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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>
109 lines
3.1 KiB
C
109 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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