From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D1FAC636D4 for ; Thu, 9 Feb 2023 11:21:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231149AbjBILVl (ORCPT ); Thu, 9 Feb 2023 06:21:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231144AbjBILUs (ORCPT ); Thu, 9 Feb 2023 06:20:48 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A56C45AB33; Thu, 9 Feb 2023 03:17:54 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 67001B81FFE; Thu, 9 Feb 2023 11:17:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D49CEC43443; Thu, 9 Feb 2023 11:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675941468; bh=i+O2QE7ECDHdDy0YYxQm3+SVGfxD/NJ028txP+HoMKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T+uAbl9PHKLcDljAY0C95RR9W3OA0YyYYb/wwKEc1CZeDO28cBKKKHTojdZJieT1w 3MiNhZ5OL6P0Ww4fhvHqZ/Y532G8dqDtdNQLLGdEyrfOeUhwZwWK4su2NgrvSHLEsi 5SJI14JIokOLu3jUic9r+ouCB3u4qR+gbOSSiCHI5HgftU1hDdTC6/q8+Uapd4fEqh +IeIkGcMXM2UHvBueRkJxgDub88IVLPg4TNn3XiySpak2ZRj9Lx6iJ/2oY1op3/mAF /yeTYbVfVrwkC6dWwTXbyADZBREIAEaujp/GcxSsmXyhSCM3xtnoUMYEneFa/dXEZY JL4zUA6GXzsdg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jakub Sitnicki , Eric Dumazet , John Fastabend , Alexei Starovoitov , Sasha Levin , davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 05/17] bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself Date: Thu, 9 Feb 2023 06:17:17 -0500 Message-Id: <20230209111731.1892569-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230209111731.1892569-1-sashal@kernel.org> References: <20230209111731.1892569-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Jakub Sitnicki [ 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 Signed-off-by: Jakub Sitnicki Acked-by: John Fastabend Link: https://lore.kernel.org/r/20230113-sockmap-fix-v2-1-1e0ee7ac2f90@cloudflare.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- 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 ae6013a8bce53..86b4e8909ad1e 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -1514,15 +1514,16 @@ 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); @@ -1535,17 +1536,18 @@ 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); @@ -1560,16 +1562,21 @@ 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