Fix premature fopen() call in mbedtls_entropy_write_seed_file #3175

Signed-off-by: Victor Krasnoshchok <ct3da21164@protonmail.ch>
This commit is contained in:
Victor Krasnoshchok 2020-08-27 00:19:55 +03:00
parent d69edda8de
commit 12b89cbc0b
No known key found for this signature in database
GPG key ID: E2B10814BCFC65CE
4 changed files with 36 additions and 5 deletions

View file

@ -0,0 +1,5 @@
Bugfix
* Fix premature fopen() call in mbedtls_entropy_write_seed_file which may
lead to the seed file corruption in case if the path to the seed file is
equal to MBEDTLS_PLATFORM_STD_NV_SEED_FILE. Contributed by Victor
Krasnoshchok in #3616.

View file

@ -489,14 +489,20 @@ int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx )
int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path )
{
int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
FILE *f;
FILE *f = NULL;
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
if( ( f = fopen( path, "wb" ) ) == NULL )
return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR );
if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 )
{
ret = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
goto exit;
}
if( ( f = fopen( path, "wb" ) ) == NULL )
{
ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR;
goto exit;
}
if( fwrite( buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f ) != MBEDTLS_ENTROPY_BLOCK_SIZE )
{
@ -509,7 +515,9 @@ int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *p
exit:
mbedtls_platform_zeroize( buf, sizeof( buf ) );
if( f != NULL )
fclose( f );
return( ret );
}

View file

@ -7,6 +7,9 @@ entropy_seed_file:"data_files/entropy_seed":0
Entropy write/update seed file
entropy_seed_file:"no_such_dir/file":MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR
Entropy write/update seed file: base NV seed file
entropy_write_base_seed_file:0
Entropy too many sources
entropy_too_many_sources:

View file

@ -140,6 +140,21 @@ exit:
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_FS_IO */
void entropy_write_base_seed_file( int ret )
{
mbedtls_entropy_context ctx;
mbedtls_entropy_init( &ctx );
TEST_ASSERT( mbedtls_entropy_write_seed_file( &ctx, MBEDTLS_PLATFORM_STD_NV_SEED_FILE ) == ret );
TEST_ASSERT( mbedtls_entropy_update_seed_file( &ctx, MBEDTLS_PLATFORM_STD_NV_SEED_FILE ) == ret );
exit:
mbedtls_entropy_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void entropy_too_many_sources( )
{