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Message-ID: <e73d11bde2d8ead36296d814ba555e60880ce9be.camel@redhat.com>
Date: Tue, 07 Jun 2022 10:33:06 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Joanne Koong <joannelkoong@...il.com>, netdev@...r.kernel.org
Cc: edumazet@...gle.com, kafai@...com, kuba@...nel.org,
davem@...emloft.net,
syzbot+015d756bbd1f8b5c8f09@...kaller.appspotmail.com,
Mat Martineau <mathew.j.martineau@...ux.intel.com>
Subject: Re: [PATCH net-next v2 1/2] net: Update bhash2 when socket's rcv
saddr changes
Hello,
On Thu, 2022-06-02 at 09:51 -0700, Joanne Koong wrote:
> Commit d5a42de8bdbe ("net: Add a second bind table hashed by port and
> address") added a second bind table, bhash2, that hashes by a socket's port
> and rcv address.
>
> However, there are two cases where the socket's rcv saddr can change
> after it has been binded:
>
> 1) The case where there is a bind() call on "::" (IPADDR_ANY) and then
> a connect() call. The kernel will assign the socket an address when it
> handles the connect()
>
> 2) In inet_sk_reselect_saddr(), which is called when rerouting fails
> when rebuilding the sk header (invoked by inet_sk_rebuild_header)
>
> In these two cases, we need to update the bhash2 table by removing the
> entry for the old address, and adding a new entry reflecting the updated
> address.
>
> Reported-by: syzbot+015d756bbd1f8b5c8f09@...kaller.appspotmail.com
> Fixes: d5a42de8bdbe ("net: Add a second bind table hashed by port and address")
> Signed-off-by: Joanne Koong <joannelkoong@...il.com>
> Reviewed-by: Eric Dumazet <edumazet@...gle.com>
> ---
> include/net/inet_hashtables.h | 6 ++-
> include/net/ipv6.h | 2 +-
> net/dccp/ipv4.c | 10 +++--
> net/dccp/ipv6.c | 4 +-
> net/ipv4/af_inet.c | 7 +++-
> net/ipv4/inet_hashtables.c | 70 ++++++++++++++++++++++++++++++++---
> net/ipv4/tcp_ipv4.c | 8 +++-
> net/ipv6/inet6_hashtables.c | 4 +-
> net/ipv6/tcp_ipv6.c | 4 +-
> 9 files changed, 97 insertions(+), 18 deletions(-)
>
> diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
> index a0887b70967b..2c331ce6ca73 100644
> --- a/include/net/inet_hashtables.h
> +++ b/include/net/inet_hashtables.h
> @@ -448,11 +448,13 @@ static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
> }
>
> int __inet_hash_connect(struct inet_timewait_death_row *death_row,
> - struct sock *sk, u64 port_offset,
> + struct sock *sk, u64 port_offset, bool prev_inaddr_any,
> int (*check_established)(struct inet_timewait_death_row *,
> struct sock *, __u16,
> struct inet_timewait_sock **));
>
> int inet_hash_connect(struct inet_timewait_death_row *death_row,
> - struct sock *sk);
> + struct sock *sk, bool prev_inaddr_any);
> +
> +int inet_bhash2_update_saddr(struct sock *sk);
> #endif /* _INET_HASHTABLES_H */
> diff --git a/include/net/ipv6.h b/include/net/ipv6.h
> index 5b38bf1a586b..6a50aca56d50 100644
> --- a/include/net/ipv6.h
> +++ b/include/net/ipv6.h
> @@ -1187,7 +1187,7 @@ int inet6_compat_ioctl(struct socket *sock, unsigned int cmd,
> unsigned long arg);
>
> int inet6_hash_connect(struct inet_timewait_death_row *death_row,
> - struct sock *sk);
> + struct sock *sk, bool prev_inaddr_any);
> int inet6_sendmsg(struct socket *sock, struct msghdr *msg, size_t size);
> int inet6_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
> int flags);
> diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
> index da6e3b20cd75..37a8bc3ee49e 100644
> --- a/net/dccp/ipv4.c
> +++ b/net/dccp/ipv4.c
> @@ -47,12 +47,13 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
> const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
> struct inet_sock *inet = inet_sk(sk);
> struct dccp_sock *dp = dccp_sk(sk);
> + struct ip_options_rcu *inet_opt;
> __be16 orig_sport, orig_dport;
> + bool prev_inaddr_any = false;
> __be32 daddr, nexthop;
> struct flowi4 *fl4;
> struct rtable *rt;
> int err;
> - struct ip_options_rcu *inet_opt;
>
> dp->dccps_role = DCCP_ROLE_CLIENT;
>
> @@ -89,8 +90,11 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
> if (inet_opt == NULL || !inet_opt->opt.srr)
> daddr = fl4->daddr;
>
> - if (inet->inet_saddr == 0)
> + if (inet->inet_saddr == 0) {
> inet->inet_saddr = fl4->saddr;
> + prev_inaddr_any = true;
> + }
> +
> sk_rcv_saddr_set(sk, inet->inet_saddr);
> inet->inet_dport = usin->sin_port;
> sk_daddr_set(sk, daddr);
> @@ -105,7 +109,7 @@ int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
> * complete initialization after this.
> */
> dccp_set_state(sk, DCCP_REQUESTING);
> - err = inet_hash_connect(&dccp_death_row, sk);
> + err = inet_hash_connect(&dccp_death_row, sk, prev_inaddr_any);
> if (err != 0)
> goto failure;
>
> diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
> index fd44638ec16b..03013522acab 100644
> --- a/net/dccp/ipv6.c
> +++ b/net/dccp/ipv6.c
> @@ -824,6 +824,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
> struct ipv6_pinfo *np = inet6_sk(sk);
> struct dccp_sock *dp = dccp_sk(sk);
> struct in6_addr *saddr = NULL, *final_p, final;
> + bool prev_inaddr_any = false;
> struct ipv6_txoptions *opt;
> struct flowi6 fl6;
> struct dst_entry *dst;
> @@ -936,6 +937,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
> if (saddr == NULL) {
> saddr = &fl6.saddr;
> sk->sk_v6_rcv_saddr = *saddr;
> + prev_inaddr_any = true;
> }
>
> /* set the source address */
> @@ -951,7 +953,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
> inet->inet_dport = usin->sin6_port;
>
> dccp_set_state(sk, DCCP_REQUESTING);
> - err = inet6_hash_connect(&dccp_death_row, sk);
> + err = inet6_hash_connect(&dccp_death_row, sk, prev_inaddr_any);
> if (err)
> goto late_failure;
>
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index 93da9f783bec..ad627a99ff9d 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -1221,10 +1221,11 @@ static int inet_sk_reselect_saddr(struct sock *sk)
> struct inet_sock *inet = inet_sk(sk);
> __be32 old_saddr = inet->inet_saddr;
> __be32 daddr = inet->inet_daddr;
> + struct ip_options_rcu *inet_opt;
> struct flowi4 *fl4;
> struct rtable *rt;
> __be32 new_saddr;
> - struct ip_options_rcu *inet_opt;
> + int err;
>
> inet_opt = rcu_dereference_protected(inet->inet_opt,
> lockdep_sock_is_held(sk));
> @@ -1253,6 +1254,10 @@ static int inet_sk_reselect_saddr(struct sock *sk)
>
> inet->inet_saddr = inet->inet_rcv_saddr = new_saddr;
>
> + err = inet_bhash2_update_saddr(sk);
> + if (err)
> + return err;
> +
> /*
> * XXX The only one ugly spot where we need to
> * XXX really change the sockets identity after
> diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
> index e8de5e699b3f..592b70663a3b 100644
> --- a/net/ipv4/inet_hashtables.c
> +++ b/net/ipv4/inet_hashtables.c
> @@ -826,6 +826,55 @@ inet_bind2_bucket_find(struct inet_hashinfo *hinfo, struct net *net,
> return bhash2;
> }
>
> +/* the lock for the socket's corresponding bhash entry must be held */
> +static int __inet_bhash2_update_saddr(struct sock *sk,
> + struct inet_hashinfo *hinfo,
> + struct net *net, int port, int l3mdev)
> +{
> + struct inet_bind2_hashbucket *head2;
> + struct inet_bind2_bucket *tb2;
> +
> + tb2 = inet_bind2_bucket_find(hinfo, net, port, l3mdev, sk,
> + &head2);
> + if (!tb2) {
> + tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep,
> + net, head2, port, l3mdev, sk);
> + if (!tb2)
> + return -ENOMEM;
> + }
> +
> + /* Remove the socket's old entry from bhash2 */
> + __sk_del_bind2_node(sk);
> +
> + sk_add_bind2_node(sk, &tb2->owners);
> + inet_csk(sk)->icsk_bind2_hash = tb2;
> +
> + return 0;
> +}
> +
> +/* This should be called if/when a socket's rcv saddr changes after it has
> + * been binded.
> + */
> +int inet_bhash2_update_saddr(struct sock *sk)
> +{
> + struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
> + int l3mdev = inet_sk_bound_l3mdev(sk);
> + struct inet_bind_hashbucket *head;
> + int port = inet_sk(sk)->inet_num;
> + struct net *net = sock_net(sk);
> + int err;
> +
> + head = &hinfo->bhash[inet_bhashfn(net, port, hinfo->bhash_size)];
> +
> + spin_lock_bh(&head->lock);
> +
> + err = __inet_bhash2_update_saddr(sk, hinfo, net, port, l3mdev);
> +
> + spin_unlock_bh(&head->lock);
> +
> + return err;
> +}
> +
> /* RFC 6056 3.3.4. Algorithm 4: Double-Hash Port Selection Algorithm
> * Note that we use 32bit integers (vs RFC 'short integers')
> * because 2^16 is not a multiple of num_ephemeral and this
> @@ -840,7 +889,7 @@ inet_bind2_bucket_find(struct inet_hashinfo *hinfo, struct net *net,
> static u32 *table_perturb;
>
> int __inet_hash_connect(struct inet_timewait_death_row *death_row,
> - struct sock *sk, u64 port_offset,
> + struct sock *sk, u64 port_offset, bool prev_inaddr_any,
> int (*check_established)(struct inet_timewait_death_row *,
> struct sock *, __u16, struct inet_timewait_sock **))
> {
> @@ -858,11 +907,24 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
> int l3mdev;
> u32 index;
>
> + l3mdev = inet_sk_bound_l3mdev(sk);
> +
> if (port) {
> head = &hinfo->bhash[inet_bhashfn(net, port,
> hinfo->bhash_size)];
> tb = inet_csk(sk)->icsk_bind_hash;
> +
> spin_lock_bh(&head->lock);
> +
> + if (prev_inaddr_any) {
> + ret = __inet_bhash2_update_saddr(sk, hinfo, net, port,
> + l3mdev);
> + if (ret) {
> + spin_unlock_bh(&head->lock);
> + return ret;
> + }
> + }
> +
> if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
> inet_ehash_nolisten(sk, NULL, NULL);
> spin_unlock_bh(&head->lock);
> @@ -875,8 +937,6 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
> return ret;
> }
>
> - l3mdev = inet_sk_bound_l3mdev(sk);
> -
> inet_get_local_port_range(net, &low, &high);
> high++; /* [32768, 60999] -> [32768, 61000[ */
> remaining = high - low;
> @@ -987,13 +1047,13 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
> * Bind a port for a connect operation and hash it.
> */
> int inet_hash_connect(struct inet_timewait_death_row *death_row,
> - struct sock *sk)
> + struct sock *sk, bool prev_inaddr_any)
> {
> u64 port_offset = 0;
>
> if (!inet_sk(sk)->inet_num)
> port_offset = inet_sk_port_offset(sk);
> - return __inet_hash_connect(death_row, sk, port_offset,
> + return __inet_hash_connect(death_row, sk, port_offset, prev_inaddr_any,
> __inet_check_established);
> }
> EXPORT_SYMBOL_GPL(inet_hash_connect);
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index dac2650f3863..adf8d750933d 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -203,6 +203,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
> struct inet_sock *inet = inet_sk(sk);
> struct tcp_sock *tp = tcp_sk(sk);
> __be16 orig_sport, orig_dport;
> + bool prev_inaddr_any = false;
> __be32 daddr, nexthop;
> struct flowi4 *fl4;
> struct rtable *rt;
> @@ -246,8 +247,11 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
> if (!inet_opt || !inet_opt->opt.srr)
> daddr = fl4->daddr;
>
> - if (!inet->inet_saddr)
> + if (!inet->inet_saddr) {
> inet->inet_saddr = fl4->saddr;
> + prev_inaddr_any = true;
> + }
> +
> sk_rcv_saddr_set(sk, inet->inet_saddr);
>
> if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) {
> @@ -273,7 +277,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
> * complete initialization after this.
> */
> tcp_set_state(sk, TCP_SYN_SENT);
> - err = inet_hash_connect(tcp_death_row, sk);
> + err = inet_hash_connect(tcp_death_row, sk, prev_inaddr_any);
> if (err)
> goto failure;
>
> diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
> index 7d53d62783b1..c87c5933f3be 100644
> --- a/net/ipv6/inet6_hashtables.c
> +++ b/net/ipv6/inet6_hashtables.c
> @@ -317,13 +317,13 @@ static u64 inet6_sk_port_offset(const struct sock *sk)
> }
>
> int inet6_hash_connect(struct inet_timewait_death_row *death_row,
> - struct sock *sk)
> + struct sock *sk, bool prev_inaddr_any)
> {
> u64 port_offset = 0;
>
> if (!inet_sk(sk)->inet_num)
> port_offset = inet6_sk_port_offset(sk);
> - return __inet_hash_connect(death_row, sk, port_offset,
> + return __inet_hash_connect(death_row, sk, port_offset, prev_inaddr_any,
> __inet6_check_established);
> }
> EXPORT_SYMBOL_GPL(inet6_hash_connect);
> diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
> index f37dd4aa91c6..81e3312c2a97 100644
> --- a/net/ipv6/tcp_ipv6.c
> +++ b/net/ipv6/tcp_ipv6.c
> @@ -152,6 +152,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
> struct ipv6_pinfo *np = tcp_inet6_sk(sk);
> struct tcp_sock *tp = tcp_sk(sk);
> struct in6_addr *saddr = NULL, *final_p, final;
> + bool prev_inaddr_any = false;
> struct ipv6_txoptions *opt;
> struct flowi6 fl6;
> struct dst_entry *dst;
> @@ -289,6 +290,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
> if (!saddr) {
> saddr = &fl6.saddr;
> sk->sk_v6_rcv_saddr = *saddr;
> + prev_inaddr_any = true;
> }
>
> /* set the source address */
> @@ -309,7 +311,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
>
> tcp_set_state(sk, TCP_SYN_SENT);
> tcp_death_row = sock_net(sk)->ipv4.tcp_death_row;
> - err = inet6_hash_connect(tcp_death_row, sk);
> + err = inet6_hash_connect(tcp_death_row, sk, prev_inaddr_any);
> if (err)
> goto late_failure;
>
I'm sorry for the late notice, but it looks like that the mptcp
syzkaller instance is still hitting the Warning in icsk_get_port on top
of the v1 of this series:
https://github.com/multipath-tcp/mptcp_net-next/issues/279
and the change in v2 should not address that. @Mat could you please
confirm the above?
Dumb question: I don't understand how the locking in bhash2 works.
Could you explain that?
What happens when 2 different processes bind different sockets on
different ports (with different bhash buckets) using different
addresses so that they hit the same bhash2 bucket? AFAICS each process
will use a different lock and access/modification to bhash2 could
happen simultaneusly?
Thanks!
Paolo
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