From patchwork Thu Feb 13 02:52:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arne Schwabe X-Patchwork-Id: 996 Return-Path: Delivered-To: patchwork@openvpn.net Delivered-To: patchwork@openvpn.net Received: from director11.mail.ord1d.rsapps.net ([172.30.191.6]) by backend30.mail.ord1d.rsapps.net with LMTP id 0BcUGANVRV7aUwAAIUCqbw for ; Thu, 13 Feb 2020 08:54:11 -0500 Received: from proxy5.mail.ord1d.rsapps.net ([172.30.191.6]) by director11.mail.ord1d.rsapps.net with LMTP id IJQLGANVRV6vLgAAvGGmqA ; Thu, 13 Feb 2020 08:54:11 -0500 Received: from smtp33.gate.ord1d ([172.30.191.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) by proxy5.mail.ord1d.rsapps.net with LMTP id aCR1FwNVRV6rZgAA8Zzt7w ; Thu, 13 Feb 2020 08:54:11 -0500 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: smtp33.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=rfc2549.org X-Suspicious-Flag: YES X-Classification-ID: 4f227260-4e68-11ea-9e02-525400041ef2-1-1 Received: from [216.105.38.7] ([216.105.38.7:57014] helo=lists.sourceforge.net) by smtp33.gate.ord1d.rsapps.net (envelope-from ) (ecelerity 4.2.38.62370 r(:)) with ESMTPS (cipher=DHE-RSA-AES256-GCM-SHA384) id 3A/9E-08233-205554E5; Thu, 13 Feb 2020 08:54:10 -0500 Received: from [127.0.0.1] (helo=sfs-ml-4.v29.lw.sourceforge.com) by sfs-ml-4.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1j2Eun-0001no-M6; Thu, 13 Feb 2020 13:52:25 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-4.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1j2Eum-0001nb-AW for openvpn-devel@lists.sourceforge.net; Thu, 13 Feb 2020 13:52:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=References:In-Reply-To:Message-Id:Date:Subject:To: From:Sender:Reply-To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: 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=6lp76JRBDyTjlsYdqZMAvQW8zvkFQu23fiBcrY585PE=; b=mV5kjVUlws8KfVH7JvBl3rViOp tIG5GE2ocv8SD2MUH4yWMY0AG0wWYaezWk+I/ZYpr8wwbNuhy+yuxvU4BZrfRvTyLU3krwxidZkNs Gi9iOQ+62MBEKadNb3Kuc1Mwa4jkpB5FhghJqwIZS1prW2eydLQKYCcudrAaFAr/TJPE=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=References:In-Reply-To:Message-Id:Date:Subject:To:From:Sender:Reply-To:Cc :MIME-Version:Content-Type:Content-Transfer-Encoding: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=6lp76JRBDyTjlsYdqZMAvQW8zvkFQu23fiBcrY585PE=; b=FODluEa50Xm4LkgADIEIpzF0Kz UDahXuh868hziQA9NLbNWu9axUTPmHcKXmZhGutk9B+gqau1IZegYOP+ffHdE9b92rKRv/hF5QpoE uiLZHIM3jVB1TySsEQTZpX3LDuZ2l42CCr1ZNIdENhMxprBVGbcC1CWOGTUPqR35xw40=; Received: from mail.blinkt.de ([192.26.174.232]) by sfi-mx-3.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.2) id 1j2Euk-0037yI-Rb for openvpn-devel@lists.sourceforge.net; Thu, 13 Feb 2020 13:52:24 +0000 Received: from kamera.blinkt.de ([2001:638:502:390:20c:29ff:fec8:535c]) by mail.blinkt.de with smtp (Exim 4.92.3 (FreeBSD)) (envelope-from ) id 1j2Eue-00025I-8Y for openvpn-devel@lists.sourceforge.net; Thu, 13 Feb 2020 14:52:16 +0100 Received: (nullmailer pid 9302 invoked by uid 10006); Thu, 13 Feb 2020 13:52:16 -0000 From: Arne Schwabe To: openvpn-devel@lists.sourceforge.net Date: Thu, 13 Feb 2020 14:52:16 +0100 Message-Id: <20200213135216.9257-1-arne@rfc2549.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.0 URIBL_BLOCKED ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [URIs: rfc2549.org] 0.2 HEADER_FROM_DIFFERENT_DOMAINS From and EnvelopeFrom 2nd level mail domains are different 0.0 SPF_NONE SPF: sender does not publish an SPF Record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-Headers-End: 1j2Euk-0037yI-Rb Subject: [Openvpn-devel] [PATCH v2 4/5] Normalise ncp-ciphers option and restrict it to 127 bytes 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: , MIME-Version: 1.0 Errors-To: openvpn-devel-bounces@lists.sourceforge.net X-getmail-retrieved-from-mailbox: Inbox In scenarios of mbed TLS vs OpenSSL we already normalise the ciphers that are send via the wire protocol via OCC to not have a mismatch warning between server and client. This is done by translate_cipher_name_from_openvpn. The same applies also to the ncp-ciphers list. Specifying non normalised names in ncp-ciphers will cause negotation not to succeed if ciphers are not in the same form. Therefore we will normalise the ciphers in options_postmutate. The alternative and a lot less user friendly alternative would be to bail if on of the ciphers in ncp-ciphers is not in its normalised form. Also restrict the ncp-ciphers list to 127. This is somewhat arbitrary but should prevent too large IV_CIPHER messages and problems sending those. The server will accept also large IV_CIPHER values from clients. Patch V2: Correct comment about normalising ciphers Signed-off-by: Arne Schwabe --- doc/openvpn.8 | 3 ++ src/openvpn/options.c | 14 ++++--- src/openvpn/ssl_ncp.c | 57 +++++++++++++++++++++++++---- src/openvpn/ssl_ncp.h | 19 +++++++++- tests/unit_tests/openvpn/test_ncp.c | 43 ++++++++++++++++++---- 5 files changed, 114 insertions(+), 22 deletions(-) diff --git a/doc/openvpn.8 b/doc/openvpn.8 index d631ebe7..c0ec80f9 100644 --- a/doc/openvpn.8 +++ b/doc/openvpn.8 @@ -4406,6 +4406,9 @@ AES\-256\-GCM:AES\-256\-CBC" set can either specify "\-\-cipher BF\-CBC" or Note, for using NCP with a OpenVPN 2.4 peer this list must include the AES\-256\-GCM and AES\-128\-GCM ciphers. + +This list is restricted to be 127 chars long after conversion to OpenVPN +ciphers. .\"********************************************************* .TP .B \-\-ncp\-disable diff --git a/src/openvpn/options.c b/src/openvpn/options.c index d057975c..06291970 100644 --- a/src/openvpn/options.c +++ b/src/openvpn/options.c @@ -2511,11 +2511,6 @@ options_postprocess_verify_ce(const struct options *options, const struct connec } #endif /* P2MP_SERVER */ - if (options->ncp_enabled && !tls_check_ncp_cipher_list(options->ncp_ciphers)) - { - msg(M_USAGE, "NCP cipher list contains unsupported ciphers."); - } - if (options->keysize) { msg(M_WARN, "WARNING: --keysize is DEPRECATED and will be removed in OpenVPN 2.6"); @@ -3093,6 +3088,15 @@ options_postprocess_mutate(struct options *o) options_postprocess_mutate_invariant(o); + if (o->ncp_enabled) + { + o->ncp_ciphers = mutate_ncp_cipher_list(o->ncp_ciphers, &o->gc); + if (o->ncp_ciphers == NULL) + { + msg(M_USAGE, "NCP cipher list contains unsupported ciphers or is too long."); + } + } + if (o->remote_list && !o->connection_list) { /* diff --git a/src/openvpn/ssl_ncp.c b/src/openvpn/ssl_ncp.c index 029ac1d5..9bebc1fd 100644 --- a/src/openvpn/ssl_ncp.c +++ b/src/openvpn/ssl_ncp.c @@ -91,27 +91,70 @@ tls_peer_supports_ncp(const char *peer_info) } } -bool -tls_check_ncp_cipher_list(const char *list) +char * +mutate_ncp_cipher_list(const char *list, struct gc_arena *gc) { - bool unsupported_cipher_found = false; + bool error_found = false; - ASSERT(list); + struct buffer new_list = alloc_buf(MAX_NCP_CIPHERS_LENGTH); char *const tmp_ciphers = string_alloc(list, NULL); const char *token = strtok(tmp_ciphers, ":"); while (token) { - if (!cipher_kt_get(translate_cipher_name_from_openvpn(token))) + /* + * Going through a roundtrip by using translate_cipher_name_from_openvpn + * and translate_cipher_name_to_openvpn also normalises the cipher name, + * e.g. replacing AeS-128-gCm with AES-128-GCM + */ + const char *cipher_name = translate_cipher_name_from_openvpn(token); + const cipher_kt_t *ktc = cipher_kt_get(cipher_name); + if (!ktc) { msg(M_WARN, "Unsupported cipher in --ncp-ciphers: %s", token); - unsupported_cipher_found = true; + error_found = true; + } + else + { + const char *ovpn_cipher_name = + translate_cipher_name_to_openvpn(cipher_kt_name(ktc)); + + if (buf_len(&new_list)> 0) + { + /* The next if condition ensure there is always space for + * a : + */ + buf_puts(&new_list, ":"); + } + + /* Ensure buffer has capacity for cipher name + : + \0 */ + if (!(buf_forward_capacity(&new_list) > + strlen(ovpn_cipher_name) + 2)) + { + msg(M_WARN, "Length of --ncp-ciphers is over the" + "limit of 127 chars"); + error_found = true; + } + else + { + buf_puts(&new_list, ovpn_cipher_name); + } } token = strtok(NULL, ":"); } + + + + char *ret = NULL; + if (!error_found && buf_len(&new_list) > 0) + { + buf_null_terminate(&new_list); + ret = string_alloc(buf_str(&new_list), gc); + } free(tmp_ciphers); + free_buf(&new_list); - return 0 < strlen(list) && !unsupported_cipher_found; + return ret; } bool diff --git a/src/openvpn/ssl_ncp.h b/src/openvpn/ssl_ncp.h index 82d008d8..62822e89 100644 --- a/src/openvpn/ssl_ncp.h +++ b/src/openvpn/ssl_ncp.h @@ -87,10 +87,17 @@ tls_peer_ncp_list(const char *peer_info); * Check whether the ciphers in the supplied list are supported. * * @param list Colon-separated list of ciphers + * @parms gc gc_arena to allocate the returned string * - * @returns true iff all ciphers in list are supported. + * @returns colon separated string of normalised (via + * translate_cipher_name_from_openvpn) and + * zero terminated string iff all ciphers + * in list are supported and the total length + * is short than MAX_NCP_CIPHERS_LENGTH. NULL + * otherwise. */ -bool tls_check_ncp_cipher_list(const char *list); +char * +mutate_ncp_cipher_list(const char *list, struct gc_arena *gc); /** * Return true iff item is present in the colon-separated zero-terminated @@ -98,4 +105,12 @@ bool tls_check_ncp_cipher_list(const char *list); */ bool tls_item_in_cipher_list(const char *item, const char *list); +/** + * The maximum length of a ncp-cipher string that is accepted. + * + * Since this list needs to be pushed as IV_CIPHERS, we are conservative + * about its length. + */ +#define MAX_NCP_CIPHERS_LENGTH 127 + #endif /* ifndef OPENVPN_SSL_NCP_H */ diff --git a/tests/unit_tests/openvpn/test_ncp.c b/tests/unit_tests/openvpn/test_ncp.c index ec85d6ef..a75e7f7a 100644 --- a/tests/unit_tests/openvpn/test_ncp.c +++ b/tests/unit_tests/openvpn/test_ncp.c @@ -47,10 +47,33 @@ const char *aes_ciphers = "AES-256-GCM:AES-128-GCM"; static void test_check_ncp_ciphers_list(void **state) { - assert_true(tls_check_ncp_cipher_list(aes_ciphers)); - assert_true(tls_check_ncp_cipher_list(bf_chacha)); - assert_false(tls_check_ncp_cipher_list("vollbit")); - assert_false(tls_check_ncp_cipher_list("AES-256-GCM:vollbit")); + struct gc_arena gc = gc_new(); + + assert_string_equal(mutate_ncp_cipher_list(aes_ciphers, &gc), aes_ciphers); + + assert_string_equal(mutate_ncp_cipher_list(bf_chacha, &gc), bf_chacha); + + assert_string_equal(mutate_ncp_cipher_list("BF-cbc:ChaCha20-Poly1305", &gc), + bf_chacha); + + + assert_ptr_equal(mutate_ncp_cipher_list("vollbit", &gc), NULL); + assert_ptr_equal(mutate_ncp_cipher_list("AES-256-GCM:vollbit", &gc), NULL); + assert_ptr_equal(mutate_ncp_cipher_list("", &gc), NULL); + + assert_ptr_equal(mutate_ncp_cipher_list( + "ChaCha20-Poly1305:ChaCha20-Poly1305:ChaCha20-Poly1305:" + "ChaCha20-Poly1305:ChaCha20-Poly1305:ChaCha20-Poly1305:" + "ChaCha20-Poly1305", &gc), NULL); + +#idef ENABLE_CRYPTO_OPENSSL + assert_string_equal(mutate_ncp_cipher_list("id-aes128-GCM:id-aes256-GCM", + &gc), aes_ciphers); +#else + assert_string_equal(mutate_ncp_cipher_list("BLOWFISH-CBC", + &gc), "BF-CBC"); + gc_free(&gc); + } static void @@ -101,7 +124,7 @@ test_poor_man(void **state) struct gc_arena gc = gc_new(); char *best_cipher; - const char *serverlist="CHACHA20_POLY1305:AES-128-GCM"; + const char *serverlist = "CHACHA20_POLY1305:AES-128-GCM"; best_cipher = ncp_get_best_cipher(serverlist, "BF-CBC", "IV_YOLO=NO\nIV_BAR=7", @@ -131,7 +154,7 @@ test_ncp_best(void **state) struct gc_arena gc = gc_new(); char *best_cipher; - const char *serverlist="CHACHA20_POLY1305:AES-128-GCM:AES-256-GCM"; + const char *serverlist = "CHACHA20_POLY1305:AES-128-GCM:AES-256-GCM"; best_cipher = ncp_get_best_cipher(serverlist, "BF-CBC", "IV_YOLO=NO\nIV_NCP=2\nIV_BAR=7", @@ -167,7 +190,6 @@ test_ncp_best(void **state) - const struct CMUnitTest ncp_tests[] = { cmocka_unit_test(test_check_ncp_ciphers_list), cmocka_unit_test(test_extract_client_ciphers), @@ -176,7 +198,12 @@ const struct CMUnitTest ncp_tests[] = { }; -int main(void) +int +main(void) { +#if defined(ENABLE_CRYPTO_OPENSSL) + OpenSSL_add_all_algorithms(); +#endif + return cmocka_run_group_tests(ncp_tests, NULL, NULL); }