Mbed TLS 3.6.1

Description

This release of Mbed TLS provides bug fixes and minor enhancements. This release includes fixes for security issues.

Mbed TLS 3.6 is a long-term support (LTS) branch. It will be supported with bug-fixes and security fixes until at least March 2027.

Security Advisories

For full details, please see the following links:

• CTR_DRBG prioritized over HMAC_DRBG as the PSA DRBG
• Stack buffer overflow in ECDSA signature conversion functions
• Limited authentication bypass in TLS 1.3 optional client authentication

❕ Release notes are truncated in GitHub's releases page: Please refer to the 3.6.1 release page.

Release Notes

API changes

• The experimental functions psa_generate_key_ext() and
  psa_key_derivation_output_key_ext() are no longer declared when compiling
  in C++. This resolves a build failure under C++ compilers that do not
  support flexible array members (a C99 feature not adopted by C++).
  Fixes #9020.

Default behavior changes

• In a PSA-client-only build (i.e. MBEDTLS_PSA_CRYPTO_CLIENT &&
  !MBEDTLS_PSA_CRYPTO_C), do not automatically enable local crypto when the
  corresponding PSA mechanism is enabled, since the server provides the
  crypto. Fixes #9126.
• A TLS handshake may now call psa_crypto_init() if TLS 1.3 is enabled.
  This can happen even if TLS 1.3 is offered but eventually not selected
  in the protocol version negotiation.
• By default, the handling of TLS 1.3 tickets by the Mbed TLS client is now
  disabled at runtime. Applications that were using TLS 1.3 tickets
  signalled by MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET return values now
  need to enable the handling of TLS 1.3 tickets through the new
  mbedtls_ssl_conf_tls13_enable_signal_new_session_tickets() API.

New deprecations

• The experimental functions psa_generate_key_ext() and
  psa_key_derivation_output_key_ext() are deprecated in favor of
  psa_generate_key_custom() and psa_key_derivation_output_key_custom().
  They have almost exactly the same interface, but the variable-length
  data is passed in a separate parameter instead of a flexible array
  member.
• The following cryptographic mechanisms are planned to be removed
  in Mbed TLS 4.0:
  • DES (including 3DES).
  • PKCS#1v1.5 encryption/decryption (RSAES-PKCS1-v1_5).
    (OAEP, PSS, and PKCS#1v1.5 signature are staying.)
  • Finite-field Diffie-Hellman with custom groups.
    (RFC 7919 groups remain supported.)
  • Elliptic curves of size 225 bits or less.
• The following cipher suites are planned to be removed from (D)TLS 1.2
  in Mbed TLS 4.0:
  • TLS_RSA_* (including TLS_RSA_PSK_), i.e. cipher suites using
    RSA decryption.
    (RSA signatures, i.e. TLS_ECDHE_RSA_, are staying.)
  • TLS_ECDH_, i.e. cipher suites using static ECDH.
    (Ephemeral ECDH, i.e. TLS_ECDHE_, is staying.)
  • TLS_DHE_, i.e. cipher suites using finite-field Diffie-Hellman.
    (Ephemeral ECDH, i.e. TLS_ECDHE_, is staying.)
  • TLS_CBC, i.e. all cipher suites using CBC.
• The following low-level application interfaces are planned to be removed
  from the public API in Mbed TLS 4.0:
  • Hashes: hkdf.h, md5.h, ripemd160.h, sha1.h, sha3.h, sha256.h, sha512.h;
  • Random generation: ctr_drbg.h, hmac_drbg.h, entropy.h;
  • Ciphers and modes: aes.h, aria.h, camellia.h, chacha20.h, chachapoly.h,
    cipher.h, cmac.h, gcm.h, poly1305.h;
  • Private key encryption mechanisms: pkcs5.h, pkcs12.h.
  • Asymmetric cryptography: bignum.h, dhm.h, ecdh.h, ecdsa.h, ecjpake.h,
    ecp.h, rsa.h.
    The cryptographic mechanisms remain present, but they will only be
    accessible via the PSA API (psa_xxx functions introduced gradually
    starting with Mbed TLS 2.17) and, where relevant, pk.h.
    For guidance on migrating application code to the PSA API, please consult
    the PSA transition guide (docs/psa-transition.md).
• The following integration interfaces are planned to be removed
  in Mbed TLS 4.0:
  • MBEDTLS_xxx_ALT replacement of cryptographic modules and functions.
    Use PSA transparent drivers instead.
  • MBEDTLS_PK_RSA_ALT and MBEDTLS_PSA_CRYPTO_SE_C.
    Use PSA opaque drivers instead.

Features

• When the new compilation option MBEDTLS_PSA_KEY_STORE_DYNAMIC is enabled,
  the number of volatile PSA keys is virtually unlimited, at the expense
  of increased code size. This option is off by default, but enabled in
  the default mbedtls_config.h. Fixes #9216.

Security

• Unlike previously documented, enabling MBEDTLS_PSA_HMAC_DRBG_MD_TYPE does
  not cause the PSA subsystem to use HMAC_DRBG: it uses HMAC_DRBG only when
  MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG and MBEDTLS_CTR_DRBG_C are disabled.
  CVE-2024-45157
• Fix a stack buffer overflow in mbedtls_ecdsa_der_to_raw() and
  mbedtls_ecdsa_raw_to_der() when the bits parameter is larger than the
  largest supported curve. In some configurations with PSA disabled,
  all values of bits are affected. This never happens in internal library
  calls, but can affect applications that call these functions directly.
  CVE-2024-45158
• With TLS 1.3, when a server enables optional authentication of the
  client, if the client-provided certificate does not have appropriate values
  in keyUsage or extKeyUsage extensions, then the return value of
  mbedtls_ssl_get_verify_result() would incorrectly have the
  MBEDTLS_X509_BADCERT_KEY_USAGE and MBEDTLS_X509_BADCERT_EXT_KEY_USAGE bits
  clear. As a result, an attacker that had a certificate valid for uses other
  than TLS client authentication could be able to use it for TLS client
  authentication anyway. Only TLS 1.3 servers were affected, and only with
  optional authentication (required would abort the handshake with a fatal
  alert).
  CVE-2024-45159

Bugfix

• Fix TLS 1.3 client build and runtime when support for session tickets is
  disabled (MBEDTLS_SSL_SESSION_TICKETS configuration option). Fixes #6395.
• Fix compilation error when memcpy() is a function-like macros. Fixes #8994.
• MBEDTLS_ASN1_PARSE_C and MBEDTLS_ASN1_WRITE_C are now automatically enabled
  as soon as MBEDTLS_RSA_C is enabled. Fixes #9041.
• Fix undefined behaviour (incrementing a NULL pointer by zero length) when
  passing in zero length additional data to multipart AEAD.
• Fix rare concurrent access bug where attempting to operate on a
  non-existent key while concurrently creating a new key could potentially
  corrupt the key store.
• Fix error handling when creating a key in a dynamic secure element
  (feature enabled by MBEDTLS_PSA_CRYPTO_SE_C). In a low memory condition,
  the creation could return PSA_SUCCESS but using or destroying the key
  would not work. Fixes #8537.
• Fix issue of redefinition warning messages for _GNU_SOURCE in
  entropy_poll.c and sha_256.c. There was a build warning during
  building for linux platform.
  Resolves #9026
• Fix a compilation warning in pk.c when PSA is enabled and RSA is disabled.
• Fix the build when MBEDTLS_PSA_CRYPTO_CONFIG is enabled and the built-in
  CMAC is enabled, but no built-in unauthenticated cipher is enabled.
  Fixes #9209.
• Fix redefinition warnings when SECP192R1 and/or SECP192K1 are disabled.
  Fixes #9029.
• Fix psa_cipher_decrypt() with CCM* rejecting messages less than 3 bytes
  long. Credit to Cryptofuzz. Fixes #9314.
• Fix interference between PSA volatile keys and built-in keys
  when MBEDTLS_PSA_CRYPTO_BUILTIN_KEYS is enabled and
  MBEDTLS_PSA_KEY_SLOT_COUNT is more than 4096.
• Document and enforce the limitation of mbedtls_psa_register_se_key()
  to persistent keys. Resolves #9253.
• Fix Clang compilation error when MBEDTLS_USE_PSA_CRYPTO is enabled
  but MBEDTLS_DHM_C is disabled. Reported by Michael Schuster in #9188.
• Fix server mode only build when MBEDTLS_SSL_SRV_C is enabled but
  MBEDTLS_SSL_CLI_C is disabled. Reported by M-Bab on GitHub in #9186.
• When MBEDTLS_PSA_CRYPTO_C was disabled and MBEDTLS_ECDSA_C enabled,
  some code was defining 0-size arrays, resulting in compilation errors.
  Fixed by disabling the offending code in configurations without PSA
  Crypto, where it never worked. Fixes #9311.
• Fix unintended performance regression when using short RSA public keys.
  Fixes #9232.
• Fixes an issue where some TLS 1.2 clients could not connect to an
  Mbed TLS 3.6.0 server, due to incorrect handling of
  legacy_compression_methods in the ClientHello.
  Fixes #8995, #9243.
• Fix TLS connections failing when the handshake selects TLS 1.3
  in an application that does not call psa_crypto_init().
  Fixes #9072.
• Fix TLS connection failure in applications using an Mbed TLS client in
  the default configuration connecting to a TLS 1.3 server sending tickets.
  See the documentation of
  mbedtls_ssl_conf_tls13_enable_signal_new_session_tickets() for more
  information.
  Fixes #8749.
• Fix a memory leak that could occur when failing to process an RSA
  key through some PSA functions due to low memory conditions.
• Fixed a regression introduced in 3.6.0 where the CA callback set with
  mbedtls_ssl_conf_ca_cb() would stop working when connections were
  upgraded to TLS 1.3. Fixed by adding support for the CA callback with TLS
  1.3.
• Fixed a regression introduced in 3.6.0 where clients that relied on
  optional/none authentication mode, by calling mbedtls_ssl_conf_authmode()
  with MBEDTLS_SSL_VERIFY_OPTIONAL or MBEDTLS_SSL_VERIFY_NONE, would stop
  working when connections were upgraded to TLS 1.3. Fixed by adding
  support for optional/none with TLS 1.3 as well. Note that the TLS 1.3
  standard makes server authentication mandatory; users are advised not to
  use authmode none, and to carefully check the results when using optional
  mode.
• Fixed a regression introduced in 3.6.0 where context-specific certificate
  verify callbacks, set with mbedtls_ssl_set_verify() as opposed to
  mbedtls_ssl_conf_verify(), would stop working when connections were
  upgraded to TLS 1.3. Fixed by adding support for context-specific verify
  callback in TLS 1.3.

Changes

• Warn if mbedtls/check_config.h is included manually, as this can
  lead to spurious errors. Error if a adjust.h header is included
  manually, as this can lead to silently inconsistent configurations,
  potentially resulting in buffer overflows.
  When migrating from Mbed TLS 2.x, if you had a custom config.h that
  included check_config.h, remove this inclusion from the Mbed TLS 3.x
  configuration file (renamed to mbedtls_config.h). This change was made
  in Mbed TLS 3.0, but was not announced in a changelog entry at the time.

Who should update

We recommend all users should update to take advantage of the bug fixes contained in this release at an appropriate point in their development lifecycle.

Note

❕ mbedtls-3.6.1.tar.bz2 are our official release files. source.tar.gz and source.zip are automatically generated snapshot's that github is generating. They do not include external dependencies, and can't be configured

Checksum

The SHA256 hashes for the archives are:

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