From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Jakub Sitnicki <jakub@cloudflare.com>,
Eric Dumazet <edumazet@google.com>,
John Fastabend <john.fastabend@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Sasha Levin <sashal@kernel.org>,
davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 6.1 11/38] bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself
Date: Thu, 9 Feb 2023 06:14:30 -0500 [thread overview]
Message-ID: <20230209111459.1891941-11-sashal@kernel.org> (raw)
In-Reply-To: <20230209111459.1891941-1-sashal@kernel.org>
From: Jakub Sitnicki <jakub@cloudflare.com>
[ Upstream commit 5b4a79ba65a1ab479903fff2e604865d229b70a9 ]
sock_map proto callbacks should never call themselves by design. Protect
against bugs like [1] and break out of the recursive loop to avoid a stack
overflow in favor of a resource leak.
[1] https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20230113-sockmap-fix-v2-1-1e0ee7ac2f90@cloudflare.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/sock_map.c | 61 +++++++++++++++++++++++++--------------------
1 file changed, 34 insertions(+), 27 deletions(-)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 22fa2c5bc6ec9..a68a7290a3b2b 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -1569,15 +1569,16 @@ void sock_map_unhash(struct sock *sk)
psock = sk_psock(sk);
if (unlikely(!psock)) {
rcu_read_unlock();
- if (sk->sk_prot->unhash)
- sk->sk_prot->unhash(sk);
- return;
+ saved_unhash = READ_ONCE(sk->sk_prot)->unhash;
+ } else {
+ saved_unhash = psock->saved_unhash;
+ sock_map_remove_links(sk, psock);
+ rcu_read_unlock();
}
-
- saved_unhash = psock->saved_unhash;
- sock_map_remove_links(sk, psock);
- rcu_read_unlock();
- saved_unhash(sk);
+ if (WARN_ON_ONCE(saved_unhash == sock_map_unhash))
+ return;
+ if (saved_unhash)
+ saved_unhash(sk);
}
EXPORT_SYMBOL_GPL(sock_map_unhash);
@@ -1590,17 +1591,18 @@ void sock_map_destroy(struct sock *sk)
psock = sk_psock_get(sk);
if (unlikely(!psock)) {
rcu_read_unlock();
- if (sk->sk_prot->destroy)
- sk->sk_prot->destroy(sk);
- return;
+ saved_destroy = READ_ONCE(sk->sk_prot)->destroy;
+ } else {
+ saved_destroy = psock->saved_destroy;
+ sock_map_remove_links(sk, psock);
+ rcu_read_unlock();
+ sk_psock_stop(psock);
+ sk_psock_put(sk, psock);
}
-
- saved_destroy = psock->saved_destroy;
- sock_map_remove_links(sk, psock);
- rcu_read_unlock();
- sk_psock_stop(psock);
- sk_psock_put(sk, psock);
- saved_destroy(sk);
+ if (WARN_ON_ONCE(saved_destroy == sock_map_destroy))
+ return;
+ if (saved_destroy)
+ saved_destroy(sk);
}
EXPORT_SYMBOL_GPL(sock_map_destroy);
@@ -1615,16 +1617,21 @@ void sock_map_close(struct sock *sk, long timeout)
if (unlikely(!psock)) {
rcu_read_unlock();
release_sock(sk);
- return sk->sk_prot->close(sk, timeout);
+ saved_close = READ_ONCE(sk->sk_prot)->close;
+ } else {
+ saved_close = psock->saved_close;
+ sock_map_remove_links(sk, psock);
+ rcu_read_unlock();
+ sk_psock_stop(psock);
+ release_sock(sk);
+ cancel_work_sync(&psock->work);
+ sk_psock_put(sk, psock);
}
-
- saved_close = psock->saved_close;
- sock_map_remove_links(sk, psock);
- rcu_read_unlock();
- sk_psock_stop(psock);
- release_sock(sk);
- cancel_work_sync(&psock->work);
- sk_psock_put(sk, psock);
+ /* Make sure we do not recurse. This is a bug.
+ * Leak the socket instead of crashing on a stack overflow.
+ */
+ if (WARN_ON_ONCE(saved_close == sock_map_close))
+ return;
saved_close(sk, timeout);
}
EXPORT_SYMBOL_GPL(sock_map_close);
--
2.39.0
prev parent reply other threads:[~2023-02-09 11:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230209111459.1891941-1-sashal@kernel.org>
2023-02-09 11:14 ` [PATCH AUTOSEL 6.1 08/38] selftests/bpf: Verify copy_register_state() preserves parent/live fields Sasha Levin
2023-02-09 11:14 ` Sasha Levin [this message]
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