u-boot/common/cmd_blob.c
Ruchika Gupta c5de15cbc8 crypto/fsl: Add command for encapsulating/decapsulating blobs
Freescale's SEC block has built-in Blob Protocol which provides
a method for protecting user-defined data across system power
cycles. SEC block protects data in a data structure called a Blob,
which provides both confidentiality and integrity protection.

Encapsulating data as a blob
Each time that the Blob Protocol is used to protect data, a
different randomly generated key is used to encrypt the data.
This random key is itself encrypted using a key which is derived
from SoC's non volatile secret key and a 16 bit Key identifier.
The resulting encrypted key along with encrypted data is called a blob.
The non volatile secure key is available for use only during secure boot.

During decapsulation, the reverse process is performed to get back
the original data.

Commands added
--------------
    blob enc - encapsulating data as a cryptgraphic blob
    blob dec - decapsulating cryptgraphic blob to get the data

Commands Syntax
---------------
	blob enc src dst len km

	Encapsulate and create blob of data $len bytes long
	at address $src and store the result at address $dst.
	$km is the 16 byte key modifier is also required for
	generation/use as key for cryptographic operation. Key
	modifier should be 16 byte long.

	blob dec src dst len km

	Decapsulate the  blob of data at address $src and
	store result of $len byte at addr $dst.
	$km is the 16 byte key modifier is also required for
	generation/use as key for cryptographic operation. Key
	modifier should be 16 byte long.

Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
2014-10-16 14:20:40 -07:00

110 lines
3.1 KiB
C

/*
*
* Command for encapsulating/decapsulating blob of memory.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <command.h>
#include <environment.h>
#include <malloc.h>
#include <asm/byteorder.h>
#include <linux/compiler.h>
DECLARE_GLOBAL_DATA_PTR;
/**
* blob_decap() - Decapsulate the data as a blob
* @key_mod: - Pointer to key modifier/key
* @src: - Address of data to be decapsulated
* @dst: - Address of data to be decapsulated
* @len: - Size of data to be decapsulated
*
* Returns zero on success,and negative on error.
*/
__weak int blob_decap(u8 *key_mod, u8 *src, u8 *dst, u32 len)
{
return 0;
}
/**
* blob_encap() - Encapsulate the data as a blob
* @key_mod: - Pointer to key modifier/key
* @src: - Address of data to be encapsulated
* @dst: - Address of data to be encapsulated
* @len: - Size of data to be encapsulated
*
* Returns zero on success,and negative on error.
*/
__weak int blob_encap(u8 *key_mod, u8 *src, u8 *dst, u32 len)
{
return 0;
}
/**
* do_blob() - Handle the "blob" command-line command
* @cmdtp: Command data struct pointer
* @flag: Command flag
* @argc: Command-line argument count
* @argv: Array of command-line arguments
*
* Returns zero on success, CMD_RET_USAGE in case of misuse and negative
* on error.
*/
static int do_blob(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
{
uint32_t key_addr, src_addr, dst_addr, len;
uint8_t *km_ptr, *src_ptr, *dst_ptr;
int enc, ret = 0;
if (argc != 6)
return CMD_RET_USAGE;
if (!strncmp(argv[1], "enc", 3))
enc = 1;
else if (!strncmp(argv[1], "dec", 3))
enc = 0;
else
return CMD_RET_USAGE;
src_addr = simple_strtoul(argv[2], NULL, 16);
dst_addr = simple_strtoul(argv[3], NULL, 16);
len = simple_strtoul(argv[4], NULL, 16);
key_addr = simple_strtoul(argv[5], NULL, 16);
km_ptr = (uint8_t *)key_addr;
src_ptr = (uint8_t *)src_addr;
dst_ptr = (uint8_t *)dst_addr;
if (enc)
ret = blob_encap(km_ptr, src_ptr, dst_ptr, len);
else
ret = blob_decap(km_ptr, src_ptr, dst_ptr, len);
return ret;
}
/***************************************************/
static char blob_help_text[] =
"enc src dst len km - Encapsulate and create blob of data\n"
" $len bytes long at address $src and\n"
" store the result at address $dst.\n"
" $km is the 16 byte key modifier\n"
" is also required for generation/use as\n"
" key for cryptographic operation. Key\n"
" modifier should be 16 byte long.\n"
"blob dec src dst len km - Decapsulate the blob of data at address\n"
" $src and store result of $len byte at\n"
" addr $dst.\n"
" $km is the 16 byte key modifier\n"
" is also required for generation/use as\n"
" key for cryptographic operation. Key\n"
" modifier should be 16 byte long.\n";
U_BOOT_CMD(
blob, 6, 1, do_blob,
"Blob encapsulation/decryption",
blob_help_text
);