Assemble changelog

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/ChangeLog b/ChangeLog
index 89572ca..43d42a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,126 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS x.x.x branch released xxxx-xx-xx
+
+API changes
+   * Some fields of mbedtls_ssl_session and mbedtls_ssl_config are in a
+     different order. This only affects applications that define such
+     structures directly or serialize them.
+
+Requirement changes
+   * Sign-magnitude and one's complement representations for signed integers are
+     not supported. Two's complement is the only supported representation.
+
+Removals
+   * Remove config option MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_CERTIFICATES,
+     which allowed SHA-1 in the default TLS configuration for certificate
+     signing. It was intended to facilitate the transition in environments
+     with SHA-1 certificates. SHA-1 is considered a weak message digest and
+     its use constitutes a security risk.
+   * Remove the partial support for running unit tests via Greentea on Mbed OS,
+     which had been unmaintained since 2018.
+
+Features
+   * The identifier of the CID TLS extension can be configured by defining
+     MBEDTLS_TLS_EXT_CID at compile time.
+   * Warn if errors from certain functions are ignored. This is currently
+     supported on GCC-like compilers and on MSVC and can be configured through
+     the macro MBEDTLS_CHECK_RETURN. The warnings are always enabled
+     (where supported) for critical functions where ignoring the return
+     value is almost always a bug. Enable the new configuration option
+     MBEDTLS_CHECK_RETURN_WARNING to get warnings for other functions. This
+     is currently implemented in the AES, DES and md modules, and will be
+     extended to other modules in the future.
+   * Add missing PSA macros declared by PSA Crypto API 1.0.0:
+     PSA_ALG_IS_SIGN_HASH, PSA_ALG_NONE, PSA_HASH_BLOCK_LENGTH, PSA_KEY_ID_NULL.
+    * Add new API mbedtls_ct_memcmp for constant time buffer comparison.
+   * Add PSA API definition for ARIA.
+
+Security
+   * Zeroize several intermediate variables used to calculate the expected
+     value when verifying a MAC or AEAD tag. This hardens the library in
+     case the value leaks through a memory disclosure vulnerability. For
+     example, a memory disclosure vulnerability could have allowed a
+     man-in-the-middle to inject fake ciphertext into a DTLS connection.
+   * In psa_cipher_generate_iv() and psa_cipher_encrypt(), do not read back
+     from the output buffer. This fixes a potential policy bypass or decryption
+     oracle vulnerability if the output buffer is in memory that is shared with
+     an untrusted application.
+
+Bugfix
+   * Stop using reserved identifiers as local variables. Fixes #4630.
+   * The GNU makefiles invoke python3 in preference to python except on Windows.
+     The check was accidentally not performed when cross-compiling for Windows
+     on Linux. Fix this. Fixes #4774.
+   * Prevent divide by zero if either of PSA_CIPHER_ENCRYPT_OUTPUT_SIZE() or
+     PSA_CIPHER_UPDATE_OUTPUT_SIZE() were called using an asymmetric key type.
+   * Fix a parameter set but unused in psa_crypto_cipher.c. Fixes #4935.
+   * Don't use the obsolete header path sys/fcntl.h in unit tests.
+     These header files cause compilation errors in musl.
+     Fixes #4969.
+   * Fix missing constraints on x86_64 and aarch64 assembly code
+     for bignum multiplication that broke some bignum operations with
+     (at least) Clang 12.
+     Fixes #4116, #4786, #4917, #4962.
+   * Fix mbedtls_cipher_crypt: AES-ECB when MBEDTLS_USE_PSA_CRYPTO is enabled.
+   * Failures of alternative implementations of AES or DES single-block
+     functions enabled with MBEDTLS_AES_ENCRYPT_ALT, MBEDTLS_AES_DECRYPT_ALT,
+     MBEDTLS_DES_CRYPT_ECB_ALT or MBEDTLS_DES3_CRYPT_ECB_ALT were ignored.
+     This does not concern the implementation provided with Mbed TLS,
+     where this function cannot fail, or full-module replacements with
+     MBEDTLS_AES_ALT or MBEDTLS_DES_ALT. Reported by Armelle Duboc in #1092.
+   * Some failures of HMAC operations were ignored. These failures could only
+     happen with an alternative implementation of the underlying hash module.
+   * Fix the error returned by psa_generate_key() for a public key. Fixes #4551.
+   * Fix the build of sample programs when neither MBEDTLS_ERROR_C nor
+     MBEDTLS_ERROR_STRERROR_DUMMY is enabled.
+   * Fix PSA_ALG_RSA_PSS verification accepting an arbitrary salt length.
+     This algorithm now accepts only the same salt length for verification
+     that it produces when signing, as documented. Use the new algorithm
+     PSA_ALG_RSA_PSS_ANY_SALT to accept any salt length. Fixes #4946.
+   * The existing predicate macro name PSA_ALG_IS_HASH_AND_SIGN is now reserved
+     for algorithm values that fully encode the hashing step, as per the PSA
+     Crypto API specification. This excludes PSA_ALG_RSA_PKCS1V15_SIGN_RAW and
+     PSA_ALG_ECDSA_ANY. The new predicate macro PSA_ALG_IS_SIGN_HASH covers
+     all algorithms that can be used with psa_{sign,verify}_hash(), including
+     these two.
+   * Fix issue in Makefile on Linux with SHARED=1, that caused shared libraries
+     not to list other shared libraries they need.
+   * Fix a bug in mbedtls_gcm_starts() when bits of iv are longer than 2^32.
+   * Fix #4884.
+   * Fix an uninitialized variable warning in test_suite_ssl.function with GCC
+     version 11.
+   * Fix the build when no SHA2 module is included. Fixes #4930.
+   * Fix the build when only the bignum module is included. Fixes #4929.
+   * Fix a potential invalid pointer dereference and infinite loop bugs in
+     pkcs12 functions when the password is empty. Fix the documentation to
+     better describe the inputs to these functions and their possible values.
+     Fixes #5136.
+   * Fix a double-free that happened after mbedtls_ssl_set_session() or
+     mbedtls_ssl_get_session() failed with MBEDTLS_ERR_SSL_ALLOC_FAILED
+     (out of memory). After that, calling mbedtls_ssl_session_free()
+     and mbedtls_ssl_free() would cause an internal session buffer to
+     be free()'d twice.
+   * The key usage flags PSA_KEY_USAGE_SIGN_MESSAGE now allows the MAC
+     operations psa_mac_compute() and psa_mac_sign_setup().
+   * The key usage flags PSA_KEY_USAGE_VERIFY_MESSAGE now allows the MAC
+     operations psa_mac_verify() and psa_mac_verify_setup().
+
+Changes
+   * Set config option MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_KEY_EXCHANGE to be
+     disabled by default.
+   * Improve the performance of base64 constant-flow code. The result is still
+     slower than the original non-constant-flow implementation, but much faster
+     than the previous constant-flow implementation. Fixes #4814.
+   * Indicate in the error returned if the nonce length used with
+     ChaCha20-Poly1305 is invalid, and not just unsupported.
+    * The mbedcrypto library includes a new source code module constant_time.c,
+      containing various functions meant to resist timing side channel attacks.
+      This module does not have a separate configuration option, and functions
+      from this module will be included in the build as required. Currently
+      most of the interface of this module is private and may change at any
+      time.
+
 = mbed TLS 2.27.0 branch released 2021-07-07
 
 API changes