From 7430d2335826665099398ce289a870f9d4b73516 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Tue, 17 Sep 2019 18:18:58 +0200 Subject: [PATCH 1/2] Add a calloc self-test Add a very basic test of calloc to the selftest program. The selftest program acts in its capacity as a platform compatibility checker rather than in its capacity as a test of the library. The main objective is to report whether calloc returns NULL for a size of 0. Also observe whether a free/alloc sequence returns the address that was just freed and whether a size overflow is properly detected. --- programs/test/selftest.c | 83 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) diff --git a/programs/test/selftest.c b/programs/test/selftest.c index 727054ee6..bd28e9a36 100644 --- a/programs/test/selftest.c +++ b/programs/test/selftest.c @@ -66,6 +66,8 @@ #else #include #include +#define mbedtls_calloc calloc +#define mbedtls_free free #define mbedtls_printf printf #define mbedtls_snprintf snprintf #define mbedtls_exit exit @@ -78,6 +80,86 @@ #endif +#if defined MBEDTLS_SELF_TEST +/* Sanity check for malloc. This is not expected to fail, and is rather + * intended to display potentially useful information about the platform, + * in particular the behavior of malloc(0). */ +static int calloc_self_test( int verbose ) +{ + int failures = 0; + void *empty1 = mbedtls_calloc( 0, 1 ); + void *empty2 = mbedtls_calloc( 0, 1 ); + void *buffer1 = mbedtls_calloc( 1, 1 ); + void *buffer2 = mbedtls_calloc( 1, 1 ); + uintptr_t old_buffer1; + + if( empty1 == NULL && empty2 == NULL ) + { + if( verbose ) + mbedtls_printf( " CALLOC(0): passed (NULL)\n" ); + } + else if( empty1 == NULL || empty2 == NULL ) + { + if( verbose ) + mbedtls_printf( " CALLOC(0): failed (mix of NULL and non-NULL)\n" ); + ++failures; + } + else if( empty1 == empty2 ) + { + if( verbose ) + mbedtls_printf( " CALLOC(0): passed (same non-null)\n" ); + } + else + { + if( verbose ) + mbedtls_printf( " CALLOC(0): passed (distinct non-null)\n" ); + } + + if( buffer1 == NULL || buffer2 == NULL ) + { + if( verbose ) + mbedtls_printf( " CALLOC(1): failed (NULL)\n" ); + ++failures; + } + else if( buffer1 == buffer2 ) + { + if( verbose ) + mbedtls_printf( " CALLOC(1): failed (same buffer twice)\n" ); + ++failures; + } + else + { + if( verbose ) + mbedtls_printf( " CALLOC(1): passed\n" ); + } + + old_buffer1 = (uintptr_t) buffer1; + mbedtls_free( buffer1 ); + buffer1 = mbedtls_calloc( 1, 1 ); + if( buffer1 == NULL ) + { + if( verbose ) + mbedtls_printf( " CALLOC(1 again): failed (NULL)\n" ); + ++failures; + } + else + { + if( verbose ) + mbedtls_printf( " CALLOC(1 again): passed (%s address)\n", + (uintptr_t) old_buffer1 == (uintptr_t) buffer1 ? + "same" : "different" ); + } + + if( verbose ) + mbedtls_printf( "\n" ); + mbedtls_free( empty1 ); + mbedtls_free( empty2 ); + mbedtls_free( buffer1 ); + mbedtls_free( buffer2 ); + return( failures ); +} +#endif /* MBEDTLS_SELF_TEST */ + static int test_snprintf( size_t n, const char ref_buf[10], int ref_ret ) { int ret; @@ -174,6 +256,7 @@ typedef struct const selftest_t selftests[] = { + {"calloc", calloc_self_test}, #if defined(MBEDTLS_MD2_C) {"md2", mbedtls_md2_self_test}, #endif From c6b098655e037a8b65a3a83e85efc6fa98c87fa8 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Tue, 17 Sep 2019 19:04:38 +0200 Subject: [PATCH 2/2] Add a test component with malloc(0) returning NULL Exercise the library functions with calloc returning NULL for a size of 0. Make this a separate job with UBSan (and ASan) to detect places where we try to dereference the result of calloc(0) or to do things like buf = calloc(size, 1); if (buf == NULL && size != 0) return INSUFFICIENT_MEMORY; memcpy(buf, source, size); which has undefined behavior when buf is NULL at the memcpy call even if size is 0. This is needed because other test components jobs either use the system malloc which returns non-NULL on Linux and FreeBSD, or the memory_buffer_alloc malloc which returns NULL but does not give as useful feedback with ASan (because the whole heap is a single C object). --- tests/configs/config-wrapper-malloc-0-null.h | 39 ++++++++++++++++++++ tests/scripts/all.sh | 15 ++++++++ 2 files changed, 54 insertions(+) create mode 100644 tests/configs/config-wrapper-malloc-0-null.h diff --git a/tests/configs/config-wrapper-malloc-0-null.h b/tests/configs/config-wrapper-malloc-0-null.h new file mode 100644 index 000000000..ed74eda63 --- /dev/null +++ b/tests/configs/config-wrapper-malloc-0-null.h @@ -0,0 +1,39 @@ +/* config.h wrapper that forces calloc(0) to return NULL. + * Used for testing. + */ +/* + * 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) + */ + +#ifndef MBEDTLS_CONFIG_H +/* Don't #define MBEDTLS_CONFIG_H, let config.h do it. */ + +#include "mbedtls/config.h" + +#include +static inline void *custom_calloc( size_t nmemb, size_t size ) +{ + if( nmemb == 0 || size == 0 ) + return( NULL ); + return( calloc( nmemb, size ) ); +} + +#define MBEDTLS_PLATFORM_MEMORY +#define MBEDTLS_PLATFORM_STD_CALLOC custom_calloc + +#endif /* MBEDTLS_CONFIG_H */ diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh index 3c4681afb..e1be1a4d4 100755 --- a/tests/scripts/all.sh +++ b/tests/scripts/all.sh @@ -992,6 +992,21 @@ component_test_platform_calloc_macro () { make test } +component_test_malloc_0_null () { + msg "build: malloc(0) returns NULL (ASan+UBSan build)" + scripts/config.pl full + scripts/config.pl unset MBEDTLS_MEMORY_BUFFER_ALLOC_C + make CC=gcc CFLAGS="'-DMBEDTLS_CONFIG_FILE=\"$PWD/tests/configs/config-wrapper-malloc-0-null.h\"' -O -Werror -Wall -Wextra -fsanitize=address,undefined" LDFLAGS='-fsanitize=address,undefined' + + msg "test: malloc(0) returns NULL (ASan+UBSan build)" + make test + + msg "selftest: malloc(0) returns NULL (ASan+UBSan build)" + # Just the calloc selftest. "make test" ran the others as part of the + # test suites. + if_build_succeeded programs/test/selftest calloc +} + component_test_aes_fewer_tables () { msg "build: default config with AES_FEWER_TABLES enabled" scripts/config.pl set MBEDTLS_AES_FEWER_TABLES