From nobody Fri Dec 19 03:12:57 2025 Received: from mail-wr1-f41.google.com (mail-wr1-f41.google.com [209.85.221.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2D9C620CCF2 for ; Wed, 12 Mar 2025 20:54:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.41 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741812897; cv=none; b=LWTpAee6CDqLsdO0ZCyLT+KN2WRtlp4K8UguSyU685zdjJslUdJtycxSSBU2iOg1tel45tdyMCKG5YIYfBbjZ7S2cIlIxyPc5avZdsNeyrPehhxJS8RnR4+htPJ5inybxgisHyoCzaa0Kuo5U8w/NAvVHXTD7NbIxPZpIujAuyo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741812897; c=relaxed/simple; bh=JSwqVjxBeHU4RACyPp9B4KuNViAULCMe3no65khXe0Y=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=gXVsxpLGPiN8q1H+WyehDI1rbG7xKJuhzrTTFkZYIu9wWUQfdoh9pgQEGqqVhReM4Xs7QMZ8gp1W5ru57OJWsUzGEGDTircIusdRmWwV1q5y7MTFRfh/6u8HNKUCl7+euNKq2CYdPl8gCFnw42LIplpLK777nor3Of9J+qPbiT8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=openvpn.net; spf=pass smtp.mailfrom=openvpn.com; dkim=pass (2048-bit key) header.d=openvpn.net header.i=@openvpn.net header.b=hG3v9/xd; arc=none smtp.client-ip=209.85.221.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=openvpn.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=openvpn.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=openvpn.net header.i=@openvpn.net header.b="hG3v9/xd" Received: by mail-wr1-f41.google.com with SMTP id ffacd0b85a97d-3913d129c1aso238021f8f.0 for ; Wed, 12 Mar 2025 13:54:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=openvpn.net; s=google; t=1741812892; x=1742417692; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=rVuW3EWeVsK9JR3HnkSCXUo7RY6n+BdBr5woCe0mSnk=; b=hG3v9/xdOp57qUaWryJVAkFgHJ8s97t5YZs+1JQ2zTS20+23MuDvCWAofuTm8RiY3K rNsqM7DRIeLw9ODOP0Ywy3P/rjzeWj3BDnTXf9GTOcBnckZsidoRInG7Avxqn7ki9xH9 GOf0iObZ91U52Lm3oAHfDOl8A3NTEMDnfmfcu8rrm9vQyAW9+Omg+xtp8LDSjzf5aYLj yQeM9WQ2ugpbau0iPoVL8H2fVyzhnzRBhlxbyaYgal4x4/kBsxEDV7MnzRYTP8CsZmxm TnqSBEPlMbCwpEyy1F9bSqkKMmHUjAnIA9B60m26s+flk+fw4Bo9v1aqCROc71cejLYm 6D0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741812892; x=1742417692; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=rVuW3EWeVsK9JR3HnkSCXUo7RY6n+BdBr5woCe0mSnk=; b=ChOgm297SpouK87nN7gwjDwZTgKMEfzIT0XvkcVyucw9urEktPlZfDrJw+ylFGp2cg p54mYt2Zy/29shk2YRO2JDecoIh1P5HPispsoGKILS6tx40sF/jstT2jwQegfcOAuBiL MnngMZceXqXcs08xRwYMB+M0aCSyQk1VYtsefUqWss9bv3jgaqj5EJB1rGtTIeHpFfXX l5yVTQSxczzyZf1Bkls613DWGGHr+gRw1ICJ8Ey3hVT6V0Rof0/lNCOXQHd47/z1ibKV WzRVqV43VZALKP9jKElhnjoip++WmJ0+jnl5YLEHOd6zbbpE1lAGckRNTwBZyP8uRp5j GFxg== X-Forwarded-Encrypted: i=1; AJvYcCWsSdM21YBf1wW3DNX5FF3NtfGWV26hoxXvy7XaDOBoNl2zY5ptZKLo13V85GvP5r/6GHX25QJNd/NwJFk=@vger.kernel.org X-Gm-Message-State: AOJu0Yy1jx8ftfdHfUtYfT6rF7vg21tW5vJz00HYqdDPcDnYMddv//Fx IOux4kGRe8CfOU+AOFXm7NCXLMh1KkcxSAlxcQ7lya8iRVTER1pvjQS0CHakebw= X-Gm-Gg: ASbGncvMn81JJLv+eRiBOq9ZQfSuiNTl4xifzbm8FRcq4zU8t5zT5qksLb94gCn4FhM bzGD3EtXKHPowxJEToa8JZ9gzctcmEeBtVpr58pbrPMV6biCvzDx/O+3D2e5QzuMBaANqJcrOVz w0CC8PbIfIZbCGpelpUvCCZxDU028bT1x0/WRkug5Z8QsbP1m3ow54hQwQ1KUDYoXdk2H4l0Fmk xAsrTF44Jzd9yTppqbDpbSkCfFZ8PurvKfVsvAQqW0GbzKLncite/ojNZtoy2rQ58WRjy+a3uPZ NkTJX0BIvYaQ9AVCvJ4TDhcN9f8ZwaW/rqsV0x9lyw== X-Google-Smtp-Source: AGHT+IGvzQi+likdI6Oaqk/TH/1q033q2DE+QddC1Idh9bv5bAEiMau09ALgvQR7B2FVM31RJVYykw== X-Received: by 2002:a5d:64a8:0:b0:390:e9e0:5cc6 with SMTP id ffacd0b85a97d-395b70b6cabmr11195f8f.1.1741812892433; Wed, 12 Mar 2025 13:54:52 -0700 (PDT) Received: from [127.0.0.1] ([2001:67c:2fbc:1:a42b:bae6:6f7d:117f]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3912c10437dsm22481393f8f.99.2025.03.12.13.54.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Mar 2025 13:54:51 -0700 (PDT) From: Antonio Quartulli Date: Wed, 12 Mar 2025 21:54:29 +0100 Subject: [PATCH net-next v23 20/23] ovpn: kill key and notify userspace in case of IV exhaustion Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250312-b4-ovpn-v23-20-76066bc0a30c@openvpn.net> References: <20250312-b4-ovpn-v23-0-76066bc0a30c@openvpn.net> In-Reply-To: <20250312-b4-ovpn-v23-0-76066bc0a30c@openvpn.net> To: netdev@vger.kernel.org, Eric Dumazet , Jakub Kicinski , Paolo Abeni , Donald Hunter , Antonio Quartulli , Shuah Khan , sd@queasysnail.net, ryazanov.s.a@gmail.com, Andrew Lunn Cc: Simon Horman , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Xiao Liang X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=5907; i=antonio@openvpn.net; h=from:subject:message-id; bh=JSwqVjxBeHU4RACyPp9B4KuNViAULCMe3no65khXe0Y=; b=owEBbQGS/pANAwAIAQtw5TqgONWHAcsmYgBn0fR8T9mQm5JueJ9e/TTQta6UwXcJoW/NVN6Ok MNTB9nIqyqJATMEAAEIAB0WIQSZq9xs+NQS5N5fwPwLcOU6oDjVhwUCZ9H0fAAKCRALcOU6oDjV h3xcCACbfTuDbkpuFYmbpeJvqdXRKpgjUACKAj5IXzr14457VYMckNKtz0cpxDXs/VcDNUrSahE yO8odEK4HK2cPgSlHqRaw0ede5qpfZSFwJUoESEgfTQ0d/TSgYO77bkm6mnED676creVqkSbhCB yOA1p0CIjT7wb6tA2+DCrzzyYE4mAW98hdj6hUdGhY+LWhDWBTSC8KV7EXtZckhApGSDfYmXbSD eX1EzA8ZLyPiuznz27lol6t4nQWgjQZGujovYSeGQ+NMKBe9gl2LGkFl5931pdBQpr0yVv6tbAg Wlun6seLD/FrJ0Lbl1KDj2q3CB/zxQMeeqJQs8MeS7E33ANi X-Developer-Key: i=antonio@openvpn.net; a=openpgp; fpr=CABDA1282017C267219885C748F0CCB68F59D14C IV wrap-around is cryptographically dangerous for a number of ciphers, therefore kill the key and inform userspace (via netlink) should the IV space go exhausted. Userspace has two ways of deciding when the key has to be renewed before exhausting the IV space: 1) time based approach: after X seconds/minutes userspace generates a new key and sends it to the kernel. This is based on guestimate and normally default timer value works well. 2) packet count based approach: after X packets/bytes userspace generates a new key and sends it to the kernel. Userspace keeps track of the amount of traffic by periodically polling GET_PEER and fetching the VPN/LINK stats. Signed-off-by: Antonio Quartulli --- drivers/net/ovpn/crypto.c | 19 ++++++++++++++ drivers/net/ovpn/crypto.h | 2 ++ drivers/net/ovpn/io.c | 13 ++++++++++ drivers/net/ovpn/netlink.c | 64 ++++++++++++++++++++++++++++++++++++++++++= ++++ drivers/net/ovpn/netlink.h | 2 ++ 5 files changed, 100 insertions(+) diff --git a/drivers/net/ovpn/crypto.c b/drivers/net/ovpn/crypto.c index 3c15d6d78f0f5ceeeb5ee39bfaaa7005d01a87fc..f6cb14c9ec4a8f12a99fe449f01= 1bd0d633bf904 100644 --- a/drivers/net/ovpn/crypto.c +++ b/drivers/net/ovpn/crypto.c @@ -54,6 +54,25 @@ void ovpn_crypto_state_release(struct ovpn_crypto_state = *cs) } } =20 +/* removes the key matching the specified id from the crypto context */ +void ovpn_crypto_kill_key(struct ovpn_crypto_state *cs, u8 key_id) +{ + struct ovpn_crypto_key_slot *ks =3D NULL; + + spin_lock_bh(&cs->lock); + if (rcu_access_pointer(cs->slots[0])->key_id =3D=3D key_id) { + ks =3D rcu_replace_pointer(cs->slots[0], NULL, + lockdep_is_held(&cs->lock)); + } else if (rcu_access_pointer(cs->slots[1])->key_id =3D=3D key_id) { + ks =3D rcu_replace_pointer(cs->slots[1], NULL, + lockdep_is_held(&cs->lock)); + } + spin_unlock_bh(&cs->lock); + + if (ks) + ovpn_crypto_key_slot_put(ks); +} + /* Reset the ovpn_crypto_state object in a way that is atomic * to RCU readers. */ diff --git a/drivers/net/ovpn/crypto.h b/drivers/net/ovpn/crypto.h index 487d24a7d26635c9ca0fd66c75717502f60e7a0c..4397253893ff2638b86b9d55bd2= 1e11d0aeacf80 100644 --- a/drivers/net/ovpn/crypto.h +++ b/drivers/net/ovpn/crypto.h @@ -140,4 +140,6 @@ int ovpn_crypto_config_get(struct ovpn_crypto_state *cs, enum ovpn_key_slot slot, struct ovpn_key_config *keyconf); =20 +void ovpn_crypto_kill_key(struct ovpn_crypto_state *cs, u8 key_id); + #endif /* _NET_OVPN_OVPNCRYPTO_H_ */ diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c index 5b673eae255033b9d7d6e7890a46686403d7c222..d81c1a2a958c73e22e548d8e63f= c78821b5eb881 100644 --- a/drivers/net/ovpn/io.c +++ b/drivers/net/ovpn/io.c @@ -255,6 +255,19 @@ void ovpn_encrypt_post(void *data, int ret) if (likely(ovpn_skb_cb(skb)->req)) aead_request_free(ovpn_skb_cb(skb)->req); =20 + if (unlikely(ret =3D=3D -ERANGE)) { + /* we ran out of IVs and we must kill the key as it can't be + * use anymore + */ + netdev_warn(peer->ovpn->dev, + "killing key %u for peer %u\n", ks->key_id, + peer->id); + ovpn_crypto_kill_key(&peer->crypto, ks->key_id); + /* let userspace know so that a new key must be negotiated */ + ovpn_nl_key_swap_notify(peer, ks->key_id); + goto err; + } + if (unlikely(ret < 0)) goto err; =20 diff --git a/drivers/net/ovpn/netlink.c b/drivers/net/ovpn/netlink.c index 0dedafea01858bddd457af0c95614e61c113682e..46500e4223d7619a342f803c67a= a760166fa6f2b 100644 --- a/drivers/net/ovpn/netlink.c +++ b/drivers/net/ovpn/netlink.c @@ -1094,6 +1094,70 @@ int ovpn_nl_key_del_doit(struct sk_buff *skb, struct= genl_info *info) return 0; } =20 +/** + * ovpn_nl_key_swap_notify - notify userspace peer's key must be renewed + * @peer: the peer whose key needs to be renewed + * @key_id: the ID of the key that needs to be renewed + * + * Return: 0 on success or a negative error code otherwise + */ +int ovpn_nl_key_swap_notify(struct ovpn_peer *peer, u8 key_id) +{ + struct ovpn_socket *sock; + struct nlattr *k_attr; + struct sk_buff *msg; + int ret =3D -EMSGSIZE; + void *hdr; + + netdev_info(peer->ovpn->dev, "peer with id %u must rekey - primary key un= usable.\n", + peer->id); + + msg =3D nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); + if (!msg) + return -ENOMEM; + + hdr =3D genlmsg_put(msg, 0, 0, &ovpn_nl_family, 0, OVPN_CMD_KEY_SWAP_NTF); + if (!hdr) { + ret =3D -ENOBUFS; + goto err_free_msg; + } + + if (nla_put_u32(msg, OVPN_A_IFINDEX, peer->ovpn->dev->ifindex)) + goto err_cancel_msg; + + k_attr =3D nla_nest_start(msg, OVPN_A_KEYCONF); + if (!k_attr) + goto err_cancel_msg; + + if (nla_put_u32(msg, OVPN_A_KEYCONF_PEER_ID, peer->id)) + goto err_cancel_msg; + + if (nla_put_u16(msg, OVPN_A_KEYCONF_KEY_ID, key_id)) + goto err_cancel_msg; + + nla_nest_end(msg, k_attr); + genlmsg_end(msg, hdr); + + rcu_read_lock(); + sock =3D rcu_dereference(peer->sock); + if (!sock) { + ret =3D -EINVAL; + goto err_unlock; + } + genlmsg_multicast_netns(&ovpn_nl_family, sock_net(sock->sock->sk), + msg, 0, OVPN_NLGRP_PEERS, GFP_ATOMIC); + rcu_read_unlock(); + + return 0; +err_unlock: + rcu_read_unlock(); +err_cancel_msg: + genlmsg_cancel(msg, hdr); +err_free_msg: + nlmsg_free(msg); + return ret; +} + /** * ovpn_nl_register - perform any needed registration in the NL subsustem * diff --git a/drivers/net/ovpn/netlink.h b/drivers/net/ovpn/netlink.h index 0d6c34e17082cc7c52dd9c5d5ed1e964925b3f4b..5dc84c8e5e803014053faa0d892= fc3a7259d40e5 100644 --- a/drivers/net/ovpn/netlink.h +++ b/drivers/net/ovpn/netlink.h @@ -12,4 +12,6 @@ int ovpn_nl_register(void); void ovpn_nl_unregister(void); =20 +int ovpn_nl_key_swap_notify(struct ovpn_peer *peer, u8 key_id); + #endif /* _NET_OVPN_NETLINK_H_ */ --=20 2.48.1