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Mbed TLS 2.16.11

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@daverodgman daverodgman released this 07 Jul 10:38
aa1d4e0

Description

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

Security Advisories

For full details, please see the following links:

https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-2

Release Notes

Security

  • Fix a bias in the generation of finite-field Diffie-Hellman-Merkle (DHM)
    private keys and of blinding values for DHM and elliptic curves (ECP)
    computations. Reported by FlorianF89 in #4245.
  • Fix a potential side channel vulnerability in ECDSA ephemeral key generation.
    An adversary who is capable of very precise timing measurements could
    learn partial information about the leading bits of the nonce used for the
    signature, allowing the recovery of the private key after observing a
    large number of signature operations. This completes a partial fix in
    Mbed TLS 2.16.4.
  • It was possible to configure MBEDTLS_ECP_MAX_BITS to a value that is
    too small, leading to buffer overflows in ECC operations. Fail the build
    in such a case.
  • An adversary with access to precise enough information about memory
    accesses (typically, an untrusted operating system attacking a secure
    enclave) could recover an RSA private key after observing the victim
    performing a single private-key operation. Found and reported by
    Zili KOU, Wenjian HE, Sharad Sinha, and Wei ZHANG.
  • An adversary with access to precise enough timing information (typically, a
    co-located process) could recover a Curve25519 or Curve448 static ECDH key
    after inputting a chosen public key and observing the victim performing the
    corresponding private-key operation. Found and reported by Leila Batina,
    Lukas Chmielewski, Björn Haase, Niels Samwel and Peter Schwabe.

Bugfix

  • Fix premature fopen() call in mbedtls_entropy_write_seed_file which may
    lead to the seed file corruption in case if the path to the seed file is
    equal to MBEDTLS_PLATFORM_STD_NV_SEED_FILE. Contributed by Victor
    Krasnoshchok in #3616.
  • Fix some cases in the bignum module where the library constructed an
    unintended representation of the value 0 which was not processed
    correctly by some bignum operations. This could happen when
    mbedtls_mpi_read_string() was called on "-0", or when
    mbedtls_mpi_mul_mpi() and mbedtls_mpi_mul_int() was called with one of
    the arguments being negative and the other being 0. Fixes #4643.
  • Fix a compilation error when MBEDTLS_ECP_RANDOMIZE_MXZ_ALT is
    defined. Fixes #4217.
  • Fix an incorrect error code when parsing a PKCS#8 private key.
  • In a TLS client, enforce the Diffie-Hellman minimum parameter size
    set with mbedtls_ssl_conf_dhm_min_bitlen() precisely. Before, the
    minimum size was rounded down to the nearest multiple of 8.
  • In library/net_sockets.c, _POSIX_C_SOURCE and _XOPEN_SOURCE are
    defined to specific values. If the code is used in a context
    where these are already defined, this can result in a compilation
    error. Instead, assume that if they are defined, the values will
    be adequate to build Mbed TLS.
  • The cipher suite TLS-RSA-WITH-CAMELLIA-256-GCM-SHA384 was not available
    when SHA-1 was disabled and was offered when SHA-1 was enabled but SHA-384
    was disabled. Fix the dependency. Fixes #4472.
  • Fix test suite code on platforms where int32_t is not int, such as
    Arm Cortex-M. Fixes #4530.
  • Fix some issues affecting MBEDTLS_ARIA_ALT implementations: a misplaced
    directive in a header and a missing initialization in the self-test.
  • Fix a missing initialization in the Camellia self-test, affecting
    MBEDTLS_CAMELLIA_ALT implementations.
  • Fix a regression introduced in 2.16.8 which broke (D)TLS CBC ciphersuites
    (when the encrypt-then-MAC extension is not in use) with some ALT
    implementations of the underlying hash (SHA-1, SHA-256, SHA-384), causing
    the affected side to wrongly reject valid messages. Fixes #4118.
  • Fix mbedtls_net_poll() and mbedtls_net_recv_timeout() often failing with
    MBEDTLS_ERR_NET_POLL_FAILED on Windows. Fixes #4465.
  • Fix a resource leak in a test suite with an alternative AES
    implementation. Fixes #4176.
  • Fix a crash in mbedtls_mpi_debug_mpi on a bignum having 0 limbs.
    Reported by lhuang04 in #4578. Fixes #4608.
  • Fix a null pointer dereference when mbedtls_mpi_exp_mod() was called with
    A=0 represented with 0 limbs. This bug could not be triggered by code
    that constructed A with one of the mbedtls_mpi_read_xxx functions
    (including in particular TLS code) since those always built an mpi object
    with at least one limb. Credit to OSS-Fuzz. Fixes #4641.
  • Fix mbedtls_mpi_gcd(G,A,B) when the value of B is zero. This had no
    effect on Mbed TLS's internal use of mbedtls_mpi_gcd(), but may affect
    applications that call mbedtls_mpi_gcd() directly. Fixes #4642.
  • mbedtls_pk_sign() and mbedtls_pk_verify() and their extended and
    restartable variants now require at least the specified hash length if
    nonzero. Before, for RSA, hash_len was ignored in favor of the length of
    the specified hash algorithm.
  • Fix which alert is sent in some cases to conform to the
    applicable RFC: on an invalid Finished message value, an
    invalid max_fragment_length extension, or an
    unsupported extension used by the server.

Changes

  • Fix the setting of the read timeout in the DTLS sample programs.
  • Remove the AES sample application programs/aes/aescrypt2 which shows
    bad cryptographic practice. Fix #1906.
  • When building the test suites with GNU make, invoke python3 or python, not
    python2. The build still works with either Python 2.7 or 3.5+, but we
    recommend using a version of Python that is supported upstream.

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.

Checksum

The SHA256 hashes for the archives are:

c18e7e9abf95e69e425260493720470021384a1728417042060a35d0b7b18b41 mbedtls-2.16.11.tar.gz
c75ec6a654fc9ef487904172633758d6f61d88a0d53329c79657221043bdb6f4 mbedtls-2.16.11.zip