platform.c

00001 /*
00002  *  Platform abstraction layer
00003  *
00004  *  Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
00005  *  SPDX-License-Identifier: Apache-2.0
00006  *
00007  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00008  *  not use this file except in compliance with the License.
00009  *  You may obtain a copy of the License at
00010  *
00011  *  http://www.apache.org/licenses/LICENSE-2.0
00012  *
00013  *  Unless required by applicable law or agreed to in writing, software
00014  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00015  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00016  *  See the License for the specific language governing permissions and
00017  *  limitations under the License.
00018  *
00019  *  This file is part of mbed TLS (https://tls.mbed.org)
00020  */
00021 
00022 #if !defined(MBEDTLS_CONFIG_FILE)
00023 #include "mbedtls/config.h"
00024 #else
00025 #include MBEDTLS_CONFIG_FILE
00026 #endif
00027 
00028 #if defined(MBEDTLS_PLATFORM_C)
00029 
00030 #include "mbedtls/platform.h"
00031 #include "mbedtls/platform_util.h"
00032 
00033 #if defined(MBEDTLS_PLATFORM_MEMORY)
00034 #if !defined(MBEDTLS_PLATFORM_STD_CALLOC)
00035 static void *platform_calloc_uninit( size_t n, size_t size )
00036 {
00037     ((void) n);
00038     ((void) size);
00039     return( NULL );
00040 }
00041 
00042 #define MBEDTLS_PLATFORM_STD_CALLOC   platform_calloc_uninit
00043 #endif /* !MBEDTLS_PLATFORM_STD_CALLOC */
00044 
00045 #if !defined(MBEDTLS_PLATFORM_STD_FREE)
00046 static void platform_free_uninit( void *ptr )
00047 {
00048     ((void) ptr);
00049 }
00050 
00051 #define MBEDTLS_PLATFORM_STD_FREE     platform_free_uninit
00052 #endif /* !MBEDTLS_PLATFORM_STD_FREE */
00053 
00054 static void * (*mbedtls_calloc_func)( size_t, size_t ) = MBEDTLS_PLATFORM_STD_CALLOC;
00055 static void (*mbedtls_free_func)( void * ) = MBEDTLS_PLATFORM_STD_FREE;
00056 
00057 void * mbedtls_calloc( size_t nmemb, size_t size )
00058 {
00059     return (*mbedtls_calloc_func)( nmemb, size );
00060 }
00061 
00062 void mbedtls_free( void * ptr )
00063 {
00064     (*mbedtls_free_func)( ptr );
00065 }
00066 
00067 int mbedtls_platform_set_calloc_free( void * (*calloc_func)( size_t, size_t ),
00068                               void (*free_func)( void * ) )
00069 {
00070     mbedtls_calloc_func = calloc_func;
00071     mbedtls_free_func = free_func;
00072     return( 0 );
00073 }
00074 #endif /* MBEDTLS_PLATFORM_MEMORY */
00075 
00076 #if defined(_WIN32)
00077 #include <stdarg.h>
00078 int mbedtls_platform_win32_snprintf( char *s, size_t n, const char *fmt, ... )
00079 {
00080     int ret;
00081     va_list argp;
00082 
00083     /* Avoid calling the invalid parameter handler by checking ourselves */
00084     if( s == NULL || n == 0 || fmt == NULL )
00085         return( -1 );
00086 
00087     va_start( argp, fmt );
00088 #if defined(_TRUNCATE) && !defined(__MINGW32__)
00089     ret = _vsnprintf_s( s, n, _TRUNCATE, fmt, argp );
00090 #else
00091     ret = _vsnprintf( s, n, fmt, argp );
00092     if( ret < 0 || (size_t) ret == n )
00093     {
00094         s[n-1] = '\0';
00095         ret = -1;
00096     }
00097 #endif
00098     va_end( argp );
00099 
00100     return( ret );
00101 }
00102 #endif
00103 
00104 #if defined(MBEDTLS_PLATFORM_SNPRINTF_ALT)
00105 #if !defined(MBEDTLS_PLATFORM_STD_SNPRINTF)
00106 /*
00107  * Make dummy function to prevent NULL pointer dereferences
00108  */
00109 static int platform_snprintf_uninit( char * s, size_t n,
00110                                      const char * format, ... )
00111 {
00112     ((void) s);
00113     ((void) n);
00114     ((void) format);
00115     return( 0 );
00116 }
00117 
00118 #define MBEDTLS_PLATFORM_STD_SNPRINTF    platform_snprintf_uninit
00119 #endif /* !MBEDTLS_PLATFORM_STD_SNPRINTF */
00120 
00121 int (*mbedtls_snprintf)( char * s, size_t n,
00122                           const char * format,
00123                           ... ) = MBEDTLS_PLATFORM_STD_SNPRINTF;
00124 
00125 int mbedtls_platform_set_snprintf( int (*snprintf_func)( char * s, size_t n,
00126                                                  const char * format,
00127                                                  ... ) )
00128 {
00129     mbedtls_snprintf = snprintf_func;
00130     return( 0 );
00131 }
00132 #endif /* MBEDTLS_PLATFORM_SNPRINTF_ALT */
00133 
00134 #if defined(MBEDTLS_PLATFORM_PRINTF_ALT)
00135 #if !defined(MBEDTLS_PLATFORM_STD_PRINTF)
00136 /*
00137  * Make dummy function to prevent NULL pointer dereferences
00138  */
00139 static int platform_printf_uninit( const char *format, ... )
00140 {
00141     ((void) format);
00142     return( 0 );
00143 }
00144 
00145 #define MBEDTLS_PLATFORM_STD_PRINTF    platform_printf_uninit
00146 #endif /* !MBEDTLS_PLATFORM_STD_PRINTF */
00147 
00148 int (*mbedtls_printf)( const char *, ... ) = MBEDTLS_PLATFORM_STD_PRINTF;
00149 
00150 int mbedtls_platform_set_printf( int (*printf_func)( const char *, ... ) )
00151 {
00152     mbedtls_printf = printf_func;
00153     return( 0 );
00154 }
00155 #endif /* MBEDTLS_PLATFORM_PRINTF_ALT */
00156 
00157 #if defined(MBEDTLS_PLATFORM_FPRINTF_ALT)
00158 #if !defined(MBEDTLS_PLATFORM_STD_FPRINTF)
00159 /*
00160  * Make dummy function to prevent NULL pointer dereferences
00161  */
00162 static int platform_fprintf_uninit( FILE *stream, const char *format, ... )
00163 {
00164     ((void) stream);
00165     ((void) format);
00166     return( 0 );
00167 }
00168 
00169 #define MBEDTLS_PLATFORM_STD_FPRINTF   platform_fprintf_uninit
00170 #endif /* !MBEDTLS_PLATFORM_STD_FPRINTF */
00171 
00172 int (*mbedtls_fprintf)( FILE *, const char *, ... ) =
00173                                         MBEDTLS_PLATFORM_STD_FPRINTF;
00174 
00175 int mbedtls_platform_set_fprintf( int (*fprintf_func)( FILE *, const char *, ... ) )
00176 {
00177     mbedtls_fprintf = fprintf_func;
00178     return( 0 );
00179 }
00180 #endif /* MBEDTLS_PLATFORM_FPRINTF_ALT */
00181 
00182 #if defined(MBEDTLS_PLATFORM_EXIT_ALT)
00183 #if !defined(MBEDTLS_PLATFORM_STD_EXIT)
00184 /*
00185  * Make dummy function to prevent NULL pointer dereferences
00186  */
00187 static void platform_exit_uninit( int status )
00188 {
00189     ((void) status);
00190 }
00191 
00192 #define MBEDTLS_PLATFORM_STD_EXIT   platform_exit_uninit
00193 #endif /* !MBEDTLS_PLATFORM_STD_EXIT */
00194 
00195 void (*mbedtls_exit)( int status ) = MBEDTLS_PLATFORM_STD_EXIT;
00196 
00197 int mbedtls_platform_set_exit( void (*exit_func)( int status ) )
00198 {
00199     mbedtls_exit = exit_func;
00200     return( 0 );
00201 }
00202 #endif /* MBEDTLS_PLATFORM_EXIT_ALT */
00203 
00204 #if defined(MBEDTLS_HAVE_TIME)
00205 
00206 #if defined(MBEDTLS_PLATFORM_TIME_ALT)
00207 #if !defined(MBEDTLS_PLATFORM_STD_TIME)
00208 /*
00209  * Make dummy function to prevent NULL pointer dereferences
00210  */
00211 static mbedtls_time_t platform_time_uninit( mbedtls_time_t* timer )
00212 {
00213     ((void) timer);
00214     return( 0 );
00215 }
00216 
00217 #define MBEDTLS_PLATFORM_STD_TIME   platform_time_uninit
00218 #endif /* !MBEDTLS_PLATFORM_STD_TIME */
00219 
00220 mbedtls_time_t (*mbedtls_time)( mbedtls_time_t* timer ) = MBEDTLS_PLATFORM_STD_TIME;
00221 
00222 int mbedtls_platform_set_time( mbedtls_time_t (*time_func)( mbedtls_time_t* timer ) )
00223 {
00224     mbedtls_time = time_func;
00225     return( 0 );
00226 }
00227 #endif /* MBEDTLS_PLATFORM_TIME_ALT */
00228 
00229 #endif /* MBEDTLS_HAVE_TIME */
00230 
00231 #if defined(MBEDTLS_ENTROPY_NV_SEED)
00232 #if !defined(MBEDTLS_PLATFORM_NO_STD_FUNCTIONS) && defined(MBEDTLS_FS_IO)
00233 /* Default implementations for the platform independent seed functions use
00234  * standard libc file functions to read from and write to a pre-defined filename
00235  */
00236 int mbedtls_platform_std_nv_seed_read( unsigned char *buf, size_t buf_len )
00237 {
00238     FILE *file;
00239     size_t n;
00240 
00241     if( ( file = fopen( MBEDTLS_PLATFORM_STD_NV_SEED_FILE, "rb" ) ) == NULL )
00242         return( -1 );
00243 
00244     if( ( n = fread( buf, 1, buf_len, file ) ) != buf_len )
00245     {
00246         fclose( file );
00247         mbedtls_platform_zeroize( buf, buf_len );
00248         return( -1 );
00249     }
00250 
00251     fclose( file );
00252     return( (int)n );
00253 }
00254 
00255 int mbedtls_platform_std_nv_seed_write( unsigned char *buf, size_t buf_len )
00256 {
00257     FILE *file;
00258     size_t n;
00259 
00260     if( ( file = fopen( MBEDTLS_PLATFORM_STD_NV_SEED_FILE, "w" ) ) == NULL )
00261         return -1;
00262 
00263     if( ( n = fwrite( buf, 1, buf_len, file ) ) != buf_len )
00264     {
00265         fclose( file );
00266         return -1;
00267     }
00268 
00269     fclose( file );
00270     return( (int)n );
00271 }
00272 #endif /* MBEDTLS_PLATFORM_NO_STD_FUNCTIONS */
00273 
00274 #if defined(MBEDTLS_PLATFORM_NV_SEED_ALT)
00275 #if !defined(MBEDTLS_PLATFORM_STD_NV_SEED_READ)
00276 /*
00277  * Make dummy function to prevent NULL pointer dereferences
00278  */
00279 static int platform_nv_seed_read_uninit( unsigned char *buf, size_t buf_len )
00280 {
00281     ((void) buf);
00282     ((void) buf_len);
00283     return( -1 );
00284 }
00285 
00286 #define MBEDTLS_PLATFORM_STD_NV_SEED_READ   platform_nv_seed_read_uninit
00287 #endif /* !MBEDTLS_PLATFORM_STD_NV_SEED_READ */
00288 
00289 #if !defined(MBEDTLS_PLATFORM_STD_NV_SEED_WRITE)
00290 /*
00291  * Make dummy function to prevent NULL pointer dereferences
00292  */
00293 static int platform_nv_seed_write_uninit( unsigned char *buf, size_t buf_len )
00294 {
00295     ((void) buf);
00296     ((void) buf_len);
00297     return( -1 );
00298 }
00299 
00300 #define MBEDTLS_PLATFORM_STD_NV_SEED_WRITE   platform_nv_seed_write_uninit
00301 #endif /* !MBEDTLS_PLATFORM_STD_NV_SEED_WRITE */
00302 
00303 int (*mbedtls_nv_seed_read)( unsigned char *buf, size_t buf_len ) =
00304             MBEDTLS_PLATFORM_STD_NV_SEED_READ;
00305 int (*mbedtls_nv_seed_write)( unsigned char *buf, size_t buf_len ) =
00306             MBEDTLS_PLATFORM_STD_NV_SEED_WRITE;
00307 
00308 int mbedtls_platform_set_nv_seed(
00309         int (*nv_seed_read_func)( unsigned char *buf, size_t buf_len ),
00310         int (*nv_seed_write_func)( unsigned char *buf, size_t buf_len ) )
00311 {
00312     mbedtls_nv_seed_read = nv_seed_read_func;
00313     mbedtls_nv_seed_write = nv_seed_write_func;
00314     return( 0 );
00315 }
00316 #endif /* MBEDTLS_PLATFORM_NV_SEED_ALT */
00317 #endif /* MBEDTLS_ENTROPY_NV_SEED */
00318 
00319 #if !defined(MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT)
00320 /*
00321  * Placeholder platform setup that does nothing by default
00322  */
00323 int mbedtls_platform_setup( mbedtls_platform_context *ctx )
00324 {
00325     (void)ctx;
00326 
00327     return( 0 );
00328 }
00329 
00330 /*
00331  * Placeholder platform teardown that does nothing by default
00332  */
00333 void mbedtls_platform_teardown( mbedtls_platform_context *ctx )
00334 {
00335     (void)ctx;
00336 }
00337 #endif /* MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT */
00338 
00339 #endif /* MBEDTLS_PLATFORM_C */