From patchwork Thu Jun 23 22:37:54 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antonio Quartulli X-Patchwork-Id: 2544 Return-Path: Delivered-To: patchwork@openvpn.net Delivered-To: patchwork@openvpn.net Received: from director12.mail.ord1d.rsapps.net ([172.30.191.6]) by backend41.mail.ord1d.rsapps.net with LMTP id CF3pBrp/tWJXXgAAqwncew (envelope-from ) for ; Fri, 24 Jun 2022 05:11:22 -0400 Received: from proxy20.mail.ord1d.rsapps.net ([172.30.191.6]) by director12.mail.ord1d.rsapps.net with LMTP id aIj0Brp/tWLHbwAAIasKDg (envelope-from ) for ; Fri, 24 Jun 2022 05:11:22 -0400 Received: from smtp31.gate.ord1d ([172.30.191.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) by proxy20.mail.ord1d.rsapps.net with LMTPS id IPiQBrp/tWJFAgAAsk8m8w (envelope-from ) for ; Fri, 24 Jun 2022 05:11:22 -0400 X-Spam-Threshold: 95 X-Spam-Score: 0 X-Spam-Flag: NO X-Virus-Scanned: OK X-Orig-To: openvpnslackdevel@openvpn.net X-Originating-Ip: [216.105.38.7] Authentication-Results: smtp31.gate.ord1d.rsapps.net; iprev=pass policy.iprev="216.105.38.7"; spf=pass smtp.mailfrom="openvpn-devel-bounces@lists.sourceforge.net" smtp.helo="lists.sourceforge.net"; dkim=fail (signature verification failed) header.d=sourceforge.net; dkim=fail (signature verification failed) header.d=sf.net; dmarc=none (p=nil; dis=none) header.from=unstable.cc X-Suspicious-Flag: YES X-Classification-ID: 9d23a1fa-f39d-11ec-a6e5-525400b3ac8c-1-1 Received: from [216.105.38.7] ([216.105.38.7:54024] helo=lists.sourceforge.net) by smtp31.gate.ord1d.rsapps.net (envelope-from ) (ecelerity 4.2.38.62370 r(:)) with ESMTPS (cipher=DHE-RSA-AES256-GCM-SHA384) id B3/36-18705-9BF75B26; Fri, 24 Jun 2022 05:11:21 -0400 Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.94.2) (envelope-from ) id 1o4fKe-0002bb-Ou; Fri, 24 Jun 2022 09:10:28 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1o4fKd-0002aX-II for openvpn-devel@lists.sourceforge.net; Fri, 24 Jun 2022 09:10:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=1DueKnzRwNGV8Cm0mI7aHiFPjc4Xtxsw7SLVamRpbXk=; b=BxX/U+X/y0kIt2jn9l5EkC4Tux L4DDCAXuQsJnS69cZcj95/SnXKHWyvvCTbm6wwAR4ZTiJ8Bcg5zqRodwjW9UtQSLiZnBmsb+BO5VJ igBxFFxKC7OBIODxCLgEQEg9fxY+mk8df9Bs9LQVoPr66vvo6AWJnHEPDA0dq1/Pq7KQ=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=1DueKnzRwNGV8Cm0mI7aHiFPjc4Xtxsw7SLVamRpbXk=; b=iYSZj60Dtzn6LKTuMNnKV1DJfX 4lG4huSeRPfEOJajIUQxVsfsLiAULMxgla5ADGdVnNSt/xEo/QKLJ5cWaXgON8Oe9+r6hFtJnxi8S CT/+lCe3qx5RdOfWLptz8mkqnOC+geU2dP3l7WeBziksMW1Uo/BR0Z56Mghs6+Vm7JUI=; Received: from s2.neomailbox.net ([5.148.176.60]) by sfi-mx-1.v28.lw.sourceforge.com with esmtps (TLS1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.94.2) id 1o4fKc-00C44x-Fm for openvpn-devel@lists.sourceforge.net; Fri, 24 Jun 2022 09:10:27 +0000 From: Antonio Quartulli To: openvpn-devel@lists.sourceforge.net Date: Fri, 24 Jun 2022 10:37:54 +0200 Message-Id: <20220624083809.23487-11-a@unstable.cc> In-Reply-To: <20220624083809.23487-1-a@unstable.cc> References: <20220624083809.23487-1-a@unstable.cc> MIME-Version: 1.0 X-Spam-Report: Spam detection software, running on the system "util-spamd-2.v13.lw.sourceforge.com", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Data channel keys are periodically regenarated and installed in ovpn-dco. However, there is a certain moment when keys are rotated in order to elect the new primary one. Check the key status in userspace so that kernelspace can be informed as well when rotations happen. Content analysis details: (-0.0 points, 6.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.0 T_SCC_BODY_TEXT_LINE No description available. X-Headers-End: 1o4fKc-00C44x-Fm Subject: [Openvpn-devel] [PATCH 10/25] dco: periodically check and possibly rotate/delete keys X-BeenThere: openvpn-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Antonio Quartulli Errors-To: openvpn-devel-bounces@lists.sourceforge.net X-getmail-retrieved-from-mailbox: Inbox Data channel keys are periodically regenarated and installed in ovpn-dco. However, there is a certain moment when keys are rotated in order to elect the new primary one. Check the key status in userspace so that kernelspace can be informed as well when rotations happen. Signed-off-by: Antonio Quartulli --- src/openvpn/dco.c | 97 +++++++++++++++++++++++++++++++++++++++++++ src/openvpn/dco.h | 14 +++++++ src/openvpn/forward.c | 19 +++++++++ 3 files changed, 130 insertions(+) diff --git a/src/openvpn/dco.c b/src/openvpn/dco.c index e38614fa..473eb564 100644 --- a/src/openvpn/dco.c +++ b/src/openvpn/dco.c @@ -92,6 +92,103 @@ init_key_dco_bi(struct tls_multi *multi, struct key_state *ks, ciphername); } +/** + * Find a usable key that is not the primary (i.e. the secondary key) + * + * @param multi The TLS struct to retrieve keys from + * @param primary The primary key that should be skipped during the scan + * + * @return The secondary key or NULL if none could be found + */ +static struct key_state * +dco_get_secondary_key(struct tls_multi *multi, const struct key_state *primary) +{ + for (int i = 0; i < KEY_SCAN_SIZE; ++i) + { + struct key_state *ks = get_key_scan(multi, i); + struct key_ctx_bi *key = &ks->crypto_options.key_ctx_bi; + + if (ks == primary) + { + continue; + } + + if (ks->state >= S_GENERATED_KEYS && ks->authenticated == KS_AUTH_TRUE) + { + ASSERT(key->initialized); + return ks; + } + } + + return NULL; +} + +void +dco_update_keys(dco_context_t *dco, struct tls_multi *multi) +{ + msg(D_DCO_DEBUG, "%s: peer_id=%d", __func__, multi->peer_id); + + /* this function checks if keys have to be swapped or erased, therefore it + * can't do much if we don't have any key installed + */ + if (multi->dco_keys_installed == 0) + { + return; + } + + struct key_state *primary = tls_select_encryption_key(multi); + ASSERT(!primary || primary->dco_status != DCO_NOT_INSTALLED); + + /* no primary key available -> no usable key exists, therefore we should + * tell DCO to simply wipe all keys + */ + if (!primary) + { + msg(D_DCO, "No encryption key found. Purging data channel keys"); + + dco_del_key(dco, multi->peer_id, OVPN_KEY_SLOT_PRIMARY); + dco_del_key(dco, multi->peer_id, OVPN_KEY_SLOT_SECONDARY); + multi->dco_keys_installed = 0; + return; + } + + struct key_state *secondary = dco_get_secondary_key(multi, primary); + ASSERT(!secondary || secondary->dco_status != DCO_NOT_INSTALLED); + + /* the current primary key was installed as secondary in DCO, this means + * that userspace has promoted it and we should tell DCO to swap keys + */ + if (primary->dco_status == DCO_INSTALLED_SECONDARY) + { + msg(D_DCO_DEBUG, "Swapping primary and secondary keys, now: id1=%d id2=%d", + primary->key_id, secondary ? secondary->key_id : -1); + + dco_swap_keys(dco, multi->peer_id); + primary->dco_status = DCO_INSTALLED_PRIMARY; + if (secondary) + { + secondary->dco_status = DCO_INSTALLED_SECONDARY; + } + } + + /* if we have no secondary key anymore, inform DCO about it */ + if (!secondary && multi->dco_keys_installed == 2) + { + dco_del_key(dco, multi->peer_id, OVPN_KEY_SLOT_SECONDARY); + multi->dco_keys_installed = 1; + } + + /* all keys that are not installed are set to NOT installed */ + for (int i = 0; i < KEY_SCAN_SIZE; ++i) + { + struct key_state *ks = get_key_scan(multi, i); + if (ks != primary && ks != secondary) + { + ks->dco_status = DCO_NOT_INSTALLED; + } + } +} + static bool dco_check_option_conflict_ce(const struct connection_entry *ce, int msglevel) { diff --git a/src/openvpn/dco.h b/src/openvpn/dco.h index b081c6fa..cb7f7e4f 100644 --- a/src/openvpn/dco.h +++ b/src/openvpn/dco.h @@ -130,6 +130,14 @@ int init_key_dco_bi(struct tls_multi *multi, struct key_state *ks, const struct key2 *key2, int key_direction, const char *ciphername, bool server); +/** + * Possibly swap or wipe keys from DCO + * + * @param dco DCO device context + * @param multi TLS multi instance + */ +void dco_update_keys(dco_context_t *dco, struct tls_multi *multi); + #else /* if defined(ENABLE_DCO) */ typedef void *dco_context_t; @@ -190,5 +198,11 @@ init_key_dco_bi(struct tls_multi *multi, struct key_state *ks, return 0; } +static inline void +dco_update_keys(dco_context_t *dco, struct tls_multi *multi) +{ + ASSERT(false); +} + #endif /* defined(ENABLE_DCO) */ #endif /* ifndef DCO_H */ diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c index 6afe152b..99898e01 100644 --- a/src/openvpn/forward.c +++ b/src/openvpn/forward.c @@ -41,6 +41,7 @@ #include "dhcp.h" #include "common.h" #include "ssl_verify.h" +#include "dco.h" #include "memdbg.h" @@ -140,6 +141,18 @@ context_reschedule_sec(struct context *c, int sec) } } +void +check_dco_key_status(struct context *c) +{ + /* DCO context is not yet initialised or enabled */ + if (!dco_enabled(&c->options)) + { + return; + } + + dco_update_keys(&c->c1.tuntap->dco, c->c2.tls_multi); +} + /* * In TLS mode, let TLS level respond to any control-channel * packets which were received, or prepare any packets for @@ -182,6 +195,12 @@ check_tls(struct context *c) interval_schedule_wakeup(&c->c2.tmp_int, &wakeup); + /* Our current code has no good hooks in the TLS machinery to update + * DCO keys. So we check the key status after the whole TLS machinery + * has been completed and potentially update them + */ + check_dco_key_status(c); + if (wakeup) { context_reschedule_sec(c, wakeup);