diff --git a/.github/issue_template.md b/.github/issue_template.md
index 7c31353..18b87fc 100644
--- a/.github/issue_template.md
+++ b/.github/issue_template.md
@@ -1,7 +1,7 @@
 Note: This is just a template, so feel free to use/remove the unnecessary things
 
 ### Description
-- Type: Bug | Enhancement\Feature Request | Question
+- Type: Bug | Enhancement\Feature Request
 - Priority: Blocker | Major | Minor
 
 ---------------------------------------------------------------
@@ -38,4 +38,4 @@
 
 ## Question
 
-**Please first check for answers in the [Mbed TLS knowledge Base](https://tls.mbed.org/kb), and preferably file an issue in the [Mbed TLS support forum](https://forums.mbed.com/c/mbed-tls)**  
+**Please first check for answers in the [Mbed TLS knowledge Base](https://tls.mbed.org/kb). If you can't find the answer you're looking for then please use the [Mbed TLS mailing list](https://lists.trustedfirmware.org/mailman/listinfo/mbed-tls)**
diff --git a/ChangeLog b/ChangeLog
index 491b86a..5c4a846 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,12 @@
      SSL module for hardware acceleration of individual records.
 
 Security
+   * Fix issue in DTLS handling of new associations with the same parameters
+     (RFC 6347 section 4.2.8): an attacker able to send forged UDP packets to
+     the server could cause it to drop established associations with
+     legitimate clients, resulting in a Denial of Service. This could only
+     happen when MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE was enabled in config.h
+     (which it is by default).
    * Fix side channel in ECC code that allowed an adversary with access to
      precise enough timing and memory access information (typically an
      untrusted operating system attacking a secure enclave) to fully recover
@@ -16,6 +22,8 @@
 Bugfix
    * Fix compilation failure when both MBEDTLS_SSL_PROTO_DTLS and
      MBEDTLS_SSL_HW_RECORD_ACCEL are enabled.
+   * Remove a spurious check in ssl_parse_client_psk_identity that triggered
+     a warning with some compilers. Fix contributed by irwir in #2856.
 
 Changes
    * Mbed Crypto is no longer a Git submodule. The crypto part of the library
diff --git a/ChangeLog.d/00README.md b/ChangeLog.d/00README.md
new file mode 100644
index 0000000..b559e23
--- /dev/null
+++ b/ChangeLog.d/00README.md
@@ -0,0 +1,67 @@
+# Pending changelog entry directory
+
+This directory contains changelog entries that have not yet been merged
+to the changelog file ([`../ChangeLog`](../ChangeLog)).
+
+## Changelog entry file format
+
+A changelog entry file must have the extension `*.txt` and must have the
+following format:
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Security
+   * Change description.
+   * Another change description.
+
+Features
+   * Yet another change description. This is a long change description that
+     spans multiple lines.
+   * Yet again another change description.
+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The permitted changelog entry categories are as follows:
+<!-- Keep this synchronized with STANDARD_CATEGORIES in assemble_changelog.py! -->
+
+    API changes
+    Default behavior changes
+    Requirement changes
+    New deprecations
+    Removals
+    Features
+    Security
+    Bugfix
+    Changes
+
+Use “Changes” for anything that doesn't fit in the other categories, such as
+performance, documentation and test improvements.
+
+## How to write a changelog entry
+
+Each entry starts with three spaces, an asterisk and a space. Continuation
+lines start with 5 spaces. Lines wrap at 79 characters.
+
+Write full English sentences with proper capitalization and punctuation. Use
+the present tense. Use the imperative where applicable. For example: “Fix a
+bug in mbedtls_xxx() ….”
+
+Include GitHub issue numbers where relevant. Use the format “#1234” for an
+Mbed TLS issue. Add other external references such as CVE numbers where
+applicable.
+
+Credit the author of the contribution if the contribution is not a member of
+the Mbed TLS development team. Also credit bug reporters where applicable.
+
+**Explain why, not how**. Remember that the audience is the users of the
+library, not its developers. In particular, for a bug fix, explain the
+consequences of the bug, not how the bug was fixed. For a new feature, explain
+why one might be interested in the feature. For an API change or a deprecation,
+explain how to update existing applications.
+
+See [existing entries](../ChangeLog) for examples.
+
+## How `ChangeLog` is updated
+
+Run [`../scripts/assemble_changelog.py`](../scripts/assemble_changelog.py)
+from a Git working copy
+to move the entries from files in `ChangeLog.d` to the main `ChangeLog` file.
diff --git a/Makefile b/Makefile
index 8e72bd1..e0eb7a5 100644
--- a/Makefile
+++ b/Makefile
@@ -124,8 +124,10 @@
 
 ## Editor navigation files
 C_SOURCE_FILES = $(wildcard include/*/*.h library/*.[hc] programs/*/*.[hc] tests/suites/*.function)
+# Exuberant-ctags invocation. Other ctags implementations may require different options.
+CTAGS = ctags --langmap=c:+.h.function -o
 tags: $(C_SOURCE_FILES)
-	ctags -o $@ $(C_SOURCE_FILES)
+	$(CTAGS) $@ $(C_SOURCE_FILES)
 TAGS: $(C_SOURCE_FILES)
 	etags -o $@ $(C_SOURCE_FILES)
 GPATH GRTAGS GSYMS GTAGS: $(C_SOURCE_FILES)
diff --git a/doxygen/mbedtls.doxyfile b/doxygen/mbedtls.doxyfile
index 4732271..148fa27 100644
--- a/doxygen/mbedtls.doxyfile
+++ b/doxygen/mbedtls.doxyfile
@@ -1594,7 +1594,7 @@
 # contain include files that are not input files but should be processed by
 # the preprocessor.
 
-INCLUDE_PATH           =
+INCLUDE_PATH           = ../include
 
 # You can use the INCLUDE_FILE_PATTERNS tag to specify one or more wildcard
 # patterns (like *.h and *.hpp) to filter out the header-files in the
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index d904d5a..fa3caa7 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -619,6 +619,23 @@
 #error "MBEDTLS_SSL_PROTO_TLS1_2 defined, but not all prerequisites"
 #endif
 
+#if (defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) ||  \
+     defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2)) && \
+    !(defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED) ||                          \
+      defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED) ||                      \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) ||                    \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) ||                  \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) ||                     \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED) ||                   \
+      defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED) ||                          \
+      defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED) ||                      \
+      defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED) ||                      \
+      defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED) ||                    \
+      defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED) )
+#error "One or more versions of the TLS protocol are enabled " \
+        "but no key exchange methods defined with MBEDTLS_KEY_EXCHANGE_xxxx"
+#endif
+
 #if defined(MBEDTLS_SSL_PROTO_DTLS)     && \
     !defined(MBEDTLS_SSL_PROTO_TLS1_1)  && \
     !defined(MBEDTLS_SSL_PROTO_TLS1_2)
@@ -763,6 +780,10 @@
 #error "MBEDTLS_X509_CREATE_C defined, but not all prerequisites"
 #endif
 
+#if defined(MBEDTLS_CERTS_C) && !defined(MBEDTLS_X509_USE_C)
+#error "MBEDTLS_CERTS_C defined, but not all prerequisites"
+#endif
+
 #if defined(MBEDTLS_X509_CRT_PARSE_C) && ( !defined(MBEDTLS_X509_USE_C) )
 #error "MBEDTLS_X509_CRT_PARSE_C defined, but not all prerequisites"
 #endif
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index d5502a9..901e26d 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1520,8 +1520,8 @@
 
 /** \def MBEDTLS_SSL_EXTENDED_MASTER_SECRET
  *
- * Enable support for Extended Master Secret, aka Session Hash
- * (draft-ietf-tls-session-hash-02).
+ * Enable support for RFC 7627: Session Hash and Extended Master Secret
+ * Extension.
  *
  * This was introduced as "the proper fix" to the Triple Handshake familiy of
  * attacks, but it is recommended to always use it (even if you disable
@@ -1539,7 +1539,8 @@
 /**
  * \def MBEDTLS_SSL_FALLBACK_SCSV
  *
- * Enable support for FALLBACK_SCSV (draft-ietf-tls-downgrade-scsv-00).
+ * Enable support for RFC 7507: Fallback Signaling Cipher Suite Value (SCSV)
+ * for Preventing Protocol Downgrade Attacks.
  *
  * For servers, it is recommended to always enable this, unless you support
  * only one version of TLS, or know for sure that none of your clients
diff --git a/library/Makefile b/library/Makefile
index 92799d9..f9cd468 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -201,8 +201,6 @@
 	echo "  LD    $@"
 	$(CC) -shared -Wl,-soname,$@ -Wl,--out-implib,$@.a -o $@ $(OBJS_CRYPTO) -lws2_32 -lwinmm -lgdi32 -static-libgcc $(LOCAL_LDFLAGS) $(LDFLAGS)
 
-libmbedcrypto.$(DLEXT): | libmbedcrypto.a
-
 .c.o:
 	echo "  CC    $<"
 	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) -o $@ -c $<
diff --git a/library/hkdf.c b/library/hkdf.c
index 379035d..82df597 100644
--- a/library/hkdf.c
+++ b/library/hkdf.c
@@ -115,7 +115,7 @@
 
     n = okm_len / hash_len;
 
-    if( (okm_len % hash_len) != 0 )
+    if( okm_len % hash_len != 0 )
     {
         n++;
     }
@@ -131,11 +131,13 @@
 
     mbedtls_md_init( &ctx );
 
-    if( (ret = mbedtls_md_setup( &ctx, md, 1) ) != 0 )
+    if( ( ret = mbedtls_md_setup( &ctx, md, 1 ) ) != 0 )
     {
         goto exit;
     }
 
+    memset( t, 0, hash_len );
+
     /*
      * Compute T = T(1) | T(2) | T(3) | ... | T(N)
      * Where T(N) is defined in RFC 5869 Section 2.3
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index c0b440a..ff6b7b6 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2344,7 +2344,7 @@
                                       unsigned char *end )
 {
     int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
-    size_t  len;
+    uint16_t  len;
     ((void) ssl);
 
     /*
@@ -2361,7 +2361,7 @@
     len = (*p)[0] << 8 | (*p)[1];
     *p += 2;
 
-    if( end - (*p) < (int) len )
+    if( end - (*p) < len )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message "
                                     "(psk_identity_hint length)" ) );
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 18fa555..428ace5 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -3197,16 +3197,17 @@
  * that looks like a ClientHello.
  *
  * - if the input looks like a ClientHello without cookies,
- *   send back HelloVerifyRequest, then
- *   return MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED
+ *   send back HelloVerifyRequest, then return 0
  * - if the input looks like a ClientHello with a valid cookie,
  *   reset the session of the current context, and
  *   return MBEDTLS_ERR_SSL_CLIENT_RECONNECT
  * - if anything goes wrong, return a specific error code
  *
- * mbedtls_ssl_read_record() will ignore the record if anything else than
- * MBEDTLS_ERR_SSL_CLIENT_RECONNECT or 0 is returned, although this function
- * cannot not return 0.
+ * This function is called (through ssl_check_client_reconnect()) when an
+ * unexpected record is found in ssl_get_next_record(), which will discard the
+ * record if we return 0, and bubble up the return value otherwise (this
+ * includes the case of MBEDTLS_ERR_SSL_CLIENT_RECONNECT and of unexpected
+ * errors, and is the right thing to do in both cases).
  */
 static int ssl_handle_possible_reconnect( mbedtls_ssl_context *ssl )
 {
@@ -3218,6 +3219,8 @@
     {
         /* If we can't use cookies to verify reachability of the peer,
          * drop the record. */
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "no cookie callbacks, "
+                                    "can't check reconnect validity" ) );
         return( 0 );
     }
 
@@ -3233,16 +3236,23 @@
 
     if( ret == MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED )
     {
+        int send_ret;
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "sending HelloVerifyRequest" ) );
+        MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network",
+                                  ssl->out_buf, len );
         /* Don't check write errors as we can't do anything here.
          * If the error is permanent we'll catch it later,
          * if it's not, then hopefully it'll work next time. */
-        (void) ssl->f_send( ssl->p_bio, ssl->out_buf, len );
-        ret = 0;
+        send_ret = ssl->f_send( ssl->p_bio, ssl->out_buf, len );
+        MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_send", send_ret );
+        (void) send_ret;
+
+        return( 0 );
     }
 
     if( ret == 0 )
     {
-        /* Got a valid cookie, partially reset context */
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "cookie is valid, resetting context" ) );
         if( ( ret = mbedtls_ssl_session_reset_int( ssl, 1 ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "reset", ret );
@@ -4415,6 +4425,7 @@
                 ssl->in_msglen = rec.data_len;
 
                 ret = ssl_check_client_reconnect( ssl );
+                MBEDTLS_SSL_DEBUG_RET( 2, "ssl_check_client_reconnect", ret );
                 if( ret != 0 )
                     return( ret );
 #endif
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 469c67e..006bc69 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -3812,7 +3812,7 @@
                                           const unsigned char *end )
 {
     int ret = 0;
-    size_t n;
+    uint16_t n;
 
     if( ssl_conf_has_psk_or_cb( ssl->conf ) == 0 )
     {
@@ -3832,7 +3832,7 @@
     n = ( (*p)[0] << 8 ) | (*p)[1];
     *p += 2;
 
-    if( n < 1 || n > 65535 || n > (size_t) ( end - *p ) )
+    if( n == 0 || n > end - *p )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client key exchange message" ) );
         return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE );
diff --git a/library/x509.c b/library/x509.c
index 7f8181b..c451332 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -1064,7 +1064,7 @@
     mbedtls_x509_crt_free( &clicert );
 #else
     ((void) verbose);
-#endif /* MBEDTLS_CERTS_C && MBEDTLS_SHA1_C */
+#endif /* MBEDTLS_CERTS_C && MBEDTLS_SHA256_C */
     return( ret );
 }
 
diff --git a/programs/pkey/ecdsa.c b/programs/pkey/ecdsa.c
index b851c31..9feb160 100644
--- a/programs/pkey/ecdsa.c
+++ b/programs/pkey/ecdsa.c
@@ -189,7 +189,7 @@
                                        sig, &sig_len,
                                        mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
     {
-        mbedtls_printf( " failed\n  ! mbedtls_ecdsa_genkey returned %d\n", ret );
+        mbedtls_printf( " failed\n  ! mbedtls_ecdsa_write_signature returned %d\n", ret );
         goto exit;
     }
     mbedtls_printf( " ok (signature length = %u)\n", (unsigned int) sig_len );
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index 979910e..7447571 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -133,6 +133,7 @@
     "                        modifying CID in first instance of the packet.\n" \
     "    protect_hvr=0/1     default: 0 (don't protect HelloVerifyRequest)\n" \
     "    protect_len=%%d      default: (don't protect packets of this size)\n" \
+    "    inject_clihlo=0/1   default: 0 (don't inject fake ClientHello)\n"  \
     "\n"                                                                    \
     "    seed=%%d             default: (use current time)\n"                \
     USAGE_PACK                                                              \
@@ -166,6 +167,7 @@
     unsigned bad_cid;           /* inject corrupted CID record              */
     int protect_hvr;            /* never drop or delay HelloVerifyRequest   */
     int protect_len;            /* never drop/delay packet of the given size*/
+    int inject_clihlo;          /* inject fake ClientHello after handshake  */
     unsigned pack;              /* merge packets into single datagram for
                                  * at most \c merge milliseconds if > 0     */
     unsigned int seed;          /* seed for "random" events                 */
@@ -314,6 +316,12 @@
             if( opt.protect_len < 0 )
                 exit_usage( p, q );
         }
+        else if( strcmp( p, "inject_clihlo" ) == 0 )
+        {
+            opt.inject_clihlo = atoi( q );
+            if( opt.inject_clihlo < 0 || opt.inject_clihlo > 1 )
+                exit_usage( p, q );
+        }
         else if( strcmp( p, "seed" ) == 0 )
         {
             opt.seed = atoi( q );
@@ -523,11 +531,41 @@
     fflush( stdout );
 }
 
+/*
+ * In order to test the server's behaviour when receiving a ClientHello after
+ * the connection is established (this could be a hard reset from the client,
+ * but the server must not drop the existing connection before establishing
+ * client reachability, see RFC 6347 Section 4.2.8), we memorize the first
+ * ClientHello we see (which can't have a cookie), then replay it after the
+ * first ApplicationData record - then we're done.
+ *
+ * This is controlled by the inject_clihlo option.
+ *
+ * We want an explicit state and a place to store the packet.
+ */
+typedef enum {
+    ICH_INIT,       /* haven't seen the first ClientHello yet */
+    ICH_CACHED,     /* cached the initial ClientHello */
+    ICH_INJECTED,   /* ClientHello already injected, done */
+} inject_clihlo_state_t;
+
+static inject_clihlo_state_t inject_clihlo_state;
+static packet initial_clihlo;
+
 int send_packet( const packet *p, const char *why )
 {
     int ret;
     mbedtls_net_context *dst = p->dst;
 
+    /* save initial ClientHello? */
+    if( opt.inject_clihlo != 0 &&
+        inject_clihlo_state == ICH_INIT &&
+        strcmp( p->type, "ClientHello" ) == 0 )
+    {
+        memcpy( &initial_clihlo, p, sizeof( packet ) );
+        inject_clihlo_state = ICH_CACHED;
+    }
+
     /* insert corrupted CID record? */
     if( opt.bad_cid != 0 &&
         strcmp( p->type, "CID" ) == 0 &&
@@ -592,6 +630,23 @@
         }
     }
 
+    /* Inject ClientHello after first ApplicationData */
+    if( opt.inject_clihlo != 0 &&
+        inject_clihlo_state == ICH_CACHED &&
+        strcmp( p->type, "ApplicationData" ) == 0 )
+    {
+        print_packet( &initial_clihlo, "injected" );
+
+        if( ( ret = dispatch_data( dst, initial_clihlo.buf,
+                                        initial_clihlo.len ) ) <= 0 )
+        {
+            mbedtls_printf( "  ! dispatch returned %d\n", ret );
+            return( ret );
+        }
+
+        inject_clihlo_state = ICH_INJECTED;
+    }
+
     return( 0 );
 }
 
diff --git a/scripts/assemble_changelog.py b/scripts/assemble_changelog.py
new file mode 100755
index 0000000..ffa3f16
--- /dev/null
+++ b/scripts/assemble_changelog.py
@@ -0,0 +1,505 @@
+#!/usr/bin/env python3
+
+"""Assemble Mbed TLS change log entries into the change log file.
+
+Add changelog entries to the first level-2 section.
+Create a new level-2 section for unreleased changes if needed.
+Remove the input files unless --keep-entries is specified.
+
+In each level-3 section, entries are sorted in chronological order
+(oldest first). From oldest to newest:
+* Merged entry files are sorted according to their merge date (date of
+  the merge commit that brought the commit that created the file into
+  the target branch).
+* Committed but unmerged entry files are sorted according to the date
+  of the commit that adds them.
+* Uncommitted entry files are sorted according to their modification time.
+
+You must run this program from within a git working directory.
+"""
+
+# Copyright (C) 2019, Arm Limited, All Rights Reserved
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# This file is part of Mbed TLS (https://tls.mbed.org)
+
+import argparse
+from collections import OrderedDict, namedtuple
+import datetime
+import functools
+import glob
+import os
+import re
+import subprocess
+import sys
+
+class InputFormatError(Exception):
+    def __init__(self, filename, line_number, message, *args, **kwargs):
+        message = '{}:{}: {}'.format(filename, line_number,
+                                     message.format(*args, **kwargs))
+        super().__init__(message)
+
+class CategoryParseError(Exception):
+    def __init__(self, line_offset, error_message):
+        self.line_offset = line_offset
+        self.error_message = error_message
+        super().__init__('{}: {}'.format(line_offset, error_message))
+
+class LostContent(Exception):
+    def __init__(self, filename, line):
+        message = ('Lost content from {}: "{}"'.format(filename, line))
+        super().__init__(message)
+
+# The category names we use in the changelog.
+# If you edit this, update ChangeLog.d/README.md.
+STANDARD_CATEGORIES = (
+    b'API changes',
+    b'Default behavior changes',
+    b'Requirement changes',
+    b'New deprecations',
+    b'Removals',
+    b'Features',
+    b'Security',
+    b'Bugfix',
+    b'Changes',
+)
+
+CategoryContent = namedtuple('CategoryContent', [
+    'name', 'title_line', # Title text and line number of the title
+    'body', 'body_line', # Body text and starting line number of the body
+])
+
+class ChangelogFormat:
+    """Virtual class documenting how to write a changelog format class."""
+
+    @classmethod
+    def extract_top_version(cls, changelog_file_content):
+        """Split out the top version section.
+
+        If the top version is already released, create a new top
+        version section for an unreleased version.
+
+        Return ``(header, top_version_title, top_version_body, trailer)``
+        where the "top version" is the existing top version section if it's
+        for unreleased changes, and a newly created section otherwise.
+        To assemble the changelog after modifying top_version_body,
+        concatenate the four pieces.
+        """
+        raise NotImplementedError
+
+    @classmethod
+    def version_title_text(cls, version_title):
+        """Return the text of a formatted version section title."""
+        raise NotImplementedError
+
+    @classmethod
+    def split_categories(cls, version_body):
+        """Split a changelog version section body into categories.
+
+        Return a list of `CategoryContent` the name is category title
+        without any formatting.
+        """
+        raise NotImplementedError
+
+    @classmethod
+    def format_category(cls, title, body):
+        """Construct the text of a category section from its title and body."""
+        raise NotImplementedError
+
+class TextChangelogFormat(ChangelogFormat):
+    """The traditional Mbed TLS changelog format."""
+
+    _unreleased_version_text = b'= mbed TLS x.x.x branch released xxxx-xx-xx'
+    @classmethod
+    def is_released_version(cls, title):
+        # Look for an incomplete release date
+        return not re.search(br'[0-9x]{4}-[0-9x]{2}-[0-9x]?x', title)
+
+    _top_version_re = re.compile(br'(?:\A|\n)(=[^\n]*\n+)(.*?\n)(?:=|$)',
+                                 re.DOTALL)
+    @classmethod
+    def extract_top_version(cls, changelog_file_content):
+        """A version section starts with a line starting with '='."""
+        m = re.search(cls._top_version_re, changelog_file_content)
+        top_version_start = m.start(1)
+        top_version_end = m.end(2)
+        top_version_title = m.group(1)
+        top_version_body = m.group(2)
+        if cls.is_released_version(top_version_title):
+            top_version_end = top_version_start
+            top_version_title = cls._unreleased_version_text + b'\n\n'
+            top_version_body = b''
+        return (changelog_file_content[:top_version_start],
+                top_version_title, top_version_body,
+                changelog_file_content[top_version_end:])
+
+    @classmethod
+    def version_title_text(cls, version_title):
+        return re.sub(br'\n.*', version_title, re.DOTALL)
+
+    _category_title_re = re.compile(br'(^\w.*)\n+', re.MULTILINE)
+    @classmethod
+    def split_categories(cls, version_body):
+        """A category title is a line with the title in column 0."""
+        if not version_body:
+            return []
+        title_matches = list(re.finditer(cls._category_title_re, version_body))
+        if not title_matches or title_matches[0].start() != 0:
+            # There is junk before the first category.
+            raise CategoryParseError(0, 'Junk found where category expected')
+        title_starts = [m.start(1) for m in title_matches]
+        body_starts = [m.end(0) for m in title_matches]
+        body_ends = title_starts[1:] + [len(version_body)]
+        bodies = [version_body[body_start:body_end].rstrip(b'\n') + b'\n'
+                  for (body_start, body_end) in zip(body_starts, body_ends)]
+        title_lines = [version_body[:pos].count(b'\n') for pos in title_starts]
+        body_lines = [version_body[:pos].count(b'\n') for pos in body_starts]
+        return [CategoryContent(title_match.group(1), title_line,
+                                body, body_line)
+                for title_match, title_line, body, body_line
+                in zip(title_matches, title_lines, bodies, body_lines)]
+
+    @classmethod
+    def format_category(cls, title, body):
+        # `split_categories` ensures that each body ends with a newline.
+        # Make sure that there is additionally a blank line between categories.
+        if not body.endswith(b'\n\n'):
+            body += b'\n'
+        return title + b'\n' + body
+
+class ChangeLog:
+    """An Mbed TLS changelog.
+
+    A changelog file consists of some header text followed by one or
+    more version sections. The version sections are in reverse
+    chronological order. Each version section consists of a title and a body.
+
+    The body of a version section consists of zero or more category
+    subsections. Each category subsection consists of a title and a body.
+
+    A changelog entry file has the same format as the body of a version section.
+
+    A `ChangelogFormat` object defines the concrete syntax of the changelog.
+    Entry files must have the same format as the changelog file.
+    """
+
+    # Only accept dotted version numbers (e.g. "3.1", not "3").
+    # Refuse ".x" in a version number where x is a letter: this indicates
+    # a version that is not yet released. Something like "3.1a" is accepted.
+    _version_number_re = re.compile(br'[0-9]+\.[0-9A-Za-z.]+')
+    _incomplete_version_number_re = re.compile(br'.*\.[A-Za-z]')
+
+    def add_categories_from_text(self, filename, line_offset,
+                                 text, allow_unknown_category):
+        """Parse a version section or entry file."""
+        try:
+            categories = self.format.split_categories(text)
+        except CategoryParseError as e:
+            raise InputFormatError(filename, line_offset + e.line_offset,
+                                   e.error_message)
+        for category in categories:
+            if not allow_unknown_category and \
+               category.name not in self.categories:
+                raise InputFormatError(filename,
+                                       line_offset + category.title_line,
+                                       'Unknown category: "{}"',
+                                       category.name.decode('utf8'))
+            self.categories[category.name] += category.body
+
+    def __init__(self, input_stream, changelog_format):
+        """Create a changelog object.
+
+        Populate the changelog object from the content of the file
+        input_stream.
+        """
+        self.format = changelog_format
+        whole_file = input_stream.read()
+        (self.header,
+         self.top_version_title, top_version_body,
+         self.trailer) = self.format.extract_top_version(whole_file)
+        # Split the top version section into categories.
+        self.categories = OrderedDict()
+        for category in STANDARD_CATEGORIES:
+            self.categories[category] = b''
+        offset = (self.header + self.top_version_title).count(b'\n') + 1
+        self.add_categories_from_text(input_stream.name, offset,
+                                      top_version_body, True)
+
+    def add_file(self, input_stream):
+        """Add changelog entries from a file.
+        """
+        self.add_categories_from_text(input_stream.name, 1,
+                                      input_stream.read(), False)
+
+    def write(self, filename):
+        """Write the changelog to the specified file.
+        """
+        with open(filename, 'wb') as out:
+            out.write(self.header)
+            out.write(self.top_version_title)
+            for title, body in self.categories.items():
+                if not body:
+                    continue
+                out.write(self.format.format_category(title, body))
+            out.write(self.trailer)
+
+
+@functools.total_ordering
+class EntryFileSortKey:
+    """This classes defines an ordering on changelog entry files: older < newer.
+
+    * Merged entry files are sorted according to their merge date (date of
+      the merge commit that brought the commit that created the file into
+      the target branch).
+    * Committed but unmerged entry files are sorted according to the date
+      of the commit that adds them.
+    * Uncommitted entry files are sorted according to their modification time.
+
+    This class assumes that the file is in a git working directory with
+    the target branch checked out.
+    """
+
+    # Categories of files. A lower number is considered older.
+    MERGED = 0
+    COMMITTED = 1
+    LOCAL = 2
+
+    @staticmethod
+    def creation_hash(filename):
+        """Return the git commit id at which the given file was created.
+
+        Return None if the file was never checked into git.
+        """
+        hashes = subprocess.check_output(['git', 'log', '--format=%H',
+                                          '--follow',
+                                          '--', filename])
+        m = re.search(b'(.+)$', hashes)
+        if not m:
+            # The git output is empty. This means that the file was
+            # never checked in.
+            return None
+        # The last commit in the log is the oldest one, which is when the
+        # file was created.
+        return m.group(0)
+
+    @staticmethod
+    def list_merges(some_hash, target, *options):
+        """List merge commits from some_hash to target.
+
+        Pass options to git to select which commits are included.
+        """
+        text = subprocess.check_output(['git', 'rev-list',
+                                        '--merges', *options,
+                                        b'..'.join([some_hash, target])])
+        return text.rstrip(b'\n').split(b'\n')
+
+    @classmethod
+    def merge_hash(cls, some_hash):
+        """Return the git commit id at which the given commit was merged.
+
+        Return None if the given commit was never merged.
+        """
+        target = b'HEAD'
+        # List the merges from some_hash to the target in two ways.
+        # The ancestry list is the ones that are both descendants of
+        # some_hash and ancestors of the target.
+        ancestry = frozenset(cls.list_merges(some_hash, target,
+                                             '--ancestry-path'))
+        # The first_parents list only contains merges that are directly
+        # on the target branch. We want it in reverse order (oldest first).
+        first_parents = cls.list_merges(some_hash, target,
+                                        '--first-parent', '--reverse')
+        # Look for the oldest merge commit that's both on the direct path
+        # and directly on the target branch. That's the place where some_hash
+        # was merged on the target branch. See
+        # https://stackoverflow.com/questions/8475448/find-merge-commit-which-include-a-specific-commit
+        for commit in first_parents:
+            if commit in ancestry:
+                return commit
+        return None
+
+    @staticmethod
+    def commit_timestamp(commit_id):
+        """Return the timestamp of the given commit."""
+        text = subprocess.check_output(['git', 'show', '-s',
+                                        '--format=%ct',
+                                        commit_id])
+        return datetime.datetime.utcfromtimestamp(int(text))
+
+    @staticmethod
+    def file_timestamp(filename):
+        """Return the modification timestamp of the given file."""
+        mtime = os.stat(filename).st_mtime
+        return datetime.datetime.fromtimestamp(mtime)
+
+    def __init__(self, filename):
+        """Determine position of the file in the changelog entry order.
+
+        This constructor returns an object that can be used with comparison
+        operators, with `sort` and `sorted`, etc. Older entries are sorted
+        before newer entries.
+        """
+        self.filename = filename
+        creation_hash = self.creation_hash(filename)
+        if not creation_hash:
+            self.category = self.LOCAL
+            self.datetime = self.file_timestamp(filename)
+            return
+        merge_hash = self.merge_hash(creation_hash)
+        if not merge_hash:
+            self.category = self.COMMITTED
+            self.datetime = self.commit_timestamp(creation_hash)
+            return
+        self.category = self.MERGED
+        self.datetime = self.commit_timestamp(merge_hash)
+
+    def sort_key(self):
+        """"Return a concrete sort key for this entry file sort key object.
+
+        ``ts1 < ts2`` is implemented as ``ts1.sort_key() < ts2.sort_key()``.
+        """
+        return (self.category, self.datetime, self.filename)
+
+    def __eq__(self, other):
+        return self.sort_key() == other.sort_key()
+
+    def __lt__(self, other):
+        return self.sort_key() < other.sort_key()
+
+
+def check_output(generated_output_file, main_input_file, merged_files):
+    """Make sanity checks on the generated output.
+
+    The intent of these sanity checks is to have reasonable confidence
+    that no content has been lost.
+
+    The sanity check is that every line that is present in an input file
+    is also present in an output file. This is not perfect but good enough
+    for now.
+    """
+    generated_output = set(open(generated_output_file, 'rb'))
+    for line in open(main_input_file, 'rb'):
+        if line not in generated_output:
+            raise LostContent('original file', line)
+    for merged_file in merged_files:
+        for line in open(merged_file, 'rb'):
+            if line not in generated_output:
+                raise LostContent(merged_file, line)
+
+def finish_output(changelog, output_file, input_file, merged_files):
+    """Write the changelog to the output file.
+
+    The input file and the list of merged files are used only for sanity
+    checks on the output.
+    """
+    if os.path.exists(output_file) and not os.path.isfile(output_file):
+        # The output is a non-regular file (e.g. pipe). Write to it directly.
+        output_temp = output_file
+    else:
+        # The output is a regular file. Write to a temporary file,
+        # then move it into place atomically.
+        output_temp = output_file + '.tmp'
+    changelog.write(output_temp)
+    check_output(output_temp, input_file, merged_files)
+    if output_temp != output_file:
+        os.rename(output_temp, output_file)
+
+def remove_merged_entries(files_to_remove):
+    for filename in files_to_remove:
+        os.remove(filename)
+
+def list_files_to_merge(options):
+    """List the entry files to merge, oldest first.
+
+    "Oldest" is defined by `EntryFileSortKey`.
+    """
+    files_to_merge = glob.glob(os.path.join(options.dir, '*.txt'))
+    files_to_merge.sort(key=EntryFileSortKey)
+    return files_to_merge
+
+def merge_entries(options):
+    """Merge changelog entries into the changelog file.
+
+    Read the changelog file from options.input.
+    Read entries to merge from the directory options.dir.
+    Write the new changelog to options.output.
+    Remove the merged entries if options.keep_entries is false.
+    """
+    with open(options.input, 'rb') as input_file:
+        changelog = ChangeLog(input_file, TextChangelogFormat)
+    files_to_merge = list_files_to_merge(options)
+    if not files_to_merge:
+        sys.stderr.write('There are no pending changelog entries.\n')
+        return
+    for filename in files_to_merge:
+        with open(filename, 'rb') as input_file:
+            changelog.add_file(input_file)
+    finish_output(changelog, options.output, options.input, files_to_merge)
+    if not options.keep_entries:
+        remove_merged_entries(files_to_merge)
+
+def show_file_timestamps(options):
+    """List the files to merge and their timestamp.
+
+    This is only intended for debugging purposes.
+    """
+    files = list_files_to_merge(options)
+    for filename in files:
+        ts = EntryFileSortKey(filename)
+        print(ts.category, ts.datetime, filename)
+
+def set_defaults(options):
+    """Add default values for missing options."""
+    output_file = getattr(options, 'output', None)
+    if output_file is None:
+        options.output = options.input
+    if getattr(options, 'keep_entries', None) is None:
+        options.keep_entries = (output_file is not None)
+
+def main():
+    """Command line entry point."""
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--dir', '-d', metavar='DIR',
+                        default='ChangeLog.d',
+                        help='Directory to read entries from'
+                             ' (default: ChangeLog.d)')
+    parser.add_argument('--input', '-i', metavar='FILE',
+                        default='ChangeLog',
+                        help='Existing changelog file to read from and augment'
+                             ' (default: ChangeLog)')
+    parser.add_argument('--keep-entries',
+                        action='store_true', dest='keep_entries', default=None,
+                        help='Keep the files containing entries'
+                             ' (default: remove them if --output/-o is not specified)')
+    parser.add_argument('--no-keep-entries',
+                        action='store_false', dest='keep_entries',
+                        help='Remove the files containing entries after they are merged'
+                             ' (default: remove them if --output/-o is not specified)')
+    parser.add_argument('--output', '-o', metavar='FILE',
+                        help='Output changelog file'
+                             ' (default: overwrite the input)')
+    parser.add_argument('--list-files-only',
+                        action='store_true',
+                        help=('Only list the files that would be processed '
+                              '(with some debugging information)'))
+    options = parser.parse_args()
+    set_defaults(options)
+    if options.list_files_only:
+        show_file_timestamps(options)
+        return
+    merge_entries(options)
+
+if __name__ == '__main__':
+    main()
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 35f742f..9b6eee1 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -7279,8 +7279,8 @@
 
 not_with_valgrind # spurious resend
 run_test    "DTLS client reconnect from same port: reference" \
-            "$P_SRV dtls=1 exchanges=2 read_timeout=1000" \
-            "$P_CLI dtls=1 exchanges=2 debug_level=2 hs_timeout=500-1000" \
+            "$P_SRV dtls=1 exchanges=2 read_timeout=20000 hs_timeout=10000-20000" \
+            "$P_CLI dtls=1 exchanges=2 debug_level=2 hs_timeout=10000-20000" \
             0 \
             -C "resend" \
             -S "The operation timed out" \
@@ -7288,8 +7288,8 @@
 
 not_with_valgrind # spurious resend
 run_test    "DTLS client reconnect from same port: reconnect" \
-            "$P_SRV dtls=1 exchanges=2 read_timeout=1000" \
-            "$P_CLI dtls=1 exchanges=2 debug_level=2 hs_timeout=500-1000 reconnect_hard=1" \
+            "$P_SRV dtls=1 exchanges=2 read_timeout=20000 hs_timeout=10000-20000" \
+            "$P_CLI dtls=1 exchanges=2 debug_level=2 hs_timeout=10000-20000 reconnect_hard=1" \
             0 \
             -C "resend" \
             -S "The operation timed out" \
@@ -7318,6 +7318,14 @@
             -s "The operation timed out" \
             -S "Client initiated reconnection from same port"
 
+run_test    "DTLS client reconnect from same port: attacker-injected" \
+            -p "$P_PXY inject_clihlo=1" \
+            "$P_SRV dtls=1 exchanges=2 debug_level=1" \
+            "$P_CLI dtls=1 exchanges=2" \
+            0 \
+            -s "possible client reconnect from the same port" \
+            -S "Client initiated reconnection from same port"
+
 # Tests for various cases of client authentication with DTLS
 # (focused on handshake flows and message parsing)
 
@@ -8387,8 +8395,8 @@
 not_with_valgrind # spurious resend due to timeout
 run_test    "DTLS proxy: reference" \
             -p "$P_PXY" \
-            "$P_SRV dtls=1 debug_level=2" \
-            "$P_CLI dtls=1 debug_level=2" \
+            "$P_SRV dtls=1 debug_level=2 hs_timeout=10000-20000" \
+            "$P_CLI dtls=1 debug_level=2 hs_timeout=10000-20000" \
             0 \
             -C "replayed record" \
             -S "replayed record" \
@@ -8405,8 +8413,8 @@
 not_with_valgrind # spurious resend due to timeout
 run_test    "DTLS proxy: duplicate every packet" \
             -p "$P_PXY duplicate=1" \
-            "$P_SRV dtls=1 dgram_packing=0 debug_level=2" \
-            "$P_CLI dtls=1 dgram_packing=0 debug_level=2" \
+            "$P_SRV dtls=1 dgram_packing=0 debug_level=2 hs_timeout=10000-20000" \
+            "$P_CLI dtls=1 dgram_packing=0 debug_level=2 hs_timeout=10000-20000" \
             0 \
             -c "replayed record" \
             -s "replayed record" \
diff --git a/tests/suites/host_test.function b/tests/suites/host_test.function
index 6467340..1069c24 100644
--- a/tests/suites/host_test.function
+++ b/tests/suites/host_test.function
@@ -425,7 +425,7 @@
  */
 static void write_outcome_result( FILE *outcome_file,
                                   size_t unmet_dep_count,
-                                  char *unmet_dependencies[],
+                                  int unmet_dependencies[],
                                   int ret,
                                   const test_info_t *info )
 {
@@ -443,7 +443,7 @@
                 mbedtls_fprintf( outcome_file, "SKIP" );
                 for( i = 0; i < unmet_dep_count; i++ )
                 {
-                    mbedtls_fprintf( outcome_file, "%c%s",
+                    mbedtls_fprintf( outcome_file, "%c%d",
                                      i == 0 ? ';' : ':',
                                      unmet_dependencies[i] );
                 }
@@ -598,7 +598,7 @@
           testfile_index++ )
     {
         size_t unmet_dep_count = 0;
-        char *unmet_dependencies[20];
+        int unmet_dependencies[20];
 
         test_filename = test_files[ testfile_index ];
 
@@ -647,19 +647,7 @@
                     int dep_id = strtol( params[i], NULL, 10 );
                     if( dep_check( dep_id ) != DEPENDENCY_SUPPORTED )
                     {
-                        if( 0 == option_verbose )
-                        {
-                            /* Only one count is needed if not verbose */
-                            unmet_dep_count++;
-                            break;
-                        }
-
-                        unmet_dependencies[ unmet_dep_count ] = strdup( params[i] );
-                        if(  unmet_dependencies[ unmet_dep_count ] == NULL )
-                        {
-                            mbedtls_fprintf( stderr, "FATAL: Out of memory\n" );
-                            mbedtls_exit( MBEDTLS_EXIT_FAILURE );
-                        }
+                        unmet_dependencies[unmet_dep_count] = dep_id;
                         unmet_dep_count++;
                     }
                 }
@@ -730,9 +718,8 @@
                     mbedtls_fprintf( stdout, "\n   Unmet dependencies: " );
                     for( i = 0; i < unmet_dep_count; i++ )
                     {
-                        mbedtls_fprintf( stdout, "%s  ",
+                        mbedtls_fprintf( stdout, "%d ",
                                         unmet_dependencies[i] );
-                        free( unmet_dependencies[i] );
                     }
                 }
                 mbedtls_fprintf( stdout, "\n" );
@@ -783,10 +770,6 @@
                 total_errors++;
         }
         fclose( file );
-
-        /* In case we encounter early end of file */
-        for( i = 0; i < unmet_dep_count; i++ )
-            free( unmet_dependencies[i] );
     }
 
     if( outcome_file != NULL )
diff --git a/tests/suites/test_suite_cipher.aes.data b/tests/suites/test_suite_cipher.aes.data
index 6293408..4dbdd52 100644
--- a/tests/suites/test_suite_cipher.aes.data
+++ b/tests/suites/test_suite_cipher.aes.data
@@ -1062,6 +1062,10 @@
 depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
 enc_dec_buf_multipart:MBEDTLS_CIPHER_AES_192_CBC:192:16:16:-1:16:16:0:32
 
+AES-256 CBC - Decrypt empty buffer
+depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
+dec_empty_buf:MBEDTLS_CIPHER_AES_256_CBC:0:0
+
 AES-256 CBC - Encrypt and decrypt 0 bytes with PKCS7 padding
 depends_on:MBEDTLS_AES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
 enc_dec_buf:MBEDTLS_CIPHER_AES_256_CBC:"AES-256-CBC":256:0:-1
diff --git a/tests/suites/test_suite_cipher.camellia.data b/tests/suites/test_suite_cipher.camellia.data
index 667f424..3e7bffa 100644
--- a/tests/suites/test_suite_cipher.camellia.data
+++ b/tests/suites/test_suite_cipher.camellia.data
@@ -1,7 +1,11 @@
-CAMELLIA CBC Decrypt empty buffer
+CAMELLIA-128 CBC - Decrypt empty buffer
 depends_on:MBEDTLS_CAMELLIA_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
 dec_empty_buf:MBEDTLS_CIPHER_CAMELLIA_128_CBC:0:0
 
+CAMELLIA-256 CBC - Decrypt empty buffer
+depends_on:MBEDTLS_CAMELLIA_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
+dec_empty_buf:MBEDTLS_CIPHER_CAMELLIA_256_CBC:0:0
+
 CAMELLIA Encrypt and decrypt 0 bytes [#1]
 depends_on:MBEDTLS_CAMELLIA_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_CIPHER_PADDING_PKCS7
 enc_dec_buf:MBEDTLS_CIPHER_CAMELLIA_128_CBC:"CAMELLIA-128-CBC":128:0:-1
diff --git a/tests/suites/test_suite_cipher.gcm.data b/tests/suites/test_suite_cipher.gcm.data
index c526b2e..8d728bd 100644
--- a/tests/suites/test_suite_cipher.gcm.data
+++ b/tests/suites/test_suite_cipher.gcm.data
@@ -2,6 +2,10 @@
 depends_on:MBEDTLS_CAMELLIA_C:MBEDTLS_GCM_C
 dec_empty_buf:MBEDTLS_CIPHER_CAMELLIA_128_GCM:0:0
 
+AES GCM Decrypt empty buffer
+depends_on:MBEDTLS_CIPHER_AES_128_GCM:MBEDTLS_GCM_C
+dec_empty_buf:MBEDTLS_CIPHER_AES_128_GCM:0:0
+
 Aria GCM Decrypt empty buffer
 depends_on:MBEDTLS_ARIA_C:MBEDTLS_GCM_C
 dec_empty_buf:MBEDTLS_CIPHER_ARIA_128_GCM:0:0
diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index b6e6e5a..bc95f6f 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -5297,6 +5297,8 @@
     size_t i;
     unsigned run;
 
+    TEST_ASSERT( bytes_arg >= 0 );
+
     ASSERT_ALLOC( output, bytes + sizeof( trail ) );
     ASSERT_ALLOC( changed, bytes );
     memcpy( output + bytes, trail, sizeof( trail ) );