From: Martin Lau <kafai@fb.com>
To: Jakub Sitnicki <jakub@cloudflare.com>
Cc: "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"kernel-team@cloudflare.com" <kernel-team@cloudflare.com>,
Eric Dumazet <edumazet@google.com>,
"John Fastabend" <john.fastabend@gmail.com>,
Lorenz Bauer <lmb@cloudflare.com>
Subject: Re: [PATCH bpf-next v2 09/11] bpf: Allow selecting reuseport socket from a SOCKMAP
Date: Mon, 13 Jan 2020 23:45:45 +0000 [thread overview]
Message-ID: <20200113234541.sru7domciovzijnx@kafai-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200110105027.257877-10-jakub@cloudflare.com>
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@cloudflare.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;
> struct sock_reuseport *reuse;
> struct sock *selected_sk;
>
> @@ -8685,12 +8686,16 @@ BPF_CALL_4(sk_select_reuseport, struct sk_reuseport_kern *, reuse_kern,
> return -ENOENT;
>
> reuse = rcu_dereference(selected_sk->sk_reuseport_cb);
> - if (!reuse)
> - /* selected_sk is unhashed (e.g. by close()) after the
> - * above map_lookup_elem(). Treat selected_sk has already
> - * been removed from the map.
> + if (!reuse) {
> + /* reuseport_array has only sk with non NULL sk_reuseport_cb.
> + * The only (!reuse) case here is - the sk has already been
> + * unhashed (e.g. by close()), so treat it as -ENOENT.
> + *
> + * Other maps (e.g. sock_map) do not provide this guarantee and
> + * the sk may never be in the reuseport group to begin with.
> */
> - return -ENOENT;
> + return is_sockarray ? -ENOENT : -EINVAL;
> + }
>
> if (unlikely(reuse->reuseport_id != reuse_kern->reuseport_id)) {
I guess the later testing patch passed is because reuseport_id is init to 0.
Note that in reuseport_array, reuseport_get_id() is called at update_elem() to
init the reuse->reuseport_id. It was done there because reuseport_array
was the only one requiring reuseport_id. It is to ensure the bpf_prog
cannot accidentally use a sk from another reuseport-group.
The same has to be done in patch 5 or may be considering to
move it to reuseport_alloc() itself.
next prev parent reply other threads:[~2020-01-13 23:46 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 10:50 [PATCH bpf-next v2 00/11] Extend SOCKMAP to store listening sockets Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 01/11] bpf, sk_msg: Don't reset saved sock proto on restore Jakub Sitnicki
2020-01-11 22:50 ` John Fastabend
2020-01-10 10:50 ` [PATCH bpf-next v2 02/11] net, sk_msg: Annotate lockless access to sk_prot on clone Jakub Sitnicki
2020-01-11 23:14 ` John Fastabend
2020-01-13 15:09 ` Jakub Sitnicki
2020-01-14 3:14 ` John Fastabend
2020-01-20 17:00 ` John Fastabend
2020-01-20 18:11 ` Jakub Sitnicki
2020-01-21 12:42 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 03/11] net, sk_msg: Clear sk_user_data pointer on clone if tagged Jakub Sitnicki
2020-01-11 23:38 ` John Fastabend
2020-01-12 12:55 ` kbuild test robot
2020-01-13 20:15 ` Martin Lau
2020-01-14 16:04 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 04/11] tcp_bpf: Don't let child socket inherit parent protocol ops on copy Jakub Sitnicki
2020-01-11 2:42 ` kbuild test robot
2020-01-11 3:02 ` kbuild test robot
2020-01-11 23:48 ` John Fastabend
2020-01-13 22:31 ` Jakub Sitnicki
2020-01-13 22:23 ` Martin Lau
2020-01-13 22:42 ` Jakub Sitnicki
2020-01-13 23:23 ` Martin Lau
2020-01-10 10:50 ` [PATCH bpf-next v2 05/11] bpf, sockmap: Allow inserting listening TCP sockets into sockmap Jakub Sitnicki
2020-01-11 23:59 ` John Fastabend
2020-01-13 15:48 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 06/11] bpf, sockmap: Don't set up sockmap progs for listening sockets Jakub Sitnicki
2020-01-12 0:51 ` John Fastabend
2020-01-12 1:07 ` John Fastabend
2020-01-13 17:59 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 07/11] bpf, sockmap: Return socket cookie on lookup from syscall Jakub Sitnicki
2020-01-12 0:56 ` John Fastabend
2020-01-13 23:12 ` Martin Lau
2020-01-14 3:16 ` John Fastabend
2020-01-14 15:48 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 08/11] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 09/11] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2020-01-12 1:00 ` John Fastabend
2020-01-13 23:45 ` Martin Lau [this message]
2020-01-15 12:41 ` Jakub Sitnicki
2020-01-13 23:51 ` Martin Lau
2020-01-15 12:57 ` Jakub Sitnicki
2020-01-10 10:50 ` [PATCH bpf-next v2 10/11] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2020-01-12 1:01 ` John Fastabend
2020-01-10 10:50 ` [PATCH bpf-next v2 11/11] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
2020-01-12 1:06 ` John Fastabend
2020-01-13 15:58 ` Jakub Sitnicki
2020-01-11 0:18 ` [PATCH bpf-next v2 00/11] Extend SOCKMAP to store " Alexei Starovoitov
2020-01-11 22:47 ` John Fastabend
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200113234541.sru7domciovzijnx@kafai-mbp.dhcp.thefacebook.com \
--to=kafai@fb.com \
--cc=bpf@vger.kernel.org \
--cc=edumazet@google.com \
--cc=jakub@cloudflare.com \
--cc=john.fastabend@gmail.com \
--cc=kernel-team@cloudflare.com \
--cc=lmb@cloudflare.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).