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Date: Tue, 6 Sep 2022 15:57:21 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: Leonard Crestez <cdleonard@...il.com>
Cc: David Ahern <dsahern@...nel.org>,
Dmitry Safonov <0x7f454c46@...il.com>,
Francesco Ruggeri <fruggeri@...sta.com>,
Salam Noureddine <noureddine@...sta.com>,
Philip Paeps <philip@...uble.is>,
Shuah Khan <shuah@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
Herbert Xu <herbert@...dor.apana.org.au>,
Kuniyuki Iwashima <kuniyu@...zon.co.jp>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Jakub Kicinski <kuba@...nel.org>,
Yuchung Cheng <ycheng@...gle.com>,
Mat Martineau <mathew.j.martineau@...ux.intel.com>,
Christoph Paasch <cpaasch@...le.com>,
Ivan Delalande <colona@...sta.com>,
Caowangbao <caowangbao@...wei.com>,
Priyaranjan Jha <priyarjha@...gle.com>,
netdev <netdev@...r.kernel.org>,
"open list:HARDWARE RANDOM NUMBER GENERATOR CORE"
<linux-crypto@...r.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v8 01/26] tcp: authopt: Initial support and key management
On Mon, Sep 5, 2022 at 12:06 AM Leonard Crestez <cdleonard@...il.com> wrote:
>
> This commit adds support to add and remove keys but does not use them
> further.
>
> Similar to tcp md5 a single pointer to a struct tcp_authopt_info* struct
> is added to struct tcp_sock, this avoids increasing memory usage. The
> data structures related to tcp_authopt are initialized on setsockopt and
> only freed on socket close.
>
Thanks Leonard.
Small points from my side, please find them attached.
> Signed-off-by: Leonard Crestez <cdleonard@...il.com>
> ---
> include/linux/tcp.h | 9 +
> include/net/net_namespace.h | 4 +
> include/net/netns/tcp_authopt.h | 12 ++
> include/net/tcp.h | 1 +
> include/net/tcp_authopt.h | 70 +++++++
> include/uapi/linux/tcp.h | 81 ++++++++
> net/ipv4/Kconfig | 14 ++
> net/ipv4/Makefile | 1 +
> net/ipv4/tcp.c | 32 ++++
> net/ipv4/tcp_authopt.c | 317 ++++++++++++++++++++++++++++++++
> net/ipv4/tcp_ipv4.c | 2 +
> 11 files changed, 543 insertions(+)
> create mode 100644 include/net/netns/tcp_authopt.h
> create mode 100644 include/net/tcp_authopt.h
> create mode 100644 net/ipv4/tcp_authopt.c
>
> diff --git a/include/linux/tcp.h b/include/linux/tcp.h
> index a9fbe22732c3..551942883f06 100644
> --- a/include/linux/tcp.h
> +++ b/include/linux/tcp.h
> @@ -170,10 +170,12 @@ struct tcp_request_sock {
> static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
> {
> return (struct tcp_request_sock *)req;
> }
>
> +struct tcp_authopt_info;
> +
> struct tcp_sock {
> /* inet_connection_sock has to be the first member of tcp_sock */
> struct inet_connection_sock inet_conn;
> u16 tcp_header_len; /* Bytes of tcp header to send */
> u16 gso_segs; /* Max number of segs per GSO packet */
> @@ -434,10 +436,14 @@ struct tcp_sock {
>
> /* TCP MD5 Signature Option information */
> struct tcp_md5sig_info __rcu *md5sig_info;
> #endif
>
> +#ifdef CONFIG_TCP_AUTHOPT
> + struct tcp_authopt_info __rcu *authopt_info;
> +#endif
> +
> /* TCP fastopen related information */
> struct tcp_fastopen_request *fastopen_req;
> /* fastopen_rsk points to request_sock that resulted in this big
> * socket. Used to retransmit SYNACKs etc.
> */
> @@ -484,10 +490,13 @@ struct tcp_timewait_sock {
> int tw_ts_recent_stamp;
> u32 tw_tx_delay;
> #ifdef CONFIG_TCP_MD5SIG
> struct tcp_md5sig_key *tw_md5_key;
> #endif
> +#ifdef CONFIG_TCP_AUTHOPT
> + struct tcp_authopt_info *tw_authopt_info;
> +#endif
> };
>
> static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
> {
> return (struct tcp_timewait_sock *)sk;
> diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
> index 8c3587d5c308..30964366951d 100644
> --- a/include/net/net_namespace.h
> +++ b/include/net/net_namespace.h
> @@ -35,10 +35,11 @@
> #include <net/netns/can.h>
> #include <net/netns/xdp.h>
> #include <net/netns/smc.h>
> #include <net/netns/bpf.h>
> #include <net/netns/mctp.h>
> +#include <net/netns/tcp_authopt.h>
> #include <net/net_trackers.h>
> #include <linux/ns_common.h>
> #include <linux/idr.h>
> #include <linux/skbuff.h>
> #include <linux/notifier.h>
> @@ -184,10 +185,13 @@ struct net {
> #endif
> struct sock *diag_nlsk;
> #if IS_ENABLED(CONFIG_SMC)
> struct netns_smc smc;
> #endif
> +#if IS_ENABLED(CONFIG_TCP_AUTHOPT)
> + struct netns_tcp_authopt tcp_authopt;
> +#endif
> } __randomize_layout;
>
> #include <linux/seq_file_net.h>
>
> /* Init's network namespace */
> diff --git a/include/net/netns/tcp_authopt.h b/include/net/netns/tcp_authopt.h
> new file mode 100644
> index 000000000000..03b7f4e58448
> --- /dev/null
> +++ b/include/net/netns/tcp_authopt.h
> @@ -0,0 +1,12 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __NETNS_TCP_AUTHOPT_H__
> +#define __NETNS_TCP_AUTHOPT_H__
> +
> +#include <linux/mutex.h>
> +
> +struct netns_tcp_authopt {
> + struct hlist_head head;
> + struct mutex mutex;
> +};
> +
> +#endif /* __NETNS_TCP_AUTHOPT_H__ */
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index d10962b9f0d0..9955a88faf9b 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -184,10 +184,11 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
> #define TCPOPT_WINDOW 3 /* Window scaling */
> #define TCPOPT_SACK_PERM 4 /* SACK Permitted */
> #define TCPOPT_SACK 5 /* SACK Block */
> #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */
> #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */
> +#define TCPOPT_AUTHOPT 29 /* Auth Option (RFC5925) */
> #define TCPOPT_MPTCP 30 /* Multipath TCP (RFC6824) */
> #define TCPOPT_FASTOPEN 34 /* Fast open (RFC7413) */
> #define TCPOPT_EXP 254 /* Experimental */
> /* Magic number to be after the option value for sharing TCP
> * experimental options. See draft-ietf-tcpm-experimental-options-00.txt
> diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h
> new file mode 100644
> index 000000000000..bc2cff82830d
> --- /dev/null
> +++ b/include/net/tcp_authopt.h
> @@ -0,0 +1,70 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +#ifndef _LINUX_TCP_AUTHOPT_H
> +#define _LINUX_TCP_AUTHOPT_H
> +
> +#include <uapi/linux/tcp.h>
> +#include <net/netns/tcp_authopt.h>
> +#include <linux/tcp.h>
> +
> +/**
> + * struct tcp_authopt_key_info - Representation of a Master Key Tuple as per RFC5925
> + *
> + * Key structure lifetime is protected by RCU so send/recv code needs to hold a
> + * single rcu_read_lock until they're done with the key.
> + *
> + * Global keys can be cached in sockets, this requires increasing kref.
> + */
> +struct tcp_authopt_key_info {
> + /** @node: node in &netns_tcp_authopt.head list */
> + struct hlist_node node;
> + /** @rcu: for kfree_rcu */
> + struct rcu_head rcu;
> + /** @ref: for kref_put */
> + struct kref ref;
> + /** @flags: Combination of &enum tcp_authopt_key_flag */
> + u32 flags;
> + /** @send_id: Same as &tcp_authopt_key.send_id */
> + u8 send_id;
> + /** @recv_id: Same as &tcp_authopt_key.recv_id */
> + u8 recv_id;
> + /** @alg_id: Same as &tcp_authopt_key.alg */
> + u8 alg_id;
> + /** @keylen: Same as &tcp_authopt_key.keylen */
> + u8 keylen;
> + /** @key: Same as &tcp_authopt_key.key */
> + u8 key[TCP_AUTHOPT_MAXKEYLEN];
> + /** @addr: Same as &tcp_authopt_key.addr */
> + struct sockaddr_storage addr;
> +};
> +
> +/**
> + * struct tcp_authopt_info - Per-socket information regarding tcp_authopt
> + *
> + * This is lazy-initialized in order to avoid increasing memory usage for
> + * regular TCP sockets. Once created it is only destroyed on socket close.
> + */
> +struct tcp_authopt_info {
> + /** @rcu: for kfree_rcu */
> + struct rcu_head rcu;
> + /** @flags: Combination of &enum tcp_authopt_flag */
> + u32 flags;
> + /** @src_isn: Local Initial Sequence Number */
> + u32 src_isn;
> + /** @dst_isn: Remote Initial Sequence Number */
> + u32 dst_isn;
> +};
> +
> +#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_clear(struct sock *sk);
> +int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen);
> +int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *key);
> +int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen);
> +#else
> +static inline void tcp_authopt_clear(struct sock *sk)
> +{
> +}
> +#endif
> +
> +#endif /* _LINUX_TCP_AUTHOPT_H */
> diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
> index 8fc09e8638b3..76d7be6b27f4 100644
> --- a/include/uapi/linux/tcp.h
> +++ b/include/uapi/linux/tcp.h
> @@ -126,10 +126,12 @@ enum {
> #define TCP_INQ 36 /* Notify bytes available to read as a cmsg on read */
>
> #define TCP_CM_INQ TCP_INQ
>
> #define TCP_TX_DELAY 37 /* delay outgoing packets by XX usec */
> +#define TCP_AUTHOPT 38 /* TCP Authentication Option (RFC5925) */
> +#define TCP_AUTHOPT_KEY 39 /* TCP Authentication Option Key (RFC5925) */
>
>
> #define TCP_REPAIR_ON 1
> #define TCP_REPAIR_OFF 0
> #define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */
> @@ -340,10 +342,89 @@ struct tcp_diag_md5sig {
> __u16 tcpm_keylen;
> __be32 tcpm_addr[4];
> __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
> };
>
> +/**
> + * enum tcp_authopt_flag - flags for `tcp_authopt.flags`
> + */
> +enum tcp_authopt_flag {
> + /**
> + * @TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED:
> + * Configure behavior of segments with TCP-AO coming from hosts for which no
> + * key is configured. The default recommended by RFC is to silently accept
> + * such connections.
> + */
> + TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED = (1 << 2),
> +};
> +
> +/**
> + * struct tcp_authopt - Per-socket options related to TCP Authentication Option
> + */
> +struct tcp_authopt {
> + /** @flags: Combination of &enum tcp_authopt_flag */
> + __u32 flags;
> +};
> +
> +/**
> + * enum tcp_authopt_key_flag - flags for `tcp_authopt.flags`
> + *
> + * @TCP_AUTHOPT_KEY_DEL: Delete the key and ignore non-id fields
> + * @TCP_AUTHOPT_KEY_EXCLUDE_OPTS: Exclude TCP options from signature
> + * @TCP_AUTHOPT_KEY_ADDR_BIND: Key only valid for `tcp_authopt.addr`
> + */
> +enum tcp_authopt_key_flag {
> + TCP_AUTHOPT_KEY_DEL = (1 << 0),
> + TCP_AUTHOPT_KEY_EXCLUDE_OPTS = (1 << 1),
> + TCP_AUTHOPT_KEY_ADDR_BIND = (1 << 2),
> +};
> +
> +/**
> + * enum tcp_authopt_alg - Algorithms for TCP Authentication Option
> + */
> +enum tcp_authopt_alg {
> + /** @TCP_AUTHOPT_ALG_HMAC_SHA_1_96: HMAC-SHA-1-96 as described in RFC5926 */
> + TCP_AUTHOPT_ALG_HMAC_SHA_1_96 = 1,
> + /** @TCP_AUTHOPT_ALG_AES_128_CMAC_96: AES-128-CMAC-96 as described in RFC5926 */
> + TCP_AUTHOPT_ALG_AES_128_CMAC_96 = 2,
> +};
> +
> +/* for TCP_AUTHOPT_KEY socket option */
> +#define TCP_AUTHOPT_MAXKEYLEN 80
> +
> +/**
> + * struct tcp_authopt_key - TCP Authentication KEY
> + *
> + * Key are identified by the combination of:
> + * - send_id
> + * - recv_id
> + * - addr (iff TCP_AUTHOPT_KEY_ADDR_BIND)
> + *
> + * RFC5925 requires that key ids must not overlap for the same TCP connection.
> + * This is not enforced by linux.
> + */
> +struct tcp_authopt_key {
> + /** @flags: Combination of &enum tcp_authopt_key_flag */
> + __u32 flags;
> + /** @send_id: keyid value for send */
> + __u8 send_id;
> + /** @recv_id: keyid value for receive */
> + __u8 recv_id;
> + /** @alg: One of &enum tcp_authopt_alg */
> + __u8 alg;
> + /** @keylen: Length of the key buffer */
> + __u8 keylen;
> + /** @key: Secret key */
> + __u8 key[TCP_AUTHOPT_MAXKEYLEN];
> + /**
> + * @addr: Key is only valid for this address
> + *
> + * Ignored unless TCP_AUTHOPT_KEY_ADDR_BIND flag is set
> + */
> + struct __kernel_sockaddr_storage addr;
> +};
> +
> /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */
>
> #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
> struct tcp_zerocopy_receive {
> __u64 address; /* in: address of mapping */
> diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
> index e983bb0c5012..75f7e3c75ea6 100644
> --- a/net/ipv4/Kconfig
> +++ b/net/ipv4/Kconfig
> @@ -739,5 +739,19 @@ config TCP_MD5SIG
> RFC2385 specifies a method of giving MD5 protection to TCP sessions.
> Its main (only?) use is to protect BGP sessions between core routers
> on the Internet.
>
> If unsure, say N.
> +
> +config TCP_AUTHOPT
> + bool "TCP: Authentication Option support (RFC5925)"
> + select CRYPTO
> + select CRYPTO_SHA1
> + select CRYPTO_HMAC
> + select CRYPTO_AES
> + select CRYPTO_CMAC
> + help
> + RFC5925 specifies a new method of giving protection to TCP sessions.
> + Its intended use is to protect BGP sessions between core routers
> + on the Internet. It obsoletes TCP MD5 (RFC2385) but is incompatible.
> +
> + If unsure, say N.
> diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
> index bbdd9c44f14e..d336f32ce177 100644
> --- a/net/ipv4/Makefile
> +++ b/net/ipv4/Makefile
> @@ -59,10 +59,11 @@ obj-$(CONFIG_TCP_CONG_NV) += tcp_nv.o
> obj-$(CONFIG_TCP_CONG_VENO) += tcp_veno.o
> obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o
> obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o
> obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o
> obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o
> +obj-$(CONFIG_TCP_AUTHOPT) += tcp_authopt.o
> obj-$(CONFIG_NET_SOCK_MSG) += tcp_bpf.o
> obj-$(CONFIG_BPF_SYSCALL) += udp_bpf.o
> obj-$(CONFIG_NETLABEL) += cipso_ipv4.o
>
> obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 306b94dedc8d..6a0357cf05b5 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -270,10 +270,11 @@
>
> #include <net/icmp.h>
> #include <net/inet_common.h>
> #include <net/tcp.h>
> #include <net/mptcp.h>
> +#include <net/tcp_authopt.h>
> #include <net/xfrm.h>
> #include <net/ip.h>
> #include <net/sock.h>
>
> #include <linux/uaccess.h>
> @@ -3703,10 +3704,18 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname,
> #ifdef CONFIG_TCP_MD5SIG
> case TCP_MD5SIG:
> case TCP_MD5SIG_EXT:
> err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
> break;
> +#endif
> +#ifdef CONFIG_TCP_AUTHOPT
> + case TCP_AUTHOPT:
> + err = tcp_set_authopt(sk, optval, optlen);
> + break;
> + case TCP_AUTHOPT_KEY:
> + err = tcp_set_authopt_key(sk, optval, optlen);
> + break;
> #endif
> case TCP_USER_TIMEOUT:
> /* Cap the max time in ms TCP will retry or probe the window
> * before giving up and aborting (ETIMEDOUT) a connection.
> */
> @@ -4354,10 +4363,33 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
> if (!err && copy_to_user(optval, &zc, len))
> err = -EFAULT;
> return err;
> }
> #endif
> +#ifdef CONFIG_TCP_AUTHOPT
> + case TCP_AUTHOPT: {
> + struct tcp_authopt info;
> + int err;
> +
> + if (get_user(len, optlen))
> + return -EFAULT;
> +
> + lock_sock(sk);
> + err = tcp_get_authopt_val(sk, &info);
> + release_sock(sk);
> +
> + if (err)
> + return err;
> + len = min_t(unsigned int, len, sizeof(info));
> + if (put_user(len, optlen))
> + return -EFAULT;
> + if (copy_to_user(optval, &info, len))
> + return -EFAULT;
> + return 0;
> + }
> +#endif
> +
> default:
> return -ENOPROTOOPT;
> }
>
> if (put_user(len, optlen))
> diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c
> new file mode 100644
> index 000000000000..d38e9c89c89d
> --- /dev/null
> +++ b/net/ipv4/tcp_authopt.c
> @@ -0,0 +1,317 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <net/tcp_authopt.h>
> +#include <net/ipv6.h>
> +#include <net/tcp.h>
> +#include <linux/kref.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);
> +
> +static inline struct netns_tcp_authopt *sock_net_tcp_authopt(const struct sock *sk)
> +{
> + return &sock_net(sk)->tcp_authopt;
> +}
> +
> +static void tcp_authopt_key_release_kref(struct kref *ref)
> +{
> + struct tcp_authopt_key_info *key = container_of(ref, struct tcp_authopt_key_info, ref);
> +
> + kfree_rcu(key, rcu);
> +}
> +
> +static void tcp_authopt_key_put(struct tcp_authopt_key_info *key)
> +{
> + if (key)
> + kref_put(&key->ref, tcp_authopt_key_release_kref);
> +}
> +
> +static void tcp_authopt_key_del(struct netns_tcp_authopt *net,
> + struct tcp_authopt_key_info *key)
> +{
> + lockdep_assert_held(&net->mutex);
> + hlist_del_rcu(&key->node);
> + key->flags |= TCP_AUTHOPT_KEY_DEL;
> + kref_put(&key->ref, tcp_authopt_key_release_kref);
> +}
> +
> +/* Free info and keys.
> + * Don't touch tp->authopt_info, it might not even be assigned yes.
> + */
> +void tcp_authopt_free(struct sock *sk, struct tcp_authopt_info *info)
> +{
> + kfree_rcu(info, rcu);
> +}
> +
> +/* Free everything and clear tcp_sock.authopt_info to NULL */
> +void tcp_authopt_clear(struct sock *sk)
> +{
> + struct tcp_authopt_info *info;
> +
> + info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk));
> + if (info) {
> + tcp_authopt_free(sk, info);
> + tcp_sk(sk)->authopt_info = NULL;
RCU rules at deletion mandate that the pointer must be cleared before
the call_rcu()/kfree_rcu() call.
It is possible that current MD5 code has an issue here, let's not copy/paste it.
> + }
> +}
> +
> +/* checks that ipv4 or ipv6 addr matches. */
> +static bool ipvx_addr_match(struct sockaddr_storage *a1,
> + struct sockaddr_storage *a2)
> +{
> + if (a1->ss_family != a2->ss_family)
> + return false;
> + if (a1->ss_family == AF_INET &&
> + (((struct sockaddr_in *)a1)->sin_addr.s_addr !=
> + ((struct sockaddr_in *)a2)->sin_addr.s_addr))
> + return false;
> + if (a1->ss_family == AF_INET6 &&
> + !ipv6_addr_equal(&((struct sockaddr_in6 *)a1)->sin6_addr,
> + &((struct sockaddr_in6 *)a2)->sin6_addr))
> + return false;
> + return true;
> +}
Always surprising to see this kind of generic helper being added in a patch.
> +
> +static bool tcp_authopt_key_match_exact(struct tcp_authopt_key_info *info,
> + struct tcp_authopt_key *key)
> +{
> + if (info->send_id != key->send_id)
> + return false;
> + if (info->recv_id != key->recv_id)
> + return false;
> + if ((info->flags & TCP_AUTHOPT_KEY_ADDR_BIND) != (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND))
> + return false;
> + if (info->flags & TCP_AUTHOPT_KEY_ADDR_BIND)
> + if (!ipvx_addr_match(&info->addr, &key->addr))
> + return false;
> +
> + return true;
> +}
> +
> +static struct tcp_authopt_key_info *tcp_authopt_key_lookup_exact(const struct sock *sk,
> + struct netns_tcp_authopt *net,
> + struct tcp_authopt_key *ukey)
> +{
> + struct tcp_authopt_key_info *key_info;
> +
> + hlist_for_each_entry_rcu(key_info, &net->head, node, lockdep_is_held(&net->mutex))
> + if (tcp_authopt_key_match_exact(key_info, ukey))
> + return key_info;
> +
> + return NULL;
> +}
> +
> +static struct tcp_authopt_info *__tcp_authopt_info_get_or_create(struct sock *sk)
> +{
> + struct tcp_sock *tp = tcp_sk(sk);
> + struct tcp_authopt_info *info;
> +
> + info = rcu_dereference_check(tp->authopt_info, lockdep_sock_is_held(sk));
> + if (info)
> + return info;
> +
> + info = kzalloc(sizeof(*info), GFP_KERNEL);
> + if (!info)
> + return ERR_PTR(-ENOMEM);
> +
> + /* Never released: */
> + static_branch_inc(&tcp_authopt_needed_key);
> + sk_gso_disable(sk);
> + rcu_assign_pointer(tp->authopt_info, info);
> +
> + return info;
> +}
> +
> +#define TCP_AUTHOPT_KNOWN_FLAGS ( \
> + TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED)
> +
> +/* Like copy_from_sockptr except tolerate different optlen for compatibility reasons
> + *
> + * If the src is shorter then it's from an old userspace and the rest of dst is
> + * filled with zeros.
> + *
> + * If the dst is shorter then src is from a newer userspace and we only accept
> + * if the rest of the option is all zeros.
> + *
> + * This allows sockopts to grow as long as for new fields zeros has no effect.
> + */
> +static int _copy_from_sockptr_tolerant(u8 *dst,
> + unsigned int dstlen,
> + sockptr_t src,
> + unsigned int srclen)
> +{
> + int err;
> +
> + /* If userspace optlen is too short fill the rest with zeros */
> + if (srclen > dstlen) {
> + if (sockptr_is_kernel(src))
> + return -EINVAL;
> + err = check_zeroed_user(src.user + dstlen, srclen - dstlen);
> + if (err < 0)
> + return err;
> + if (err == 0)
> + return -EINVAL;
> + }
> + err = copy_from_sockptr(dst, src, min(srclen, dstlen));
> + if (err)
> + return err;
> + if (srclen < dstlen)
> + memset(dst + srclen, 0, dstlen - srclen);
> +
> + return err;
> +}
> +
> +int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen)
> +{
> + struct tcp_authopt opt;
> + struct tcp_authopt_info *info;
> + int err;
> +
> + sock_owned_by_me(sk);
> +
> + err = _copy_from_sockptr_tolerant((u8 *)&opt, sizeof(opt), optval, optlen);
> + if (err)
> + return err;
> +
> + if (opt.flags & ~TCP_AUTHOPT_KNOWN_FLAGS)
> + return -EINVAL;
> +
> + info = __tcp_authopt_info_get_or_create(sk);
> + if (IS_ERR(info))
> + return PTR_ERR(info);
> +
> + info->flags = opt.flags & TCP_AUTHOPT_KNOWN_FLAGS;
> +
> + return 0;
> +}
> +
> +int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *opt)
> +{
> + struct tcp_sock *tp = tcp_sk(sk);
> + struct tcp_authopt_info *info;
> +
> + memset(opt, 0, sizeof(*opt));
> + sock_owned_by_me(sk);
> +
> + info = rcu_dereference_check(tp->authopt_info, lockdep_sock_is_held(sk));
Probably not a big deal, but it seems the prior sock_owned_by_me()
might be redundant.
> + if (!info)
> + return -ENOENT;
> +
> + opt->flags = info->flags & TCP_AUTHOPT_KNOWN_FLAGS;
> +
> + return 0;
> +}
> +
> +#define TCP_AUTHOPT_KEY_KNOWN_FLAGS ( \
> + TCP_AUTHOPT_KEY_DEL | \
> + TCP_AUTHOPT_KEY_EXCLUDE_OPTS | \
> + TCP_AUTHOPT_KEY_ADDR_BIND)
> +
> +int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
> +{
> + struct tcp_authopt_key opt;
> + struct tcp_authopt_info *info;
> + struct tcp_authopt_key_info *key_info, *old_key_info;
> + struct netns_tcp_authopt *net = sock_net_tcp_authopt(sk);
> + int err;
> +
> + sock_owned_by_me(sk);
> + if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
> + return -EPERM;
> +
> + err = _copy_from_sockptr_tolerant((u8 *)&opt, sizeof(opt), optval, optlen);
> + if (err)
> + return err;
> +
> + if (opt.flags & ~TCP_AUTHOPT_KEY_KNOWN_FLAGS)
> + return -EINVAL;
> +
> + if (opt.keylen > TCP_AUTHOPT_MAXKEYLEN)
> + return -EINVAL;
> +
> + /* Delete is a special case: */
> + if (opt.flags & TCP_AUTHOPT_KEY_DEL) {
> + mutex_lock(&net->mutex);
> + key_info = tcp_authopt_key_lookup_exact(sk, net, &opt);
> + if (key_info) {
> + tcp_authopt_key_del(net, key_info);
> + err = 0;
> + } else {
> + err = -ENOENT;
> + }
> + mutex_unlock(&net->mutex);
> + return err;
> + }
> +
> + /* check key family */
> + if (opt.flags & TCP_AUTHOPT_KEY_ADDR_BIND) {
> + if (sk->sk_family != opt.addr.ss_family)
> + return -EINVAL;
> + }
> +
> + /* Initialize tcp_authopt_info if not already set */
> + info = __tcp_authopt_info_get_or_create(sk);
> + if (IS_ERR(info))
> + return PTR_ERR(info);
> +
> + key_info = kmalloc(sizeof(*key_info), GFP_KERNEL | __GFP_ZERO);
kzalloc() ?
> + if (!key_info)
> + return -ENOMEM;
> + mutex_lock(&net->mutex);
> + kref_init(&key_info->ref);
> + /* If an old key exists with exact ID then remove and replace.
> + * RCU-protected readers might observe both and pick any.
> + */
> + old_key_info = tcp_authopt_key_lookup_exact(sk, net, &opt);
> + if (old_key_info)
> + tcp_authopt_key_del(net, old_key_info);
> + key_info->flags = opt.flags & TCP_AUTHOPT_KEY_KNOWN_FLAGS;
> + key_info->send_id = opt.send_id;
> + key_info->recv_id = opt.recv_id;
> + key_info->alg_id = opt.alg;
> + key_info->keylen = opt.keylen;
> + memcpy(key_info->key, opt.key, opt.keylen);
> + memcpy(&key_info->addr, &opt.addr, sizeof(key_info->addr));
> + hlist_add_head_rcu(&key_info->node, &net->head);
> + mutex_unlock(&net->mutex);
> +
> + return 0;
> +}
> +
> +static int tcp_authopt_init_net(struct net *full_net)
Hmmm... our convention is to use "struct net *net"
> +{
> + struct netns_tcp_authopt *net = &full_net->tcp_authopt;
Here, you should use a different name ...
> +
> + mutex_init(&net->mutex);
> + INIT_HLIST_HEAD(&net->head);
> +
> + return 0;
> +}
> +
> +static void tcp_authopt_exit_net(struct net *full_net)
> +{
> + struct netns_tcp_authopt *net = &full_net->tcp_authopt;
> + struct tcp_authopt_key_info *key;
> + struct hlist_node *n;
> +
Same remark here. Please reserve @net for a "struct net" pointer.
> + mutex_lock(&net->mutex);
> +
> + hlist_for_each_entry_safe(key, n, &net->head, node) {
> + hlist_del_rcu(&key->node);
> + tcp_authopt_key_put(key);
> + }
> +
> + mutex_unlock(&net->mutex);
> +}
> +
> +static struct pernet_operations net_ops = {
> + .init = tcp_authopt_init_net,
> + .exit = tcp_authopt_exit_net,
> +};
> +
> +static int __init tcp_authopt_init(void)
> +{
> + return register_pernet_subsys(&net_ops);
> +}
> +late_initcall(tcp_authopt_init);
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index 01b31f5c7aba..f6d1dba31ca4 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -60,10 +60,11 @@
>
> #include <net/net_namespace.h>
> #include <net/icmp.h>
> #include <net/inet_hashtables.h>
> #include <net/tcp.h>
> +#include <net/tcp_authopt.h>
> #include <net/transp_v6.h>
> #include <net/ipv6.h>
> #include <net/inet_common.h>
> #include <net/timewait_sock.h>
> #include <net/xfrm.h>
> @@ -2267,10 +2268,11 @@ void tcp_v4_destroy_sock(struct sock *sk)
> tcp_clear_md5_list(sk);
> kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu);
> tp->md5sig_info = NULL;
> }
> #endif
> + tcp_authopt_clear(sk);
Do we really own the socket lock at this point ?
>
> /* Clean up a referenced TCP bind bucket. */
> if (inet_csk(sk)->icsk_bind_hash)
> inet_put_port(sk);
>
> --
> 2.25.1
>
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