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2d25e837cc
This also checks that the bootloader and vmlinuz headers, if present, are within the signed part of the kernel blob; the vboot1 routines didn't do that. That wasn't harmful at firmware boot time because the vboot1 routines would only load as much data as was signed, but in vboot2 loading the kernel data is the responsibility of the caller so we need to check. BUG=chromium:487699 BRANCH=none TEST=make -j runtests Change-Id: I73eb4831e5d3d7a642b6cb85cb55857d87fcc0af Signed-off-by: Randall Spangler <rspangler@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/270797
113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
/* Copyright 2015 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*
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* Kernel verified boot functions
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*/
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#include "2sysincludes.h"
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#include "2rsa.h"
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#include "2sha.h"
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#include "vb2_common.h"
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int vb2_verify_kernel_preamble(struct vb2_kernel_preamble *preamble,
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uint32_t size,
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const struct vb2_public_key *key,
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const struct vb2_workbuf *wb)
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{
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struct vb2_signature *sig = &preamble->preamble_signature;
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VB2_DEBUG("Verifying kernel preamble.\n");
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/* Sanity checks before attempting signature of data */
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if(size < sizeof(*preamble)) {
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VB2_DEBUG("Not enough data for preamble header.\n");
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return VB2_ERROR_PREAMBLE_TOO_SMALL_FOR_HEADER;
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}
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if (preamble->header_version_major !=
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KERNEL_PREAMBLE_HEADER_VERSION_MAJOR) {
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VB2_DEBUG("Incompatible kernel preamble header version.\n");
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return VB2_ERROR_PREAMBLE_HEADER_VERSION;
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}
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if (preamble->header_version_minor < 2) {
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VB2_DEBUG("Old preamble header format not supported\n");
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return VB2_ERROR_PREAMBLE_HEADER_OLD;
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}
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if (size < preamble->preamble_size) {
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VB2_DEBUG("Not enough data for preamble.\n");
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return VB2_ERROR_PREAMBLE_SIZE;
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}
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/* Check signature */
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if (vb2_verify_signature_inside(preamble, preamble->preamble_size,
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sig)) {
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VB2_DEBUG("Preamble signature off end of preamble\n");
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return VB2_ERROR_PREAMBLE_SIG_OUTSIDE;
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}
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/* Make sure advertised signature data sizes are sane. */
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if (preamble->preamble_size < sig->data_size) {
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VB2_DEBUG("Signature calculated past end of the block\n");
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return VB2_ERROR_PREAMBLE_SIGNED_TOO_MUCH;
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}
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if (vb2_verify_data((const uint8_t *)preamble, size, sig, key, wb)) {
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VB2_DEBUG("Preamble signature validation failed\n");
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return VB2_ERROR_PREAMBLE_SIG_INVALID;
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}
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/* Verify we signed enough data */
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if (sig->data_size < sizeof(struct vb2_fw_preamble)) {
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VB2_DEBUG("Didn't sign enough data\n");
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return VB2_ERROR_PREAMBLE_SIGNED_TOO_LITTLE;
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}
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/* Verify body signature is inside the signed data */
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if (vb2_verify_signature_inside(preamble, sig->data_size,
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&preamble->body_signature)) {
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VB2_DEBUG("Body signature off end of preamble\n");
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return VB2_ERROR_PREAMBLE_BODY_SIG_OUTSIDE;
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}
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/*
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* If bootloader is present, verify it's covered by the body
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* signature.
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*/
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if (preamble->bootloader_size) {
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const void *body_ptr =
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(const void *)(uintptr_t)preamble->body_load_address;
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const void *bootloader_ptr =
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(const void *)(uintptr_t)preamble->bootloader_address;
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if (vb2_verify_member_inside(body_ptr,
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preamble->body_signature.data_size,
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bootloader_ptr,
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preamble->bootloader_size,
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0, 0)) {
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VB2_DEBUG("Bootloader off end of signed data\n");
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return VB2_ERROR_PREAMBLE_BOOTLOADER_OUTSIDE;
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}
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}
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/*
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* If vmlinuz header is present, verify it's covered by the body
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* signature.
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*/
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if (preamble->vmlinuz_header_size) {
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const void *body_ptr =
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(const void *)(uintptr_t)preamble->body_load_address;
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const void *vmlinuz_header_ptr = (const void *)
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(uintptr_t)preamble->vmlinuz_header_address;
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if (vb2_verify_member_inside(body_ptr,
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preamble->body_signature.data_size,
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vmlinuz_header_ptr,
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preamble->vmlinuz_header_size,
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0, 0)) {
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VB2_DEBUG("Vmlinuz header off end of signed data\n");
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return VB2_ERROR_PREAMBLE_VMLINUZ_HEADER_OUTSIDE;
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}
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}
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/* Success */
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return VB2_SUCCESS;
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}
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