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Paolo Abenigregkh
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net/ulp: prevent ULP without clone op from entering the LISTEN status
[ Upstream commit 2c02d41 ] When an ULP-enabled socket enters the LISTEN status, the listener ULP data pointer is copied inside the child/accepted sockets by sk_clone_lock(). The relevant ULP can take care of de-duplicating the context pointer via the clone() operation, but only MPTCP and SMC implement such op. Other ULPs may end-up with a double-free at socket disposal time. We can't simply clear the ULP data at clone time, as TLS replaces the socket ops with custom ones assuming a valid TLS ULP context is available. Instead completely prevent clone-less ULP sockets from entering the LISTEN status. Fixes: 734942c ("tcp: ULP infrastructure") Reported-by: slipper <[email protected]> Signed-off-by: Paolo Abeni <[email protected]> Link: https://lore.kernel.org/r/4b80c3d1dbe3d0ab072f80450c202d9bc88b4b03.1672740602.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
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net/ipv4/inet_connection_sock.c

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1200,12 +1200,26 @@ void inet_csk_prepare_forced_close(struct sock *sk)
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}
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EXPORT_SYMBOL(inet_csk_prepare_forced_close);
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1203+
static int inet_ulp_can_listen(const struct sock *sk)
1204+
{
1205+
const struct inet_connection_sock *icsk = inet_csk(sk);
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1207+
if (icsk->icsk_ulp_ops && !icsk->icsk_ulp_ops->clone)
1208+
return -EINVAL;
1209+
1210+
return 0;
1211+
}
1212+
12031213
int inet_csk_listen_start(struct sock *sk)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
12061216
struct inet_sock *inet = inet_sk(sk);
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int err;
12081218

1219+
err = inet_ulp_can_listen(sk);
1220+
if (unlikely(err))
1221+
return err;
1222+
12091223
reqsk_queue_alloc(&icsk->icsk_accept_queue);
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12111225
sk->sk_ack_backlog = 0;

net/ipv4/tcp_ulp.c

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -139,6 +139,10 @@ static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
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if (sk->sk_socket)
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clear_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
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142+
err = -EINVAL;
143+
if (!ulp_ops->clone && sk->sk_state == TCP_LISTEN)
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goto out_err;
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err = ulp_ops->init(sk);
143147
if (err)
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goto out_err;

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