/* * PSA ITS simulator over stdio files. */ /* * Copyright The Mbed TLS Contributors * 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. */ #include "common.h" #if defined(MBEDTLS_PSA_ITS_FILE_C) #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #define mbedtls_snprintf snprintf #endif #if defined(_WIN32) #include #endif #include "psa_crypto_its.h" #include #include #include #include #if !defined(PSA_ITS_STORAGE_PREFIX) #define PSA_ITS_STORAGE_PREFIX "" #endif #define PSA_ITS_STORAGE_FILENAME_PATTERN "%08x%08x" #define PSA_ITS_STORAGE_SUFFIX ".psa_its" #define PSA_ITS_STORAGE_FILENAME_LENGTH \ ( sizeof( PSA_ITS_STORAGE_PREFIX ) - 1 + /*prefix without terminating 0*/ \ 16 + /*UID (64-bit number in hex)*/ \ sizeof( PSA_ITS_STORAGE_SUFFIX ) - 1 + /*suffix without terminating 0*/ \ 1 /*terminating null byte*/ ) #define PSA_ITS_STORAGE_TEMP \ PSA_ITS_STORAGE_PREFIX "tempfile" PSA_ITS_STORAGE_SUFFIX /* The maximum value of psa_storage_info_t.size */ #define PSA_ITS_MAX_SIZE 0xffffffff #define PSA_ITS_MAGIC_STRING "PSA\0ITS\0" #define PSA_ITS_MAGIC_LENGTH 8 /* As rename fails on Windows if the new filepath already exists, * use MoveFileExA with the MOVEFILE_REPLACE_EXISTING flag instead. * Returns 0 on success, nonzero on failure. */ #if defined(_WIN32) #define rename_replace_existing( oldpath, newpath ) \ ( ! MoveFileExA( oldpath, newpath, MOVEFILE_REPLACE_EXISTING ) ) #else #define rename_replace_existing( oldpath, newpath ) rename( oldpath, newpath ) #endif typedef struct { uint8_t magic[PSA_ITS_MAGIC_LENGTH]; uint8_t size[sizeof( uint32_t )]; uint8_t flags[sizeof( psa_storage_create_flags_t )]; } psa_its_file_header_t; static void psa_its_fill_filename( psa_storage_uid_t uid, char *filename ) { /* Break up the UID into two 32-bit pieces so as not to rely on * long long support in snprintf. */ mbedtls_snprintf( filename, PSA_ITS_STORAGE_FILENAME_LENGTH, "%s" PSA_ITS_STORAGE_FILENAME_PATTERN "%s", PSA_ITS_STORAGE_PREFIX, (unsigned) ( uid >> 32 ), (unsigned) ( uid & 0xffffffff ), PSA_ITS_STORAGE_SUFFIX ); } static psa_status_t psa_its_read_file( psa_storage_uid_t uid, struct psa_storage_info_t *p_info, FILE **p_stream ) { char filename[PSA_ITS_STORAGE_FILENAME_LENGTH]; psa_its_file_header_t header; size_t n; *p_stream = NULL; psa_its_fill_filename( uid, filename ); *p_stream = fopen( filename, "rb" ); if( *p_stream == NULL ) return( PSA_ERROR_DOES_NOT_EXIST ); /* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */ mbedtls_setbuf( *p_stream, NULL ); n = fread( &header, 1, sizeof( header ), *p_stream ); if( n != sizeof( header ) ) return( PSA_ERROR_DATA_CORRUPT ); if( memcmp( header.magic, PSA_ITS_MAGIC_STRING, PSA_ITS_MAGIC_LENGTH ) != 0 ) return( PSA_ERROR_DATA_CORRUPT ); p_info->size = ( header.size[0] | header.size[1] << 8 | header.size[2] << 16 | header.size[3] << 24 ); p_info->flags = ( header.flags[0] | header.flags[1] << 8 | header.flags[2] << 16 | header.flags[3] << 24 ); return( PSA_SUCCESS ); } psa_status_t psa_its_get_info( psa_storage_uid_t uid, struct psa_storage_info_t *p_info ) { psa_status_t status; FILE *stream = NULL; status = psa_its_read_file( uid, p_info, &stream ); if( stream != NULL ) fclose( stream ); return( status ); } psa_status_t psa_its_get( psa_storage_uid_t uid, uint32_t data_offset, uint32_t data_length, void *p_data, size_t *p_data_length ) { psa_status_t status; FILE *stream = NULL; size_t n; struct psa_storage_info_t info; status = psa_its_read_file( uid, &info, &stream ); if( status != PSA_SUCCESS ) goto exit; status = PSA_ERROR_INVALID_ARGUMENT; if( data_offset + data_length < data_offset ) goto exit; #if SIZE_MAX < 0xffffffff if( data_offset + data_length > SIZE_MAX ) goto exit; #endif if( data_offset + data_length > info.size ) goto exit; status = PSA_ERROR_STORAGE_FAILURE; #if LONG_MAX < 0xffffffff while( data_offset > LONG_MAX ) { if( fseek( stream, LONG_MAX, SEEK_CUR ) != 0 ) goto exit; data_offset -= LONG_MAX; } #endif if( fseek( stream, data_offset, SEEK_CUR ) != 0 ) goto exit; n = fread( p_data, 1, data_length, stream ); if( n != data_length ) goto exit; status = PSA_SUCCESS; if( p_data_length != NULL ) *p_data_length = n; exit: if( stream != NULL ) fclose( stream ); return( status ); } psa_status_t psa_its_set( psa_storage_uid_t uid, uint32_t data_length, const void *p_data, psa_storage_create_flags_t create_flags ) { if( uid == 0 ) { return( PSA_ERROR_INVALID_HANDLE ); } psa_status_t status = PSA_ERROR_STORAGE_FAILURE; char filename[PSA_ITS_STORAGE_FILENAME_LENGTH]; FILE *stream = NULL; psa_its_file_header_t header; size_t n; memcpy( header.magic, PSA_ITS_MAGIC_STRING, PSA_ITS_MAGIC_LENGTH ); MBEDTLS_PUT_UINT32_LE( data_length, header.size, 0 ); MBEDTLS_PUT_UINT32_LE( create_flags, header.flags, 0 ); psa_its_fill_filename( uid, filename ); stream = fopen( PSA_ITS_STORAGE_TEMP, "wb" ); if( stream == NULL ) goto exit; /* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */ mbedtls_setbuf( stream, NULL ); status = PSA_ERROR_INSUFFICIENT_STORAGE; n = fwrite( &header, 1, sizeof( header ), stream ); if( n != sizeof( header ) ) goto exit; if( data_length != 0 ) { n = fwrite( p_data, 1, data_length, stream ); if( n != data_length ) goto exit; } status = PSA_SUCCESS; exit: if( stream != NULL ) { int ret = fclose( stream ); if( status == PSA_SUCCESS && ret != 0 ) status = PSA_ERROR_INSUFFICIENT_STORAGE; } if( status == PSA_SUCCESS ) { if( rename_replace_existing( PSA_ITS_STORAGE_TEMP, filename ) != 0 ) status = PSA_ERROR_STORAGE_FAILURE; } /* The temporary file may still exist, but only in failure cases where * we're already reporting an error. So there's nothing we can do on * failure. If the function succeeded, and in some error cases, the * temporary file doesn't exist and so remove() is expected to fail. * Thus we just ignore the return status of remove(). */ (void) remove( PSA_ITS_STORAGE_TEMP ); return( status ); } psa_status_t psa_its_remove( psa_storage_uid_t uid ) { char filename[PSA_ITS_STORAGE_FILENAME_LENGTH]; FILE *stream; psa_its_fill_filename( uid, filename ); stream = fopen( filename, "rb" ); if( stream == NULL ) return( PSA_ERROR_DOES_NOT_EXIST ); fclose( stream ); if( remove( filename ) != 0 ) return( PSA_ERROR_STORAGE_FAILURE ); return( PSA_SUCCESS ); } #endif /* MBEDTLS_PSA_ITS_FILE_C */