #ifdef CONFIG_TCP_MD5SIG /* - * This gets called for each TCP segment that arrives - * so we want to be efficient. * We have 3 drop cases: * o No MD5 hash and one expected. * o MD5 hash and we're not expecting one. * o MD5 hash and its wrong. */ - const __u8 *hash_location = NULL; struct tcp_md5sig_key *hash_expected; const struct iphdr *iph = ip_hdr(skb); const struct tcphdr *th = tcp_hdr(skb); const union tcp_md5_addr *addr; unsigned char newhash[16]; @@ -1431,11 +1429,10 @@ static bool tcp_v4_inbound_md5_hash(const struct sock *sk, */ l3index = sdif ? dif : 0;

addr = (union tcp_md5_addr *)&iph->saddr; hash_expected = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); - hash_location = tcp_parse_md5sig_option(th);

/* We've parsed the options - do we have a hash? */ if (!hash_expected && !hash_location) return false;

@@ -1954,10 +1951,49 @@ 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_sig_check(struct sock *sk, + struct sk_buff *skb, + int dif, + int sdif) +{ + const u8 *md5, *ao; + int ret; + + ret = tcp_parse_sig_options(tcp_hdr(skb), &md5, &ao); + if (ret) + return ret; + ret = tcp_authopt_inbound_check(sk, skb, ao); + if (ret < 0) + return ret; + if (ret == 1) + return 0; + return tcp_v4_inbound_md5_hash(sk, skb, dif, sdif, md5); +} + +static int tcp_v4_sig_check_req(struct request_sock *req, + struct sk_buff *skb, + int dif, + int sdif) +{ + struct sock *lsk = req->rsk_listener; + const u8 *md5, *ao; + int ret; + + ret = tcp_parse_sig_options(tcp_hdr(skb), &md5, &ao); + if (ret) + return ret; + ret = tcp_authopt_inbound_check_req(req, skb, ao); + if (ret < 0) + return ret; + if (ret == 1) + return 0; + return tcp_v4_inbound_md5_hash(lsk, skb, dif, sdif, md5); +} + /* * From tcp_input.c */

int tcp_v4_rcv(struct sk_buff *skb) @@ -2011,11 +2047,11 @@ 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_sig_check_req(req, skb, dif, sdif))) { sk_drops_add(sk, skb); reqsk_put(req); goto discard_it; } if (tcp_checksum_complete(skb)) { @@ -2081,11 +2117,11 @@ 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_sig_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..19f749b60231 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 (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 5079832af5c1..b959e8b949b6 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> @@ -410,10 +411,11 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp)

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

static void smc_options_write(__be32 *ptr, u16 *options) @@ -434,16 +436,22 @@ 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_info *authopt_info; + 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) { @@ -616,10 +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); } @@ -751,10 +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_info, &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, @@ -763,12 +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; @@ -847,12 +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 @@ -918,13 +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; @@ -1274,10 +1321,14 @@ 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); @@ -1362,10 +1413,17 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, sk_gso_disable(sk); tp->af_specific->calc_md5_hash(opts.hash_location, md5, sk, skb); } #endif +#ifdef CONFIG_TCP_AUTHOPT + if (opts.authopt_key) { + sk_gso_disable(sk); + tcp_authopt_hash(opts.hash_location, opts.authopt_key, opts.authopt_info, 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, @@ -1831,12 +1889,21 @@ 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) { @@ -3551,10 +3618,14 @@ 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, @@ -3588,10 +3659,20 @@ 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, + opts.authopt_info, + 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 e98fc6f12c61..3105a367d6b5 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> @@ -772,14 +773,14 @@ static int tcp_v6_md5_hash_skb(char *md5_hash,

#endif

static bool tcp_v6_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, - int dif, int sdif) + int dif, int sdif, + const u8 *hash_location) { #ifdef CONFIG_TCP_MD5SIG - const __u8 *hash_location = NULL; struct tcp_md5sig_key *hash_expected; const struct ipv6hdr *ip6h = ipv6_hdr(skb); const struct tcphdr *th = tcp_hdr(skb); int genhash, l3index; u8 newhash[16]; @@ -788,11 +789,10 @@ static bool tcp_v6_inbound_md5_hash(const struct sock *sk, * in an L3 domain and dif is set to the l3mdev */ l3index = sdif ? dif : 0;

hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr, l3index); - hash_location = tcp_parse_md5sig_option(th);

/* We've parsed the options - do we have a hash? */ if (!hash_expected && !hash_location) return false;

@@ -1619,10 +1619,49 @@ 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_sig_check(struct sock *sk, + struct sk_buff *skb, + int dif, + int sdif) +{ + const u8 *md5, *ao; + int ret; + + ret = tcp_parse_sig_options(tcp_hdr(skb), &md5, &ao); + if (ret) + return ret; + ret = tcp_authopt_inbound_check(sk, skb, ao); + if (ret < 0) + return ret; + if (ret == 1) + return 0; + return tcp_v6_inbound_md5_hash(sk, skb, dif, sdif, md5); +} + +static int tcp_v6_sig_check_req(struct request_sock *req, + struct sk_buff *skb, + int dif, + int sdif) +{ + struct sock *lsk = req->rsk_listener; + const u8 *md5, *ao; + int ret; + + ret = tcp_parse_sig_options(tcp_hdr(skb), &md5, &ao); + if (ret) + return ret; + ret = tcp_authopt_inbound_check_req(req, skb, ao); + if (ret < 0) + return ret; + if (ret == 1) + return 0; + return tcp_v6_inbound_md5_hash(lsk, skb, dif, sdif, md5); +} + INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) { int sdif = inet6_sdif(skb); int dif = inet6_iif(skb); const struct tcphdr *th; @@ -1671,11 +1710,11 @@ 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_sig_check_req(req, skb, dif, sdif)) { sk_drops_add(sk, skb); reqsk_put(req); goto discard_it; } if (tcp_checksum_complete(skb)) { @@ -1738,11 +1777,11 @@ 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_sig_check(sk, skb, dif, sdif)) goto discard_and_relse;

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

Add a compute_sne function which finds the value of SNE for a certain SEQ given an already known "recent" SNE/SEQ. This is implemented using the standard tcp before/after macro and will work for SEQ values that are without 2^31 of the SEQ for which we know the SNE.

For updating we advance the value for rcv_sne at the same time as rcv_nxt and for snd_sne at the same time as snd_nxt. We could track other values (for example snd_una) but this is good enough and works very easily for timewait socket.

This implementation is different from RFC suggestions and doesn't require additional flags. It does pass tests from this draft: https://datatracker.ietf.org/doc/draft-touch-sne/

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/net/tcp_authopt.h | 34 ++++++++++++++ net/ipv4/tcp_authopt.c | 98 ++++++++++++++++++++++++++++++++++++++- net/ipv4/tcp_input.c | 1 + net/ipv4/tcp_output.c | 1 + 4 files changed, 132 insertions(+), 2 deletions(-)

diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index 4e872af7b180..d5d344d599f7 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -62,10 +62,14 @@ struct tcp_authopt_info { u32 flags; /** @src_isn: Local Initial Sequence Number */ u32 src_isn; /** @dst_isn: Remote Initial Sequence Number */ u32 dst_isn; + /** @rcv_sne: Recv-side Sequence Number Extension tracking tcp_sock.rcv_nxt */ + u32 rcv_sne; + /** @snd_sne: Send-side Sequence Number Extension tracking tcp_sock.snd_nxt */ + u32 snd_sne; };

/* TCP authopt as found in header */ struct tcphdr_authopt { u8 num; @@ -180,10 +184,34 @@ static inline int tcp_authopt_inbound_check_req(struct request_sock *req, struct if (info) return __tcp_authopt_inbound_check((struct sock *)req, skb, info, opt); } return 0; } +void __tcp_authopt_update_rcv_sne(struct tcp_sock *tp, struct tcp_authopt_info *info, u32 seq); +static inline void tcp_authopt_update_rcv_sne(struct tcp_sock *tp, u32 seq) +{ + struct tcp_authopt_info *info; + + if (tcp_authopt_needed) { + info = rcu_dereference_protected(tp->authopt_info, + lockdep_sock_is_held((struct sock *)tp)); + if (info) + __tcp_authopt_update_rcv_sne(tp, info, seq); + } +} +void __tcp_authopt_update_snd_sne(struct tcp_sock *tp, struct tcp_authopt_info *info, u32 seq); +static inline void tcp_authopt_update_snd_sne(struct tcp_sock *tp, u32 seq) +{ + struct tcp_authopt_info *info; + + if (tcp_authopt_needed) { + info = rcu_dereference_protected(tp->authopt_info, + lockdep_sock_is_held((struct sock *)tp)); + if (info) + __tcp_authopt_update_snd_sne(tp, info, seq); + } +} #else static inline int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen) { return -ENOPROTOOPT; } @@ -230,8 +258,14 @@ static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb static inline int tcp_authopt_inbound_check_req(struct request_sock *sk, struct sk_buff *skb, const u8 *opt) { return 0; } +static inline void tcp_authopt_update_rcv_sne(struct tcp_sock *tp, u32 seq) +{ +} +static inline void tcp_authopt_update_snd_sne(struct tcp_sock *tp, u32 seq) +{ +} #endif

#endif /* _LINUX_TCP_AUTHOPT_H */ diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index 85de430d3326..05234923cb9f 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -631,10 +631,97 @@ static int tcp_authopt_get_isn(struct sock *sk, *disn = htonl(info->dst_isn); } return 0; }

+/* compute_sne - Calculate Sequence Number Extension + * + * Give old upper/lower 32bit values and a new lower 32bit value determine the + * new value of the upper 32 bit. The new sequence number can be 2^31 before or + * after prev_seq but TCP window scaling should limit this further. + * + * For correct accounting the stored SNE value should be only updated together + * with the SEQ. + */ +static u32 compute_sne(u32 sne, u32 prev_seq, u32 seq) +{ + if (before(seq, prev_seq)) { + if (seq > prev_seq) + --sne; + } else { + if (seq < prev_seq) + ++sne; + } + + return sne; +} + +/* Update rcv_sne, must be called immediately before rcv_nxt update */ +void __tcp_authopt_update_rcv_sne(struct tcp_sock *tp, + struct tcp_authopt_info *info, u32 seq) +{ + info->rcv_sne = compute_sne(info->rcv_sne, tp->rcv_nxt, seq); +} + +/* Update snd_sne, must be called immediately before snd_nxt update */ +void __tcp_authopt_update_snd_sne(struct tcp_sock *tp, + struct tcp_authopt_info *info, u32 seq) +{ + info->snd_sne = compute_sne(info->snd_sne, tp->snd_nxt, seq); +} + +/* Compute SNE for a specific packet (by seq). */ +static int compute_packet_sne(struct sock *sk, struct tcp_authopt_info *info, + u32 seq, bool input, __be32 *sne) +{ + u32 rcv_nxt, snd_nxt; + + // For TCP_NEW_SYN_RECV we have no tcp_authopt_info but tcp_request_sock holds ISN. + if (sk->sk_state == TCP_NEW_SYN_RECV) { + struct tcp_request_sock *rsk = tcp_rsk((struct request_sock *)sk); + + if (input) + *sne = htonl(compute_sne(0, rsk->rcv_isn, seq)); + else + *sne = htonl(compute_sne(0, rsk->snt_isn, seq)); + return 0; + } + + /* TCP_LISTEN only receives SYN */ + if (sk->sk_state == TCP_LISTEN && input) + return 0; + + /* TCP_SYN_SENT only sends SYN and receives SYN/ACK + * For the input case rcv_nxt is initialized after the packet is + * validated so tcp_sk(sk)->rcv_nxt is not initialized. + */ + if (sk->sk_state == TCP_SYN_SENT) + return 0; + + if (sk->sk_state == TCP_TIME_WAIT) { + rcv_nxt = tcp_twsk(sk)->tw_rcv_nxt; + snd_nxt = tcp_twsk(sk)->tw_snd_nxt; + } else { + if (WARN_ONCE(!sk_fullsock(sk), + "unexpected minisock sk=%p state=%d", sk, + sk->sk_state)) + return -EINVAL; + rcv_nxt = tcp_sk(sk)->rcv_nxt; + snd_nxt = tcp_sk(sk)->snd_nxt; + } + + if (WARN_ONCE(!info, "unexpected missing info for sk=%p sk_state=%d", sk, sk->sk_state)) + return -EINVAL; + + if (input) + *sne = htonl(compute_sne(info->rcv_sne, rcv_nxt, seq)); + else + *sne = htonl(compute_sne(info->snd_sne, snd_nxt, seq)); + + return 0; +} + /* Feed one buffer into ahash * The buffer is assumed to be DMA-able */ static int crypto_ahash_buf(struct ahash_request *req, u8 *buf, uint len) { @@ -686,10 +773,13 @@ int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct r if (!new_info) return -ENOMEM;

new_info->src_isn = tcp_rsk(req)->snt_isn; new_info->dst_isn = tcp_rsk(req)->rcv_isn; + /* Caller is tcp_create_openreq_child and already initializes snd_nxt/rcv_nxt */ + new_info->snd_sne = compute_sne(0, new_info->src_isn, tcp_sk(newsk)->snd_nxt); + new_info->rcv_sne = compute_sne(0, new_info->dst_isn, tcp_sk(newsk)->rcv_nxt); 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; @@ -703,10 +793,12 @@ int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct r void __tcp_authopt_finish_connect(struct sock *sk, struct sk_buff *skb, struct tcp_authopt_info *info) { info->src_isn = ntohl(tcp_hdr(skb)->ack_seq) - 1; info->dst_isn = ntohl(tcp_hdr(skb)->seq); + info->snd_sne = compute_sne(0, info->src_isn, tcp_sk(sk)->snd_nxt); + info->rcv_sne = compute_sne(0, info->dst_isn, tcp_sk(sk)->rcv_nxt); }

/* feed traffic key into ahash */ static int tcp_authopt_ahash_traffic_key(struct tcp_authopt_alg_pool *pool, struct sock *sk, @@ -952,14 +1044,16 @@ static int tcp_authopt_hash_packet(struct tcp_authopt_alg_pool *pool, bool ipv6, bool include_options, u8 *macbuf) { struct tcphdr *th = tcp_hdr(skb); + __be32 sne = 0; int err;

- /* NOTE: SNE unimplemented */ - __be32 sne = 0; + err = compute_packet_sne(sk, info, ntohl(th->seq), input, &sne); + if (err) + return err;

err = crypto_ahash_init(pool->req); if (err) return err;

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 4c9e403971fb..bc0a90c72391 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3517,10 +3517,11 @@ static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq) { u32 delta = seq - tp->rcv_nxt;

sock_owned_by_me((struct sock *)tp); + tcp_authopt_update_rcv_sne(tp, seq); tp->bytes_received += delta; WRITE_ONCE(tp->rcv_nxt, seq); }

/* Update our send window. diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index b959e8b949b6..6a6024a0b9e9 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -67,10 +67,11 @@ static void tcp_event_new_data_sent(struct sock *sk, struct sk_buff *skb) { struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); unsigned int prior_packets = tp->packets_out;

+ tcp_authopt_update_snd_sne(tp, TCP_SKB_CB(skb)->end_seq); WRITE_ONCE(tp->snd_nxt, TCP_SKB_CB(skb)->end_seq);

__skb_unlink(skb, &sk->sk_write_queue); tcp_rbtree_insert(&sk->tcp_rtx_queue, skb);

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 | 144 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 151 insertions(+)

diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index d5d344d599f7..411e7a0bdd43 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -111,10 +111,17 @@ 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 tcp_authopt_info *info, 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 f1213c7db63b..a4f3eac20b29 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -935,10 +935,72 @@ static int tcp_authopt_get_traffic_key(struct sock *sk, out: tcp_authopt_put_kdf_pool(key, pool); 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 tcp_authopt_alg_pool *pool; + struct tcp_v4_authopt_context_data data; + + BUILD_BUG_ON(sizeof(data) != 22); + + pool = tcp_authopt_get_kdf_pool(key); + if (IS_ERR(pool)) + return PTR_ERR(pool); + + err = tcp_authopt_setkey(pool, key); + if (err) + goto out; + err = crypto_ahash_init(pool->req); + if (err) + goto out; + + // RFC5926 section 3.1.1.1 + // Separate to keep alignment semi-sane + err = crypto_ahash_buf(pool->req, "\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_ahash_digestsize(pool->tfm) * 8); + + err = crypto_ahash_buf(pool->req, (u8 *)&data, sizeof(data)); + if (err) + goto out; + ahash_request_set_crypt(pool->req, NULL, traffic_key, 0); + err = crypto_ahash_final(pool->req); + if (err) + goto out; + +out: + tcp_authopt_put_kdf_pool(key, pool); + return err; +} + static int crypto_ahash_buf_zero(struct ahash_request *req, int len) { u8 zeros[TCP_AUTHOPT_MACLEN] = {0}; int buflen, err;

@@ -1198,10 +1260,92 @@ int tcp_authopt_hash(char *hash_location, memset(hash_location, 0, TCP_AUTHOPT_MACLEN); return err; } EXPORT_SYMBOL(tcp_authopt_hash);

+/** + * tcp_v4_authopt_hash_reply - Hash tcp+ipv4 header without SKB + * + * @hash_location: output buffer + * @info: sending socket's tcp_authopt_info + * @key: signing key, from tcp_authopt_select_key. + * @saddr: source address + * @daddr: destination address + * @th: Pointer to TCP header and options + */ +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 tcp_authopt_alg_pool *pool; + u8 macbuf[TCP_AUTHOPT_MAXMACBUF]; + u8 traffic_key[TCP_AUTHOPT_MAX_TRAFFIC_KEY_LEN]; + __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 */ + pool = tcp_authopt_get_mac_pool(key); + if (IS_ERR(pool)) + return PTR_ERR(pool); + err = crypto_ahash_setkey(pool->tfm, traffic_key, key->alg->traffic_key_len); + if (err) + goto out_err; + err = crypto_ahash_init(pool->req); + if (err) + return err; + + err = crypto_ahash_buf(pool->req, (u8 *)&sne, 4); + if (err) + return err; + + err = tcp_authopt_hash_tcp4_pseudoheader(pool, 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_ahash_buf(pool->req, (u8 *)th, sizeof(*th)); + if (err) + goto out_err; + + // TCP options + err = tcp_authopt_hash_opts(pool, th, (struct tcphdr_authopt *)(hash_location - 4), + !(key->flags & TCP_AUTHOPT_KEY_EXCLUDE_OPTS)); + if (err) + goto out_err; + + ahash_request_set_crypt(pool->req, NULL, macbuf, 0); + err = crypto_ahash_final(pool->req); + if (err) + goto out_err; + memcpy(hash_location, macbuf, TCP_AUTHOPT_MACLEN); + + tcp_authopt_put_mac_pool(key, pool); + return 0; + +out_err: + tcp_authopt_put_mac_pool(key, pool); +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, bool *anykey)

The RFC requires that TCP can report the keyid and rnextkeyid values being sent or received, implement this via getsockopt values.

The RFC also requires that user can select the sending key and that the sending key is automatically switched based on rnextkeyid. These requirements can conflict so we implement both and add a flag which specifies if user or peer request takes priority.

Also add an option to control rnextkeyid explicitly from userspace.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- Documentation/networking/tcp_authopt.rst | 25 ++++++ include/net/tcp_authopt.h | 38 ++++++++- include/uapi/linux/tcp.h | 31 ++++++++ net/ipv4/tcp_authopt.c | 98 +++++++++++++++++++++++- net/ipv4/tcp_ipv4.c | 2 +- net/ipv6/tcp_ipv6.c | 2 +- 6 files changed, 189 insertions(+), 7 deletions(-)

diff --git a/Documentation/networking/tcp_authopt.rst b/Documentation/networking/tcp_authopt.rst index 484f66f41ad5..cded87a70d05 100644 --- a/Documentation/networking/tcp_authopt.rst +++ b/Documentation/networking/tcp_authopt.rst @@ -35,10 +35,35 @@ Keys can be bound to remote addresses in a way that is similar to TCP_MD5.

RFC5925 requires that key ids do not overlap when tcp identifiers (addr/port) overlap. This is not enforced by linux, configuring ambiguous keys will result in packet drops and lost connections.

+Key selection +------------- + +On getsockopt(TCP_AUTHOPT) information is provided about keyid/rnextkeyid in +the last send packet and about the keyid/rnextkeyd in the last valid received +packet. + +By default the sending keyid is selected to match the "rnextkeyid" value sent +by the remote side. If that keyid is not available (or for new connections) a +random matching key is selected. + +If the `TCP_AUTHOPT_LOCK_KEYID` is set then the sending key is selected by the +`tcp_authopt.send_local_id` field and rnextkeyid is ignored. If no key with +local_id == send_local_id is configured then a random matching key is +selected. + +The current sending key is cached in the socket and will not change unless +requested by remote rnextkeyid or by setsockopt. + +The rnextkeyid value sent on the wire is usually the recv_id of the current +key used for sending. If the TCP_AUTHOPT_LOCK_RNEXTKEY flag is set in +`tcp_authopt.flags` the value of `tcp_authopt.send_rnextkeyid` is send +instead. This can be used to implement smooth rollover: the peer will switch +its keyid to the received rnextkeyid when it is available. + ABI Reference =============

.. kernel-doc:: include/uapi/linux/tcp.h :identifiers: tcp_authopt tcp_authopt_flag tcp_authopt_key tcp_authopt_key_flag tcp_authopt_alg diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index 411e7a0bdd43..020637265ce9 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -66,10 +66,43 @@ struct tcp_authopt_info { u32 dst_isn; /** @rcv_sne: Recv-side Sequence Number Extension tracking tcp_sock.rcv_nxt */ u32 rcv_sne; /** @snd_sne: Send-side Sequence Number Extension tracking tcp_sock.snd_nxt */ u32 snd_sne; + + /** + * @send_keyid: keyid currently being sent + * + * This is controlled by userspace by userspace if + * TCP_AUTHOPT_FLAG_LOCK_KEYID, otherwise we try to match recv_rnextkeyid + */ + u8 send_keyid; + /** + * @send_rnextkeyid: rnextkeyid currently being sent + * + * This is controlled by userspace if TCP_AUTHOPT_FLAG_LOCK_RNEXTKEYID is set + */ + u8 send_rnextkeyid; + /** + * @recv_keyid: last keyid received from remote + * + * This is reported to userspace but has no other special behavior attached. + */ + u8 recv_keyid; + /** + * @recv_rnextkeyid: last rnextkeyid received from remote + * + * Linux tries to honor this unless TCP_AUTHOPT_FLAG_LOCK_KEYID is set + */ + u8 recv_rnextkeyid; + + /** + * @send_key: Current key used for sending, cached. + * + * Once a key is found it only changes by user or remote request. + */ + struct tcp_authopt_key_info *send_key; };

/* TCP authopt as found in header */ struct tcphdr_authopt { u8 num; @@ -91,22 +124,23 @@ 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); + u8 *rnextkeyid, + bool locked); static inline struct tcp_authopt_key_info *tcp_authopt_select_key( const struct sock *sk, const struct sock *addr_sk, struct tcp_authopt_info **info, u8 *rnextkeyid) { if (tcp_authopt_needed) { *info = rcu_dereference(tcp_sk(sk)->authopt_info);

if (*info) - return __tcp_authopt_select_key(sk, *info, addr_sk, rnextkeyid); + return __tcp_authopt_select_key(sk, *info, addr_sk, rnextkeyid, true); } return NULL; } int tcp_authopt_hash( char *hash_location, diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 76d7be6b27f4..e02176390519 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -346,10 +346,24 @@ struct tcp_diag_md5sig {

/** * enum tcp_authopt_flag - flags for `tcp_authopt.flags` */ enum tcp_authopt_flag { + /** + * @TCP_AUTHOPT_FLAG_LOCK_KEYID: keyid controlled by sockopt + * + * If this is set `tcp_authopt.send_keyid` is used to determined sending + * key. Otherwise a key with send_id == recv_rnextkeyid is preferred. + */ + TCP_AUTHOPT_FLAG_LOCK_KEYID = (1 << 0), + /** + * @TCP_AUTHOPT_FLAG_LOCK_RNEXTKEYID: Override rnextkeyid from userspace + * + * If this is set then `tcp_authopt.send_rnextkeyid` is sent on outbound + * packets. Other the recv_id of the current sending key is sent. + */ + TCP_AUTHOPT_FLAG_LOCK_RNEXTKEYID = (1 << 1), /** * @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. @@ -361,10 +375,27 @@ enum tcp_authopt_flag { * struct tcp_authopt - Per-socket options related to TCP Authentication Option */ struct tcp_authopt { /** @flags: Combination of &enum tcp_authopt_flag */ __u32 flags; + /** + * @send_keyid: `tcp_authopt_key.send_id` of preferred send key + * + * This is only used if `TCP_AUTHOPT_FLAG_LOCK_KEYID` is set. + */ + __u8 send_keyid; + /** + * @send_rnextkeyid: The rnextkeyid to send in packets + * + * This is controlled by the user iff TCP_AUTHOPT_FLAG_LOCK_RNEXTKEYID is + * set. Otherwise rnextkeyid is the recv_id of the current key. + */ + __u8 send_rnextkeyid; + /** @recv_keyid: A recently-received keyid value. Only for getsockopt. */ + __u8 recv_keyid; + /** @recv_rnextkeyid: A recently-received rnextkeyid value. Only for getsockopt. */ + __u8 recv_rnextkeyid; };

/** * enum tcp_authopt_key_flag - flags for `tcp_authopt.flags` * diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index a4f3eac20b29..a8950c9a7e84 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -309,20 +309,76 @@ static struct tcp_authopt_key_info *tcp_authopt_lookup_send(struct tcp_authopt_i * * @sk: socket * @info: socket's tcp_authopt_info * @addr_sk: socket used for address lookup. Same as sk except for synack case * @rnextkeyid: value of rnextkeyid caller should write in packet + * @locked: If we're holding the socket lock. This is false for some timewait and reset cases * * 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) + u8 *rnextkeyid, + bool locked) { - return tcp_authopt_lookup_send(info, addr_sk, -1); + struct tcp_authopt_key_info *key, *new_key = NULL; + + /* Listen sockets don't refer to any specific connection so we don't try + * to keep using the same key and ignore any received keyids. + */ + if (sk->sk_state == TCP_LISTEN) { + int send_keyid = -1; + + if (info->flags & TCP_AUTHOPT_FLAG_LOCK_KEYID) + send_keyid = info->send_keyid; + key = tcp_authopt_lookup_send(info, addr_sk, send_keyid); + if (key) + *rnextkeyid = key->recv_id; + + return key; + } + + if (locked) + key = rcu_dereference_protected(info->send_key, lockdep_sock_is_held(sk)); + else + key = rcu_dereference(info->send_key); + + /* Try to keep the same sending key unless user or peer requires a different key + * User request (via TCP_AUTHOPT_FLAG_LOCK_KEYID) always overrides peer request. + */ + if (info->flags & TCP_AUTHOPT_FLAG_LOCK_KEYID) { + int send_keyid = info->send_keyid; + + if (!key || key->send_id != send_keyid) + new_key = tcp_authopt_lookup_send(info, addr_sk, send_keyid); + } else { + if (!key || key->send_id != info->recv_rnextkeyid) + new_key = tcp_authopt_lookup_send(info, addr_sk, info->recv_rnextkeyid); + } + /* If no key found with specific send_id try anything else. */ + if (!key && !new_key) + new_key = tcp_authopt_lookup_send(info, addr_sk, -1); + + /* Update current key only if we hold the socket lock, otherwise we might + * store a pointer that goes stale + */ + if (new_key && key != new_key) { + key = new_key; + if (locked) + rcu_assign_pointer(info->send_key, key); + } + + if (key) { + if (info->flags & TCP_AUTHOPT_FLAG_LOCK_RNEXTKEYID) + *rnextkeyid = info->send_rnextkeyid; + else + *rnextkeyid = info->send_rnextkeyid = key->recv_id; + } + + return key; } EXPORT_SYMBOL(__tcp_authopt_select_key);

static struct tcp_authopt_info *__tcp_authopt_info_get_or_create(struct sock *sk) { @@ -345,10 +401,12 @@ static struct tcp_authopt_info *__tcp_authopt_info_get_or_create(struct sock *sk

return info; }

#define TCP_AUTHOPT_KNOWN_FLAGS ( \ + TCP_AUTHOPT_FLAG_LOCK_KEYID | \ + TCP_AUTHOPT_FLAG_LOCK_RNEXTKEYID | \ 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 @@ -416,18 +474,23 @@ int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen) info = __tcp_authopt_info_get_or_create(sk); if (IS_ERR(info)) return PTR_ERR(info);

info->flags = opt.flags & TCP_AUTHOPT_KNOWN_FLAGS; + if (opt.flags & TCP_AUTHOPT_FLAG_LOCK_KEYID) + info->send_keyid = opt.send_keyid; + if (opt.flags & TCP_AUTHOPT_FLAG_LOCK_RNEXTKEYID) + info->send_rnextkeyid = opt.send_rnextkeyid;

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; + struct tcp_authopt_key_info *send_key; int err;

memset(opt, 0, sizeof(*opt)); sock_owned_by_me(sk); err = check_sysctl_tcp_authopt(); @@ -437,10 +500,22 @@ int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *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; + /* These keyids might be undefined, for example before connect. + * Reporting zero is not strictly correct because there are no reserved + * values. + */ + send_key = rcu_dereference_check(info->send_key, lockdep_sock_is_held(sk)); + if (send_key) + opt->send_keyid = send_key->send_id; + else + opt->send_keyid = 0; + opt->send_rnextkeyid = info->send_rnextkeyid; + opt->recv_keyid = info->recv_keyid; + opt->recv_rnextkeyid = info->recv_rnextkeyid;

return 0; }

/* Free key nicely, for living sockets */ @@ -448,10 +523,12 @@ 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); + if (rcu_dereference_protected(info->send_key, lockdep_sock_is_held(sk)) == key) + rcu_assign_pointer(info->send_key, NULL); atomic_sub(sizeof(*key), &sk->sk_omem_alloc); kfree_rcu(key, rcu); }

/* Free info and keys. @@ -1422,11 +1499,11 @@ int __tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb, NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); print_tcpao_notice("TCP Authentication Unexpected: Rejected", skb); return -EINVAL; } print_tcpao_notice("TCP Authentication Unexpected: Accepted", skb); - return 0; + goto accept; } if (opt && !key) { /* Keys are configured for peer but with different keyid than packet */ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); print_tcpao_notice("TCP Authentication Failed", skb); @@ -1445,8 +1522,23 @@ int __tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb, NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTHOPTFAILURE); print_tcpao_notice("TCP Authentication Failed", skb); return -EINVAL; }

+accept: + /* Doing this for all valid packets will results in keyids temporarily + * flipping back and forth if packets are reordered or retransmitted + * but keys should eventually stabilize. + * + * This is connection-specific so don't store for listen sockets. + * + * We could store rnextkeyid from SYN in a request sock and use it for + * the SYNACK but we don't. + */ + if (sk->sk_state != TCP_LISTEN) { + info->recv_keyid = opt->keyid; + info->recv_rnextkeyid = opt->rnextkeyid; + } + return 1; } EXPORT_SYMBOL(__tcp_authopt_inbound_check); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index be531e2f52ae..edfb76f76485 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -664,11 +664,11 @@ static int tcp_v4_authopt_handle_reply(const struct sock *sk, info = tcp_twsk(sk)->tw_authopt_info; else info = tcp_sk(sk)->authopt_info; if (!info) return 0; - key_info = __tcp_authopt_select_key(sk, info, sk, &rnextkeyid); + key_info = __tcp_authopt_select_key(sk, info, sk, &rnextkeyid, false); if (!key_info) return 0; *optptr = htonl((TCPOPT_AUTHOPT << 24) | (TCPOLEN_AUTHOPT_OUTPUT << 16) | (key_info->send_id << 8) | diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index cd8544d08a36..6ed13f8f489f 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -901,11 +901,11 @@ static int tcp_v6_send_response_init_authopt(const struct sock *sk, *info = tcp_twsk(sk)->tw_authopt_info; else *info = rcu_dereference(tcp_sk(sk)->authopt_info); if (!*info) return 0; - *key = __tcp_authopt_select_key(sk, *info, sk, rnextkeyid); + *key = __tcp_authopt_select_key(sk, *info, sk, rnextkeyid, false); if (*key) return TCPOLEN_AUTHOPT_OUTPUT; return 0; }

Add flags to allow marking individual keys and invalid for send or recv. Making keys assymetric this way is not mentioned in RFC5925 but RFC8177 requires that keys inside a keychain have independent "accept" and "send" lifetimes.

Flag names are negative so that the default behavior is for keys to be valid for both send and recv.

Setting both NOSEND and NORECV for a certain peer address can be used on a listen socket can be used to mean "TCP-AO is required from this peer but no keys are currently valid".

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- include/uapi/linux/tcp.h | 4 ++++ net/ipv4/tcp_authopt.c | 9 ++++++++- 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index a7f5f918ed5a..ed27feb93b0e 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -401,16 +401,20 @@ struct tcp_authopt { * * @TCP_AUTHOPT_KEY_DEL: Delete the key and ignore non-id fields * @TCP_AUTHOPT_KEY_EXCLUDE_OPTS: Exclude TCP options from signature * @TCP_AUTHOPT_KEY_ADDR_BIND: Key only valid for `tcp_authopt.addr` * @TCP_AUTHOPT_KEY_IFINDEX: Key only valid for `tcp_authopt.ifindex` + * @TCP_AUTHOPT_KEY_NOSEND: Key invalid for send (expired) + * @TCP_AUTHOPT_KEY_NORECV: Key invalid for recv (expired) */ enum tcp_authopt_key_flag { TCP_AUTHOPT_KEY_DEL = (1 << 0), TCP_AUTHOPT_KEY_EXCLUDE_OPTS = (1 << 1), TCP_AUTHOPT_KEY_ADDR_BIND = (1 << 2), TCP_AUTHOPT_KEY_IFINDEX = (1 << 3), + TCP_AUTHOPT_KEY_NOSEND = (1 << 4), + TCP_AUTHOPT_KEY_NORECV = (1 << 5), };

/** * enum tcp_authopt_alg - Algorithms for TCP Authentication Option */ diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index b3fd12fcb948..946d598258b1 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -311,10 +311,12 @@ static struct tcp_authopt_key_info *tcp_authopt_lookup_send(struct tcp_authopt_i int l3index = -1;

hlist_for_each_entry_rcu(key, &info->head, node, 0) { if (send_id >= 0 && key->send_id != send_id) continue; + if (key->flags & TCP_AUTHOPT_KEY_NOSEND) + continue; if (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND) if (!tcp_authopt_key_match_sk_addr(key, addr_sk)) continue; if (key->flags & TCP_AUTHOPT_KEY_IFINDEX) { if (l3index < 0) @@ -593,11 +595,13 @@ void tcp_authopt_clear(struct sock *sk)

#define TCP_AUTHOPT_KEY_KNOWN_FLAGS ( \ TCP_AUTHOPT_KEY_DEL | \ TCP_AUTHOPT_KEY_EXCLUDE_OPTS | \ TCP_AUTHOPT_KEY_ADDR_BIND | \ - TCP_AUTHOPT_KEY_IFINDEX) + TCP_AUTHOPT_KEY_IFINDEX | \ + TCP_AUTHOPT_KEY_NOSEND | \ + TCP_AUTHOPT_KEY_NORECV)

int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) { struct tcp_authopt_key opt; struct tcp_authopt_info *info; @@ -1496,10 +1500,13 @@ static struct tcp_authopt_key_info *tcp_authopt_lookup_recv(struct sock *sk,

if (l3index != key->l3index) continue; } *anykey = true; + // If only keys with norecv flag are present still consider that + if (key->flags & TCP_AUTHOPT_KEY_NORECV) + continue; if (recv_id >= 0 && key->recv_id != recv_id) continue; if (better_key_match(result, key)) result = key; else if (result)

This is in preparation for reusing the same option for TCP-AO

Reviewed-by: David Ahern dsahern@kernel.org Signed-off-by: Leonard Crestez cdleonard@gmail.com --- tools/testing/selftests/net/nettest.c | 50 +++++++++++++-------------- 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/tools/testing/selftests/net/nettest.c b/tools/testing/selftests/net/nettest.c index d9a6fd2cd9d3..3841e5fec7c7 100644 --- a/tools/testing/selftests/net/nettest.c +++ b/tools/testing/selftests/net/nettest.c @@ -94,17 +94,17 @@ struct sock_args { const char *clientns; const char *serverns;

const char *password; const char *client_pw; - /* prefix for MD5 password */ - const char *md5_prefix_str; + /* prefix for MD5/AO*/ + const char *key_addr_prefix_str; union { struct sockaddr_in v4; struct sockaddr_in6 v6; - } md5_prefix; - unsigned int prefix_len; + } key_addr; + unsigned int key_addr_prefix_len; /* 0: default, -1: force off, +1: force on */ int bind_key_ifindex;

/* expected addresses and device index for connection */ const char *expected_dev; @@ -264,16 +264,16 @@ static int tcp_md5sig(int sd, void *addr, socklen_t alen, struct sock_args *args int rc;

md5sig.tcpm_keylen = keylen; memcpy(md5sig.tcpm_key, args->password, keylen);

- if (args->prefix_len) { + if (args->key_addr_prefix_len) { opt = TCP_MD5SIG_EXT; md5sig.tcpm_flags |= TCP_MD5SIG_FLAG_PREFIX;

- md5sig.tcpm_prefixlen = args->prefix_len; - addr = &args->md5_prefix; + md5sig.tcpm_prefixlen = args->key_addr_prefix_len; + addr = &args->key_addr; } memcpy(&md5sig.tcpm_addr, addr, alen);

if ((args->ifindex && args->bind_key_ifindex >= 0) || args->bind_key_ifindex >= 1) { opt = TCP_MD5SIG_EXT; @@ -309,17 +309,17 @@ static int tcp_md5_remote(int sd, struct sock_args *args) int alen;

switch (args->version) { case AF_INET: sin.sin_port = htons(args->port); - sin.sin_addr = args->md5_prefix.v4.sin_addr; + sin.sin_addr = args->key_addr.v4.sin_addr; addr = &sin; alen = sizeof(sin); break; case AF_INET6: sin6.sin6_port = htons(args->port); - sin6.sin6_addr = args->md5_prefix.v6.sin6_addr; + sin6.sin6_addr = args->key_addr.v6.sin6_addr; addr = &sin6; alen = sizeof(sin6); break; default: log_error("unknown address family\n"); @@ -705,11 +705,11 @@ enum addr_type { ADDR_TYPE_LOCAL, ADDR_TYPE_REMOTE, ADDR_TYPE_MCAST, ADDR_TYPE_EXPECTED_LOCAL, ADDR_TYPE_EXPECTED_REMOTE, - ADDR_TYPE_MD5_PREFIX, + ADDR_TYPE_KEY_PREFIX, };

static int convert_addr(struct sock_args *args, const char *_str, enum addr_type atype) { @@ -745,32 +745,32 @@ static int convert_addr(struct sock_args *args, const char *_str, break; case ADDR_TYPE_EXPECTED_REMOTE: desc = "expected remote"; addr = &args->expected_raddr; break; - case ADDR_TYPE_MD5_PREFIX: - desc = "md5 prefix"; + case ADDR_TYPE_KEY_PREFIX: + desc = "key addr prefix"; if (family == AF_INET) { - args->md5_prefix.v4.sin_family = AF_INET; - addr = &args->md5_prefix.v4.sin_addr; + args->key_addr.v4.sin_family = AF_INET; + addr = &args->key_addr.v4.sin_addr; } else if (family == AF_INET6) { - args->md5_prefix.v6.sin6_family = AF_INET6; - addr = &args->md5_prefix.v6.sin6_addr; + args->key_addr.v6.sin6_family = AF_INET6; + addr = &args->key_addr.v6.sin6_addr; } else return 1;

sep = strchr(str, '/'); if (sep) { *sep = '\0'; sep++; if (str_to_uint(sep, 1, pfx_len_max, - &args->prefix_len) != 0) { - fprintf(stderr, "Invalid port\n"); + &args->key_addr_prefix_len) != 0) { + fprintf(stderr, "Invalid prefix\n"); return 1; } } else { - args->prefix_len = 0; + args->key_addr_prefix_len = 0; } break; default: log_error("unknown address type\n"); exit(1); @@ -835,13 +835,13 @@ static int validate_addresses(struct sock_args *args)

if (args->remote_addr_str && convert_addr(args, args->remote_addr_str, ADDR_TYPE_REMOTE) < 0) return 1;

- if (args->md5_prefix_str && - convert_addr(args, args->md5_prefix_str, - ADDR_TYPE_MD5_PREFIX) < 0) + if (args->key_addr_prefix_str && + convert_addr(args, args->key_addr_prefix_str, + ADDR_TYPE_KEY_PREFIX) < 0) return 1;

if (args->expected_laddr_str && convert_addr(args, args->expected_laddr_str, ADDR_TYPE_EXPECTED_LOCAL)) @@ -2020,11 +2020,11 @@ int main(int argc, char *argv[]) break; case 'X': args.client_pw = optarg; break; case 'm': - args.md5_prefix_str = optarg; + args.key_addr_prefix_str = optarg; break; case 'S': args.use_setsockopt = 1; break; case 'f': @@ -2079,17 +2079,17 @@ int main(int argc, char *argv[]) return 1; } }

if (args.password && - ((!args.has_remote_ip && !args.md5_prefix_str) || + ((!args.has_remote_ip && !args.key_addr_prefix_str) || args.type != SOCK_STREAM)) { log_error("MD5 passwords apply to TCP only and require a remote ip for the password\n"); return 1; }

- if (args.md5_prefix_str && !args.password) { + if (args.key_addr_prefix_str && !args.password) { log_error("Prefix range for MD5 protection specified without a password\n"); return 1; }

if (iter == 0) {

Tests are mostly copied from tcp_md5 with minor changes.

It covers VRF support but only based on binding multiple servers: not multiple keys bound to different interfaces.

Also add a specific -t tcp_authopt to run only these tests specifically.

Signed-off-by: Leonard Crestez cdleonard@gmail.com --- tools/testing/selftests/net/fcnal-test.sh | 298 ++++++++++++++++++++++ 1 file changed, 298 insertions(+)

diff --git a/tools/testing/selftests/net/fcnal-test.sh b/tools/testing/selftests/net/fcnal-test.sh index 32d5f7bc588e..e99b44f0ae5a 100755 --- a/tools/testing/selftests/net/fcnal-test.sh +++ b/tools/testing/selftests/net/fcnal-test.sh @@ -807,10 +807,301 @@ ipv4_ping() }

################################################################################ # IPv4 TCP

+# +# TCP Authentication Option Tests +# + +# try to enable tcp_authopt sysctl +enable_tcp_authopt() +{ + if [[ -e /proc/sys/net/ipv4/tcp_authopt ]]; then + sysctl -w net.ipv4.tcp_authopt=1 + fi +} + +# check if tcp_authopt is compiled with a client-side bind test +has_tcp_authopt() +{ + run_cmd_nsb nettest -b -A ${MD5_PW} -r ${NSA_IP} +} + +ipv4_tcp_authopt_novrf() +{ + enable_tcp_authopt + if ! has_tcp_authopt; then + echo "TCP-AO appears to be missing, skip" + return 0 + fi + + log_start + run_cmd nettest -s -A ${MD5_PW} -m ${NSB_IP} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 0 "AO: Single address config" + + log_start + run_cmd nettest -s & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 2 "AO: Server no config, client uses password" + + log_start + run_cmd nettest -s -A ${MD5_PW} -m ${NSB_IP} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_WRONG_PW} + log_test $? 2 "AO: Client uses wrong password" + + log_start + run_cmd nettest -s -A ${MD5_PW} -m ${NSB_LO_IP} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 2 "AO: Client address does not match address configured on server" + + # client in prefix + log_start + run_cmd nettest -s -A ${MD5_PW} -m ${NS_NET} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 0 "AO: Prefix config" + + # client in prefix, wrong password + log_start + show_hint "Should timeout since client uses wrong password" + run_cmd nettest -s -A ${MD5_PW} -m ${NS_NET} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_WRONG_PW} + log_test $? 2 "AO: Prefix config, client uses wrong password" + + # client outside of prefix + log_start + show_hint "Should timeout due to MD5 mismatch" + run_cmd nettest -s -A ${MD5_PW} -m ${NS_NET} & + sleep 1 + run_cmd_nsb nettest -c ${NSB_LO_IP} -r ${NSA_IP} -A ${MD5_PW} + log_test $? 2 "AO: Prefix config, client address not in configured prefix" +} + +ipv6_tcp_authopt_novrf() +{ + enable_tcp_authopt + if ! has_tcp_authopt; then + echo "TCP-AO appears to be missing, skip" + return 0 + fi + + log_start + run_cmd nettest -6 -s -A ${MD5_PW} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 0 "AO: Simple correct config" + + log_start + run_cmd nettest -6 -s + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 2 "AO: Server no config, client uses password" + + log_start + run_cmd nettest -6 -s -A ${MD5_PW} -m ${NSB_IP6} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_WRONG_PW} + log_test $? 2 "AO: Client uses wrong password" + + log_start + run_cmd nettest -6 -s -A ${MD5_PW} -m ${NSB_LO_IP6} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 2 "AO: Client address does not match address configured on server" +} + +ipv4_tcp_authopt_vrf() +{ + enable_tcp_authopt + if ! has_tcp_authopt; then + echo "TCP-AO appears to be missing, skip" + return 0 + fi + + log_start + run_cmd nettest -s -I ${VRF} -A ${MD5_PW} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Simple config" + + # + # duplicate config between default VRF and a VRF + # + + log_start + run_cmd nettest -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP} & + run_cmd nettest -s -A ${MD5_WRONG_PW} -m ${NSB_IP} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Servers in default-VRF and VRF, client in VRF" + + log_start + run_cmd nettest -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP} & + run_cmd nettest -s -A ${MD5_WRONG_PW} -m ${NSB_IP} & + sleep 1 + run_cmd_nsc nettest -r ${NSA_IP} -A ${MD5_WRONG_PW} + log_test $? 0 "AO: VRF: Servers in default-VRF and VRF, client in default-VRF" + + log_start + show_hint "Should timeout since client in default VRF uses VRF password" + run_cmd nettest -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP} & + run_cmd nettest -s -A ${MD5_WRONG_PW} -m ${NSB_IP} & + sleep 1 + run_cmd_nsc nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 2 "AO: VRF: Servers in default VRF and VRF, conn in default-VRF with VRF pw" + + log_start + show_hint "Should timeout since client in VRF uses default VRF password" + run_cmd nettest -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP} & + run_cmd nettest -s -A ${MD5_WRONG_PW} -m ${NSB_IP} & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_WRONG_PW} + log_test $? 2 "AO: VRF: Servers in default VRF and VRF, conn in VRF with default-VRF pw" + + test_ipv4_tcp_authopt_vrf__global_server__bind_ifindex0 +} + +test_ipv4_tcp_authopt_vrf__global_server__bind_ifindex0() +{ + # This particular test needs tcp_l3mdev_accept=1 for Global server to accept VRF connections + local old_tcp_l3mdev_accept + old_tcp_l3mdev_accept=$(get_sysctl net.ipv4.tcp_l3mdev_accept) + set_sysctl net.ipv4.tcp_l3mdev_accept=1 + + log_start + run_cmd nettest -s -A ${MD5_PW} --force-bind-key-ifindex & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 2 "AO: VRF: Global server, Key bound to ifindex=0 rejects VRF connection" + + log_start + run_cmd nettest -s -A ${MD5_PW} --force-bind-key-ifindex & + sleep 1 + run_cmd_nsc nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Global server, key bound to ifindex=0 accepts non-VRF connection" + log_start + + run_cmd nettest -s -A ${MD5_PW} --no-bind-key-ifindex & + sleep 1 + run_cmd_nsb nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Global server, key not bound to ifindex accepts VRF connection" + + log_start + run_cmd nettest -s -A ${MD5_PW} --no-bind-key-ifindex & + sleep 1 + run_cmd_nsc nettest -r ${NSA_IP} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Global server, key not bound to ifindex accepts non-VRF connection" + + # restore value + set_sysctl net.ipv4.tcp_l3mdev_accept="$old_tcp_l3mdev_accept" +} + +ipv6_tcp_authopt_vrf() +{ + enable_tcp_authopt + if ! has_tcp_authopt; then + echo "TCP-AO appears to be missing, skip" + return 0 + fi + + log_start + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Simple config" + + # + # duplicate config between default VRF and a VRF + # + + log_start + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NSB_IP6} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Servers in default-VRF and VRF, client in VRF" + + log_start + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NSB_IP6} & + sleep 1 + run_cmd_nsc nettest -6 -r ${NSA_IP6} -A ${MD5_WRONG_PW} + log_test $? 0 "AO: VRF: Servers in default-VRF and VRF, client in default-VRF" + + log_start + show_hint "Should timeout since client in default VRF uses VRF password" + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NSB_IP6} & + sleep 1 + run_cmd_nsc nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 2 "AO: VRF: Servers in default VRF and VRF, conn in default-VRF with VRF pw" + + log_start + show_hint "Should timeout since client in VRF uses default VRF password" + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NSB_IP6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NSB_IP6} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_WRONG_PW} + log_test $? 2 "AO: VRF: Servers in default VRF and VRF, conn in VRF with default-VRF pw" + + log_start + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NS_NET6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NS_NET6} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 0 "AO: VRF: Prefix config in default VRF and VRF, conn in VRF" + + log_start + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NS_NET6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NS_NET6} & + sleep 1 + run_cmd_nsc nettest -6 -r ${NSA_IP6} -A ${MD5_WRONG_PW} + log_test $? 0 "AO: VRF: Prefix config in default VRF and VRF, conn in default VRF" + + log_start + show_hint "Should timeout since client in default VRF uses VRF password" + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NS_NET6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NS_NET6} & + sleep 1 + run_cmd_nsc nettest -6 -r ${NSA_IP6} -A ${MD5_PW} + log_test $? 2 "AO: VRF: Prefix config in def VRF and VRF, conn in def VRF with VRF pw" + + log_start + show_hint "Should timeout since client in VRF uses default VRF password" + run_cmd nettest -6 -s -I ${VRF} -A ${MD5_PW} -m ${NS_NET6} & + run_cmd nettest -6 -s -A ${MD5_WRONG_PW} -m ${NS_NET6} & + sleep 1 + run_cmd_nsb nettest -6 -r ${NSA_IP6} -A ${MD5_WRONG_PW} + log_test $? 2 "AO: VRF: Prefix config in dev VRF and VRF, conn in VRF with def VRF pw" +} + +only_tcp_authopt() +{ + log_section "TCP Authentication Option" + + setup + set_sysctl net.ipv4.tcp_l3mdev_accept=0 + log_subsection "TCP-AO IPv4 no VRF" + ipv4_tcp_authopt_novrf + log_subsection "TCP-AO IPv6 no VRF" + ipv6_tcp_authopt_novrf + + setup "yes" + set_sysctl net.ipv4.tcp_l3mdev_accept=0 + log_subsection "TCP-AO IPv4 VRF" + ipv4_tcp_authopt_vrf + log_subsection "TCP-AO IPv6 VRF" + ipv6_tcp_authopt_vrf +} + # # MD5 tests without VRF # ipv4_tcp_md5_novrf() { @@ -1192,10 +1483,11 @@ ipv4_tcp_novrf() show_hint "Should fail 'Connection refused'" run_cmd nettest -d ${NSA_DEV} -r ${a} log_test_addr ${a} $? 1 "No server, device client, local conn"

ipv4_tcp_md5_novrf + ipv4_tcp_authopt_novrf }

ipv4_tcp_vrf() { local a @@ -1246,10 +1538,12 @@ ipv4_tcp_vrf() run_cmd nettest -r ${a} -d ${NSA_DEV} log_test_addr ${a} $? 1 "Global server, local connection"

# run MD5 tests ipv4_tcp_md5 + # run AO tests + ipv6_tcp_md5_vrf

# # enable VRF global server # log_subsection "VRF Global server enabled" @@ -2672,10 +2966,11 @@ ipv6_tcp_novrf() run_cmd nettest -6 -d ${NSA_DEV} -r ${a} log_test_addr ${a} $? 1 "No server, device client, local conn" done

ipv6_tcp_md5_novrf + ipv6_tcp_authopt_novrf }

ipv6_tcp_vrf() { local a @@ -2742,10 +3037,12 @@ ipv6_tcp_vrf() run_cmd nettest -6 -r ${a} -d ${NSA_DEV} log_test_addr ${a} $? 1 "Global server, local connection"

# run MD5 tests ipv6_tcp_md5 + # run AO tests + ipv6_tcp_authopt_vrf

# # enable VRF global server # log_subsection "VRF Global server enabled" @@ -4102,10 +4399,11 @@ 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;; esac