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/* Copyright 2015 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.
*
* Kernel verified boot functions
*/
#include "2sysincludes.h"
#include "2rsa.h"
#include "2sha.h"
#include "vb2_common.h"
int vb2_verify_kernel_preamble(struct vb2_kernel_preamble *preamble,
uint32_t size,
const struct vb2_public_key *key,
const struct vb2_workbuf *wb)
{
struct vb2_signature *sig = &preamble->preamble_signature;
VB2_DEBUG("Verifying kernel preamble.\n");
/* Sanity checks before attempting signature of data */
if(size < sizeof(*preamble)) {
VB2_DEBUG("Not enough data for preamble header.\n");
return VB2_ERROR_PREAMBLE_TOO_SMALL_FOR_HEADER;
}
if (preamble->header_version_major !=
KERNEL_PREAMBLE_HEADER_VERSION_MAJOR) {
VB2_DEBUG("Incompatible kernel preamble header version.\n");
return VB2_ERROR_PREAMBLE_HEADER_VERSION;
}
if (preamble->header_version_minor < 2) {
VB2_DEBUG("Old preamble header format not supported\n");
return VB2_ERROR_PREAMBLE_HEADER_OLD;
}
if (size < preamble->preamble_size) {
VB2_DEBUG("Not enough data for preamble.\n");
return VB2_ERROR_PREAMBLE_SIZE;
}
/* Check signature */
if (vb2_verify_signature_inside(preamble, preamble->preamble_size,
sig)) {
VB2_DEBUG("Preamble signature off end of preamble\n");
return VB2_ERROR_PREAMBLE_SIG_OUTSIDE;
}
/* Make sure advertised signature data sizes are sane. */
if (preamble->preamble_size < sig->data_size) {
VB2_DEBUG("Signature calculated past end of the block\n");
return VB2_ERROR_PREAMBLE_SIGNED_TOO_MUCH;
}
if (vb2_verify_data((const uint8_t *)preamble, size, sig, key, wb)) {
VB2_DEBUG("Preamble signature validation failed\n");
return VB2_ERROR_PREAMBLE_SIG_INVALID;
}
/* Verify we signed enough data */
if (sig->data_size < sizeof(struct vb2_fw_preamble)) {
VB2_DEBUG("Didn't sign enough data\n");
return VB2_ERROR_PREAMBLE_SIGNED_TOO_LITTLE;
}
/* Verify body signature is inside the signed data */
if (vb2_verify_signature_inside(preamble, sig->data_size,
&preamble->body_signature)) {
VB2_DEBUG("Body signature off end of preamble\n");
return VB2_ERROR_PREAMBLE_BODY_SIG_OUTSIDE;
}
/*
* If bootloader is present, verify it's covered by the body
* signature.
*/
if (preamble->bootloader_size) {
const void *body_ptr =
(const void *)(uintptr_t)preamble->body_load_address;
const void *bootloader_ptr =
(const void *)(uintptr_t)preamble->bootloader_address;
if (vb2_verify_member_inside(body_ptr,
preamble->body_signature.data_size,
bootloader_ptr,
preamble->bootloader_size,
0, 0)) {
VB2_DEBUG("Bootloader off end of signed data\n");
return VB2_ERROR_PREAMBLE_BOOTLOADER_OUTSIDE;
}
}
/*
* If vmlinuz header is present, verify it's covered by the body
* signature.
*/
if (preamble->vmlinuz_header_size) {
const void *body_ptr =
(const void *)(uintptr_t)preamble->body_load_address;
const void *vmlinuz_header_ptr = (const void *)
(uintptr_t)preamble->vmlinuz_header_address;
if (vb2_verify_member_inside(body_ptr,
preamble->body_signature.data_size,
vmlinuz_header_ptr,
preamble->vmlinuz_header_size,
0, 0)) {
VB2_DEBUG("Vmlinuz header off end of signed data\n");
return VB2_ERROR_PREAMBLE_VMLINUZ_HEADER_OUTSIDE;
}
}
/* Success */
return VB2_SUCCESS;
}
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