Merge remote-tracking branch 'origin/pr/2738' into development

* origin/pr/2738:
  Test with MBEDTLS_ECP_RESTARTABLE
diff --git a/.gitignore b/.gitignore
index 789f57e..0f95b4c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -31,6 +31,17 @@
 # Python build artifacts:
 *.pyc
 
+# CMake generates *.dir/ folders for in-tree builds (used by MSVC projects), ignore all of those:
+*.dir/
+
+# Visual Studio artifacts
+/visualc/VS2010/.localhistory/
+/visualc/VS2010/.vs/
+/visualc/VS2010/Debug/
+/visualc/VS2010/Release/
+/visualc/VS2010/*.vcxproj.filters
+/visualc/VS2010/*.vcxproj.user
+
 # Generated documentation:
 /apidoc
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 38c8006..67ec7cc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,8 @@
     project("mbed TLS" C)
 endif()
 
+set(MBEDTLS_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+
 option(USE_PKCS11_HELPER_LIBRARY "Build mbed TLS with the pkcs11-helper library." OFF)
 option(ENABLE_ZLIB_SUPPORT "Build mbed TLS with zlib library." OFF)
 
@@ -127,7 +129,10 @@
     # note: starting with CMake 2.8 we could use CMAKE_C_COMPILER_VERSION
     execute_process(COMMAND ${CMAKE_C_COMPILER} -dumpversion
                     OUTPUT_VARIABLE GCC_VERSION)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -W -Wdeclaration-after-statement -Wwrite-strings")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wwrite-strings")
+    if (GCC_VERSION VERSION_GREATER 4.3 OR GCC_VERSION VERSION_EQUAL 4.3)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wvla")
+    endif()
     if (GCC_VERSION VERSION_GREATER 4.5 OR GCC_VERSION VERSION_EQUAL 4.5)
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wlogical-op")
     endif()
@@ -144,7 +149,7 @@
 endif(CMAKE_COMPILER_IS_GNU)
 
 if(CMAKE_COMPILER_IS_CLANG)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -W -Wdeclaration-after-statement -Wwrite-strings -Wpointer-arith -Wimplicit-fallthrough -Wshadow")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wwrite-strings -Wpointer-arith -Wimplicit-fallthrough -Wshadow -Wvla")
     set(CMAKE_C_FLAGS_RELEASE     "-O2")
     set(CMAKE_C_FLAGS_DEBUG       "-O0 -g3")
     set(CMAKE_C_FLAGS_COVERAGE    "-O0 -g3 --coverage")
diff --git a/ChangeLog b/ChangeLog
index a461008..20491ed 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -74,6 +74,11 @@
      irwir.
    * Enable Suite B with subset of ECP curves. Make sure the code compiles even
      if some curves are not defined. Fixes #1591 reported by dbedev.
+   * Fix misuse of signed arithmetic in the HAVEGE module. #2598
+   * Avoid use of statically sized stack buffers for certificate writing.
+     This previously limited the maximum size of DER encoded certificates
+     in mbedtls_x509write_crt_der() to 2Kb. Reported by soccerGB in #2631.
+   * Fix partial zeroing in x509_get_other_name. Found and fixed by ekse, #2716.
 
 API Changes
    * Extend the MBEDTLS_SSL_EXPORT_KEYS to export the handshake randbytes,
@@ -82,6 +87,7 @@
    * Add DER-encoded test CRTs to library/certs.c, allowing
      the example programs ssl_server2 and ssl_client2 to be run
      if MBEDTLS_FS_IO and MBEDTLS_PEM_PARSE_C are unset. Fixes #2254.
+   * The HAVEGE state type now uses uint32_t elements instead of int.
 
 Changes
    * Server's RSA certificate in certs.c was SHA-1 signed. In the default
@@ -103,6 +109,25 @@
    * Make it easier to define MBEDTLS_PARAM_FAILED as assert (which config.h
      suggests). #2671
    * Make `make clean` clean all programs always. Fixes #1862.
+   * Add a Dockerfile and helper scripts (all-in-docker.sh, basic-in-docker.sh,
+     docker-env.sh) to simplify running test suites on a Linux host. Contributed
+     by Peter Kolbus (Garmin).
+   * Enable building of Mbed TLS as a CMake subproject. Suggested and fixed by
+     Ashley Duncan in #2609.
+   * Add `reproducible` option to `ssl_client2` and `ssl_server2` to enable
+     test runs without variability. Contributed by Philippe Antoine (Catena
+     cyber) in #2681.
+   * Extended .gitignore to ignore Visual Studio artifacts. Fixed by ConfusedSushi.
+   * Enable building of Mbed TLS as a CMake subproject. Suggested and fixed by
+     Ashley Duncan in #2609.
+   * Add `reproducible` option to `ssl_client2` and `ssl_server2` to enable
+     test runs without variability. Contributed by Philippe Antoine (Catena
+     cyber) in #2681.
+   * Enable building of Mbed TLS as a CMake subproject. Suggested and fixed by
+     Ashley Duncan in #2609.
+   * Add `reproducible` option to `ssl_client2` and `ssl_server2` to enable
+     test runs without variability. Contributed by Philippe Antoine (Catena
+     cyber) in #2681.
 
 = mbed TLS 2.17.0 branch released 2019-03-19
 
diff --git a/README.md b/README.md
index 5b01603..83b3234 100644
--- a/README.md
+++ b/README.md
@@ -64,7 +64,7 @@
 
 Setting the variable `SHARED` in your environment will build shared libraries in addition to the static libraries. Setting `DEBUG` gives you a debug build. You can override `CFLAGS` and `LDFLAGS` by setting them in your environment or on the make command line; compiler warning options may be overridden separately using `WARNING_CFLAGS`. Some directory-specific options (for example, `-I` directives) are still preserved.
 
-Please note that setting `CFLAGS` overrides its default value of `-O2` and setting `WARNING_CFLAGS` overrides its default value (starting with `-Wall -W`), so if you just want to add some warning options to the default ones, you can do so by setting `CFLAGS=-O2 -Werror` for example. Setting `WARNING_CFLAGS` is useful when you want to get rid of its default content (for example because your compiler doesn't accept `-Wall` as an option). Directory-specific options cannot be overridden from the command line.
+Please note that setting `CFLAGS` overrides its default value of `-O2` and setting `WARNING_CFLAGS` overrides its default value (starting with `-Wall -Wextra`), so if you just want to add some warning options to the default ones, you can do so by setting `CFLAGS=-O2 -Werror` for example. Setting `WARNING_CFLAGS` is useful when you want to get rid of its default content (for example because your compiler doesn't accept `-Wall` as an option). Directory-specific options cannot be overridden from the command line.
 
 Depending on your platform, you might run into some issues. Please check the Makefiles in `library/`, `programs/` and `tests/` for options to manually add or remove for specific platforms. You can also check [the Mbed TLS Knowledge Base](https://tls.mbed.org/kb) for articles on your platform or issue.
 
@@ -146,6 +146,12 @@
 your value of CFLAGS doesn't override the content provided by cmake (depending
 on the build mode as seen above), it's merely prepended to it.
 
+#### Mbed TLS as a subproject
+
+Mbed TLS, like Mbed Crypto, supports being built as a CMake subproject. One can
+use `add_subdirectory()` from a parent CMake project to include Mbed TLS as a
+subproject.
+
 ### Microsoft Visual Studio
 
 The build files for Microsoft Visual Studio are generated for Visual Studio 2010.
diff --git a/crypto b/crypto
index 86268e1..b6229e3 160000
--- a/crypto
+++ b/crypto
@@ -1 +1 @@
-Subproject commit 86268e1d302355ad8fd8e5ca5f1a7c7af8640678
+Subproject commit b6229e304e69e672dec653700467c696d32d19ae
diff --git a/include/mbedtls/havege.h b/include/mbedtls/havege.h
index 4c1c860..749257a 100644
--- a/include/mbedtls/havege.h
+++ b/include/mbedtls/havege.h
@@ -31,6 +31,7 @@
 #endif
 
 #include <stddef.h>
+#include <stdint.h>
 
 #define MBEDTLS_HAVEGE_COLLECT_SIZE 1024
 
@@ -43,9 +44,9 @@
  */
 typedef struct mbedtls_havege_state
 {
-    int PT1, PT2, offset[2];
-    int pool[MBEDTLS_HAVEGE_COLLECT_SIZE];
-    int WALK[8192];
+    uint32_t PT1, PT2, offset[2];
+    uint32_t pool[MBEDTLS_HAVEGE_COLLECT_SIZE];
+    uint32_t WALK[8192];
 }
 mbedtls_havege_state;
 
diff --git a/include/mbedtls/pem.h b/include/mbedtls/pem.h
index a29e9ce..b37f987 100644
--- a/include/mbedtls/pem.h
+++ b/include/mbedtls/pem.h
@@ -112,17 +112,27 @@
  * \brief           Write a buffer of PEM information from a DER encoded
  *                  buffer.
  *
- * \param header    header string to write
- * \param footer    footer string to write
- * \param der_data  DER data to write
- * \param der_len   length of the DER data
- * \param buf       buffer to write to
- * \param buf_len   length of output buffer
- * \param olen      total length written / required (if buf_len is not enough)
+ * \param header    The header string to write.
+ * \param footer    The footer string to write.
+ * \param der_data  The DER data to encode.
+ * \param der_len   The length of the DER data \p der_data in Bytes.
+ * \param buf       The buffer to write to.
+ * \param buf_len   The length of the output buffer \p buf in Bytes.
+ * \param olen      The address at which to store the total length written
+ *                  or required (if \p buf_len is not enough).
  *
- * \return          0 on success, or a specific PEM or BASE64 error code. On
- *                  MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL olen is the required
- *                  size.
+ * \note            You may pass \c NULL for \p buf and \c 0 for \p buf_len
+ *                  to request the length of the resulting PEM buffer in
+ *                  `*olen`.
+ *
+ * \note            This function may be called with overlapping \p der_data
+ *                  and \p buf buffers.
+ *
+ * \return          \c 0 on success.
+ * \return          #MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL if \p buf isn't large
+ *                  enough to hold the PEM buffer. In  this case, `*olen` holds
+ *                  the required minimum size of \p buf.
+ * \return          Another PEM or BASE64 error code on other kinds of failure.
  */
 int mbedtls_pem_write_buffer( const char *header, const char *footer,
                       const unsigned char *der_data, size_t der_len,
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 1004cb3..7f0819e 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -151,15 +151,15 @@
     set_target_properties(${mbedx509_static_target} PROPERTIES OUTPUT_NAME mbedx509)
     target_link_libraries(${mbedx509_static_target} ${libs} ${mbedcrypto_static_target})
     target_include_directories(${mbedx509_static_target}
-        PUBLIC ${CMAKE_SOURCE_DIR}/include/
-        PUBLIC ${CMAKE_SOURCE_DIR}/crypto/include/)
+        PUBLIC ${MBEDTLS_DIR}/include/
+        PUBLIC ${MBEDTLS_DIR}/crypto/include/)
 
     add_library(${mbedtls_static_target} STATIC ${src_tls})
     set_target_properties(${mbedtls_static_target} PROPERTIES OUTPUT_NAME mbedtls)
     target_link_libraries(${mbedtls_static_target} ${libs} ${mbedx509_static_target})
     target_include_directories(${mbedtls_static_target}
-        PUBLIC ${CMAKE_SOURCE_DIR}/include/
-        PUBLIC ${CMAKE_SOURCE_DIR}/crypto/include/
+        PUBLIC ${MBEDTLS_DIR}/include/
+        PUBLIC ${MBEDTLS_DIR}/crypto/include/
         )
 
 
@@ -175,15 +175,15 @@
     set_target_properties(mbedx509 PROPERTIES VERSION 2.17.0 SOVERSION 0)
     target_link_libraries(mbedx509 ${libs} mbedcrypto)
     target_include_directories(mbedx509
-        PUBLIC ${CMAKE_SOURCE_DIR}/include/
-        PUBLIC ${CMAKE_SOURCE_DIR}/crypto/include/)
+        PUBLIC ${MBEDTLS_DIR}/include/
+        PUBLIC ${MBEDTLS_DIR}/crypto/include/)
 
     add_library(mbedtls SHARED ${src_tls})
     set_target_properties(mbedtls PROPERTIES VERSION 2.17.0 SOVERSION 12)
     target_link_libraries(mbedtls ${libs} mbedx509)
     target_include_directories(mbedtls
-        PUBLIC ${CMAKE_SOURCE_DIR}/include/
-        PUBLIC ${CMAKE_SOURCE_DIR}/crypto/include/)
+        PUBLIC ${MBEDTLS_DIR}/include/
+        PUBLIC ${MBEDTLS_DIR}/crypto/include/)
 
       install(TARGETS mbedtls mbedx509
               DESTINATION ${LIB_INSTALL_DIR}
diff --git a/library/Makefile b/library/Makefile
index 60f3ae0..8b2e572 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -2,7 +2,7 @@
 # Also see "include/mbedtls/config.h"
 
 CFLAGS	?= -O2
-WARNING_CFLAGS ?=  -Wall -W -Wdeclaration-after-statement
+WARNING_CFLAGS ?=  -Wall -Wextra
 LDFLAGS ?=
 
 LOCAL_CFLAGS = $(WARNING_CFLAGS) -I../include -D_FILE_OFFSET_BITS=64
diff --git a/library/x509_crt.c b/library/x509_crt.c
index d101bc7..b2c19db 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1687,7 +1687,7 @@
 
     if( p + len >= end )
     {
-        mbedtls_platform_zeroize( other_name, sizeof( other_name ) );
+        mbedtls_platform_zeroize( other_name, sizeof( *other_name ) );
         return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
     }
@@ -1709,7 +1709,7 @@
 
     if( p + len >= end )
     {
-        mbedtls_platform_zeroize( other_name, sizeof( other_name ) );
+        mbedtls_platform_zeroize( other_name, sizeof( *other_name ) );
         return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
     }
@@ -1725,7 +1725,7 @@
     if( p != end )
     {
         mbedtls_platform_zeroize( other_name,
-                                  sizeof( other_name ) );
+                                  sizeof( *other_name ) );
         return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH );
     }
diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index b6cb745..3c23214 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -64,39 +64,44 @@
     mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x509write_cert ) );
 }
 
-void mbedtls_x509write_crt_set_version( mbedtls_x509write_cert *ctx, int version )
+void mbedtls_x509write_crt_set_version( mbedtls_x509write_cert *ctx,
+                                        int version )
 {
     ctx->version = version;
 }
 
-void mbedtls_x509write_crt_set_md_alg( mbedtls_x509write_cert *ctx, mbedtls_md_type_t md_alg )
+void mbedtls_x509write_crt_set_md_alg( mbedtls_x509write_cert *ctx,
+                                       mbedtls_md_type_t md_alg )
 {
     ctx->md_alg = md_alg;
 }
 
-void mbedtls_x509write_crt_set_subject_key( mbedtls_x509write_cert *ctx, mbedtls_pk_context *key )
+void mbedtls_x509write_crt_set_subject_key( mbedtls_x509write_cert *ctx,
+                                            mbedtls_pk_context *key )
 {
     ctx->subject_key = key;
 }
 
-void mbedtls_x509write_crt_set_issuer_key( mbedtls_x509write_cert *ctx, mbedtls_pk_context *key )
+void mbedtls_x509write_crt_set_issuer_key( mbedtls_x509write_cert *ctx,
+                                           mbedtls_pk_context *key )
 {
     ctx->issuer_key = key;
 }
 
 int mbedtls_x509write_crt_set_subject_name( mbedtls_x509write_cert *ctx,
-                                    const char *subject_name )
+                                            const char *subject_name )
 {
     return mbedtls_x509_string_to_names( &ctx->subject, subject_name );
 }
 
 int mbedtls_x509write_crt_set_issuer_name( mbedtls_x509write_cert *ctx,
-                                   const char *issuer_name )
+                                           const char *issuer_name )
 {
     return mbedtls_x509_string_to_names( &ctx->issuer, issuer_name );
 }
 
-int mbedtls_x509write_crt_set_serial( mbedtls_x509write_cert *ctx, const mbedtls_mpi *serial )
+int mbedtls_x509write_crt_set_serial( mbedtls_x509write_cert *ctx,
+                                      const mbedtls_mpi *serial )
 {
     int ret;
 
@@ -106,8 +111,9 @@
     return( 0 );
 }
 
-int mbedtls_x509write_crt_set_validity( mbedtls_x509write_cert *ctx, const char *not_before,
-                                const char *not_after )
+int mbedtls_x509write_crt_set_validity( mbedtls_x509write_cert *ctx,
+                                        const char *not_before,
+                                        const char *not_after )
 {
     if( strlen( not_before ) != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 ||
         strlen( not_after )  != MBEDTLS_X509_RFC5280_UTC_TIME_LEN - 1 )
@@ -127,12 +133,12 @@
                                  int critical,
                                  const unsigned char *val, size_t val_len )
 {
-    return mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,
-                               critical, val, val_len );
+    return( mbedtls_x509_set_extension( &ctx->extensions, oid, oid_len,
+                                        critical, val, val_len ) );
 }
 
 int mbedtls_x509write_crt_set_basic_constraints( mbedtls_x509write_cert *ctx,
-                                         int is_ca, int max_pathlen )
+                                                 int is_ca, int max_pathlen )
 {
     int ret;
     unsigned char buf[9];
@@ -148,18 +154,21 @@
     {
         if( max_pathlen >= 0 )
         {
-            MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf, max_pathlen ) );
+            MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_int( &c, buf,
+                                                               max_pathlen ) );
         }
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_bool( &c, buf, 1 ) );
     }
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf,
+                                                MBEDTLS_ASN1_CONSTRUCTED |
                                                 MBEDTLS_ASN1_SEQUENCE ) );
 
-    return mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_BASIC_CONSTRAINTS,
-                                        MBEDTLS_OID_SIZE( MBEDTLS_OID_BASIC_CONSTRAINTS ),
-                                        0, buf + sizeof(buf) - len, len );
+    return(
+        mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_BASIC_CONSTRAINTS,
+                             MBEDTLS_OID_SIZE( MBEDTLS_OID_BASIC_CONSTRAINTS ),
+                             0, buf + sizeof(buf) - len, len ) );
 }
 
 #if defined(MBEDTLS_SHA1_C)
@@ -171,7 +180,8 @@
     size_t len = 0;
 
     memset( buf, 0, sizeof(buf) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, ctx->subject_key ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+                mbedtls_pk_write_pubkey( &c, buf, ctx->subject_key ) );
 
     ret = mbedtls_sha1_ret( buf + sizeof( buf ) - len, len,
                             buf + sizeof( buf ) - 20 );
@@ -181,11 +191,13 @@
     len = 20;
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_OCTET_STRING ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+            mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_OCTET_STRING ) );
 
-    return mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER,
-                                        MBEDTLS_OID_SIZE( MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER ),
-                                        0, buf + sizeof(buf) - len, len );
+    return mbedtls_x509write_crt_set_extension( ctx,
+                 MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER,
+                 MBEDTLS_OID_SIZE( MBEDTLS_OID_SUBJECT_KEY_IDENTIFIER ),
+                 0, buf + sizeof(buf) - len, len );
 }
 
 int mbedtls_x509write_crt_set_authority_key_identifier( mbedtls_x509write_cert *ctx )
@@ -196,7 +208,8 @@
     size_t len = 0;
 
     memset( buf, 0, sizeof(buf) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, ctx->issuer_key ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+                          mbedtls_pk_write_pubkey( &c, buf, ctx->issuer_key ) );
 
     ret = mbedtls_sha1_ret( buf + sizeof( buf ) - len, len,
                             buf + sizeof( buf ) - 20 );
@@ -206,15 +219,19 @@
     len = 20;
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | 0 ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+        mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC | 0 ) );
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                MBEDTLS_ASN1_SEQUENCE ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+                          mbedtls_asn1_write_tag( &c, buf,
+                                                  MBEDTLS_ASN1_CONSTRUCTED |
+                                                  MBEDTLS_ASN1_SEQUENCE ) );
 
-    return mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER,
-                                   MBEDTLS_OID_SIZE( MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER ),
-                                   0, buf + sizeof( buf ) - len, len );
+    return mbedtls_x509write_crt_set_extension(
+        ctx, MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER,
+        MBEDTLS_OID_SIZE( MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER ),
+        0, buf + sizeof( buf ) - len, len );
 }
 #endif /* MBEDTLS_SHA1_C */
 
@@ -249,8 +266,8 @@
         return( MBEDTLS_ERR_X509_INVALID_FORMAT );
 
     ret = mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_KEY_USAGE,
-                                       MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),
-                                       1, c, (size_t)ret );
+                                   MBEDTLS_OID_SIZE( MBEDTLS_OID_KEY_USAGE ),
+                                   1, c, (size_t)ret );
     if( ret != 0 )
         return( ret );
 
@@ -271,8 +288,8 @@
         return( ret );
 
     ret = mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_NS_CERT_TYPE,
-                                       MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),
-                                       0, c, (size_t)ret );
+                                   MBEDTLS_OID_SIZE( MBEDTLS_OID_NS_CERT_TYPE ),
+                                   0, c, (size_t)ret );
     if( ret != 0 )
         return( ret );
 
@@ -294,7 +311,8 @@
                                              (const unsigned char *) t + 2,
                                              size - 2 ) );
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_UTC_TIME ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
+                                             MBEDTLS_ASN1_UTC_TIME ) );
     }
     else
     {
@@ -302,15 +320,17 @@
                                                   (const unsigned char *) t,
                                                   size ) );
         MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_GENERALIZED_TIME ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
+                                             MBEDTLS_ASN1_GENERALIZED_TIME ) );
     }
 
     return( (int) len );
 }
 
-int mbedtls_x509write_crt_der( mbedtls_x509write_cert *ctx, unsigned char *buf, size_t size,
-                       int (*f_rng)(void *, unsigned char *, size_t),
-                       void *p_rng )
+int mbedtls_x509write_crt_der( mbedtls_x509write_cert *ctx,
+                               unsigned char *buf, size_t size,
+                               int (*f_rng)(void *, unsigned char *, size_t),
+                               void *p_rng )
 {
     int ret;
     const char *sig_oid;
@@ -318,15 +338,14 @@
     unsigned char *c, *c2;
     unsigned char hash[64];
     unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
-    unsigned char tmp_buf[2048];
     size_t sub_len = 0, pub_len = 0, sig_and_oid_len = 0, sig_len;
     size_t len = 0;
     mbedtls_pk_type_t pk_alg;
 
     /*
-     * Prepare data to be signed in tmp_buf
+     * Prepare data to be signed at the end of the target buffer
      */
-    c = tmp_buf + sizeof( tmp_buf );
+    c = buf + size;
 
     /* Signature algorithm needed in TBS, and later for actual signature */
 
@@ -352,27 +371,36 @@
     /* Only for v3 */
     if( ctx->version == MBEDTLS_X509_CRT_VERSION_3 )
     {
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                           MBEDTLS_ASN1_SEQUENCE ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
-                                                           MBEDTLS_ASN1_CONSTRUCTED | 3 ) );
+        MBEDTLS_ASN1_CHK_ADD( len,
+                              mbedtls_x509_write_extensions( &c,
+                                                      buf, ctx->extensions ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+        MBEDTLS_ASN1_CHK_ADD( len,
+                              mbedtls_asn1_write_tag( &c, buf,
+                                                      MBEDTLS_ASN1_CONSTRUCTED |
+                                                      MBEDTLS_ASN1_SEQUENCE ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+        MBEDTLS_ASN1_CHK_ADD( len,
+                              mbedtls_asn1_write_tag( &c, buf,
+                                               MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+                                               MBEDTLS_ASN1_CONSTRUCTED | 3 ) );
     }
 
     /*
      *  SubjectPublicKeyInfo
      */
-    MBEDTLS_ASN1_CHK_ADD( pub_len, mbedtls_pk_write_pubkey_der( ctx->subject_key,
-                                                tmp_buf, c - tmp_buf ) );
+    MBEDTLS_ASN1_CHK_ADD( pub_len,
+                          mbedtls_pk_write_pubkey_der( ctx->subject_key,
+                                                       buf, c - buf ) );
     c -= pub_len;
     len += pub_len;
 
     /*
      *  Subject  ::=  Name
      */
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->subject ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+                          mbedtls_x509_write_names( &c, buf,
+                                                    ctx->subject ) );
 
     /*
      *  Validity ::= SEQUENCE {
@@ -381,32 +409,39 @@
      */
     sub_len = 0;
 
-    MBEDTLS_ASN1_CHK_ADD( sub_len, x509_write_time( &c, tmp_buf, ctx->not_after,
-                                            MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
+    MBEDTLS_ASN1_CHK_ADD( sub_len,
+                          x509_write_time( &c, buf, ctx->not_after,
+                                        MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
 
-    MBEDTLS_ASN1_CHK_ADD( sub_len, x509_write_time( &c, tmp_buf, ctx->not_before,
-                                            MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
+    MBEDTLS_ASN1_CHK_ADD( sub_len,
+                          x509_write_time( &c, buf, ctx->not_before,
+                                        MBEDTLS_X509_RFC5280_UTC_TIME_LEN ) );
 
     len += sub_len;
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, sub_len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                    MBEDTLS_ASN1_SEQUENCE ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, sub_len ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+                          mbedtls_asn1_write_tag( &c, buf,
+                                                  MBEDTLS_ASN1_CONSTRUCTED |
+                                                  MBEDTLS_ASN1_SEQUENCE ) );
 
     /*
      *  Issuer  ::=  Name
      */
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, tmp_buf, ctx->issuer ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_names( &c, buf,
+                                                         ctx->issuer ) );
 
     /*
      *  Signature   ::=  AlgorithmIdentifier
      */
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_algorithm_identifier( &c, tmp_buf,
-                       sig_oid, strlen( sig_oid ), 0 ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+                          mbedtls_asn1_write_algorithm_identifier( &c, buf,
+                                              sig_oid, strlen( sig_oid ), 0 ) );
 
     /*
      *  Serial   ::=  INTEGER
      */
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, tmp_buf, &ctx->serial ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_mpi( &c, buf,
+                                                       &ctx->serial ) );
 
     /*
      *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
@@ -416,48 +451,67 @@
     if( ctx->version != MBEDTLS_X509_CRT_VERSION_1 )
     {
         sub_len = 0;
-        MBEDTLS_ASN1_CHK_ADD( sub_len, mbedtls_asn1_write_int( &c, tmp_buf, ctx->version ) );
+        MBEDTLS_ASN1_CHK_ADD( sub_len,
+                              mbedtls_asn1_write_int( &c, buf, ctx->version ) );
         len += sub_len;
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, sub_len ) );
-        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
-                                                           MBEDTLS_ASN1_CONSTRUCTED | 0 ) );
+        MBEDTLS_ASN1_CHK_ADD( len,
+                              mbedtls_asn1_write_len( &c, buf, sub_len ) );
+        MBEDTLS_ASN1_CHK_ADD( len,
+                              mbedtls_asn1_write_tag( &c, buf,
+                                               MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+                                               MBEDTLS_ASN1_CONSTRUCTED | 0 ) );
     }
 
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                       MBEDTLS_ASN1_SEQUENCE ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len,
+                mbedtls_asn1_write_tag( &c, buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                                     MBEDTLS_ASN1_SEQUENCE ) );
 
     /*
      * Make signature
      */
+
+    /* Compute hash of CRT. */
     if( ( ret = mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c,
                             len, hash ) ) != 0 )
     {
         return( ret );
     }
 
-    if( ( ret = mbedtls_pk_sign( ctx->issuer_key, ctx->md_alg, hash, 0, sig, &sig_len,
-                         f_rng, p_rng ) ) != 0 )
+    if( ( ret = mbedtls_pk_sign( ctx->issuer_key, ctx->md_alg,
+                                 hash, 0, sig, &sig_len,
+                                 f_rng, p_rng ) ) != 0 )
     {
         return( ret );
     }
 
-    /*
-     * Write data to output buffer
-     */
+    /* Move CRT to the front of the buffer to have space
+     * for the signature. */
+    memmove( buf, c, len );
+    c = buf + len;
+
+    /* Add signature at the end of the buffer,
+     * making sure that it doesn't underflow
+     * into the CRT buffer. */
     c2 = buf + size;
-    MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, buf,
+    MBEDTLS_ASN1_CHK_ADD( sig_and_oid_len, mbedtls_x509_write_sig( &c2, c,
                                         sig_oid, sig_oid_len, sig, sig_len ) );
 
-    if( len > (size_t)( c2 - buf ) )
-        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+    /*
+     * Memory layout after this step:
+     *
+     * buf       c=buf+len                c2            buf+size
+     * [CRT0,...,CRTn, UNUSED, ..., UNUSED, SIG0, ..., SIGm]
+     */
 
-    c2 -= len;
-    memcpy( c2, c, len );
+    /* Move raw CRT to just before the signature. */
+    c = c2 - len;
+    memmove( c, buf, len );
 
     len += sig_and_oid_len;
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c2, buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c2, buf, MBEDTLS_ASN1_CONSTRUCTED |
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, buf,
+                                                 MBEDTLS_ASN1_CONSTRUCTED |
                                                  MBEDTLS_ASN1_SEQUENCE ) );
 
     return( (int) len );
@@ -467,23 +521,23 @@
 #define PEM_END_CRT             "-----END CERTIFICATE-----\n"
 
 #if defined(MBEDTLS_PEM_WRITE_C)
-int mbedtls_x509write_crt_pem( mbedtls_x509write_cert *crt, unsigned char *buf, size_t size,
-                       int (*f_rng)(void *, unsigned char *, size_t),
-                       void *p_rng )
+int mbedtls_x509write_crt_pem( mbedtls_x509write_cert *crt,
+                               unsigned char *buf, size_t size,
+                               int (*f_rng)(void *, unsigned char *, size_t),
+                               void *p_rng )
 {
     int ret;
-    unsigned char output_buf[4096];
-    size_t olen = 0;
+    size_t olen;
 
-    if( ( ret = mbedtls_x509write_crt_der( crt, output_buf, sizeof(output_buf),
+    if( ( ret = mbedtls_x509write_crt_der( crt, buf, size,
                                    f_rng, p_rng ) ) < 0 )
     {
         return( ret );
     }
 
     if( ( ret = mbedtls_pem_write_buffer( PEM_BEGIN_CRT, PEM_END_CRT,
-                                  output_buf + sizeof(output_buf) - ret,
-                                  ret, buf, size, &olen ) ) != 0 )
+                                          buf + size - ret, ret,
+                                          buf, size, &olen ) ) != 0 )
     {
         return( ret );
     }
diff --git a/programs/Makefile b/programs/Makefile
index 2cb7366..4c05d91 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -3,8 +3,8 @@
 # To compile with PKCS11: add "-lpkcs11-helper" to LDFLAGS
 
 CFLAGS	?= -O2
-WARNING_CFLAGS ?= -Wall -W -Wdeclaration-after-statement
-WARNING_CXXFLAGS ?= -Wall -W
+WARNING_CFLAGS ?= -Wall -Wextra
+WARNING_CXXFLAGS ?= -Wall -Wextra
 LDFLAGS ?=
 
 LOCAL_CFLAGS = $(WARNING_CFLAGS) -I../include -D_FILE_OFFSET_BITS=64
diff --git a/programs/test/cmake_subproject/.gitignore b/programs/test/cmake_subproject/.gitignore
new file mode 100644
index 0000000..464833b
--- /dev/null
+++ b/programs/test/cmake_subproject/.gitignore
@@ -0,0 +1,3 @@
+build
+Makefile
+cmake_subproject
diff --git a/programs/test/cmake_subproject/CMakeLists.txt b/programs/test/cmake_subproject/CMakeLists.txt
new file mode 100644
index 0000000..f5f4191
--- /dev/null
+++ b/programs/test/cmake_subproject/CMakeLists.txt
@@ -0,0 +1,19 @@
+cmake_minimum_required(VERSION 2.6)
+
+# We use the parent Mbed TLS directory as the MBEDTLS_DIR for this test. Other
+# projects that use Mbed TLS as a subproject are likely to add by their own
+# relative paths.
+set(MBEDTLS_DIR ../../../)
+
+# Add Mbed TLS as a subdirectory.
+add_subdirectory(${MBEDTLS_DIR} build)
+
+# Link against all the Mbed TLS libraries.
+set(libs
+    mbedtls
+    mbedcrypto
+    mbedx509
+)
+
+add_executable(cmake_subproject cmake_subproject.c)
+target_link_libraries(cmake_subproject ${libs})
diff --git a/programs/test/cmake_subproject/cmake_subproject.c b/programs/test/cmake_subproject/cmake_subproject.c
new file mode 100644
index 0000000..ca899bc
--- /dev/null
+++ b/programs/test/cmake_subproject/cmake_subproject.c
@@ -0,0 +1,56 @@
+/*
+ *  Simple program to test that CMake builds with Mbed TLS as a subdirectory
+ *  work correctly.
+ *
+ *  Copyright (C) 2006-2019, 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)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdio.h>
+#include <stdlib.h>
+#define mbedtls_fprintf         fprintf
+#define mbedtls_printf          printf
+#define mbedtls_exit            exit
+#define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
+#define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
+#endif /* MBEDTLS_PLATFORM_C */
+
+#include "mbedtls/version.h"
+
+/* The main reason to build this is for testing the CMake build, so the program
+ * doesn't need to do very much. It calls a single library function to ensure
+ * linkage works, but that is all. */
+int main()
+{
+    /* This version string is 18 bytes long, as advised by version.h. */
+    char version[18];
+
+    mbedtls_version_get_string_full( version );
+
+    mbedtls_printf( "Built against %s\n", version );
+
+    return( 0 );
+}
diff --git a/scripts/abi_check.py b/scripts/abi_check.py
index 502c7ae..533aaea 100755
--- a/scripts/abi_check.py
+++ b/scripts/abi_check.py
@@ -59,9 +59,7 @@
 
     @staticmethod
     def check_repo_path():
-        current_dir = os.path.realpath('.')
-        root_dir = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
-        if current_dir != root_dir:
+        if not all(os.path.isdir(d) for d in ["include", "library", "tests"]):
             raise Exception("Must be run from Mbed TLS root")
 
     def _setup_logger(self):
@@ -108,6 +106,12 @@
             stderr=subprocess.STDOUT
         )
         self.log.debug(worktree_output.decode("utf-8"))
+        version.commit = subprocess.check_output(
+            [self.git_command, "rev-parse", worktree_rev],
+            cwd=git_worktree_path,
+            stderr=subprocess.STDOUT
+        ).decode("ascii").rstrip()
+        self.log.debug("Commit is {}".format(version.commit))
         return git_worktree_path
 
     def _update_git_submodules(self, git_worktree_path, version):
@@ -163,6 +167,13 @@
                     os.path.join(root, file)
                 )
 
+    @staticmethod
+    def _pretty_revision(version):
+        if version.revision == version.commit:
+            return version.revision
+        else:
+            return "{} ({})".format(version.revision, version.commit)
+
     def _get_abi_dumps_from_shared_libraries(self, version):
         """Generate the ABI dumps for the specified git revision.
         The shared libraries must have been built and the module paths
@@ -177,7 +188,7 @@
                 "abi-dumper",
                 module_path,
                 "-o", output_path,
-                "-lver", version.revision
+                "-lver", self._pretty_revision(version),
             ]
             abi_dump_output = subprocess.check_output(
                 abi_dump_command,
@@ -222,70 +233,84 @@
                 if not problems.getchildren():
                     report.remove(problems)
 
+    def _abi_compliance_command(self, mbed_module, output_path):
+        """Build the command to run to analyze the library mbed_module.
+        The report will be placed in output_path."""
+        abi_compliance_command = [
+            "abi-compliance-checker",
+            "-l", mbed_module,
+            "-old", self.old_version.abi_dumps[mbed_module],
+            "-new", self.new_version.abi_dumps[mbed_module],
+            "-strict",
+            "-report-path", output_path,
+        ]
+        if self.skip_file:
+            abi_compliance_command += ["-skip-symbols", self.skip_file,
+                                       "-skip-types", self.skip_file]
+        if self.brief:
+            abi_compliance_command += ["-report-format", "xml",
+                                       "-stdout"]
+        return abi_compliance_command
+
+    def _is_library_compatible(self, mbed_module, compatibility_report):
+        """Test if the library mbed_module has remained compatible.
+        Append a message regarding compatibility to compatibility_report."""
+        output_path = os.path.join(
+            self.report_dir, "{}-{}-{}.html".format(
+                mbed_module, self.old_version.revision,
+                self.new_version.revision
+            )
+        )
+        try:
+            subprocess.check_output(
+                self._abi_compliance_command(mbed_module, output_path),
+                stderr=subprocess.STDOUT
+            )
+        except subprocess.CalledProcessError as err:
+            if err.returncode != 1:
+                raise err
+            if self.brief:
+                self.log.info(
+                    "Compatibility issues found for {}".format(mbed_module)
+                )
+                report_root = ET.fromstring(err.output.decode("utf-8"))
+                self._remove_extra_detail_from_report(report_root)
+                self.log.info(ET.tostring(report_root).decode("utf-8"))
+            else:
+                self.can_remove_report_dir = False
+                compatibility_report.append(
+                    "Compatibility issues found for {}, "
+                    "for details see {}".format(mbed_module, output_path)
+                )
+            return False
+        compatibility_report.append(
+            "No compatibility issues for {}".format(mbed_module)
+        )
+        if not (self.keep_all_reports or self.brief):
+            os.remove(output_path)
+        return True
+
     def get_abi_compatibility_report(self):
         """Generate a report of the differences between the reference ABI
         and the new ABI. ABI dumps from self.old_version and self.new_version
         must be available."""
-        compatibility_report = ""
+        compatibility_report = ["Checking evolution from {} to {}".format(
+            self._pretty_revision(self.old_version),
+            self._pretty_revision(self.new_version)
+        )]
         compliance_return_code = 0
         shared_modules = list(set(self.old_version.modules.keys()) &
                               set(self.new_version.modules.keys()))
         for mbed_module in shared_modules:
-            output_path = os.path.join(
-                self.report_dir, "{}-{}-{}.html".format(
-                    mbed_module, self.old_version.revision,
-                    self.new_version.revision
-                )
-            )
-            abi_compliance_command = [
-                "abi-compliance-checker",
-                "-l", mbed_module,
-                "-old", self.old_version.abi_dumps[mbed_module],
-                "-new", self.new_version.abi_dumps[mbed_module],
-                "-strict",
-                "-report-path", output_path,
-            ]
-            if self.skip_file:
-                abi_compliance_command += ["-skip-symbols", self.skip_file,
-                                           "-skip-types", self.skip_file]
-            if self.brief:
-                abi_compliance_command += ["-report-format", "xml",
-                                           "-stdout"]
-            try:
-                subprocess.check_output(
-                    abi_compliance_command,
-                    stderr=subprocess.STDOUT
-                )
-            except subprocess.CalledProcessError as err:
-                if err.returncode == 1:
-                    compliance_return_code = 1
-                    if self.brief:
-                        self.log.info(
-                            "Compatibility issues found for {}".format(mbed_module)
-                        )
-                        report_root = ET.fromstring(err.output.decode("utf-8"))
-                        self._remove_extra_detail_from_report(report_root)
-                        self.log.info(ET.tostring(report_root).decode("utf-8"))
-                    else:
-                        self.can_remove_report_dir = False
-                        compatibility_report += (
-                            "Compatibility issues found for {}, "
-                            "for details see {}\n".format(mbed_module, output_path)
-                        )
-                else:
-                    raise err
-            else:
-                compatibility_report += (
-                    "No compatibility issues for {}\n".format(mbed_module)
-                )
-                if not (self.keep_all_reports or self.brief):
-                    os.remove(output_path)
+            if not self._is_library_compatible(mbed_module,
+                                               compatibility_report):
+                compliance_return_code = 1
         for version in [self.old_version, self.new_version]:
             for mbed_module, mbed_module_dump in version.abi_dumps.items():
                 os.remove(mbed_module_dump)
         if self.can_remove_report_dir:
             os.rmdir(self.report_dir)
-        self.log.info(compatibility_report)
+        self.log.info("\n".join(compatibility_report))
         return compliance_return_code
 
     def check_for_abi_changes(self):
@@ -357,7 +382,9 @@
         )
         parser.add_argument(
             "-s", "--skip-file", type=str,
-            help="path to file containing symbols and types to skip"
+            help=("path to file containing symbols and types to skip "
+                  "(typically \"-s identifiers\" after running "
+                  "\"tests/scripts/list-identifiers.sh --internal\")")
         )
         parser.add_argument(
             "-b", "--brief", action="store_true",
@@ -371,6 +398,7 @@
             version="old",
             repository=abi_args.old_repo,
             revision=abi_args.old_rev,
+            commit=None,
             crypto_repository=abi_args.old_crypto_repo,
             crypto_revision=abi_args.old_crypto_rev,
             abi_dumps={},
@@ -380,6 +408,7 @@
             version="new",
             repository=abi_args.new_repo,
             revision=abi_args.new_rev,
+            commit=None,
             crypto_repository=abi_args.new_crypto_repo,
             crypto_revision=abi_args.new_crypto_rev,
             abi_dumps={},
diff --git a/tests/Makefile b/tests/Makefile
index 27ce338..1679ee4 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -3,7 +3,7 @@
 # To compile with PKCS11: add "-lpkcs11-helper" to LDFLAGS
 
 CFLAGS	?= -O2
-WARNING_CFLAGS ?= -Wall -W -Wdeclaration-after-statement -Wunused
+WARNING_CFLAGS ?= -Wall -Wextra
 LDFLAGS ?=
 
 LOCAL_CFLAGS = $(WARNING_CFLAGS) -I../include -D_FILE_OFFSET_BITS=64
diff --git a/tests/compat-in-docker.sh b/tests/compat-in-docker.sh
new file mode 100755
index 0000000..67a0807
--- /dev/null
+++ b/tests/compat-in-docker.sh
@@ -0,0 +1,65 @@
+#!/bin/bash -eu
+
+# compat-in-docker.sh
+#
+# Purpose
+# -------
+# This runs compat.sh in a Docker container.
+#
+# Notes for users
+# ---------------
+# If OPENSSL_CMD, GNUTLS_CLI, or GNUTLS_SERV are specified the path must
+# correspond to an executable inside the Docker container. The special
+# values "next" (OpenSSL only) and "legacy" are also allowed as shorthand
+# for the installations inside the container.
+#
+# See also:
+# - scripts/docker_env.sh for general Docker prerequisites and other information.
+# - compat.sh for notes about invocation of that script.
+
+# Copyright (C) 2006-2019, Arm Limited (or its affiliates), All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# This file is part of Mbed TLS (https://tls.mbed.org)
+
+source tests/scripts/docker_env.sh
+
+case "${OPENSSL_CMD:-default}" in
+    "legacy")  export OPENSSL_CMD="/usr/local/openssl-1.0.1j/bin/openssl";;
+    "next")    export OPENSSL_CMD="/usr/local/openssl-1.1.1a/bin/openssl";;
+    *) ;;
+esac
+
+case "${GNUTLS_CLI:-default}" in
+    "legacy")  export GNUTLS_CLI="/usr/local/gnutls-3.3.8/bin/gnutls-cli";;
+    "next")  export GNUTLS_CLI="/usr/local/gnutls-3.6.5/bin/gnutls-cli";;
+    *) ;;
+esac
+
+case "${GNUTLS_SERV:-default}" in
+    "legacy")  export GNUTLS_SERV="/usr/local/gnutls-3.3.8/bin/gnutls-serv";;
+    "next")  export GNUTLS_SERV="/usr/local/gnutls-3.6.5/bin/gnutls-serv";;
+    *) ;;
+esac
+
+run_in_docker \
+    -e M_CLI \
+    -e M_SRV \
+    -e GNUTLS_CLI \
+    -e GNUTLS_SERV \
+    -e OPENSSL_CMD \
+    -e OSSL_NO_DTLS \
+    tests/compat.sh \
+    $@
diff --git a/tests/docker/bionic/Dockerfile b/tests/docker/bionic/Dockerfile
new file mode 100644
index 0000000..1b2d40f
--- /dev/null
+++ b/tests/docker/bionic/Dockerfile
@@ -0,0 +1,168 @@
+# Dockerfile
+#
+# Purpose
+# -------
+# Defines a Docker container suitable to build and run all tests (all.sh),
+# except for those that use a proprietary toolchain.
+
+# Copyright (C) 2006-2019, Arm Limited (or its affiliates), 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)
+ARG MAKEFLAGS_PARALLEL=""
+ARG MY_REGISTRY=
+
+FROM ${MY_REGISTRY}ubuntu:bionic
+
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN apt-get update \
+    && apt-get -y install software-properties-common \
+    && rm -rf /var/lib/apt/lists
+
+RUN add-apt-repository -y ppa:team-gcc-arm-embedded/ppa
+
+RUN apt-get update \
+    && apt-get -y install \
+    # mbedtls build/test dependencies
+    build-essential \
+    clang \
+    cmake \
+    doxygen \
+    gcc-arm-none-eabi \
+    gcc-mingw-w64-i686 \
+    gcc-multilib \
+    g++-multilib \
+    gdb \
+    git \
+    graphviz \
+    lsof \
+    python \
+    python3-pip \
+    python3 \
+    pylint3 \
+    valgrind \
+    wget \
+    # libnettle build dependencies
+    libgmp-dev \
+    m4 \
+    pkg-config \
+    && rm -rf /var/lib/apt/lists/*
+
+# Build a static, legacy openssl from sources with sslv3 enabled
+# Based on https://gist.github.com/bmaupin/8caca3a1e8c3c5686141 (build-openssl.sh)
+# Note: openssl-1.0.2 and earlier has known build issues with parallel make.
+RUN cd /tmp \
+    && wget https://www.openssl.org/source/old/1.0.1/openssl-1.0.1j.tar.gz -qO- | tar xz \
+    && cd openssl-1.0.1j \
+    && ./config --openssldir=/usr/local/openssl-1.0.1j no-shared \
+    && (make ${MAKEFLAGS_PARALLEL} || make -j 1) \
+    && make install_sw \
+    && rm -rf /tmp/openssl*
+ENV OPENSSL_LEGACY=/usr/local/openssl-1.0.1j/bin/openssl
+
+# Build OPENSSL as 1.0.2g
+RUN cd /tmp \
+    && wget https://www.openssl.org/source/old/1.0.2/openssl-1.0.2g.tar.gz -qO- | tar xz \
+    && cd openssl-1.0.2g \
+    && ./config --openssldir=/usr/local/openssl-1.0.2g no-shared \
+    && (make ${MAKEFLAGS_PARALLEL} || make -j 1) \
+    && make install_sw \
+    && rm -rf /tmp/openssl*
+ENV OPENSSL=/usr/local/openssl-1.0.2g/bin/openssl
+
+# Build a new openssl binary for ARIA/CHACHA20 support
+# Based on https://gist.github.com/bmaupin/8caca3a1e8c3c5686141 (build-openssl.sh)
+RUN cd /tmp \
+    && wget https://www.openssl.org/source/openssl-1.1.1a.tar.gz -qO- | tar xz \
+    && cd openssl-1.1.1a \
+    && ./config --prefix=/usr/local/openssl-1.1.1a -Wl,--enable-new-dtags,-rpath,'${LIBRPATH}' no-shared \
+    && make ${MAKEFLAGS_PARALLEL} \
+    && make install_sw \
+    && rm -rf /tmp/openssl*
+ENV OPENSSL_NEXT=/usr/local/openssl-1.1.1a/bin/openssl
+
+# Build libnettle 2.7.1 (needed by legacy gnutls)
+RUN cd /tmp \
+    && wget https://ftp.gnu.org/gnu/nettle/nettle-2.7.1.tar.gz -qO- | tar xz \
+    && cd nettle-2.7.1 \
+    && ./configure --disable-documentation \
+    && make ${MAKEFLAGS_PARALLEL} \
+    && make install \
+    && /sbin/ldconfig \
+    && rm -rf /tmp/nettle*
+
+# Build legacy gnutls (3.3.8)
+RUN cd /tmp \
+    && wget https://www.gnupg.org/ftp/gcrypt/gnutls/v3.3/gnutls-3.3.8.tar.xz -qO- | tar xJ \
+    && cd gnutls-3.3.8 \
+    && ./configure --prefix=/usr/local/gnutls-3.3.8 --exec_prefix=/usr/local/gnutls-3.3.8 --disable-shared --disable-guile --disable-doc \
+    && make ${MAKEFLAGS_PARALLEL} \
+    && make install \
+    && rm -rf /tmp/gnutls*
+ENV GNUTLS_LEGACY_CLI=/usr/local/gnutls-3.3.8/bin/gnutls-cli
+ENV GNUTLS_LEGACY_SERV=/usr/local/gnutls-3.3.8/bin/gnutls-serv
+
+# Build libnettle 3.1 (needed by gnutls)
+RUN cd /tmp \
+    && wget https://ftp.gnu.org/gnu/nettle/nettle-3.1.tar.gz -qO- | tar xz \
+    && cd nettle-3.1 \
+    && ./configure --disable-documentation \
+    && make ${MAKEFLAGS_PARALLEL} \
+    && make install \
+    && /sbin/ldconfig \
+    && rm -rf /tmp/nettle*
+
+# Build gnutls (3.4.10)
+RUN cd /tmp \
+    && wget https://www.gnupg.org/ftp/gcrypt/gnutls/v3.4/gnutls-3.4.10.tar.xz -qO- | tar xJ \
+    && cd gnutls-3.4.10 \
+    && ./configure --prefix=/usr/local/gnutls-3.4.10 --exec_prefix=/usr/local/gnutls-3.4.10 \
+        --with-included-libtasn1 --without-p11-kit \
+        --disable-shared --disable-guile --disable-doc \
+    && make ${MAKEFLAGS_PARALLEL} \
+    && make install \
+    && rm -rf /tmp/gnutls*
+ENV GNUTLS_CLI=/usr/local/gnutls-3.4.10/bin/gnutls-cli
+ENV GNUTLS_SERV=/usr/local/gnutls-3.4.10/bin/gnutls-serv
+
+# Build libnettle 3.4 (needed by gnutls next)
+RUN cd /tmp \
+    && wget https://ftp.gnu.org/gnu/nettle/nettle-3.4.1.tar.gz -qO- | tar xz \
+    && cd nettle-3.4.1 \
+    && ./configure --disable-documentation \
+    && make ${MAKEFLAGS_PARALLEL} \
+    && make install \
+    && /sbin/ldconfig \
+    && rm -rf /tmp/nettle*
+
+# Build gnutls next (3.6.5)
+RUN cd /tmp \
+    && wget https://www.gnupg.org/ftp/gcrypt/gnutls/v3.6/gnutls-3.6.5.tar.xz -qO- | tar xJ \
+    && cd gnutls-3.6.5 \
+    && ./configure --prefix=/usr/local/gnutls-3.6.5 --exec_prefix=/usr/local/gnutls-3.6.5 \
+        --with-included-libtasn1 --with-included-unistring --without-p11-kit \
+        --disable-shared --disable-guile --disable-doc \
+    && make ${MAKEFLAGS_PARALLEL} \
+    && make install \
+    && rm -rf /tmp/gnutls*
+
+ENV GNUTLS_NEXT_CLI=/usr/local/gnutls-3.6.5/bin/gnutls-cli
+ENV GNUTLS_NEXT_SERV=/usr/local/gnutls-3.6.5/bin/gnutls-serv
+
+RUN pip3 install --no-cache-dir \
+    mbed-host-tests \
+    mock
diff --git a/tests/make-in-docker.sh b/tests/make-in-docker.sh
new file mode 100755
index 0000000..4fbfe1c
--- /dev/null
+++ b/tests/make-in-docker.sh
@@ -0,0 +1,31 @@
+#!/bin/bash -eu
+
+# make-in-docker.sh
+#
+# Purpose
+# -------
+# This runs make in a Docker container.
+#
+# See also:
+# - scripts/docker_env.sh for general Docker prerequisites and other information.
+
+# Copyright (C) 2006-2019, Arm Limited (or its affiliates), 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)
+
+source tests/scripts/docker_env.sh
+
+run_in_docker make $@
diff --git a/tests/scripts/all-in-docker.sh b/tests/scripts/all-in-docker.sh
new file mode 100755
index 0000000..ee9a092
--- /dev/null
+++ b/tests/scripts/all-in-docker.sh
@@ -0,0 +1,37 @@
+#!/bin/bash -eu
+
+# all-in-docker.sh
+#
+# Purpose
+# -------
+# This runs all.sh (except for armcc) in a Docker container.
+#
+# Notes for users
+# ---------------
+# See docker_env.sh for prerequisites and other information.
+#
+# See also all.sh for notes about invocation of that script.
+
+# Copyright (C) 2006-2019, Arm Limited (or its affiliates), 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)
+
+source tests/scripts/docker_env.sh
+
+# Run tests that are possible with openly available compilers
+run_in_docker tests/scripts/all.sh \
+    --no-armcc \
+    $@
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index e5c6e43..13a6f85 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -242,6 +242,11 @@
     git checkout -- Makefile library/Makefile programs/Makefile tests/Makefile
     cd ..
 
+    # Remove any artifacts from the component_test_cmake_as_subdirectory test.
+    rm -rf programs/test/cmake_subproject/build
+    rm -f programs/test/cmake_subproject/Makefile
+    rm -f programs/test/cmake_subproject/cmake_subproject
+
     if [ -f "$CONFIG_BAK" ]; then
         mv "$CONFIG_BAK" "$CONFIG_H"
     fi
@@ -1219,6 +1224,19 @@
     unset MBEDTLS_ROOT_DIR
 }
 
+component_test_cmake_as_subdirectory () {
+    msg "build: cmake 'as-subdirectory' build"
+    MBEDTLS_ROOT_DIR="$PWD"
+
+    cd programs/test/cmake_subproject
+    cmake .
+    make
+    if_build_succeeded ./cmake_subproject
+
+    cd "$MBEDTLS_ROOT_DIR"
+    unset MBEDTLS_ROOT_DIR
+}
+
 component_test_zeroize () {
     # Test that the function mbedtls_platform_zeroize() is not optimized away by
     # different combinations of compilers and optimization flags by using an
diff --git a/tests/scripts/basic-in-docker.sh b/tests/scripts/basic-in-docker.sh
new file mode 100755
index 0000000..37ed5ea
--- /dev/null
+++ b/tests/scripts/basic-in-docker.sh
@@ -0,0 +1,50 @@
+#!/bin/bash -eu
+
+# basic-in-docker.sh
+#
+# Purpose
+# -------
+# This runs a rough equivalent of the travis.yml in a Docker container.
+# The tests are run for both clang and gcc.
+#
+# Notes for users
+# ---------------
+# See docker_env.sh for prerequisites and other information.
+
+# Copyright (C) 2006-2019, Arm Limited (or its affiliates), 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)
+
+source tests/scripts/docker_env.sh
+
+run_in_docker tests/scripts/recursion.pl library/*.c
+run_in_docker tests/scripts/check-generated-files.sh
+run_in_docker tests/scripts/check-doxy-blocks.pl
+run_in_docker tests/scripts/check-names.sh
+run_in_docker tests/scripts/check-files.py
+run_in_docker tests/scripts/doxygen.sh
+
+for compiler in clang gcc; do
+    run_in_docker -e CC=${compiler} cmake -D CMAKE_BUILD_TYPE:String="Check" .
+    run_in_docker -e CC=${compiler} make
+    run_in_docker -e CC=${compiler} make test
+    run_in_docker programs/test/selftest
+    run_in_docker -e OSSL_NO_DTLS=1 tests/compat.sh
+    run_in_docker tests/ssl-opt.sh -e '\(DTLS\|SCSV\).*openssl'
+    run_in_docker tests/scripts/test-ref-configs.pl
+    run_in_docker tests/scripts/curves.pl
+    run_in_docker tests/scripts/key-exchanges.pl
+done
diff --git a/tests/scripts/check-files.py b/tests/scripts/check-files.py
index 00fd0ed..255bed8 100755
--- a/tests/scripts/check-files.py
+++ b/tests/scripts/check-files.py
@@ -1,14 +1,12 @@
 #!/usr/bin/env python3
+
+# This file is part of Mbed TLS (https://tls.mbed.org)
+# Copyright (c) 2018, Arm Limited, All Rights Reserved
+
 """
-This file is part of Mbed TLS (https://tls.mbed.org)
-
-Copyright (c) 2018, Arm Limited, All Rights Reserved
-
-Purpose
-
 This script checks the current state of the source code for minor issues,
 including incorrect file permissions, presence of tabs, non-Unix line endings,
-trailing whitespace, presence of UTF-8 BOM, and TODO comments.
+trailing whitespace, and presence of UTF-8 BOM.
 Note: requires python 3, must be run from Mbed TLS root.
 """
 
@@ -170,19 +168,6 @@
             return True
         return False
 
-class TodoIssueTracker(LineIssueTracker):
-    """Track lines containing ``TODO``."""
-
-    heading = "TODO present:"
-    files_exemptions = frozenset([
-        os.path.basename(__file__),
-        "benchmark.c",
-        "pull_request_template.md",
-    ])
-
-    def issue_with_line(self, line, _filepath):
-        return b"todo" in line.lower()
-
 
 class IntegrityChecker(object):
     """Sanity-check files under the current directory."""
@@ -211,7 +196,6 @@
             TrailingWhitespaceIssueTracker(),
             TabIssueTracker(),
             MergeArtifactIssueTracker(),
-            TodoIssueTracker(),
         ]
 
     @staticmethod
@@ -257,15 +241,7 @@
 
 
 def run_main():
-    parser = argparse.ArgumentParser(
-        description=(
-            "This script checks the current state of the source code for "
-            "minor issues, including incorrect file permissions, "
-            "presence of tabs, non-Unix line endings, trailing whitespace, "
-            "presence of UTF-8 BOM, and TODO comments. "
-            "Note: requires python 3, must be run from Mbed TLS root."
-        )
-    )
+    parser = argparse.ArgumentParser(description=__doc__)
     parser.add_argument(
         "-l", "--log_file", type=str, help="path to optional output log",
     )
diff --git a/tests/scripts/docker_env.sh b/tests/scripts/docker_env.sh
new file mode 100755
index 0000000..8bdc425
--- /dev/null
+++ b/tests/scripts/docker_env.sh
@@ -0,0 +1,93 @@
+#!/bin/bash -eu
+
+# docker_env.sh
+#
+# Purpose
+# -------
+#
+# This is a helper script to enable running tests under a Docker container,
+# thus making it easier to get set up as well as isolating test dependencies
+# (which include legacy/insecure configurations of openssl and gnutls).
+#
+# Notes for users
+# ---------------
+# This script expects a Linux x86_64 system with a recent version of Docker
+# installed and available for use, as well as http/https access. If a proxy
+# server must be used, invoke this script with the usual environment variables
+# (http_proxy and https_proxy) set appropriately. If an alternate Docker
+# registry is needed, specify MBEDTLS_DOCKER_REGISTRY to point at the
+# host name.
+#
+#
+# Running this script directly will check for Docker availability and set up
+# the Docker image.
+
+# Copyright (C) 2006-2019, Arm Limited (or its affiliates), 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)
+
+
+# default values, can be overridden by the environment
+: ${MBEDTLS_DOCKER_GUEST:=bionic}
+
+
+DOCKER_IMAGE_TAG="armmbed/mbedtls-test:${MBEDTLS_DOCKER_GUEST}"
+
+# Make sure docker is available
+if ! which docker > /dev/null; then
+    echo "Docker is required but doesn't seem to be installed. See https://www.docker.com/ to get started"
+    exit 1
+fi
+
+# Figure out if we need to 'sudo docker'
+if groups | grep docker > /dev/null; then
+    DOCKER="docker"
+else
+    echo "Using sudo to invoke docker since you're not a member of the docker group..."
+    DOCKER="sudo docker"
+fi
+
+# Build the Docker image
+echo "Getting docker image up to date (this may take a few minutes)..."
+${DOCKER} image build \
+    -t ${DOCKER_IMAGE_TAG} \
+    --cache-from=${DOCKER_IMAGE_TAG} \
+    --build-arg MAKEFLAGS_PARALLEL="-j $(nproc)" \
+    --network host \
+    ${http_proxy+--build-arg http_proxy=${http_proxy}} \
+    ${https_proxy+--build-arg https_proxy=${https_proxy}} \
+    ${MBEDTLS_DOCKER_REGISTRY+--build-arg MY_REGISTRY="${MBEDTLS_DOCKER_REGISTRY}/"} \
+    tests/docker/${MBEDTLS_DOCKER_GUEST}
+
+run_in_docker()
+{
+    ENV_ARGS=""
+    while [ "$1" == "-e" ]; do
+        ENV_ARGS="${ENV_ARGS} $1 $2"
+        shift 2
+    done
+
+    ${DOCKER} container run -it --rm \
+        --cap-add SYS_PTRACE \
+        --user "$(id -u):$(id -g)" \
+        --volume $PWD:$PWD \
+        --workdir $PWD \
+        -e MAKEFLAGS \
+        -e PYLINTHOME=/tmp/.pylintd \
+        ${ENV_ARGS} \
+        ${DOCKER_IMAGE_TAG} \
+        $@
+}
diff --git a/tests/ssl-opt-in-docker.sh b/tests/ssl-opt-in-docker.sh
new file mode 100755
index 0000000..e6e469d
--- /dev/null
+++ b/tests/ssl-opt-in-docker.sh
@@ -0,0 +1,65 @@
+#!/bin/bash -eu
+
+# ssl-opt-in-docker.sh
+#
+# Purpose
+# -------
+# This runs ssl-opt.sh in a Docker container.
+#
+# Notes for users
+# ---------------
+# If OPENSSL_CMD, GNUTLS_CLI, or GNUTLS_SERV are specified, the path must
+# correspond to an executable inside the Docker container. The special
+# values "next" and "legacy" are also allowed as shorthand for the
+# installations inside the container.
+#
+# See also:
+# - scripts/docker_env.sh for general Docker prerequisites and other information.
+# - ssl-opt.sh for notes about invocation of that script.
+
+# Copyright (C) 2006-2019, Arm Limited (or its affiliates), All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# This file is part of Mbed TLS (https://tls.mbed.org)
+
+source tests/scripts/docker_env.sh
+
+case "${OPENSSL_CMD:-default}" in
+    "legacy")  export OPENSSL_CMD="/usr/local/openssl-1.0.1j/bin/openssl";;
+    "next")    export OPENSSL_CMD="/usr/local/openssl-1.1.1a/bin/openssl";;
+    *) ;;
+esac
+
+case "${GNUTLS_CLI:-default}" in
+    "legacy")  export GNUTLS_CLI="/usr/local/gnutls-3.3.8/bin/gnutls-cli";;
+    "next")  export GNUTLS_CLI="/usr/local/gnutls-3.6.5/bin/gnutls-cli";;
+    *) ;;
+esac
+
+case "${GNUTLS_SERV:-default}" in
+    "legacy")  export GNUTLS_SERV="/usr/local/gnutls-3.3.8/bin/gnutls-serv";;
+    "next")  export GNUTLS_SERV="/usr/local/gnutls-3.6.5/bin/gnutls-serv";;
+    *) ;;
+esac
+
+run_in_docker \
+    -e P_SRV \
+    -e P_CLI \
+    -e P_PXY \
+    -e GNUTLS_CLI \
+    -e GNUTLS_SERV \
+    -e OPENSSL_CMD \
+    tests/ssl-opt.sh \
+    $@