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