netdev - Re: [PATCH bpf-next v2 09/11] bpf: Allow selecting reuseport socket from a SOCKMAP

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]

Message-ID: <20200113235100.ewx2dviaolg6n6a2@kafai-mbp.dhcp.thefacebook.com>
Date:   Mon, 13 Jan 2020 23:51:03 +0000
From:   Martin Lau <kafai@...com>
To:     Jakub Sitnicki <jakub@...udflare.com>
CC:     "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "kernel-team@...udflare.com" <kernel-team@...udflare.com>,
        Eric Dumazet <edumazet@...gle.com>,
        "John Fastabend" <john.fastabend@...il.com>,
        Lorenz Bauer <lmb@...udflare.com>
Subject: Re: [PATCH bpf-next v2 09/11] bpf: Allow selecting reuseport socket
 from a SOCKMAP

On Fri, Jan 10, 2020 at 11:50:25AM +0100, Jakub Sitnicki wrote:
> SOCKMAP now supports storing references to listening sockets. Nothing keeps
> us from using it as an array of sockets to select from in SK_REUSEPORT
> programs.
> 
> Whitelist the map type with the BPF helper for selecting socket.
> 
> The restriction that the socket has to be a member of a reuseport group
> still applies. Socket from a SOCKMAP that does not have sk_reuseport_cb set
> is not a valid target and we signal it with -EINVAL.
> 
> Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
> ---
>  kernel/bpf/verifier.c |  6 ++++--
>  net/core/filter.c     | 15 ++++++++++-----
>  2 files changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index f5af759a8a5f..0ee5f1594b5c 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -3697,7 +3697,8 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
>  		if (func_id != BPF_FUNC_sk_redirect_map &&
>  		    func_id != BPF_FUNC_sock_map_update &&
>  		    func_id != BPF_FUNC_map_delete_elem &&
> -		    func_id != BPF_FUNC_msg_redirect_map)
> +		    func_id != BPF_FUNC_msg_redirect_map &&
> +		    func_id != BPF_FUNC_sk_select_reuseport)
>  			goto error;
>  		break;
>  	case BPF_MAP_TYPE_SOCKHASH:
> @@ -3778,7 +3779,8 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
>  			goto error;
>  		break;
>  	case BPF_FUNC_sk_select_reuseport:
> -		if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY)
> +		if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
> +		    map->map_type != BPF_MAP_TYPE_SOCKMAP)
>  			goto error;
>  		break;
>  	case BPF_FUNC_map_peek_elem:
> diff --git a/net/core/filter.c b/net/core/filter.c
> index a702761ef369..c79c62a54167 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -8677,6 +8677,7 @@ struct sock *bpf_run_sk_reuseport(struct sock_reuseport *reuse, struct sock *sk,
>  BPF_CALL_4(sk_select_reuseport, struct sk_reuseport_kern *, reuse_kern,
>  	   struct bpf_map *, map, void *, key, u32, flags)
>  {
> +	bool is_sockarray = map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY;
A nit.
Since map_type is tested, reuseport_array_lookup_elem() or sock_map_lookup()
can directly be called also.  mostly for consideration.  will not insist.


>  	struct sock_reuseport *reuse;
>  	struct sock *selected_sk;
>