Introduce platform-layer functions for reading/writing seed from NV
Introduces mbedtls_nv_seed_read() and mbedtls_nv_seed_write().
The platform-layer functions are only available when
MBEDTLS_ENTROPY_NV_SEED is enabled.
diff --git a/library/platform.c b/library/platform.c
index 89a2bd6..68ca45d 100644
--- a/library/platform.c
+++ b/library/platform.c
@@ -1,7 +1,7 @@
/*
* Platform abstraction layer
*
- * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ * Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
@@ -213,4 +213,91 @@
}
#endif /* MBEDTLS_PLATFORM_TIME_ALT */
+#if defined(MBEDTLS_ENTROPY_NV_SEED)
+#if !defined(MBEDTLS_PLATFORM_NO_STD_FUNCTIONS) && defined(MBEDTLS_FS_IO)
+/* Default implementations for the platform independent seed functions use
+ * standard libc file functions to read from and write to a pre-defined filename
+ */
+int mbedtls_platform_std_nv_seed_read( unsigned char *buf, size_t buf_len )
+{
+ FILE *file;
+ size_t n;
+
+ if( ( file = fopen( MBEDTLS_PLATFORM_STD_NV_SEED_FILE, "rb" ) ) == NULL )
+ return -1;
+
+ if( ( n = fread( buf, 1, buf_len, file ) ) != buf_len )
+ {
+ fclose( file );
+ return -1;
+ }
+
+ fclose( file );
+ return( n );
+}
+
+int mbedtls_platform_std_nv_seed_write( unsigned char *buf, size_t buf_len )
+{
+ FILE *file;
+ size_t n;
+
+ if( ( file = fopen( MBEDTLS_PLATFORM_STD_NV_SEED_FILE, "w" ) ) == NULL )
+ return -1;
+
+ if( ( n = fwrite( buf, 1, buf_len, file ) ) != buf_len )
+ {
+ fclose( file );
+ return -1;
+ }
+
+ fclose( file );
+ return( n );
+}
+#endif /* MBEDTLS_PLATFORM_NO_STD_FUNCTIONS */
+
+#if defined(MBEDTLS_PLATFORM_NV_SEED_ALT)
+#if !defined(MBEDTLS_PLATFORM_STD_NV_SEED_READ)
+/*
+ * Make dummy function to prevent NULL pointer dereferences
+ */
+static int platform_nv_seed_read_uninit( unsigned char *buf, size_t buf_len )
+{
+ ((void) buf);
+ ((void) buf_len);
+ return( -1 );
+}
+
+#define MBEDTLS_PLATFORM_STD_NV_SEED_READ platform_nv_seed_read_uninit
+#endif /* !MBEDTLS_PLATFORM_STD_NV_SEED_READ */
+
+#if !defined(MBEDTLS_PLATFORM_STD_NV_SEED_WRITE)
+/*
+ * Make dummy function to prevent NULL pointer dereferences
+ */
+static int platform_nv_seed_write_uninit( unsigned char *buf, size_t buf_len )
+{
+ ((void) buf);
+ ((void) buf_len);
+ return( -1 );
+}
+
+#define MBEDTLS_PLATFORM_STD_NV_SEED_WRITE platform_nv_seed_write_uninit
+#endif /* !MBEDTLS_PLATFORM_STD_NV_SEED_WRITE */
+
+int (*mbedtls_nv_seed_read)( unsigned char *buf, size_t buf_len ) =
+ MBEDTLS_PLATFORM_STD_NV_SEED_READ;
+int (*mbedtls_nv_seed_write)( unsigned char *buf, size_t buf_len ) =
+ MBEDTLS_PLATFORM_STD_NV_SEED_WRITE;
+
+int mbedtls_platform_set_nv_seed(
+ int (*nv_seed_read_func)( unsigned char *buf, size_t buf_len ),
+ int (*nv_seed_write_func)( unsigned char *buf, size_t buf_len ) )
+{
+ mbedtls_nv_seed_read = nv_seed_read_func;
+ mbedtls_nv_seed_write = nv_seed_write_func;
+ return( 0 );
+}
+#endif /* MBEDTLS_PLATFORM_NV_SEED_ALT */
+#endif /* MBEDTLS_ENTROPY_NV_SEED */
+
#endif /* MBEDTLS_PLATFORM_C */