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From: Lorenz Bauer <lmb@cloudflare.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	John Fastabend <john.fastabend@gmail.com>,
	Jakub Sitnicki <jakub@cloudflare.com>,
	Lorenz Bauer <lmb@cloudflare.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: kernel-team@cloudflare.com, netdev@vger.kernel.org,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH bpf-next 1/4] bpf: sockmap: enable map_update_elem from bpf_iter
Date: Fri, 25 Sep 2020 10:56:27 +0100	[thread overview]
Message-ID: <20200925095630.49207-2-lmb@cloudflare.com> (raw)
In-Reply-To: <20200925095630.49207-1-lmb@cloudflare.com>

Allow passing a pointer to a BTF struct sock_common* when updating
a sockmap or sockhash. Since BTF pointers can fault and therefore be
NULL at runtime we need to add an additional !sk check to
sock_map_update_elem. Doing this allows calling map_update_elem on
sockmap from bpf_iter context, which uses BTF pointers.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
 kernel/bpf/verifier.c | 2 +-
 net/core/sock_map.c   | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d4ba29fb17a6..5bd0239da8b6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3943,7 +3943,7 @@ static int resolve_map_arg_type(struct bpf_verifier_env *env,
 	case BPF_MAP_TYPE_SOCKMAP:
 	case BPF_MAP_TYPE_SOCKHASH:
 		if (*arg_type == ARG_PTR_TO_MAP_VALUE) {
-			*arg_type = ARG_PTR_TO_SOCKET;
+			*arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON;
 		} else {
 			verbose(env, "invalid arg_type for sockmap/sockhash\n");
 			return -EINVAL;
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index e1f05e3fa1d0..497e7df466d4 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -610,6 +610,9 @@ static int sock_map_update_elem(struct bpf_map *map, void *key,
 	struct sock *sk = (struct sock *)value;
 	int ret;
 
+	if (unlikely(!sk))
+		return -EINVAL;
+
 	if (!sock_map_sk_is_suitable(sk))
 		return -EOPNOTSUPP;
 
-- 
2.25.1


  reply	other threads:[~2020-09-25  9:56 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25  9:56 [PATCH bpf-next 0/4] Sockmap copying Lorenz Bauer
2020-09-25  9:56 ` Lorenz Bauer [this message]
2020-09-25 12:01   ` [PATCH bpf-next 1/4] bpf: sockmap: enable map_update_elem from bpf_iter kernel test robot
2020-09-25 21:53   ` Martin KaFai Lau
2020-09-28  9:06     ` Lorenz Bauer
2020-09-25  9:56 ` [PATCH bpf-next 2/4] selftests: bpf: Add helper to compare socket cookies Lorenz Bauer
2020-09-25  9:56 ` [PATCH bpf-next 3/4] bpf: selftests: remove shared header from sockmap iter test Lorenz Bauer
2020-09-25  9:56 ` [PATCH bpf-next 4/4] selftest: bpf: Test copying a sockmap and sockhash Lorenz Bauer

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