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g: common: introduce generic crypto API

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On boards based on the g chip cryptographic functions come from
hardware, they should be implemented in chip/g as opposed to a
particular board.

The common modules (like nvmem) should be using some generic API,
which hopefully will be implemented by other chips, or could be
replaced by a purely software implementation where crypto hardware
support is not available.

Crypto API definition is being added in include/ and the g chip
implementation (a wrapper around dcrypto functions) is being added in
chip/g.

test/nvmem_vars.h needed to be edited to avoid conflict with
<string.h>.

BRANCH=none
BUG=chrome-os-partner:62260
TEST=make buildall -j still passes. Booting reef with the new image
     works fine too.

Change-Id: Ifef281215f89239966882ecbe3e90c8351b9b91a
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/431313
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Nagendra Modadugu <ngm@google.com>
This commit is contained in:
Vadim Bendebury
2017-01-22 21:25:42 -08:00
committed by chrome-bot
parent 09fca7bddb
commit 7d2e4fbf5b
9 changed files with 116 additions and 45 deletions
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55
include/crypto_api.h Normal file
View File

@@ -0,0 +1,55 @@
/*
* Copyright 2017 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef __INCLUDE_CRYPTO_API_H
#define __INCLUDE_CRYPTO_API_H
#include "util.h"
/**
* Calculate hash of an arbitrary data
*
* Up to SHA_DIGEST_SIZE byte hash can be generated, if hash_len is
* longer - it is padded with zeros.
*
* @param p_buf: pointer to beginning of data
* @param num_bytes: length of data in bytes
* @param p_hash: pointer to where computed hash will be stored
* @param hash_len: length in bytes to use from sha computation. If this
* value exceeds SHA1 size (20 bytes), the rest of the
* hash is filled up with zeros.
*/
void app_compute_hash(uint8_t *p_buf, size_t num_bytes,
uint8_t *p_hash, size_t hash_len);
#define CIPHER_SALT_SIZE 16
/*
* Encrypt/decrypt a flat blob.
*
* Encrypt or decrypt the input buffer, and write the correspondingly
* ciphered output to out. The number of bytes produced is equal to
* the number of input bytes.
*
* This API is expected to be applied to a single contiguous region. WARNING:
* Presently calling this function more than once with "in" pointing to
* logically different buffers will result in using the same IV value
* internally and as such reduce encryption efficiency.
*
* @param salt pointer to a unique value to be associated with this blob,
* used for derivation of the proper IV, the size of this value
* is as defined by CIPHER_SALT_SIZE above.
* WARNING: a given salt/"in" pair must be unique (it is an ERROR
* to use a given salt with more than one unique buffer). For an
* example, a good salt would be a digest of the plaintext input.
* @param out Destination pointer where to write plaintext / ciphertext.
* @param in Source pointer where to read ciphertext / plaintext.
* @param len Number of bytes to read from in / write to out.
* @return non-zero on success, and zero otherwise.
*/
int app_cipher(const void *salt, void *out, const void *in, size_t size);
#endif /* __INCLUDE_CRYPTO_API_H */

13
include/nvmem.h
View File

@@ -6,6 +6,8 @@
#ifndef __CROS_EC_NVMEM_UTILS_H
#define __CROS_EC_NVMEM_UTILS_H
#include "crypto_api.h"
/*
* In order to provide maximum robustness for NvMem operations, the NvMem space
* is divided into two equal sized partitions. A partition contains a tag
@@ -166,17 +168,6 @@ int nvmem_commit(void);
*/
int nvmem_setup(uint8_t generation);
/**
* Compute sha1 (lower 4 bytes or equivalent checksum) for NvMem tag
*
* @param p_buf: pointer to beginning of data
* @param num_bytes: length of data in bytes
* @param p_sha: pointer to where computed sha will be stored
* @param sha_len: length in bytes to use from sha computation
*/
void nvmem_compute_sha(uint8_t *p_buf, int num_bytes, uint8_t *p_sha,
int sha_len);
/*
* Temporarily stopping NVMEM commits could be beneficial. One use case is
* when TPM operations need to be sped up.