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Tue, 15 Oct 2024 18:04:20 -0700 (PDT) Received: from serenity.mandelbit.com ([2001:67c:2fbc:1:4c1a:a7c8:72f5:4282]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-37d7fa8778csm2886765f8f.25.2024.10.15.18.04.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Oct 2024 18:04:19 -0700 (PDT) From: Antonio Quartulli Date: Wed, 16 Oct 2024 03:03:19 +0200 Subject: [PATCH net-next v9 19/23] ovpn: implement key add/del/swap via netlink Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241016-b4-ovpn-v9-19-aabe9d225ad5@openvpn.net> References: <20241016-b4-ovpn-v9-0-aabe9d225ad5@openvpn.net> In-Reply-To: <20241016-b4-ovpn-v9-0-aabe9d225ad5@openvpn.net> To: Eric Dumazet , Jakub Kicinski , Paolo Abeni , Donald Hunter , Antonio Quartulli , Shuah Khan , donald.hunter@gmail.com, sd@queasysnail.net, ryazanov.s.a@gmail.com, Andrew Lunn Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, openvpn-devel@lists.sourceforge.net, linux-kselftest@vger.kernel.org X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=7966; i=antonio@openvpn.net; h=from:subject:message-id; bh=uBijmJW2oOVCVWghW03aDeybZ37xU5VWTwEgFTeWMTM=; b=owEBbQGS/pANAwAIAQtw5TqgONWHAcsmYgBnDxDw/CaDBhVBcSDw3zjfvyyeXM+Ti6K3p4oxg bjVrQPq5rKJATMEAAEIAB0WIQSZq9xs+NQS5N5fwPwLcOU6oDjVhwUCZw8Q8AAKCRALcOU6oDjV h6ICCAC2fKYU+0wxtQcofn51AHb/XtsWkZneMhtxvqgo08DNF5FjPCZzyQrBB7w8F3wNfR9FhfS P7Lhyt44Uw0zQw9/0sxAAvn8t8dP9jXiw5IcJUkqIjLcHJT6G3ajM5Cr85hgSJylmWx3xg20mXY 3UqxYQm9c6osbd4WN4a0YDHWuJVGOtnHy2udH4i4Rg/FO5A5W2qn7biMSlcgRztyVEcnM3UM1mG VTeQHSbry9eGuBbfg2vOSwmHrtWlFtkNlamTmijLHavdQXe0JAe5eHubPp+I5pEN9/vBas99mmB o0HMVUrshT8amJE+CGEwzWxfT0FnvVq10uteT6keyHesgeVB X-Developer-Key: i=antonio@openvpn.net; a=openpgp; fpr=CABDA1282017C267219885C748F0CCB68F59D14C X-Patchwork-Delegate: kuba@kernel.org This change introduces the netlink commands needed to add, delete and swap keys for a specific peer. Userspace is expected to use these commands to create, destroy and rotate session keys for a specific peer. Signed-off-by: Antonio Quartulli --- drivers/net/ovpn/netlink.c | 210 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 207 insertions(+), 3 deletions(-) diff --git a/drivers/net/ovpn/netlink.c b/drivers/net/ovpn/netlink.c index d504445325ef82db04f87367c858adaf025f6297..bb96645205b6704f7066b7de9a003e01e63c10f7 100644 --- a/drivers/net/ovpn/netlink.c +++ b/drivers/net/ovpn/netlink.c @@ -679,9 +679,140 @@ int ovpn_nl_peer_del_doit(struct sk_buff *skb, struct genl_info *info) return ret; } +static int ovpn_nl_get_key_dir(struct genl_info *info, struct nlattr *key, + enum ovpn_cipher_alg cipher, + struct ovpn_key_direction *dir) +{ + struct nlattr *attrs[OVPN_A_KEYDIR_MAX + 1]; + int ret; + + ret = nla_parse_nested(attrs, OVPN_A_KEYDIR_MAX, key, + ovpn_keydir_nl_policy, info->extack); + if (ret) + return ret; + + switch (cipher) { + case OVPN_CIPHER_ALG_AES_GCM: + case OVPN_CIPHER_ALG_CHACHA20_POLY1305: + if (NL_REQ_ATTR_CHECK(info->extack, key, attrs, + OVPN_A_KEYDIR_CIPHER_KEY) || + NL_REQ_ATTR_CHECK(info->extack, key, attrs, + OVPN_A_KEYDIR_NONCE_TAIL)) + return -EINVAL; + + dir->cipher_key = nla_data(attrs[OVPN_A_KEYDIR_CIPHER_KEY]); + dir->cipher_key_size = nla_len(attrs[OVPN_A_KEYDIR_CIPHER_KEY]); + + /* These algorithms require a 96bit nonce, + * Construct it by combining 4-bytes packet id and + * 8-bytes nonce-tail from userspace + */ + dir->nonce_tail = nla_data(attrs[OVPN_A_KEYDIR_NONCE_TAIL]); + dir->nonce_tail_size = nla_len(attrs[OVPN_A_KEYDIR_NONCE_TAIL]); + break; + default: + NL_SET_ERR_MSG_MOD(info->extack, "unsupported cipher"); + return -EINVAL; + } + + return 0; +} + +/** + * ovpn_nl_key_new_doit - configure a new key for the specified peer + * @skb: incoming netlink message + * @info: genetlink metadata + * + * This function allows the user to install a new key in the peer crypto + * state. + * Each peer has two 'slots', namely 'primary' and 'secondary', where + * keys can be installed. The key in the 'primary' slot is used for + * encryption, while both keys can be used for decryption by matching the + * key ID carried in the incoming packet. + * + * The user is responsible for rotating keys when necessary. The user + * may fetch peer traffic statistics via netlink in order to better + * identify the right time to rotate keys. + * The renegotiation follows these steps: + * 1. a new key is computed by the user and is installed in the 'secondary' + * slot + * 2. at user discretion (usually after a predetermined time) 'primary' and + * 'secondary' contents are swapped and the new key starts being used for + * encryption, while the old key is kept around for decryption of late + * packets. + * + * Return: 0 on success or a negative error code otherwise. + */ int ovpn_nl_key_new_doit(struct sk_buff *skb, struct genl_info *info) { - return -EOPNOTSUPP; + struct nlattr *attrs[OVPN_A_KEYCONF_MAX + 1]; + struct ovpn_struct *ovpn = info->user_ptr[0]; + struct ovpn_peer_key_reset pkr; + struct ovpn_peer *peer; + u32 peer_id; + int ret; + + if (GENL_REQ_ATTR_CHECK(info, OVPN_A_KEYCONF)) + return -EINVAL; + + ret = nla_parse_nested(attrs, OVPN_A_KEYCONF_MAX, + info->attrs[OVPN_A_KEYCONF], + ovpn_keyconf_nl_policy, info->extack); + if (ret) + return ret; + + if (NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_PEER_ID)) + return -EINVAL; + + if (NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_SLOT) || + NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_KEY_ID) || + NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_CIPHER_ALG) || + NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_ENCRYPT_DIR) || + NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_DECRYPT_DIR)) + return -EINVAL; + + peer_id = nla_get_u32(attrs[OVPN_A_KEYCONF_PEER_ID]); + pkr.slot = nla_get_u8(attrs[OVPN_A_KEYCONF_SLOT]); + pkr.key.key_id = nla_get_u16(attrs[OVPN_A_KEYCONF_KEY_ID]); + pkr.key.cipher_alg = nla_get_u16(attrs[OVPN_A_KEYCONF_CIPHER_ALG]); + + ret = ovpn_nl_get_key_dir(info, attrs[OVPN_A_KEYCONF_ENCRYPT_DIR], + pkr.key.cipher_alg, &pkr.key.encrypt); + if (ret < 0) + return ret; + + ret = ovpn_nl_get_key_dir(info, attrs[OVPN_A_KEYCONF_DECRYPT_DIR], + pkr.key.cipher_alg, &pkr.key.decrypt); + if (ret < 0) + return ret; + + peer = ovpn_peer_get_by_id(ovpn, peer_id); + if (!peer) { + NL_SET_ERR_MSG_FMT_MOD(info->extack, + "no peer with id %u to set key for", + peer_id); + return -ENOENT; + } + + ret = ovpn_crypto_state_reset(&peer->crypto, &pkr); + if (ret < 0) { + NL_SET_ERR_MSG_FMT_MOD(info->extack, + "cannot install new key for peer %u", + peer_id); + goto out; + } + + netdev_dbg(ovpn->dev, "%s: new key installed (id=%u) for peer %u\n", + __func__, pkr.key.key_id, peer_id); +out: + ovpn_peer_put(peer); + return ret; } int ovpn_nl_key_get_doit(struct sk_buff *skb, struct genl_info *info) @@ -691,12 +822,85 @@ int ovpn_nl_key_get_doit(struct sk_buff *skb, struct genl_info *info) int ovpn_nl_key_swap_doit(struct sk_buff *skb, struct genl_info *info) { - return -EOPNOTSUPP; + struct ovpn_struct *ovpn = info->user_ptr[0]; + struct nlattr *attrs[OVPN_A_PEER_MAX + 1]; + struct ovpn_peer *peer; + u32 peer_id; + int ret; + + if (GENL_REQ_ATTR_CHECK(info, OVPN_A_KEYCONF)) + return -EINVAL; + + ret = nla_parse_nested(attrs, OVPN_A_KEYCONF_MAX, + info->attrs[OVPN_A_KEYCONF], + ovpn_keyconf_nl_policy, info->extack); + if (ret) + return ret; + + if (NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_PEER_ID)) + return -EINVAL; + + peer_id = nla_get_u32(attrs[OVPN_A_KEYCONF_PEER_ID]); + + peer = ovpn_peer_get_by_id(ovpn, peer_id); + if (!peer) { + NL_SET_ERR_MSG_FMT_MOD(info->extack, + "no peer with id %u to swap keys for", + peer_id); + return -ENOENT; + } + + ovpn_crypto_key_slots_swap(&peer->crypto); + ovpn_peer_put(peer); + + return 0; } int ovpn_nl_key_del_doit(struct sk_buff *skb, struct genl_info *info) { - return -EOPNOTSUPP; + struct nlattr *attrs[OVPN_A_KEYCONF_MAX + 1]; + struct ovpn_struct *ovpn = info->user_ptr[0]; + enum ovpn_key_slot slot; + struct ovpn_peer *peer; + u32 peer_id; + int ret; + + if (GENL_REQ_ATTR_CHECK(info, OVPN_A_KEYCONF)) + return -EINVAL; + + ret = nla_parse_nested(attrs, OVPN_A_KEYCONF_MAX, + info->attrs[OVPN_A_KEYCONF], + ovpn_keyconf_nl_policy, info->extack); + if (ret) + return ret; + + if (NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_PEER_ID)) + return -EINVAL; + + if (ret) + return ret; + + if (NL_REQ_ATTR_CHECK(info->extack, info->attrs[OVPN_A_KEYCONF], attrs, + OVPN_A_KEYCONF_SLOT)) + return -EINVAL; + + peer_id = nla_get_u32(attrs[OVPN_A_KEYCONF_PEER_ID]); + slot = nla_get_u8(attrs[OVPN_A_KEYCONF_SLOT]); + + peer = ovpn_peer_get_by_id(ovpn, peer_id); + if (!peer) { + NL_SET_ERR_MSG_FMT_MOD(info->extack, + "no peer with id %u to delete key for", + peer_id); + return -ENOENT; + } + + ovpn_crypto_key_slot_delete(&peer->crypto, slot); + ovpn_peer_put(peer); + + return 0; } /**