GnuTLS Transport Layer Security Library

GnuTLS NEWS -- History of user-visible changes. -*- outline -*- Bug numbers referenced in this log correspond to bug numbers at our issue tracker, available at https://gitlab.com/gnutls/gnutls/issues Copyright (C) 2000-2016 Free Software Foundation, Inc. Copyright (C) 2013-2019 Nikos Mavrogiannopoulos See the end for copying conditions. * Version 3.8.2 (released 2023-11-14) ** libgnutls: Fix timing side-channel inside RSA-PSK key exchange. [GNUTLS-SA-2023-10-23, CVSS: medium] [CVE-2023-5981] ** libgnutls: Add API functions to perform ECDH and DH key agreement The functionality has been there for a long time though they were not available as part of the public API. This enables applications to implement custom protocols leveraging non-interactive key agreement with ECDH and DH. ** libgnutls: Added support for AES-GCM-SIV ciphers (RFC 8452) The new algorithms GNUTLS_CIPHER_AES_128_SIV_GCM and GNUTLS_CIPHER_AES_256_SIV_GCM have been added to be used through the AEAD interface. Note that, unlike GNUTLS_CIPHER_AES_{128,256}_SIV_GCM, the authentication tag is appended to the ciphertext, not prepended. ** libgnutls: transparent KTLS support is extended to FreeBSD kernel The kernel TLS feature can now be enabled on FreeBSD as well as Linux when compiled with the --enable-ktls configure option. ** gnutls-cli: New option --starttls-name Depending on deployment, application protocols such as XMPP may require a different origin address than the external address to be presented prior to STARTTLS negotiation. The --starttls-name can be used to specify specify the addresses separately. ** API and ABI modifications: gnutls_pubkey_import_dh_raw: New function gnutls_privkey_import_dh_raw: New function gnutls_pubkey_export_dh_raw: New function gnutls_privkey_export_dh_raw: New function gnutls_x509_privkey_import_dh_raw: New function gnutls_privkey_derive_secret: New function GNUTLS_KEYGEN_DH: New enum member of gnutls_keygen_types_t GNUTLS_CIPHER_AES_128_SIV_GCM: Added GNUTLS_CIPHER_AES_256_SIV_GCM: Added * Version 3.8.1 (released 2023-08-03) ** libgnutls: ClientHello extensions are randomized by default To make fingerprinting harder, TLS extensions in ClientHello messages are shuffled. As this behavior may cause compatibility issue with legacy applications that do not accept the last extension without payload, the behavior can be reverted with the %NO_SHUFFLE_EXTENSIONS priority keyword. ** libgnutls: Add support for RFC 9258 external PSK importer. This enables to deploy the same PSK across multiple TLS versions (TLS 1.2 and TLS 1.3) in a secure manner. To use, the application needs to set up a callback that formats the PSK identity using gnutls_psk_format_imported_identity(). ** libgnutls: %GNUTLS_NO_EXTENSIONS has been renamed to %GNUTLS_NO_DEFAULT_EXTENSIONS. ** libgnutls: Add additional PBKDF limit checks in FIPS mode as defined in SP 800-132. Minimum salt length is 128 bits and minimum iterations bound is 1000 for PBKDF in FIPS mode. ** libgnutls: Add a mechanism to control whether to enforce extended master secret (RFC 7627). FIPS 140-3 mandates the use of TLS session hash (extended master secret, EMS) in TLS 1.2. To enforce this, a new priority keyword %FORCE_SESSION_HASH is added and if it is set and EMS is not set, the peer aborts the connection. This behavior is the default in FIPS mode, though it can be overridden through the configuration file with the "tls-session-hash" option. In either case non-EMS PRF is reported as a non-approved operation through the FIPS service indicator. ** New option --attime to specify current time. To make testing with different timestamp to the system easier, the tools doing certificate verification now provide a new option --attime, which takes an arbitrary time. ** API and ABI modifications: gnutls_psk_client_credentials_function3: New typedef gnutls_psk_server_credentials_function3: New typedef gnutls_psk_set_server_credentials_function3: New function gnutls_psk_set_client_credentials_function3: New function gnutls_psk_format_imported_identity: New function GNUTLS_PSK_KEY_EXT: New enum member of gnutls_psk_key_flags * Version 3.8.0 (released 2023-02-09) ** libgnutls: Fix a Bleichenbacher oracle in the TLS RSA key exchange. Reported by Hubert Kario (#1050). Fix developed by Alexander Sosedkin. [GNUTLS-SA-2020-07-14, CVSS: medium] [CVE-2023-0361] ** libgnutls: C++ library is now header only. All definitions from gnutlsxx.c have been moved into gnutlsxx.h. Users of the C++ interface have two options: 1. include gnutlsxx.h in their application and link against the C library. (default) 2. include gnutlsxx.h in their application, compile with GNUTLS_GNUTLSXX_NO_HEADERONLY macro defined and link against the C++ library. ** libgnutls: GNUTLS_NO_STATUS_REQUEST flag and %NO_STATUS_REQUEST priority modifier have been added to allow disabling of the status_request TLS extension in the client side. ** libgnutls: TLS heartbeat is disabled by default. The heartbeat extension in TLS (RFC 6520) is not widely used given other implementations dropped support for it. To enable back support for it, supply --enable-heartbeat-support to configure script. ** libgnutls: SRP authentication is now disabled by default. It is disabled because the SRP authentication in TLS is not up to date with the latest TLS standards and its ciphersuites are based on the CBC mode and SHA-1. To enable it back, supply --enable-srp-authentication option to configure script. ** libgnutls: All code has been indented using "indent -ppi1 -linux". CI/CD has been adjusted to catch regressions. This is implemented through devel/indent-gnutls, devel/indent-maybe and .gitlab-ci.yml’s commit-check. You may run devel/indent-gnutls to fix any indentation issues if you make code modifications. ** guile: Guile-bindings removed. They have been extracted into a separate project to reduce complexity and to simplify maintenance, see <https://gitlab.com/gnutls/guile/>. ** minitasn1: Upgraded to libtasn1 version 4.19. ** API and ABI modifications: GNUTLS_NO_STATUS_REQUEST: New flag GNUTLS_SRTP_AEAD_AES_128_GCM: New gnutls_srtp_profile_t enum member GNUTLS_SRTP_AEAD_AES_256_GCM: New gnutls_srtp_profile_t enum member * Version 3.7.8 (released 2022-09-27) ** libgnutls: In FIPS140 mode, RSA signature verification is an approved operation if the key has modulus with known sizes (1024, 1280, 1536, and 1792 bits), in addition to any modulus sizes larger than 2048 bits, according to SP800-131A rev2. ** libgnutls: gnutls_session_channel_binding performs additional checks when GNUTLS_CB_TLS_EXPORTER is requested. According to RFC9622 4.2, the "tls-exporter" channel binding is only usable when the handshake is bound to a unique master secret (i.e., either TLS 1.3 or extended master secret extension is negotiated). Otherwise the function now returns error. ** libgnutls: usage of the following functions, which are designed to loosen restrictions imposed by allowlisting mode of configuration, has been additionally restricted. Invoking them is now only allowed if system-wide TLS priority string has not been initialized yet: gnutls_digest_set_secure gnutls_sign_set_secure gnutls_sign_set_secure_for_certs gnutls_protocol_set_enabled ** API and ABI modifications: No changes since last version. * Version 3.7.7 (released 2022-07-28) ** libgnutls: Fixed double free during verification of pkcs7 signatures. Reported by Jaak Ristioja (#1383). [GNUTLS-SA-2022-07-07, CVSS: medium] [CVE-2022-2509] ** libgnutls: gnutls_hkdf_expand now only accepts LENGTH argument less than or equal to 255 times hash digest size, to comply with RFC 5869 2.3. ** libgnutls: Length limit for TLS PSK usernames has been increased from 128 to 65535 characters (#1323). ** libgnutls: AES-GCM encryption function now limits plaintext length to 2^39-256 bits, according to SP800-38D 5.2.1.1. ** libgnutls: New block cipher functions have been added to transparently handle padding. gnutls_cipher_encrypt3 and gnutls_cipher_decrypt3 can be used in combination of GNUTLS_CIPHER_PADDING_PKCS7 flag to automatically add/remove padding if the length of the original plaintext is not a multiple of the block size. ** libgnutls: New function for manual FIPS self-testing. ** API and ABI modifications: gnutls_fips140_run_self_tests: New function gnutls_cipher_encrypt3: New function gnutls_cipher_decrypt3: New function gnutls_cipher_padding_flags_t: New enum ** guile: Guile 1.8 is no longer supported ** guile: Session record port treats premature termination as EOF Previously, a ‘gnutls-error’ exception with the ‘error/premature-termination’ value would be thrown while reading from a session record port when the underlying session was terminated prematurely. This was inconvenient since users of the port may not be prepared to handle such an exception. Reading from the session record port now returns the end-of-file object instead of throwing an exception, just like it would for a proper session termination. ** guile: Session record ports can have a ‘close’ procedure. The ‘session-record-port’ procedure now takes an optional second parameter, and a new ‘set-session-record-port-close!’ procedure is provided to specify a ‘close’ procedure for a session record port. This ‘close’ procedure lets users specify cleanup operations for when the port is closed, such as closing the file descriptor or port that backs the underlying session. * Version 3.7.6 (released 2022-05-27) ** libgnutls: Fixed invalid write when gnutls_realloc_zero() is called with new_size < old_size. This bug caused heap corruption when gnutls_realloc_zero() has been set as gmp reallocfunc (!1592, #1367, #1368, #1369). ** API and ABI modifications: No changes since last version. * Version 3.7.5 (released 2022-05-15) ** libgnutls: The GNUTLS_NO_TICKETS_TLS12 flag and %NO_TICKETS_TLS12 priority modifier have been added to disable session ticket usage in TLS 1.2 because it does not provide forward secrecy (#477). On the other hand, since session tickets in TLS 1.3 do provide forward secrecy, the PFS priority string now only disables session tickets in TLS 1.2. Future backward incompatibility: in the next major release of GnuTLS, we plan to remove those flag and modifier, and make GNUTLS_NO_TICKETS and %NO_TICKETS only affect TLS 1.2. ** gnutls-cli, gnutls-serv: Channel binding for printing information has been changed from tls-unique to tls-exporter as tls-unique is not supported in TLS 1.3. ** libgnutls: Certificate sanity checks has been enhanced to make gnutls more RFC 5280 compliant (!1583). Following changes were included: - critical extensions are parsed when loading x509 certificate to prohibit any random octet strings. Requires strict-x509 configure option to be enabled - garbage bits in Key Usage extension are prohibited - empty DirectoryStrings in Distinguished name structures of Issuer and Subject name are prohibited ** libgnutls: Removed 3DES from FIPS approved algorithms (#1353). According to the section 2 of SP800-131A Rev.2, 3DES algorithm will be disallowed for encryption after December 31, 2023: https://csrc.nist.gov/publications/detail/sp/800-131a/rev-2/final ** libgnutls: Optimized support for AES-SIV-CMAC algorithms (#1217, #1312). The existing AEAD API that works in a scatter-gather fashion (gnutls_aead_cipher_encryptv2) has been extended to support AES-SIV-CMAC. For further optimization, new function (gnutls_aead_cipher_set_key) has been added to set key on the existing AEAD handle without re-allocation. ** libgnutls: HKDF and AES-GCM algorithms are now approved in FIPS-140 mode when used in TLS (#1311). ** The configure arguments for Brotli and Zstandard (zstd) support have changed to reflect the previous help text: they are now --with-brotli/--with-zstd respectively (#1342). ** Detecting the Zstandard (zstd) library in configure has been fixed (#1343). ** API and ABI modifications: GNUTLS_NO_TICKETS_TLS12: New flag gnutls_aead_cipher_set_key: New function * Version 3.7.4 (released 2022-03-17) ** libgnutls: Added support for certificate compression as defined in RFC8879 (#1301). New API functions (gnutls_compress_certificate_get_selected_method and gnutls_compress_certificate_set_methods) allow client and server to set their preferences. ** certtool: Added option --compress-cert that allows user to specify compression methods for certificate compression. ** libgnutls: GnuTLS can now be compiled with --enable-strict-x509 configure option to enforce stricter certificate sanity checks that are compliant with RFC5280. ** libgnutls: Removed IA5String type from DirectoryString within issuer and subject name to make DirectoryString RFC5280 compliant. ** libgnutls: Added function (gnutls_record_send_file) to send file content from open file descriptor (!1486). The implementation is optimized if KTLS (kernel TLS) is enabled. ** libgnutls: Added function (gnutls_ciphersuite_get) to retrieve the name of current ciphersuite from TLS session (#1291). ** libgnutls: The run-time dependency on tpm2-tss is now re-implemented using dlopen, so GnuTLS does not indirectly link to other crypto libraries until TPM2 functionality is utilized (!1544). ** API and ABI modifications: GNUTLS_COMP_BROTLI: New gnutls_compression_method_t enum member GNUTLS_COMP_ZSTD: New gnutls_compression_method_t enum member gnutls_compress_certificate_get_selected_method: Added gnutls_compress_certificate_set_methods: Added gnutls_ciphersuite_get: New function gnutls_record_send_file: New function libgnutlsxx: Soname bumped due to ABI breakage introduced in 3.7.1 * Version 3.7.3 (released 2022-01-17) ** libgnutls: The allowlisting configuration mode has been added to the system-wide settings. In this mode, all the algorithms are initially marked as insecure or disabled, while the applications can re-enable them either through the [overrides] section of the configuration file or the new API (#1172). ** The build infrastructure no longer depends on GNU AutoGen for generating command-line option handling, template file parsing in certtool, and documentation generation (#773, #774). This change also removes run-time or bundled dependency on the libopts library, and requires Python 3.6 or later to regenerate the distribution tarball. Note that this brings in known backward incompatibility in command-line tools, such as long options are now case sensitive, while previously they were treated in a case insensitive manner: for example --RSA is no longer a valid option of certtool. The existing scripts using GnuTLS tools may need adjustment for this change. ** libgnutls: The tpm2-tss-engine compatible private blobs can be loaded and used as a gnutls_privkey_t (#594). The code was originally written for the OpenConnect VPN project by David Woodhouse. To generate such blobs, use the tpm2tss-genkey tool from tpm2-tss-engine: https://github.com/tpm2-software/tpm2-tss-engine/#rsa-operations or the tpm2_encodeobject tool from unreleased tpm2-tools. ** libgnutls: The library now transparently enables Linux KTLS (kernel TLS) when the feature is compiled in with --enable-ktls configuration option (#1113). If the KTLS initialization fails it automatically falls back to the user space implementation. ** certtool: The certtool command can now read the Certificate Transparency (RFC 6962) SCT extension (#232). New API functions are also provided to access and manipulate the extension values. ** certtool: The certtool command can now generate, manipulate, and evaluate x25519 and x448 public keys, private keys, and certificates. ** libgnutls: Disabling a hashing algorithm through "insecure-hash" configuration directive now also disables TLS ciphersuites that use it as a PRF algorithm. ** libgnutls: PKCS#12 files are now created with modern algorithms by default (!1499). Previously certtool used PKCS12-3DES-SHA1 for key derivation and HMAC-SHA1 as an integity measure in PKCS#12. Now it uses AES-128-CBC with PBKDF2 and SHA-256 for both key derivation and MAC algorithms, and the default PBKDF2 iteration count has been increased to 600000. ** libgnutls: PKCS#12 keys derived using GOST algorithm now uses HMAC_GOSTR3411_2012_512 instead of HMAC_GOSTR3411_2012_256 for integrity, to conform with the latest TC-26 requirements (#1225). ** libgnutls: The library now provides a means to report the status of approved cryptographic operations (!1465). To adhere to the FIPS140-3 IG 2.4.C., this complements the existing mechanism to prohibit the use of unapproved algorithms by making the library unusable state. ** gnutls-cli: The gnutls-cli command now provides a --list-config option to print the library configuration (!1508). ** libgnutls: Fixed possible race condition in gnutls_x509_trust_list_verify_crt2 when a single trust list object is shared among multiple threads (#1277). [GNUTLS-SA-2022-01-17, CVSS: low] ** API and ABI modifications: GNUTLS_PRIVKEY_FLAG_RSA_PSS_FIXED_SALT_LENGTH: new flag in gnutls_privkey_flags_t GNUTLS_VERIFY_RSA_PSS_FIXED_SALT_LENGTH: new flag in gnutls_certificate_verify_flags gnutls_ecc_curve_set_enabled: Added. gnutls_sign_set_secure: Added. gnutls_sign_set_secure_for_certs: Added. gnutls_digest_set_secure: Added. gnutls_protocol_set_enabled: Added. gnutls_fips140_context_init: New function gnutls_fips140_context_deinit: New function gnutls_fips140_push_context: New function gnutls_fips140_pop_context: New function gnutls_fips140_get_operation_state: New function gnutls_fips140_operation_state_t: New enum gnutls_transport_is_ktls_enabled: New function gnutls_get_library_configuration: New function * Version 3.7.2 (released 2021-05-29) ** libgnutls: The priority string option %DISABLE_TLS13_COMPAT_MODE was added to disable TLS 1.3 middlebox compatibility mode ** libgnutls: The Linux kernel AF_ALG based acceleration has been added. This can be enabled with --enable-afalg configure option, when libkcapi package is installed (#308). ** libgnutls: Fixed timing of early data exchange. Previously, the client was sending early data after receiving Server Hello, which not only negates the benefit of 0-RTT, but also works under certain assumptions hold (e.g., the same ciphersuite is selected in initial and resumption handshake) (#1146). ** certtool: When signing a CSR, CRL distribution point (CDP) is no longer copied from the signing CA by default (#1126). ** libgnutls: The GNUTLS_NO_EXPLICIT_INIT envvar has been renamed to GNUTLS_NO_IMPLICIT_INIT to reflect the purpose (#1178). The former is now deprecated and will be removed in the future releases. ** certtool: When producing certificates and certificate requests, subject DN components that are provided individually will now be ordered by assumed scale (e.g. Country before State, Organization before OrganizationalUnit). This change also affects the order in which certtool prompts interactively. Please rely on the template mechanism for automated use of certtool! (#1243) ** API and ABI modifications: gnutls_early_cipher_get: Added gnutls_early_prf_hash_get: Added ** guile: Writes to a session record port no longer throw an exception upon GNUTLS_E_AGAIN or GNUTLS_E_INTERRUPTED. * Version 3.7.1 (released 2021-03-10) ** libgnutls: Fixed potential use-after-free in sending "key_share" and "pre_shared_key" extensions. When sending those extensions, the client may dereference a pointer no longer valid after realloc. This happens only when the client sends a large Client Hello message, e.g., when HRR is sent in a resumed session previously negotiated large FFDHE parameters, because the initial allocation of the buffer is large enough without having to call realloc (#1151). [GNUTLS-SA-2021-03-10, CVSS: low] ** libgnutls: Fixed a regression in handling duplicated certs in a chain (#1131). ** libgnutls: Fixed sending of session ID in TLS 1.3 middlebox compatibility mode. In that mode the client shall always send a non-zero session ID to make the handshake resemble the TLS 1.2 resumption; this was not true in the previous versions (#1074). ** libgnutls: W32 performance improvement with a new sendmsg()-like transport implementation (!1377). ** libgnutls: Removed dependency on the external 'fipscheck' package, when compiled with --enable-fips140-mode (#1101). ** libgnutls: Added padlock acceleration for AES-192-CBC (#1004). ** API and ABI modifications: No changes since last version. * Version 3.7.0 (released 2020-12-02) ** libgnutls: Depend on nettle 3.6 (!1322). ** libgnutls: Added a new API that provides a callback function to retrieve missing certificates from incomplete certificate chains (#202, #968, #1100). ** libgnutls: Added a new API that provides a callback function to output the complete path to the trusted root during certificate chain verification (#1012). ** libgnutls: OIDs exposed as gnutls_datum_t no longer account for the terminating null bytes, while the data field is null terminated. The affected API functions are: gnutls_ocsp_req_get_extension, gnutls_ocsp_resp_get_response, and gnutls_ocsp_resp_get_extension (#805). ** libgnutls: Added a new set of API to enable QUIC implementation (#826, #849, #850). ** libgnutls: The crypto implementation override APIs deprecated in 3.6.9 are now no-op (#790). ** libgnutls: Added MAGMA/KUZNYECHIK CTR-ACPKM and CMAC support (!1161). ** libgnutls: Support for padlock has been fixed to make it work with Zhaoxin CPU (#1079). ** libgnutls: The maximum PIN length for PKCS #11 has been increased from 31 bytes to 255 bytes (#932). ** API and ABI modifications: gnutls_x509_trust_list_set_getissuer_function: Added gnutls_x509_trust_list_get_ptr: Added gnutls_x509_trust_list_set_ptr: Added gnutls_session_set_verify_output_function: Added gnutls_record_encryption_level_t: New enum gnutls_handshake_read_func: New callback type gnutls_handshake_set_read_function: New function gnutls_handshake_write: New function gnutls_handshake_secret_func: New callback type gnutls_handshake_set_secret_function: New function gnutls_alert_read_func: New callback type gnutls_alert_set_read_function: New function gnutls_crypto_register_cipher: Deprecated; no-op gnutls_crypto_register_aead_cipher: Deprecated; no-op gnutls_crypto_register_mac: Deprecated; no-op gnutls_crypto_register_digest: Deprecated; no-op * Version 3.6.15 (releases 2020-09-04) ** libgnutls: Fixed "no_renegotiation" alert handling at incorrect timing. The server sending a "no_renegotiation" alert in an unexpected timing, followed by an invalid second handshake was able to cause a TLS 1.3 client to crash via a null-pointer dereference. The crash happens in the application's error handling path, where the gnutls_deinit function is called after detecting a handshake failure (#1071). [GNUTLS-SA-2020-09-04, CVSS: medium] ** libgnutls: If FIPS self-tests are failed, gnutls_fips140_mode_enabled() now indicates that with a false return value (!1306). ** libgnutls: Under FIPS mode, the generated ECDH/DH public keys are checked accordingly to SP800-56A rev 3 (!1295, !1299). ** libgnutls: gnutls_x509_crt_export2() now returns 0 upon success, rather than the size of the internal base64 blob (#1025). The new behavior aligns to the existing documentation. ** libgnutls: Certificate verification failure due to OCSP must-stapling is not honered is now correctly marked with the GNUTLS_CERT_INVALID flag (!1317). The new behavior aligns to the existing documentation. ** libgnutls: The audit log message for weak hashes is no longer printed twice (!1301). ** libgnutls: Fixed version negotiation when TLS 1.3 is enabled and TLS 1.2 is disabled in the priority string. Previously, even when TLS 1.2 is explicitly disabled with "-VERS-TLS1.2", the server still offered TLS 1.2 if TLS 1.3 is enabled (#1054). ** API and ABI modifications: No changes since last version. * Version 3.6.14 (released 2020-06-03) ** libgnutls: Fixed insecure session ticket key construction, since 3.6.4. The TLS server would not bind the session ticket encryption key with a value supplied by the application until the initial key rotation, allowing attacker to bypass authentication in TLS 1.3 and recover previous conversations in TLS 1.2 (#1011). [GNUTLS-SA-2020-06-03, CVSS: high] ** libgnutls: Fixed handling of certificate chain with cross-signed intermediate CA certificates (#1008). ** libgnutls: Fixed reception of empty session ticket under TLS 1.2 (#997). ** libgnutls: gnutls_x509_crt_print() is enhanced to recognizes commonName (2.5.4.3), decodes certificate policy OIDs (!1245), and prints Authority Key Identifier (AKI) properly (#989, #991). ** certtool: PKCS #7 attributes are now printed with symbolic names (!1246). ** libgnutls: Added several improvements on Windows Vista and later releases (!1257, !1254, !1256). Most notably the system random number generator now uses Windows BCrypt* API if available (!1255). ** libgnutls: Use accelerated AES-XTS implementation if possible (!1244). Also both accelerated and non-accelerated implementations check key block according to FIPS-140-2 IG A.9 (!1233). ** libgnutls: Added support for AES-SIV ciphers (#463). ** libgnutls: Added support for 192-bit AES-GCM cipher (!1267). ** libgnutls: No longer use internal symbols exported from Nettle (!1235) ** API and ABI modifications: GNUTLS_CIPHER_AES_128_SIV: Added GNUTLS_CIPHER_AES_256_SIV: Added GNUTLS_CIPHER_AES_192_GCM: Added GNUTLS_NO_AUTO_SEND_TICKET: Added gnutls_ext_get_name2: Added gnutls_pkcs7_print_signature_info: Added * Version 3.6.13 (released 2020-03-31) ** libgnutls: Fix a DTLS-protocol regression (caused by TLS1.3 support), since 3.6.3. The DTLS client would not contribute any randomness to the DTLS negotiation, breaking the security guarantees of the DTLS protocol (#960) [GNUTLS-SA-2020-03-31, CVSS: high] ** libgnutls: Added new APIs to access KDF algorithms (#813). ** libgnutls: Added new callback gnutls_keylog_func that enables a custom logging functionality. ** libgnutls: Added support for non-null terminated usernames in PSK negotiation (#586). ** gnutls-cli-debug: Improved support for old servers that only support SSL 3.0. ** API and ABI modifications: gnutls_hkdf_extract: Added gnutls_hkdf_expand: Added gnutls_pbkdf2: Added gnutls_session_get_keylog_function: Added gnutls_session_set_keylog_function: Added gnutls_prf_hash_get: Added gnutls_psk_server_get_username2: Added gnutls_psk_set_client_credentials2: Added gnutls_psk_set_client_credentials_function2: Added gnutls_psk_set_server_credentials_function2: Added * Version 3.6.12 (released 2020-02-01) ** libgnutls: Introduced TLS session flag (gnutls_session_get_flags()) to identify sessions that client request OCSP status request (#829). ** libgnutls: Added support for X448 key exchange (RFC 7748) and Ed448 signature algorithm (RFC 8032) under TLS (#86). ** libgnutls: Added the default-priority-string option to system configuration; it allows overriding the compiled-in default-priority-string. ** libgnutls: Added support for GOST CNT_IMIT ciphersuite (as defined by draft-smyshlyaev-tls12-gost-suites-07). By default this ciphersuite is disabled. It can be enabled by adding +GOST to priority string. In the future this priority string may enable other GOST ciphersuites as well. Note, that server will fail to negotiate GOST ciphersuites if TLS 1.3 is enabled both on a server and a client. It is recommended for now to disable TLS 1.3 in setups where GOST ciphersuites are enabled on GnuTLS-based servers. ** libgnutls: added priority shortcuts for different GOST categories like CIPHER-GOST-ALL, MAC-GOST-ALL, KX-GOST-ALL, SIGN-GOST-ALL, GROUP-GOST-ALL. ** libgnutls: Reject certificates with invalid time fields. That is we reject certificates with invalid characters in Time fields, or invalid time formatting To continue accepting the invalid form compile with --disable-strict-der-time (#207, #870). ** libgnutls: Reject certificates which contain duplicate extensions. We were previously printing warnings when printing such a certificate, but that is not always sufficient to flag such certificates as invalid. Instead we now refuse to import them (#887). ** libgnutls: If a CA is found in the trusted list, check in addition to time validity, whether the algorithms comply to the expected level prior to accepting it. This addresses the problem of accepting CAs which would have been marked as insecure otherwise (#877). ** libgnutls: The min-verification-profile from system configuration applies for all certificate verifications, not only under TLS. The configuration can be overridden using the GNUTLS_SYSTEM_PRIORITY_FILE environment variable. ** libgnutls: The stapled OCSP certificate verification adheres to the convention used throughout the library of setting the 'GNUTLS_CERT_INVALID' flag. ** libgnutls: On client side only send OCSP staples if they have been requested by the server, and on server side always advertise that we support OCSP stapling (#876). ** libgnutls: Introduced the gnutls_ocsp_req_const_t which is compatible with gnutls_ocsp_req_t but const. ** certtool: Added the --verify-profile option to set a certificate verification profile. Use '--verify-profile low' for certificate verification to apply the 'NORMAL' verification profile. ** certtool: The add_extension template option is considered even when generating a certificate from a certificate request. ** API and ABI modifications: GNUTLS_SFLAGS_CLI_REQUESTED_OCSP: Added GNUTLS_SFLAGS_SERV_REQUESTED_OCSP: Added gnutls_ocsp_req_const_t: Added