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| author | Jakub Sitnicki <jakub@cloudflare.com> | 2023-01-21 13:41:43 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-01-24 21:32:55 -0800 |
| commit | 5b4a79ba65a1ab479903fff2e604865d229b70a9 (patch) | |
| tree | a66f61b356c2708795f7a336ac4a5dfe5dc1239c /net | |
| parent | 74bc3a5acc82f020d2e126f56c535d02d1e74e37 (diff) | |
| download | linux-stable-5b4a79ba65a1ab479903fff2e604865d229b70a9.tar.gz linux-stable-5b4a79ba65a1ab479903fff2e604865d229b70a9.tar.bz2 linux-stable-5b4a79ba65a1ab479903fff2e604865d229b70a9.zip | |
bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/sock_map.c | 61 |
1 files changed, 34 insertions, 27 deletions
diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 22fa2c5bc6ec..a68a7290a3b2 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); |