PR#3: Updates in TLS protocol section - defensive-coding-guide

		`@@ -2,13 +2,25 @@`
		`<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [`
		`]>`
		`<chapter id="chap-Defensive_Coding-TLS">`
		`- <title>Transport Layer Security</title>`
		`+ <title>Transport Layer Security (TLS)</title>`
		`<para>`
		`Transport Layer Security (TLS, formerly Secure Sockets`
		`Layer/SSL) is the recommended way to to protect integrity and`
		`confidentiality while data is transferred over an untrusted`
		`- network connection, and to identify the endpoint.`
		`+ network connection, and to identify the endpoint. At this`
		`+ chapter we describe the available libraries in Fedora as well`
		`+ as known pitfalls, and safe ways to write applications with them.`
		`</para>`
		`+ <para>`
		`+ When using any library, in addition to this guide, it is recommended to consult the`
		`+ library' documentation.`
		`+ </para>`
		`+ <itemizedlist>`
		`+ <listitem><para><ulink url="https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS">NSS documentation</ulink></para></listitem>`
		`+ <listitem><para><ulink url="http://www.gnutls.org/manual/">GNUTLS documentation</ulink></para></listitem>`
		`+ <listitem><para><ulink url="https://www.openssl.org/docs/">OpenSSL documentation</ulink></para></listitem>`
		`+ <listitem><para><ulink url="https://docs.oracle.com/javase/8/docs/technotes/guides/security/jsse/JSSERefGuide.html">OpenJDK documentation</ulink></para></listitem>`
		`+ </itemizedlist>`
		`<section id="sect-Defensive_Coding-TLS-Pitfalls">`
		`<title>Common Pitfalls</title>`
		`<para>`
		`@@ -215,58 +227,10 @@`
		`<section id="sect-Defensive_Coding-TLS-Pitfalls-GNUTLS">`
		`<title>GNUTLS Pitfalls</title>`
		`<para>`
		`- Older versions of GNUTLS had several peculiarities. As of`
		`- GNUTLS 3.3.10, they have been addressed, so these are only a`
		`- concern for applications which have to run with older GNUTLS`
		`- versions.`
		`+ Older versions of GNUTLS had several peculiarities described`
		`+ in previous versions of this guide; as of GNUTLS 3.3.10, these`
		`+ issues are no longer applicable.`
		`</para>`
		`- <itemizedlist>`
		`- <listitem>`
		`- <para>`
		`- The dynamic shared object provided by GNTULS links to`
		`- <filename>libpthread.so.0</filename>. Loading the`
		`- threading library too late causes problems, so the main`
		`- program should be linked with <literal>-lpthread</literal>`
		`- as well. As a result, it can be difficult to use GNUTLS`
		`- in a plugin which is loaded with the`
		`- <function>dlopen</function> function. Another side effect`
		`- is that applications which merely link against GNUTLS`
		`- (even without actually using it) may incur a substantial`
		`- overhead because other libraries automatically switch to`
		`- thread-safe algorithms.`
		`- </para>`
		`- </listitem>`
		`- <listitem>`
		`- <para>`
		`- The <function>gnutls_global_init</function> function must`
		`- be called before using any functionality provided by the`
		`- library. This function is not thread-safe, so external`
		`- locking is required, but it is not clear which lock should`
		`- be used. Omitting the synchronization does not just lead`
		`- to a memory leak, as it is suggested in the GNUTLS`
		`- documentation, but to undefined behavior because there is`
		`- no barrier that would enforce memory ordering.`
		`- </para>`
		`- </listitem>`
		`- <listitem>`
		`- <para>`
		`- The <function>gnutls_global_deinit</function> function`
		`- does not actually deallocate all resources allocated by`
		`- <function>gnutls_global_init</function>. It is currently`
		`- not thread-safe. Therefore, it is best to avoid calling`
		`- it altogether.`
		`- </para>`
		`- </listitem>`
		`- <listitem>`
		`- <para>`
		`- The X.509 implementation in GNUTLS is rather lenient. For`
		`- example, it is possible to create and process X.509`
		`- version 1 certificates which carry extensions. These`
		`- certificates are (correctly) rejected by other`
		`- implementations.`
		`- </para>`
		`- </listitem>`
		`- </itemizedlist>`
		`</section>`
		`<section id="sect-Defensive_Coding-TLS-Pitfalls-OpenJDK">`
		`<title>OpenJDK Pitfalls</title>`
		`@@ -329,16 +293,17 @@`
		`<para>`
		`The client must configure the TLS library to use a set of`
		`trusted root certificates. These certificates are provided`
		`- by the system in <filename`
		`- class="directory">/etc/ssl/certs</filename> or files derived`
		`- from it.`
		`+ by the system in various formats and files. These are documented in <literal>update-ca-trust</literal>`
		`+ man page in Fedora. Portable applications should not hard-code`
		`+ any paths; they should rely on APIs which set the default`
		`+ for the system trust store.`
		`</para>`
		`</listitem>`
		`<listitem>`
		`<para>`
		`The client selects sufficiently strong cryptographic`
		`primitives and disables insecure ones (such as no-op`
		`- encryption). Compression and SSL version 2 support must be`
		`+ encryption). Compression support and SSL version 3 or lower must be`
		`disabled (including the SSLv2-compatible handshake).`
		`</para>`
		`</listitem>`
		`@@ -522,19 +487,6 @@`
		`exploratory and needs to be replaced before production use.`
		`</para>`
		`<para>`
		`- The GNUTLS library needs explicit initialization:`
		`- </para>`
		`- <informalexample id="ex-Defensive_Coding-TLS-GNUTLS-Init">`
		`- <xi:include href="snippets/Features-TLS-GNUTLS-Init.xml"`
		`- xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`- </informalexample>`
		`- <para>`
		`- Failing to do so can result in obscure failures in Base64`
		`- decoding. See <xref`
		`- linkend="sect-Defensive_Coding-TLS-Pitfalls-GNUTLS"/> for`
		`- additional aspects of initialization.`
		`- </para>`
		`- <para>`
		`Before setting up TLS connections, a credentials objects has`
		`to be allocated and initialized with the set of trusted root`
		`CAs (<xref`
		`@@ -576,7 +528,7 @@`
		`</example>`
		`<para>`
		`After the handshake has been completed, the server certificate`
		`- needs to be verified (<xref`
		`+ needs to be verified against the server's hostname (<xref`
		`linkend="ex-Defensive_Coding-TLS-Client-GNUTLS-Verify"/>). In`
		`the example, the user-defined`
		`<function>certificate_validity_override</function> function is`
		`@@ -590,29 +542,6 @@`
		`xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`</example>`
		`<para>`
		`- In the next step (<xref`
		`- linkend="ex-Defensive_Coding-TLS-Client-GNUTLS-Match"/>, the`
		`- certificate must be matched against the host name (note the`
		`- unusual return value from`
		`- <function>gnutls_x509_crt_check_hostname</function>). Again,`
		`- an override function`
		`- <function>certificate_host_name_override</function> is called.`
		`- Note that the override must be keyed to the certificate`
		`- <emphasis>and</emphasis> the host name. The function call can`
		`- be omitted if the override is not needed.`
		`- </para>`
		`- <example id="ex-Defensive_Coding-TLS-Client-GNUTLS-Match">`
		`- <title>Matching the server host name and certificate in a`
		`- GNUTLS client</title>`
		`- <xi:include href="snippets/Features-TLS-Client-GNUTLS-Match.xml"`
		`- xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`- </example>`
		`- <para>`
		`- In newer GNUTLS versions, certificate checking and host name`
		`- validation can be combined using the`
		`- <function>gnutls_certificate_verify_peers3</function> function.`
		`- </para>`
		`- <para>`
		`An established TLS session can be used for sending and`
		`receiving data, as in <xref`
		`linkend="ex-Defensive_Coding-TLS-GNUTLS-Use"/>.`
		`@@ -630,7 +559,7 @@`
		`linkend="ex-Defensive_Coding-TLS-GNUTLS-Disconnect"/>).`
		`</para>`
		`<example id="ex-Defensive_Coding-TLS-GNUTLS-Disconnect">`
		`- <title>Using a GNUTLS session</title>`
		`+ <title>Closing a GNUTLS session in an orderly fashion</title>`
		`<xi:include href="snippets/Features-TLS-GNUTLS-Disconnect.xml"`
		`xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`</example>`
		`@@ -1010,4 +939,138 @@`
		`</informalexample>`
		`</section>`
		`</section>`
		`- </chapter>`
		`+ <section id="sect-Defensive_Coding-TLS-Server">`
		`+ <title>TLS Server</title>`
		`+ <para>`
		`+ Secure use of TLS in a server generally involves all of the`
		`+ following steps. (Individual instructions for specific TLS`
		`+ implementations follow in the next sections.)`
		`+ </para>`
		`+ <itemizedlist>`
		`+ <listitem>`
		`+ <para>`
		`+ The server selects sufficiently strong cryptographic`
		`+ primitives and disables insecure ones (such as no-op`
		`+ encryption). Compression support and SSL version 3 or lower must be`
		`+ disabled (including the SSLv2-compatible handshake).`
		`+ </para>`
		`+ </listitem>`
		`+ <listitem>`
		`+ <para>`
		`+ The server sets its certificate and key files. The server may`
		`+ have multiple such files, either because it is serving multiple host`
		`+ names, or because (for example) it has both RSA and ECDSA parameters.`
		`+ </para>`
		`+ </listitem>`
		`+ <listitem>`
		`+ <para>`
		`+ The server needs to specify an OCSP status request response file.`
		`+ That is, a response from the certificate issuer's OCSP server which`
		`+ states that the certificate is valid. This response file should be updated`
		`+ during the server's operational lifetime. The update frequency depends`
		`+ on the OCSP server's update frequency. Typically that's between few days`
		`+ and a week.`
		`+ </para>`
		`+ <para>`
		`+ Setting this file allows the connecting clients to obtain and verify the`
		`+ OCSP response for the server's certificate as soon, without contacting`
		`+ third party servers. This is often called a stapled OCSP response, and`
		`+ it is possible for the server to require his clients to check the OCSP response`
		`+ by marking his certificate as OCSP MUST-staple (which is defined on`
		`+ any unfortunately named RFC: "rfc7633: Transport Layer Security (TLS) Feature Extension".`
		`+ </para>`
		`+ </listitem>`
		`+ </itemizedlist>`
		`+ <section id="sect-Defensive_Coding-TLS-Server-GNUTLS">`
		`+ <title>Implementation of TLS Servers With GNUTLS</title>`
		`+ <para>`
		`+ While there are several types of TLS Servers, in this example we explore`
		`+ a basic TLS server where the server is authenticated by the client using`
		`+ certificate authentication.`
		`+ </para>`
		`+ <para>`
		`+ Before setting up TLS connections, a credentials objects has`
		`+ to be allocated and initialized with the server's certificate`
		`+ and keys (<xref`
		`+ linkend="ex-Defensive_Coding-TLS-Server-GNUTLS-Credentials"/>).`
		`+ </para>`
		`+ <para>`
		`+ In the case of a Hardware Security Module, the <function>gnutls_certificate_set_x509_key_file</function>`
		`+ should be provided with PKCS#11 URLs for the key and/or the certificate instead of files.`
		`+ </para>`
		`+ <example id="ex-Defensive_Coding-TLS-Server-GNUTLS-Credentials">`
		`+ <title>Initializing a GNUTLS credentials structure</title>`
		`+ <xi:include href="snippets/Features-TLS-Server-GNUTLS-Credentials.xml"`
		`+ xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`+ </example>`
		`+ <para>`
		`+ Similarly a set of acceptable ciphersuites must be generated`
		`+ (<xref`
		`+ linkend="ex-Defensive_Coding-TLS-Server-GNUTLS-Priorities"/>).`
		`+ </para>`
		`+ <example id="ex-Defensive_Coding-TLS-Server-GNUTLS-Priorities">`
		`+ <title>Initializing a GNUTLS priorities structure</title>`
		`+ <xi:include href="snippets/Features-TLS-Server-GNUTLS-Priorities.xml"`
		`+ xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`+ </example>`
		`+ <para>`
		`+ After the last TLS connection has been closed, these credentials`
		`+ and priorities cache objects should be freed:`
		`+ </para>`
		`+ <informalexample>`
		`+ <xi:include href="snippets/Features-TLS-Server-GNUTLS-Credentials-Close.xml"`
		`+ xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`+ </informalexample>`
		`+ <para>`
		`+ During its lifetime, the credentials object can be used to`
		`+ initialize TLS session objects from multiple threads, provided`
		`+ that it is not changed.`
		`+ </para>`
		`+ <para>`
		`+ To support session resumption, GNUTLS requires to specify a set of`
		`+ functions for storage and retrieval of session data. To support resumption`
		`+ using session tickets (i.e., the client is expected to store its resumption data),`
		`+ GNUTLS requires to generate an encryption key using <function>gnutls_session_ticket_key_generate</function>`
		`+ and associate it with a server session with <function>gnutls_session_ticket_enable_server</function>.`
		`+ We will not explore session resumption in our example.`
		`+ </para>`
		`+ <para>`
		`+ The server may specify whether it requires a client to authenticate`
		`+ itself using a certificate or not. If a client sends a certificate`
		`+ the server must verify it similarly to a Client verifying a server's`
		`+ certificate (<xref`
		`+ linkend="ex-Defensive_Coding-TLS-Client-GNUTLS-Verify"/>). That`
		`+ verification should occur in a callback set using <function>gnutls_session_set_verify_function</function>.`
		`+ We will not explore further this option in this guide.`
		`+ </para>`
		`+ <example id="ex-Defensive_Coding-TLS-Server-GNUTLS-Accept">`
		`+ <title>Establishing a TLS server connection using GNUTLS</title>`
		`+ <xi:include href="snippets/Features-TLS-Server-GNUTLS-Accept.xml"`
		`+ xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`+ </example>`
		`+ <para>`
		`+ An established TLS session can be used for sending and`
		`+ receiving data, identically as in the client case <xref`
		`+ linkend="ex-Defensive_Coding-TLS-GNUTLS-Use"/>.`
		`+ </para>`
		`+ <example id="ex-Defensive_Coding-TLS-Server-GNUTLS-Use">`
		`+ <title>Using a GNUTLS session</title>`
		`+ <xi:include href="snippets/Features-TLS-GNUTLS-Use.xml"`
		`+ xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`+ </example>`
		`+ <para>`
		`+ To shut down a connection in an orderly manner, you`
		`+ should call the <function>gnutls_bye</function> function,`
		`+ and, the session object can be deallocated using`
		`+ <function>gnutls_deinit</function>. This is similar to the client`
		`+ case, but in this case the server doesn't wait for the client`
		`+ reply of the connection (see <xref`
		`+ linkend="ex-Defensive_Coding-TLS-Server-GNUTLS-Disconnect"/>).`
		`+ </para>`
		`+ <example id="ex-Defensive_Coding-TLS-Server-GNUTLS-Disconnect">`
		`+ <title>Closing a GNUTLS session in an orderly fashion</title>`
		`+ <xi:include href="snippets/Features-TLS-Server-GNUTLS-Disconnect.xml"`
		`+ xmlns:xi="http://www.w3.org/2001/XInclude" />`
		`+ </example>`
		`+ </section>`
		`+ </section></chapter>`

en-US/snippets/Features-TLS-Client-GNUTLS-Connect.xml

file modified

+1 -1

		`@@ -31,7 +31,7 @@`

		`// Associate the socket with the session object and set the server`
		`// name.`
		`- gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t)(uintptr_t)sockfd);`
		`+ gnutls_transport_set_int(session, sockfd);`
		`ret = gnutls_server_name_set(session, GNUTLS_NAME_DNS,`
		`host, strlen(host));`
		`if (ret != GNUTLS_E_SUCCESS) {`

en-US/snippets/Features-TLS-Client-GNUTLS-Credentials.xml

file modified

+5 -9

		`@@ -11,19 +11,15 @@`
		`gnutls_strerror(ret));`
		`exit(1);`
		`}`
		`- // gnutls_certificate_set_x509_system_trust needs GNUTLS version 3.0`
		`- // or newer, so we hard-code the path to the certificate store`
		`- // instead.`
		`- static const char ca_bundle[] = "/etc/ssl/certs/ca-bundle.crt";`
		`- ret = gnutls_certificate_set_x509_trust_file`
		`- (cred, ca_bundle, GNUTLS_X509_FMT_PEM);`
		`+`
		`+ ret = gnutls_certificate_set_x509_system_trust(cred);`
		`if (ret == 0) {`
		`- fprintf(stderr, "error: no certificates found in: %s\n", ca_bundle);`
		`+ fprintf(stderr, "error: no certificates found in system trust store\n");`
		`exit(1);`
		`}`
		`if (ret < 0) {`
		`- fprintf(stderr, "error: gnutls_certificate_set_x509_trust_files(%s): %s\n",`
		`- ca_bundle, gnutls_strerror(ret));`
		`+ fprintf(stderr, "error: gnutls_certificate_set_x509_system_trust: %s\n",`
		`+ gnutls_strerror(ret));`
		`exit(1);`
		`}`
		`</programlisting>`

en-US/snippets/Features-TLS-Client-GNUTLS-Verify.xml

file modified

+2 -2

		`@@ -15,9 +15,9 @@`

		`// Validate the certificate chain.`
		`unsigned status = (unsigned)-1;`
		`- ret = gnutls_certificate_verify_peers2(session, &status);`
		`+ ret = gnutls_certificate_verify_peers3(session, host, &status);`
		`if (ret != GNUTLS_E_SUCCESS) {`
		`- fprintf(stderr, "error: gnutls_certificate_verify_peers2: %s\n",`
		`+ fprintf(stderr, "error: gnutls_certificate_verify_peers3: %s\n",`
		`gnutls_strerror(ret));`
		`exit(1);`
		`}`

en-US/snippets/Features-TLS-GNUTLS-Init.xml

file modified

		`@@ -3,5 +3,7 @@`
		`]>`
		`<!-- Automatically generated file. Do not edit. -->`
		`<programlisting language="C">`
		`+ // This is only necessary if compatibility with GnuTLS prior to`
		`+ // 3.3.0 is required.`
		`gnutls_global_init();`
		`</programlisting>`

en-US/snippets/Features-TLS-NSS-Init.xml

file modified

		`@@ -16,6 +16,14 @@`

		`// Ciphers to enable.`
		`static const PRUint16 good_ciphers[] = {`
		`+ TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,`
		`+ TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,`
		`+ TLS_RSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_RSA_WITH_AES_256_GCM_SHA384,`
		`+ TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_DHE_RSA_WITH_AES_256_GCM_SHA384,`
		`TLS_RSA_WITH_AES_128_CBC_SHA,`
		`TLS_RSA_WITH_AES_256_CBC_SHA,`
		`SSL_RSA_WITH_3DES_EDE_CBC_SHA,`

en-US/snippets/Features-TLS-Server-GNUTLS-Accept.xml

file added

+45

		`@@ -0,0 +1,45 @@`
		`+ <?xml version='1.0' encoding='utf-8' ?>`
		`+ <!DOCTYPE programlisting PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [`
		`+ ]>`
		`+ <!-- Automatically generated file. Do not edit. -->`
		`+ <programlisting language="C">`
		`+ // Create the session object.`
		`+ for (;;) {`
		`+ gnutls_session_t session;`
		`+`
		`+ sa_cli_len = sizeof(sa_cli);`
		`+ sockfd = accept(listenfd, (struct sockaddr *) &sa_cli, &sa_cli_len);`
		`+`
		`+ ret = gnutls_init(&session, GNUTLS_SERVER);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_init: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ // Set the acceptable ciphersuites`
		`+ ret = gnutls_priority_set(session, priority_cache);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_priority_set: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ // Set the server's certificate object`
		`+ ret = gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, cred);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_credentials_set: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ gnutls_certificate_server_set_request(session, GNUTLS_CERT_IGNORE);`
		`+`
		`+ gnutls_transport_set_int(session, sockfd);`
		`+`
		`+ // Establish the session.`
		`+ ret = gnutls_handshake(session);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_handshake: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ </programlisting>`

en-US/snippets/Features-TLS-Server-GNUTLS-Credentials-Close.xml

file added

		`@@ -0,0 +1,8 @@`
		`+ <?xml version='1.0' encoding='utf-8' ?>`
		`+ <!DOCTYPE programlisting PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [`
		`+ ]>`
		`+ <!-- Automatically generated file. Do not edit. -->`
		`+ <programlisting language="C">`
		`+ gnutls_priority_deinit(priority_cache);`
		`+ gnutls_certificate_free_credentials(cred);`
		`+ </programlisting>`

en-US/snippets/Features-TLS-Server-GNUTLS-Credentials.xml

file added

+42

		`@@ -0,0 +1,42 @@`
		`+ <?xml version='1.0' encoding='utf-8' ?>`
		`+ <!DOCTYPE programlisting PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [`
		`+ ]>`
		`+ <!-- Automatically generated file. Do not edit. -->`
		`+ <programlisting language="C">`
		`+ // Load the trusted CA certificates.`
		`+ const char *keyfile = argv[2];`
		`+ const char *certfile = argv[3];`
		`+ const char *ocspfile = NULL;`
		`+`
		`+ if (argc > 4)`
		`+ ocspfile = argv[4];`
		`+`
		`+ gnutls_certificate_credentials_t cred = NULL;`
		`+ int ret = gnutls_certificate_allocate_credentials(&cred);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_certificate_allocate_credentials: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ // Set the server certificate and key files. These can be PEM`
		`+ // files, or PKCS#11 URLs in case an HSM is in use.`
		`+ ret =`
		`+ gnutls_certificate_set_x509_key_file(cred, certfile, keyfile,`
		`+ GNUTLS_X509_FMT_PEM);`
		`+ if (ret < 0) {`
		`+ fprintf(stderr, "error: gnutls_certificate_set_x509_key_file: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ if (ocspfile) {`
		`+ ret = gnutls_certificate_set_ocsp_status_request_file(cred, ocspfile, 0);`
		`+ if (ret < 0) {`
		`+ fprintf(stderr,`
		`+ "error: gnutls_certificate_set_ocsp_status_request_file: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ }`
		`+ </programlisting>`

en-US/snippets/Features-TLS-Server-GNUTLS-Disconnect.xml

file added

+14

		`@@ -0,0 +1,14 @@`
		`+ <?xml version='1.0' encoding='utf-8' ?>`
		`+ <!DOCTYPE programlisting PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [`
		`+ ]>`
		`+ <!-- Automatically generated file. Do not edit. -->`
		`+ <programlisting language="C">`
		`+ // Initiate an orderly connection shutdown.`
		`+ ret = gnutls_bye(session, GNUTLS_SHUT_WR);`
		`+ if (ret < 0) {`
		`+ fprintf(stderr, "error: gnutls_bye: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ // Free the session object.`
		`+ gnutls_deinit(session);`
		`+ </programlisting>`

en-US/snippets/Features-TLS-Server-GNUTLS-Priorities.xml

file added

+18

		`@@ -0,0 +1,18 @@`
		`+ <?xml version='1.0' encoding='utf-8' ?>`
		`+ <!DOCTYPE programlisting PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [`
		`+ ]>`
		`+ <!-- Automatically generated file. Do not edit. -->`
		`+ <programlisting language="C">`
		`+ // Create the ciphersuite priorities object`
		`+ gnutls_priority_t priority_cache;`
		`+ const char *errpos = NULL;`
		`+`
		`+ ret = gnutls_priority_init(&priority_cache, "PERFORMANCE:%SERVER_PRECEDENCE", &errpos);`
		`+ if (ret == GNUTLS_E_PARSING_ERROR) {`
		`+ fprintf(stderr, "error: gnutls_priority_init parsing error at: %s\n", errpos);`
		`+ exit(1);`
		`+ } else if (ret < 0) {`
		`+ fprintf(stderr, "error: gnutls_priority_init: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ </programlisting>`

src/TLS-Client-GNUTLS.c

file modified

+10 -39

		`@@ -84,6 +84,8 @@`
		`}`

		`//+ Features TLS-GNUTLS-Init`
		`+ // This is only necessary if compatibility with GnuTLS prior to`
		`+ // 3.3.0 is required.`
		`gnutls_global_init();`
		`//-`

		`@@ -96,19 +98,15 @@`
		`gnutls_strerror(ret));`
		`exit(1);`
		`}`
		`- // gnutls_certificate_set_x509_system_trust needs GNUTLS version 3.0`
		`- // or newer, so we hard-code the path to the certificate store`
		`- // instead.`
		`- static const char ca_bundle[] = "/etc/ssl/certs/ca-bundle.crt";`
		`- ret = gnutls_certificate_set_x509_trust_file`
		`- (cred, ca_bundle, GNUTLS_X509_FMT_PEM);`
		`+`
		`+ ret = gnutls_certificate_set_x509_system_trust(cred);`
		`if (ret == 0) {`
		`- fprintf(stderr, "error: no certificates found in: %s\n", ca_bundle);`
		`+ fprintf(stderr, "error: no certificates found in system trust store\n");`
		`exit(1);`
		`}`
		`if (ret < 0) {`
		`- fprintf(stderr, "error: gnutls_certificate_set_x509_trust_files(%s): %s\n",`
		`- ca_bundle, gnutls_strerror(ret));`
		`+ fprintf(stderr, "error: gnutls_certificate_set_x509_system_trust: %s\n",`
		`+ gnutls_strerror(ret));`
		`exit(1);`
		`}`
		`//-`
		`@@ -162,7 +160,7 @@`

		`// Associate the socket with the session object and set the server`
		`// name.`
		`- gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t)(uintptr_t)sockfd);`
		`+ gnutls_transport_set_int(session, sockfd);`
		`ret = gnutls_server_name_set(session, GNUTLS_NAME_DNS,`
		`host, strlen(host));`
		`if (ret != GNUTLS_E_SUCCESS) {`
		`@@ -193,9 +191,9 @@`

		`// Validate the certificate chain.`
		`unsigned status = (unsigned)-1;`
		`- ret = gnutls_certificate_verify_peers2(session, &status);`
		`+ ret = gnutls_certificate_verify_peers3(session, host, &status);`
		`if (ret != GNUTLS_E_SUCCESS) {`
		`- fprintf(stderr, "error: gnutls_certificate_verify_peers2: %s\n",`
		`+ fprintf(stderr, "error: gnutls_certificate_verify_peers3: %s\n",`
		`gnutls_strerror(ret));`
		`exit(1);`
		`}`
		`@@ -219,33 +217,6 @@`
		`}`
		`//-`

		`- //+ Features TLS-Client-GNUTLS-Match`
		`- // Match the peer certificate against the host name.`
		`- // We can only obtain a set of DER-encoded certificates from the`
		`- // session object, so we have to re-parse the peer certificate into`
		`- // a certificate object.`
		`- gnutls_x509_crt_t cert;`
		`- ret = gnutls_x509_crt_init(&cert);`
		`- if (ret != GNUTLS_E_SUCCESS) {`
		`- fprintf(stderr, "error: gnutls_x509_crt_init: %s\n",`
		`- gnutls_strerror(ret));`
		`- exit(1);`
		`- }`
		`- // The peer certificate is the first certificate in the list.`
		`- ret = gnutls_x509_crt_import(cert, certs, GNUTLS_X509_FMT_DER);`
		`- if (ret != GNUTLS_E_SUCCESS) {`
		`- fprintf(stderr, "error: gnutls_x509_crt_import: %s\n",`
		`- gnutls_strerror(ret));`
		`- exit(1);`
		`- }`
		`- ret = gnutls_x509_crt_check_hostname(cert, host);`
		`- if (ret == 0 && !certificate_host_name_override(certs[0], host)) {`
		`- fprintf(stderr, "error: host name does not match certificate\n");`
		`- exit(1);`
		`- }`
		`- gnutls_x509_crt_deinit(cert);`
		`- //-`
		`-`
		`//+ Features TLS-GNUTLS-Use`
		`char buf[4096];`
		`snprintf(buf, sizeof(buf), "GET / HTTP/1.0\r\nHost: %s\r\n\r\n", host);`

src/TLS-Client-NSS.c

file modified

		`@@ -107,6 +107,14 @@`

		`// Ciphers to enable.`
		`static const PRUint16 good_ciphers[] = {`
		`+ TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,`
		`+ TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,`
		`+ TLS_RSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_RSA_WITH_AES_256_GCM_SHA384,`
		`+ TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,`
		`+ TLS_DHE_RSA_WITH_AES_256_GCM_SHA384,`
		`TLS_RSA_WITH_AES_128_CBC_SHA,`
		`TLS_RSA_WITH_AES_256_CBC_SHA,`
		`SSL_RSA_WITH_3DES_EDE_CBC_SHA,`

src/TLS-Server-GNUTLS.c

file added

+162

		`@@ -0,0 +1,162 @@`
		`+ #include <assert.h>`
		`+ #include <netinet/in.h>`
		`+ #include <netinet/tcp.h>`
		`+ #include <stdio.h>`
		`+ #include <stdlib.h>`
		`+ #include <string.h>`
		`+ #include <sys/socket.h>`
		`+ #include <sys/types.h>`
		`+ #include <unistd.h>`
		`+`
		`+ #include <gnutls/gnutls.h>`
		`+ #include <gnutls/crypto.h>`
		`+ #include <gnutls/x509.h>`
		`+`
		`+ #include "tcp_connect.h"`
		`+`
		`+ static void __attribute__ ((noreturn))`
		`+ usage(const char *progname)`
		`+ {`
		`+ fprintf(stderr, "usage: %s PORT KEY CERT OCSP\n", progname);`
		`+ exit(2);`
		`+ }`
		`+`
		`+ int main(int argc, char **argv)`
		`+ {`
		`+ if (argc < 4) {`
		`+ usage(argv[0]);`
		`+ }`
		`+ //+ Features TLS-GNUTLS-Init`
		`+ // This is only necessary if compatibility with GnuTLS prior to`
		`+ // 3.3.0 is required.`
		`+ gnutls_global_init();`
		`+ //-`
		`+`
		`+ //+ Features TLS-Server-GNUTLS-Credentials`
		`+ // Load the trusted CA certificates.`
		`+ const char *keyfile = argv[2];`
		`+ const char *certfile = argv[3];`
		`+ const char *ocspfile = NULL;`
		`+`
		`+ if (argc > 4)`
		`+ ocspfile = argv[4];`
		`+`
		`+ gnutls_certificate_credentials_t cred = NULL;`
		`+ int ret = gnutls_certificate_allocate_credentials(&cred);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_certificate_allocate_credentials: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ // Set the server certificate and key files. These can be PEM`
		`+ // files, or PKCS#11 URLs in case an HSM is in use.`
		`+ ret =`
		`+ gnutls_certificate_set_x509_key_file(cred, certfile, keyfile,`
		`+ GNUTLS_X509_FMT_PEM);`
		`+ if (ret < 0) {`
		`+ fprintf(stderr, "error: gnutls_certificate_set_x509_key_file: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ if (ocspfile) {`
		`+ ret = gnutls_certificate_set_ocsp_status_request_file(cred, ocspfile, 0);`
		`+ if (ret < 0) {`
		`+ fprintf(stderr,`
		`+ "error: gnutls_certificate_set_ocsp_status_request_file: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ }`
		`+ //-`
		`+ //+ Features TLS-Server-GNUTLS-Priorities`
		`+ // Create the ciphersuite priorities object`
		`+ gnutls_priority_t priority_cache;`
		`+ const char *errpos = NULL;`
		`+`
		`+ ret = gnutls_priority_init(&priority_cache, "PERFORMANCE:%SERVER_PRECEDENCE", &errpos);`
		`+ if (ret == GNUTLS_E_PARSING_ERROR) {`
		`+ fprintf(stderr, "error: gnutls_priority_init parsing error at: %s\n", errpos);`
		`+ exit(1);`
		`+ } else if (ret < 0) {`
		`+ fprintf(stderr, "error: gnutls_priority_init: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ //-`
		`+`
		`+ const int port = atoi(argv[1]);`
		`+ struct sockaddr_in sa_serv;`
		`+ struct sockaddr_storage sa_cli;`
		`+ socklen_t sa_cli_len;`
		`+ int sockfd, listenfd;`
		`+`
		`+ listenfd = socket(AF_INET, SOCK_STREAM, 0);`
		`+ memset(&sa_serv, '\0', sizeof(sa_serv));`
		`+ sa_serv.sin_family = AF_INET;`
		`+ sa_serv.sin_addr.s_addr = INADDR_ANY;`
		`+ sa_serv.sin_port = htons(port);`
		`+`
		`+ if (bind(listenfd, (struct sockaddr *)&sa_serv, sizeof(sa_serv)) < 0) {`
		`+ perror("bind");`
		`+ exit(1);`
		`+ }`
		`+ //+ Features TLS-Server-GNUTLS-Accept`
		`+ // Create the session object.`
		`+ for (;;) {`
		`+ gnutls_session_t session;`
		`+`
		`+ sa_cli_len = sizeof(sa_cli);`
		`+ sockfd = accept(listenfd, (struct sockaddr *) &sa_cli, &sa_cli_len);`
		`+`
		`+ ret = gnutls_init(&session, GNUTLS_SERVER);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_init: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ // Set the acceptable ciphersuites`
		`+ ret = gnutls_priority_set(session, priority_cache);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_priority_set: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ // Set the server's certificate object`
		`+ ret = gnutls_credentials_set(session, GNUTLS_CRD_CERTIFICATE, cred);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_credentials_set: %s\n",`
		`+ gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+`
		`+ gnutls_certificate_server_set_request(session, GNUTLS_CERT_IGNORE);`
		`+`
		`+ gnutls_transport_set_int(session, sockfd);`
		`+`
		`+ // Establish the session.`
		`+ ret = gnutls_handshake(session);`
		`+ if (ret != GNUTLS_E_SUCCESS) {`
		`+ fprintf(stderr, "error: gnutls_handshake: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ //-`
		`+`
		`+ //+ Features TLS-Server-GNUTLS-Disconnect`
		`+ // Initiate an orderly connection shutdown.`
		`+ ret = gnutls_bye(session, GNUTLS_SHUT_WR);`
		`+ if (ret < 0) {`
		`+ fprintf(stderr, "error: gnutls_bye: %s\n", gnutls_strerror(ret));`
		`+ exit(1);`
		`+ }`
		`+ // Free the session object.`
		`+ gnutls_deinit(session);`
		`+ //-`
		`+ close(sockfd);`
		`+ }`
		`+ //+ Features TLS-Server-GNUTLS-Credentials-Close`
		`+ gnutls_priority_deinit(priority_cache);`
		`+ gnutls_certificate_free_credentials(cred);`
		`+ //-`
		`+ }`

src/src.mk

file modified

+2 -1

		`@@ -34,8 +34,9 @@`
		`compile_and_link += C-String-Functions`
		`compile_and_link += TLS-Client-OpenSSL`
		`LIBS_TLS-Client-OpenSSL = -lssl -lcrypto`
		`- compile_and_link += TLS-Client-GNUTLS`
		`+ compile_and_link += TLS-Client-GNUTLS TLS-Server-GNUTLS`
		`LIBS_TLS-Client-GNUTLS = -lgnutls`
		`+ LIBS_TLS-Server-GNUTLS = -lgnutls`
		`compile_and_link += TLS-Client-NSS`
		`CFLAGS_TLS-Client-NSS = -I/usr/include/nspr4 -I/usr/include/nss3`
		`LIBS_TLS-Client-NSS = -lnss3 -lnspr4 -lssl3`

nmav commented 7 years ago

This update brings the gnutls description up-to-date with current Fedora releases, mentions the shared system certificates in Fedora, adds a server example with gnutls, and updates the set of algorithms used in NSS client example.

rebased

7 years ago