From: Jakub Sitnicki <jakub@cloudflare.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Lorenz Bauer <lmb@cloudflare.com>, Martin Lau <kafai@fb.com>
Subject: [PATCH bpf-next v3 07/12] bpf, sockmap: Return socket cookie on lookup from syscall
Date: Wed, 22 Jan 2020 14:05:44 +0100 [thread overview]
Message-ID: <20200122130549.832236-8-jakub@cloudflare.com> (raw)
In-Reply-To: <20200122130549.832236-1-jakub@cloudflare.com>
Tooling that populates the SOCKMAP with sockets from user-space needs a way
to inspect its contents. Returning the struct sock * that SOCKMAP holds to
user-space is neither safe nor useful. An approach established by
REUSEPORT_SOCKARRAY is to return a socket cookie (a unique identifier)
instead.
Since socket cookies are u64 values, SOCKMAP needs to support such a value
size for lookup to be possible. This requires special handling on update,
though. Attempts to do a lookup on SOCKMAP holding u32 values will be met
with ENOSPC error.
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
---
net/core/sock_map.c | 29 +++++++++++++++++++++++++++--
1 file changed, 27 insertions(+), 2 deletions(-)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 439f1e0b995e..cabe85892ba3 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -10,6 +10,7 @@
#include <linux/skmsg.h>
#include <linux/list.h>
#include <linux/jhash.h>
+#include <linux/sock_diag.h>
struct bpf_stab {
struct bpf_map map;
@@ -31,7 +32,8 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
return ERR_PTR(-EPERM);
if (attr->max_entries == 0 ||
attr->key_size != 4 ||
- attr->value_size != 4 ||
+ (attr->value_size != sizeof(u32) &&
+ attr->value_size != sizeof(u64)) ||
attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);
@@ -298,6 +300,21 @@ static void *sock_map_lookup(struct bpf_map *map, void *key)
return ERR_PTR(-EOPNOTSUPP);
}
+static void *sock_map_lookup_sys(struct bpf_map *map, void *key)
+{
+ struct sock *sk;
+
+ if (map->value_size != sizeof(u64))
+ return ERR_PTR(-ENOSPC);
+
+ sk = __sock_map_lookup_elem(map, *(u32 *)key);
+ if (!sk)
+ return ERR_PTR(-ENOENT);
+
+ sock_gen_cookie(sk);
+ return &sk->sk_cookie;
+}
+
static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test,
struct sock **psk)
{
@@ -460,12 +477,19 @@ static bool sock_map_redirect_okay(const struct sock *sk)
static int sock_map_update_elem(struct bpf_map *map, void *key,
void *value, u64 flags)
{
- u32 ufd = *(u32 *)value;
u32 idx = *(u32 *)key;
struct socket *sock;
struct sock *sk;
+ u64 ufd;
int ret;
+ if (map->value_size == sizeof(u64))
+ ufd = *(u64 *)value;
+ else
+ ufd = *(u32 *)value;
+ if (ufd > S32_MAX)
+ return -EINVAL;
+
sock = sockfd_lookup(ufd, &ret);
if (!sock)
return ret;
@@ -569,6 +593,7 @@ const struct bpf_map_ops sock_map_ops = {
.map_alloc = sock_map_alloc,
.map_free = sock_map_free,
.map_get_next_key = sock_map_get_next_key,
+ .map_lookup_elem_sys_only = sock_map_lookup_sys,
.map_update_elem = sock_map_update_elem,
.map_delete_elem = sock_map_delete_elem,
.map_lookup_elem = sock_map_lookup,
--
2.24.1
next prev parent reply other threads:[~2020-01-22 13:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 13:05 [PATCH bpf-next v3 00/12] Extend SOCKMAP to store listening sockets Jakub Sitnicki
2020-01-22 13:05 ` [PATCH bpf-next v3 01/12] bpf, sk_msg: Don't clear saved sock proto on restore Jakub Sitnicki
2020-01-22 13:05 ` [PATCH bpf-next v3 02/12] net, sk_msg: Annotate lockless access to sk_prot on clone Jakub Sitnicki
2020-01-22 22:57 ` Martin Lau
2020-01-22 13:05 ` [PATCH bpf-next v3 03/12] net, sk_msg: Clear sk_user_data pointer on clone if tagged Jakub Sitnicki
2020-01-22 13:05 ` [PATCH bpf-next v3 04/12] tcp_bpf: Don't let child socket inherit parent protocol ops on copy Jakub Sitnicki
2020-01-22 20:35 ` Martin Lau
2020-01-23 10:34 ` Jakub Sitnicki
2020-01-22 13:05 ` [PATCH bpf-next v3 05/12] bpf, sockmap: Allow inserting listening TCP sockets into sockmap Jakub Sitnicki
2020-01-22 20:52 ` Martin Lau
2020-01-23 10:41 ` Jakub Sitnicki
2020-01-22 13:05 ` [PATCH bpf-next v3 06/12] bpf, sockmap: Don't set up sockmap progs for listening sockets Jakub Sitnicki
2020-01-22 16:24 ` Lorenz Bauer
2020-01-22 18:07 ` Jakub Sitnicki
2020-01-22 23:11 ` Martin Lau
2020-01-22 13:05 ` Jakub Sitnicki [this message]
2020-01-22 13:05 ` [PATCH bpf-next v3 08/12] bpf, sockmap: Let all kernel-land lookup values in SOCKMAP Jakub Sitnicki
2020-01-22 23:02 ` Martin Lau
2020-01-22 13:05 ` [PATCH bpf-next v3 09/12] bpf: Allow selecting reuseport socket from a SOCKMAP Jakub Sitnicki
2020-01-22 23:08 ` Martin Lau
2020-01-22 13:05 ` [PATCH bpf-next v3 10/12] net: Generate reuseport group ID on group creation Jakub Sitnicki
2020-01-22 22:53 ` Martin Lau
2020-01-23 10:59 ` Jakub Sitnicki
2020-01-22 13:05 ` [PATCH bpf-next v3 11/12] selftests/bpf: Extend SK_REUSEPORT tests to cover SOCKMAP Jakub Sitnicki
2020-01-22 13:05 ` [PATCH bpf-next v3 12/12] selftests/bpf: Tests for SOCKMAP holding listening sockets Jakub Sitnicki
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