diff --git a/ChangeLog b/ChangeLog
index c94218e..69b4b63 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -64,6 +64,8 @@
    * Fix buffer length assertions in the ssl_parse_certificate_request()
      function which leads to a potential one byte overread of the message
      buffer.
+   * Fix invalid buffer sizes passed to zlib during record compression and
+     decompression.
 
 Changes
    * Remove some redundant code in bignum.c. Contributed by Alexey Skalozub.
@@ -109,6 +111,7 @@
      MBEDTLS_XXX_ALT macro. This means that alternative implementations do
      not need to copy the declarations, and ensures that they will have the
      same API.
+   * Add platform setup and teardown calls in test suites.
 
 = mbed TLS 2.8.0 branch released 2018-03-16
 
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index e8063d2..8a903c5 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2108,6 +2108,7 @@
 {
     int ret;
     unsigned char *msg_post = ssl->out_msg;
+    ptrdiff_t bytes_written = ssl->out_msg - ssl->out_buf;
     size_t len_pre = ssl->out_msglen;
     unsigned char *msg_pre = ssl->compress_buf;
 
@@ -2127,7 +2128,7 @@
     ssl->transform_out->ctx_deflate.next_in = msg_pre;
     ssl->transform_out->ctx_deflate.avail_in = len_pre;
     ssl->transform_out->ctx_deflate.next_out = msg_post;
-    ssl->transform_out->ctx_deflate.avail_out = MBEDTLS_SSL_BUFFER_LEN;
+    ssl->transform_out->ctx_deflate.avail_out = MBEDTLS_SSL_BUFFER_LEN - bytes_written;
 
     ret = deflate( &ssl->transform_out->ctx_deflate, Z_SYNC_FLUSH );
     if( ret != Z_OK )
@@ -2137,7 +2138,7 @@
     }
 
     ssl->out_msglen = MBEDTLS_SSL_BUFFER_LEN -
-                      ssl->transform_out->ctx_deflate.avail_out;
+                      ssl->transform_out->ctx_deflate.avail_out - bytes_written;
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "after compression: msglen = %d, ",
                    ssl->out_msglen ) );
@@ -2154,6 +2155,7 @@
 {
     int ret;
     unsigned char *msg_post = ssl->in_msg;
+    ptrdiff_t header_bytes = ssl->in_msg - ssl->in_buf;
     size_t len_pre = ssl->in_msglen;
     unsigned char *msg_pre = ssl->compress_buf;
 
@@ -2173,7 +2175,8 @@
     ssl->transform_in->ctx_inflate.next_in = msg_pre;
     ssl->transform_in->ctx_inflate.avail_in = len_pre;
     ssl->transform_in->ctx_inflate.next_out = msg_post;
-    ssl->transform_in->ctx_inflate.avail_out = MBEDTLS_SSL_MAX_CONTENT_LEN;
+    ssl->transform_in->ctx_inflate.avail_out = MBEDTLS_SSL_BUFFER_LEN -
+                                               header_bytes;
 
     ret = inflate( &ssl->transform_in->ctx_inflate, Z_SYNC_FLUSH );
     if( ret != Z_OK )
@@ -2182,8 +2185,8 @@
         return( MBEDTLS_ERR_SSL_COMPRESSION_FAILED );
     }
 
-    ssl->in_msglen = MBEDTLS_SSL_MAX_CONTENT_LEN -
-                     ssl->transform_in->ctx_inflate.avail_out;
+    ssl->in_msglen = MBEDTLS_SSL_BUFFER_LEN -
+                     ssl->transform_in->ctx_inflate.avail_out - header_bytes;
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "after decompression: msglen = %d, ",
                    ssl->in_msglen ) );
diff --git a/tests/suites/helpers.function b/tests/suites/helpers.function
index eef41c7..f82694a 100644
--- a/tests/suites/helpers.function
+++ b/tests/suites/helpers.function
@@ -109,6 +109,9 @@
 }
 test_info;
 
+#if defined(MBEDTLS_PLATFORM_C)
+mbedtls_platform_context platform_ctx;
+#endif
 
 /*----------------------------------------------------------------------------*/
 /* Helper flags for complex dependencies */
@@ -127,6 +130,21 @@
 
 /*----------------------------------------------------------------------------*/
 /* Helper Functions */
+static int platform_setup()
+{
+    int ret = 0;
+#if defined(MBEDTLS_PLATFORM_C)
+    ret = mbedtls_platform_setup( &platform_ctx );
+#endif /* MBEDTLS_PLATFORM_C */
+    return( ret );
+}
+
+static void platform_teardown()
+{
+#if defined(MBEDTLS_PLATFORM_C)
+    mbedtls_platform_teardown( &platform_ctx );
+#endif /* MBEDTLS_PLATFORM_C */
+}
 
 #if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
 static int redirect_output( FILE** out_stream, const char* path )
diff --git a/tests/suites/main_test.function b/tests/suites/main_test.function
index 042085f..1390f9f 100644
--- a/tests/suites/main_test.function
+++ b/tests/suites/main_test.function
@@ -281,6 +281,18 @@
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) && \
     !defined(TEST_SUITE_MEMORY_BUFFER_ALLOC)
     unsigned char alloc_buf[1000000];
+#endif 
+    /* Platform setup should be called in the beginning */
+    ret = platform_setup();
+    if( ret != 0 )
+    {
+        mbedtls_fprintf( stderr,
+                         "FATAL: Failed to initialize platform - error %d\n",
+                         ret );
+        return( -1 );
+    }
+#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) && \
+    !defined(TEST_SUITE_MEMORY_BUFFER_ALLOC)
     mbedtls_memory_buffer_alloc_init( alloc_buf, sizeof(alloc_buf) );
 #endif
 
@@ -293,6 +305,7 @@
     if( pointer != NULL )
     {
         mbedtls_fprintf( stderr, "all-bits-zero is not a NULL pointer\n" );
+        platform_teardown();
         return( 1 );
     }
 
@@ -302,7 +315,8 @@
     if( run_test_snprintf() != 0 )
     {
         mbedtls_fprintf( stderr, "the snprintf implementation is broken\n" );
-        return( 0 );
+        platform_teardown();
+        return( 1 );
     }
 
     while( arg_index < argc)
@@ -318,6 +332,7 @@
                  strcmp(next_arg, "-h" ) == 0 )
         {
             mbedtls_fprintf( stdout, USAGE );
+            platform_teardown();
             mbedtls_exit( EXIT_SUCCESS );
         }
         else
@@ -357,6 +372,7 @@
         {
             mbedtls_fprintf( stderr, "Failed to open test file: %s\n",
                              test_filename );
+            platform_teardown();
             return( 1 );
         }
 
@@ -366,6 +382,7 @@
             {
                 mbedtls_fprintf( stderr,
                     "FATAL: Dep count larger than zero at start of loop\n" );
+                platform_teardown();
                 mbedtls_exit( MBEDTLS_EXIT_FAILURE );
             }
             unmet_dep_count = 0;
@@ -402,6 +419,7 @@
                         if(  unmet_dependencies[ unmet_dep_count ] == NULL )
                         {
                             mbedtls_fprintf( stderr, "FATAL: Out of memory\n" );
+                            platform_teardown();
                             mbedtls_exit( MBEDTLS_EXIT_FAILURE );
                         }
                         unmet_dep_count++;
@@ -427,6 +445,7 @@
                     stdout_fd = redirect_output( &stdout, "/dev/null" );
                     if( stdout_fd == -1 )
                     {
+                        platform_teardown();
                         /* Redirection has failed with no stdout so exit */
                         exit( 1 );
                     }
@@ -439,6 +458,7 @@
                 if( !option_verbose && restore_output( &stdout, stdout_fd ) )
                 {
                         /* Redirection has failed with no stdout so exit */
+                        platform_teardown();
                         exit( 1 );
                 }
 #endif /* __unix__ || __APPLE__ __MACH__ */
@@ -490,6 +510,7 @@
             {
                 mbedtls_fprintf( stderr, "FAILED: FATAL PARSE ERROR\n" );
                 fclose( file );
+                platform_teardown();
                 mbedtls_exit( 2 );
             }
             else
@@ -501,6 +522,7 @@
             {
                 mbedtls_fprintf( stderr, "Should be empty %d\n",
                                  (int) strlen( buf ) );
+                platform_teardown();
                 return( 1 );
             }
         }
@@ -533,5 +555,6 @@
         close_output( stdout );
 #endif /* __unix__ || __APPLE__ __MACH__ */
 
+    platform_teardown();
     return( total_errors != 0 );
 }