netdev - Re: [PATCH bpf-next 4/7] bpf: sockmap: allow UDP sockets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 26 Feb 2020 10:47:07 -0800
From:   Martin KaFai Lau <kafai@...com>
To:     Lorenz Bauer <lmb@...udflare.com>
CC:     <ast@...nel.org>, <daniel@...earbox.net>,
        <john.fastabend@...il.com>, <netdev@...r.kernel.org>,
        <bpf@...r.kernel.org>, <kernel-team@...udflare.com>
Subject: Re: [PATCH bpf-next 4/7] bpf: sockmap: allow UDP sockets

On Tue, Feb 25, 2020 at 01:56:33PM +0000, Lorenz Bauer wrote:
> Add basic psock hooks for UDP sockets. This allows adding and
> removing sockets, as well as automatic removal on unhash and close.
> 
> Signed-off-by: Lorenz Bauer <lmb@...udflare.com>
> ---
>  MAINTAINERS         |  1 +
>  include/linux/udp.h |  4 ++++
>  net/core/sock_map.c | 47 +++++++++++++++++++++++-----------------
>  net/ipv4/Makefile   |  1 +
>  net/ipv4/udp_bpf.c  | 53 +++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 86 insertions(+), 20 deletions(-)
>  create mode 100644 net/ipv4/udp_bpf.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2af5fa73155e..495ba52038ad 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9358,6 +9358,7 @@ F:	include/linux/skmsg.h
>  F:	net/core/skmsg.c
>  F:	net/core/sock_map.c
>  F:	net/ipv4/tcp_bpf.c
> +F:	net/ipv4/udp_bpf.c
>  
>  LANTIQ / INTEL Ethernet drivers
>  M:	Hauke Mehrtens <hauke@...ke-m.de>
> diff --git a/include/linux/udp.h b/include/linux/udp.h
> index aa84597bdc33..d90d8fd5f73d 100644
> --- a/include/linux/udp.h
> +++ b/include/linux/udp.h
> @@ -143,4 +143,8 @@ static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
>  
>  #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
>  
> +#if defined(CONFIG_NET_SOCK_MSG)
> +int udp_bpf_init(struct sock *sk);
> +#endif
> +
>  #endif	/* _LINUX_UDP_H */
> diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> index c84cc9fc7f6b..f998192c425f 100644
> --- a/net/core/sock_map.c
> +++ b/net/core/sock_map.c
> @@ -153,7 +153,7 @@ static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
>  	rcu_read_lock();
>  	psock = sk_psock(sk);
>  	if (psock) {
> -		if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) {
> +		if (sk->sk_prot->close != sock_map_close) {
>  			psock = ERR_PTR(-EBUSY);
>  			goto out;
>  		}
> @@ -166,6 +166,14 @@ static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
>  	return psock;
>  }
>  
> +static int sock_map_init_hooks(struct sock *sk)
> +{
> +	if (sk->sk_type == SOCK_DGRAM)
> +		return udp_bpf_init(sk);
> +	else
> +		return tcp_bpf_init(sk);
> +}
> +
>  static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
>  			 struct sock *sk)
>  {
> @@ -220,7 +228,7 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
>  	if (msg_parser)
>  		psock_set_prog(&psock->progs.msg_parser, msg_parser);
>  
> -	ret = tcp_bpf_init(sk);
> +	ret = sock_map_init_hooks(sk);
>  	if (ret < 0)
>  		goto out_drop;
>  
> @@ -267,7 +275,7 @@ static int sock_map_link_no_progs(struct bpf_map *map, struct sock *sk)
>  		return -ENOMEM;
>  
>  init:
> -	ret = tcp_bpf_init(sk);
> +	ret = sock_map_init_hooks(sk);
>  	if (ret < 0)
>  		sk_psock_put(sk, psock);
>  	return ret;
> @@ -394,9 +402,14 @@ static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next)
>  	return 0;
>  }
>  
> +static bool sock_map_sk_is_tcp(const struct sock *sk)
> +{
> +	return sk->sk_type == SOCK_STREAM && sk->sk_protocol == IPPROTO_TCP;
> +}
> +
>  static bool sock_map_redirect_allowed(const struct sock *sk)
>  {
> -	return sk->sk_state != TCP_LISTEN;
> +	return sock_map_sk_is_tcp(sk) && sk->sk_state != TCP_LISTEN;
>  }
>  
>  static int sock_map_update_common(struct bpf_map *map, u32 idx,
> @@ -466,15 +479,17 @@ static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops)
>  	       ops->op == BPF_SOCK_OPS_TCP_LISTEN_CB;
>  }
>  
> +static bool sock_map_sk_is_udp(const struct sock *sk)
> +{
> +	return sk->sk_type == SOCK_DGRAM && sk->sk_protocol == IPPROTO_UDP;
> +}
> +
>  static bool sock_map_sk_is_suitable(const struct sock *sk)
>  {
> -	return sk->sk_type == SOCK_STREAM &&
> -	       sk->sk_protocol == IPPROTO_TCP;
> -}
> +	const int tcp_flags = TCPF_ESTABLISHED | TCPF_LISTEN | TCPF_SYN_RECV;
hmm... I thought this patch is for adding UDP only.  However, if I read
it correctly, the tcp_flags is changed (| TCPF_SYN_RECV)?
Please elaborate in the commit message.

>  
> -static bool sock_map_sk_state_allowed(const struct sock *sk)
> -{
> -	return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN);
> +	return (sock_map_sk_is_udp(sk) && sk_hashed(sk)) ||
> +	       (sock_map_sk_is_tcp(sk) && (1 << sk->sk_state) & tcp_flags);
>  }
>  
>  static int sock_map_update_elem(struct bpf_map *map, void *key,