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/* Copyright (c) 2014 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.
*
* Externally-callable APIs
* (Firmware portion)
*/
#include "2sysincludes.h"
#include "2api.h"
#include "2common.h"
#include "2misc.h"
#include "2nvstorage.h"
#include "2secdata.h"
#include "2sha.h"
#include "2rsa.h"
#include "vb21_common.h"
vb2_error_t vb21api_fw_phase3(struct vb2_context *ctx)
{
vb2_error_t rv;
/* Verify firmware keyblock */
rv = vb21_load_fw_keyblock(ctx);
if (rv) {
vb2_fail(ctx, VB2_RECOVERY_RO_INVALID_RW, rv);
return rv;
}
/* Verify firmware preamble */
rv = vb21_load_fw_preamble(ctx);
if (rv) {
vb2_fail(ctx, VB2_RECOVERY_RO_INVALID_RW, rv);
return rv;
}
return VB2_SUCCESS;
}
vb2_error_t vb21api_init_hash(struct vb2_context *ctx,
const struct vb2_id *id,
uint32_t *size)
{
struct vb2_shared_data *sd = vb2_get_sd(ctx);
const struct vb21_fw_preamble *pre;
const struct vb21_signature *sig = NULL;
struct vb2_digest_context *dc;
struct vb2_workbuf wb;
uint32_t hash_offset;
int i, rv;
vb2_workbuf_from_ctx(ctx, &wb);
/* Get preamble pointer */
if (!sd->preamble_size)
return VB2_ERROR_API_INIT_HASH_PREAMBLE;
pre = (const struct vb21_fw_preamble *)
vb2_member_of(sd, sd->preamble_offset);
/* Find the matching signature */
hash_offset = pre->hash_offset;
for (i = 0; i < pre->hash_count; i++) {
sig = (const struct vb21_signature *)
((uint8_t *)pre + hash_offset);
if (!memcmp(id, &sig->id, sizeof(*id)))
break;
hash_offset += sig->c.total_size;
}
if (i >= pre->hash_count)
return VB2_ERROR_API_INIT_HASH_ID; /* No match */
/* Allocate workbuf space for the hash */
if (sd->hash_size) {
dc = (struct vb2_digest_context *)
vb2_member_of(sd, sd->hash_offset);
} else {
uint32_t dig_size = sizeof(*dc);
dc = vb2_workbuf_alloc(&wb, dig_size);
if (!dc)
return VB2_ERROR_API_INIT_HASH_WORKBUF;
sd->hash_offset = vb2_offset_of(sd, dc);
sd->hash_size = dig_size;
vb2_set_workbuf_used(ctx, sd->hash_offset + dig_size);
}
sd->hash_tag = vb2_offset_of(sd, sig);
sd->hash_remaining_size = sig->data_size;
if (size)
*size = sig->data_size;
if (!(pre->flags & VB21_FIRMWARE_PREAMBLE_DISALLOW_HWCRYPTO)) {
rv = vb2ex_hwcrypto_digest_init(sig->hash_alg, sig->data_size);
if (!rv) {
VB2_DEBUG("Using HW crypto engine for hash_alg %d\n",
sig->hash_alg);
dc->hash_alg = sig->hash_alg;
dc->using_hwcrypto = 1;
return VB2_SUCCESS;
}
if (rv != VB2_ERROR_EX_HWCRYPTO_UNSUPPORTED)
return rv;
VB2_DEBUG("HW crypto for hash_alg %d not supported, using SW\n",
sig->hash_alg);
} else {
VB2_DEBUG("HW crypto forbidden by preamble, using SW\n");
}
return vb2_digest_init(dc, sig->hash_alg);
}
vb2_error_t vb21api_check_hash(struct vb2_context *ctx)
{
struct vb2_shared_data *sd = vb2_get_sd(ctx);
struct vb2_digest_context *dc = (struct vb2_digest_context *)
vb2_member_of(sd, sd->hash_offset);
struct vb2_workbuf wb;
uint8_t *digest;
uint32_t digest_size = vb2_digest_size(dc->hash_alg);
const struct vb21_signature *sig;
vb2_error_t rv;
vb2_workbuf_from_ctx(ctx, &wb);
/* Get signature pointer */
if (!sd->hash_tag)
return VB2_ERROR_API_CHECK_HASH_TAG;
sig = vb2_member_of(sd, sd->hash_tag);
/* Must have initialized hash digest work area */
if (!sd->hash_size)
return VB2_ERROR_API_CHECK_HASH_WORKBUF;
/* Should have hashed the right amount of data */
if (sd->hash_remaining_size)
return VB2_ERROR_API_CHECK_HASH_SIZE;
/* Allocate the digest */
digest = vb2_workbuf_alloc(&wb, digest_size);
if (!digest)
return VB2_ERROR_API_CHECK_HASH_WORKBUF_DIGEST;
/* Finalize the digest */
if (dc->using_hwcrypto)
rv = vb2ex_hwcrypto_digest_finalize(digest, digest_size);
else
rv = vb2_digest_finalize(dc, digest, digest_size);
if (rv)
return rv;
/* Compare with the signature */
if (vb2_safe_memcmp(digest, (const uint8_t *)sig + sig->sig_offset,
digest_size))
return VB2_ERROR_API_CHECK_HASH_SIG;
/* TODO: the old check-hash function called vb2_fail() on any mismatch.
* I don't think it should do that; the caller should. */
return VB2_SUCCESS;
}
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