From: Jakub Sitnicki <jakub@cloudflare.com> mainline inclusion from mainline-v6.2-rc7 commit 5b4a79ba65a1ab479903fff2e604865d229b70a9 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I65HYE CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... --------------------------- 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.... Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Liu Jian <liujian56@huawei.com> --- 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 0e00e9a0d22d..66b7f3fb01ed 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -1623,15 +1623,16 @@ 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); } void sock_map_destroy(struct sock *sk) @@ -1643,17 +1644,18 @@ 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); @@ -1668,16 +1670,21 @@ 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); } -- 2.34.1