Add an acceptance test for memory usage after handshake

Signed-off-by: Piotr Nowicki <piotr.nowicki@arm.com>
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>

programs/ssl/ssl_server2.c

@@ -1838,7 +1838,10 @@ int main( int argc, char *argv[] )
 
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
     mbedtls_memory_buffer_alloc_init( alloc_buf, sizeof(alloc_buf) );
-#endif
+#if defined(MBEDTLS_MEMORY_DEBUG)
+    size_t current_heap_memory, peak_heap_memory, heap_blocks;
+#endif  /* MBEDTLS_MEMORY_DEBUG */
+#endif  /* MBEDTLS_MEMORY_BUFFER_ALLOC_C */
 
     /*
      * Make sure memory references are valid in case we exit early.
@@ -3742,6 +3745,13 @@ handshake:
     }
 #endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
 
+#if defined(MBEDTLS_MEMORY_DEBUG)
+    mbedtls_memory_buffer_alloc_cur_get( &current_heap_memory, &heap_blocks );
+    mbedtls_memory_buffer_alloc_max_get( &peak_heap_memory, &heap_blocks );
+    mbedtls_printf( "Heap memory usage after handshake: %lu bytes. Peak memory usage was %lu\n",
+                    (unsigned long) current_heap_memory, (unsigned long) peak_heap_memory );
+#endif  /* MBEDTLS_MEMORY_DEBUG */
+
     if( opt.exchanges == 0 )
         goto close_notify;
 

tests/scripts/all.sh

@@ -1194,6 +1194,23 @@ component_test_variable_ssl_in_out_buffer_len_record_splitting () {
     if_build_succeeded tests/compat.sh
 }
 
+component_test_ssl_alloc_buffer_and_mfl () {
+    msg "build: default config with memory buffer allocator and MFL extension"
+    scripts/config.py set MBEDTLS_MEMORY_BUFFER_ALLOC_C
+    scripts/config.py set MBEDTLS_PLATFORM_MEMORY
+    scripts/config.py set MBEDTLS_MEMORY_DEBUG
+    scripts/config.py set MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
+    scripts/config.py set MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH
+    CC=gcc cmake .
+    make
+
+    msg "test: MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH, MBEDTLS_MEMORY_BUFFER_ALLOC_C, MBEDTLS_MEMORY_DEBUG and MBEDTLS_SSL_MAX_FRAGMENT_LENGTH"
+    make test
+
+    msg "test: MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH, MBEDTLS_MEMORY_BUFFER_ALLOC_C, MBEDTLS_MEMORY_DEBUG and MBEDTLS_SSL_MAX_FRAGMENT_LENGTH"
+    if_build_succeeded tests/ssl-opt.sh -f "Handshake memory usage"
+}
+
 component_test_when_no_ciphersuites_have_mac () {
     msg "build: when no ciphersuites have MAC"
     scripts/config.py unset MBEDTLS_CIPHER_NULL_CIPHER

tests/ssl-opt.sh

@@ -223,7 +223,7 @@ requires_config_value_at_most() {
 }
 
 requires_ciphersuite_enabled() {
-    if [ -z "$($P_CLI --help | grep $1)" ]; then
+    if [ -z "$($P_CLI --help 2>/dev/null | grep $1)" ]; then
         SKIP_NEXT="YES"
     fi
 }
@@ -525,6 +525,45 @@ check_server_hello_time() {
     fi
 }
 
+# Get handshake memory usage from server or client output and put it into the variable specified by the first argument
+handshake_memory_get() {
+    OUTPUT_VARIABLE="$1"
+    OUTPUT_FILE="$2"
+
+    # Get memory usage from a pattern like "Heap memory usage after handshake: 23112 bytes. Peak memory usage was 33112"
+    MEM_USAGE=$(sed -n 's/.*Heap memory usage after handshake: //p' < "$OUTPUT_FILE" | grep -o "[0-9]*" | head -1)
+
+    # Check if memory usage was read
+    if [ -z "$MEM_USAGE" ]; then
+        echo "Error: Can not read the value of handshake memory usage"
+        return 1
+    else
+        eval "$OUTPUT_VARIABLE=$MEM_USAGE"
+        return 0
+    fi
+}
+
+# Get handshake memory usage from server or client output and check if this value
+# is not higher than the maximum given by the first argument
+handshake_memory_check() {
+    MAX_MEMORY="$1"
+    OUTPUT_FILE="$2"
+
+    # Get memory usage
+    if ! handshake_memory_get "MEMORY_USAGE" "$OUTPUT_FILE"; then
+        return 1
+    fi
+
+    # Check if memory usage is below max value
+    if [ "$MEMORY_USAGE" -gt "$MAX_MEMORY" ]; then
+        echo "\nFailed: Handshake memory usage was $MEMORY_USAGE bytes," \
+             "but should be below $MAX_MEMORY bytes"
+        return 1
+    else
+        return 0
+    fi
+}
+
 # wait for client to terminate and set CLI_EXIT
 # must be called right after starting the client
 wait_client_done() {
@@ -865,6 +904,58 @@ run_test_psa_force_curve() {
                 -C "error"
 }
 
+# Test that the server's memory usage after a handshake is reduced when a client specifies
+# a maximum fragment length.
+#  first argument ($1) is MFL for SSL client
+#  second argument ($2) is memory usage for SSL client with default MFL (16k)
+run_test_memory_after_hanshake_with_mfl()
+{
+    # The test passes if the difference is around 2*(16k-MFL)
+    local MEMORY_USAGE_LIMIT="$(( $2 - ( 2 * ( 16384 - $1 )) ))"
+
+    # Leave some margin for robustness
+    MEMORY_USAGE_LIMIT="$(( ( MEMORY_USAGE_LIMIT * 110 ) / 100 ))"
+
+    run_test    "Handshake memory usage (MFL $1)" \
+                "$P_SRV debug_level=3 auth_mode=required force_version=tls1_2" \
+                "$P_CLI debug_level=3 force_version=tls1_2 \
+                    crt_file=data_files/server5.crt key_file=data_files/server5.key \
+                    force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM max_frag_len=$1" \
+                0 \
+                -F "handshake_memory_check $MEMORY_USAGE_LIMIT"
+}
+
+
+# Test that the server's memory usage after a handshake is reduced when a client specifies
+# different values of Maximum Fragment Length: default (16k), 4k, 2k, 1k and 512 bytes
+run_tests_memory_after_hanshake()
+{
+    # all tests in this sequence requires the same configuration (see requires_config_enabled())
+    SKIP_THIS_TESTS="$SKIP_NEXT"
+
+    # first test with default MFU is to get reference memory usage
+    MEMORY_USAGE_MFL_16K=0
+    run_test    "Handshake memory usage initial (MFL 16384 - default)" \
+                "$P_SRV debug_level=3 auth_mode=required force_version=tls1_2" \
+                "$P_CLI debug_level=3 force_version=tls1_2 \
+                    crt_file=data_files/server5.crt key_file=data_files/server5.key \
+                    force_ciphersuite=TLS-ECDHE-ECDSA-WITH-AES-128-CCM" \
+                0 \
+                -F "handshake_memory_get MEMORY_USAGE_MFL_16K"
+
+    SKIP_NEXT="$SKIP_THIS_TESTS"
+    run_test_memory_after_hanshake_with_mfl 4096 "$MEMORY_USAGE_MFL_16K"
+
+    SKIP_NEXT="$SKIP_THIS_TESTS"
+    run_test_memory_after_hanshake_with_mfl 2048 "$MEMORY_USAGE_MFL_16K"
+
+    SKIP_NEXT="$SKIP_THIS_TESTS"
+    run_test_memory_after_hanshake_with_mfl 1024 "$MEMORY_USAGE_MFL_16K"
+
+    SKIP_NEXT="$SKIP_THIS_TESTS"
+    run_test_memory_after_hanshake_with_mfl 512 "$MEMORY_USAGE_MFL_16K"
+}
+
 cleanup() {
     rm -f $CLI_OUT $SRV_OUT $PXY_OUT $SESSION
     test -n "${SRV_PID:-}" && kill $SRV_PID >/dev/null 2>&1
@@ -8820,6 +8911,12 @@ run_test    "export keys functionality" \
             -c "exported keylen is " \
             -c "exported ivlen is "
 
+# Test heap memory usage after handshake
+requires_config_enabled MBEDTLS_MEMORY_DEBUG
+requires_config_enabled MBEDTLS_MEMORY_BUFFER_ALLOC_C
+requires_config_enabled MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
+run_tests_memory_after_hanshake
+
 # Final report
 
 echo "------------------------------------------------------------------------"