firmware/lib/vboot_api_kernel.c

/* Copyright (c) 2013 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.
 *
 * High-level firmware wrapper API - entry points for kernel selection
 */

#include "2api.h"
#include "2common.h"
#include "2misc.h"
#include "2nvstorage.h"
#include "2rsa.h"
#include "2secdata.h"
#include "2sysincludes.h"
#include "load_kernel_fw.h"
#include "vboot_api.h"
#include "vboot_struct.h"

static int is_valid_disk(VbDiskInfo *info, uint32_t disk_flags)
{
	return info->bytes_per_lba >= 512 &&
		(info->bytes_per_lba & (info->bytes_per_lba - 1)) == 0 &&
		info->lba_count >= 16 &&
		(info->flags & disk_flags & VB_DISK_FLAG_SELECT_MASK) &&
		((info->flags & VB_DISK_FLAG_SELECT_MASK) &
		 ((info->flags & VB_DISK_FLAG_SELECT_MASK) - 1)) == 0;
}

static vb2_error_t VbTryLoadKernelImpl(struct vb2_context *ctx,
				       uint32_t disk_flags, int minios,
				       uint32_t minios_flags,
				       VbSelectAndLoadKernelParams *kparams)
{
	vb2_error_t rv = VB2_ERROR_LK_NO_DISK_FOUND;
	VbDiskInfo* disk_info = NULL;
	uint32_t disk_count = 0;
	uint32_t i;
	vb2_error_t new_rv;

	VB2_ASSERT(kparams);
	kparams->disk_handle = NULL;

	/* Find disks */
	if (VB2_SUCCESS != VbExDiskGetInfo(&disk_info, &disk_count, disk_flags))
		disk_count = 0;

	/* Loop over disks */
	for (i = 0; i < disk_count; i++) {
		VB2_DEBUG("trying disk %d\n", (int)i);

		if (!is_valid_disk(&disk_info[i], disk_flags)) {
			VB2_DEBUG("  skipping: bytes_per_lba=%" PRIu64
				  " lba_count=%" PRIu64 " flags=%#x\n",
				  disk_info[i].bytes_per_lba,
				  disk_info[i].lba_count,
				  disk_info[i].flags);
			continue;
		}
		kparams->disk_handle = disk_info[i].handle;

		if (minios) {
			new_rv = LoadMiniOsKernel(ctx, kparams,
						  &disk_info[i], minios_flags);
			VB2_DEBUG("LoadMiniOsKernel() = %#x\n", new_rv);
		} else {
			new_rv = LoadKernel(ctx, kparams, &disk_info[i]);
			VB2_DEBUG("LoadKernel() = %#x\n", new_rv);
		}

		/* Stop now if we found a kernel. */
		if (VB2_SUCCESS == new_rv) {
			VbExDiskFreeInfo(disk_info, disk_info[i].handle);
			return VB2_SUCCESS;
		}

		/* Don't update error if we already have a more specific one. */
		if (VB2_ERROR_LK_INVALID_KERNEL_FOUND != rv)
			rv = new_rv;
	}

	/* If we drop out of the loop, we didn't find any usable kernel. */
	if (!(ctx->flags & VB2_CONTEXT_RECOVERY_MODE) &&
	    !(ctx->flags & VB2_CONTEXT_DEVELOPER_MODE)) {
		switch (rv) {
		case VB2_ERROR_LK_INVALID_KERNEL_FOUND:
			vb2api_fail(ctx, VB2_RECOVERY_RW_INVALID_OS, rv);
			break;
		case VB2_ERROR_LK_NO_KERNEL_FOUND:
			vb2api_fail(ctx, VB2_RECOVERY_RW_NO_KERNEL, rv);
			break;
		case VB2_ERROR_LK_NO_DISK_FOUND:
			vb2api_fail(ctx, VB2_RECOVERY_RW_NO_DISK, rv);
			break;
		default:
			vb2api_fail(ctx, VB2_RECOVERY_LK_UNSPECIFIED, rv);
			break;
		}
	}

	/* If we didn't find any good kernels, don't return a disk handle. */
	VbExDiskFreeInfo(disk_info, NULL);

	return rv;
}

test_mockable
vb2_error_t VbTryLoadKernel(struct vb2_context *ctx, uint32_t disk_flags,
			    VbSelectAndLoadKernelParams *kparams)
{
	ctx->flags &= ~VB2_CONTEXT_DISABLE_TPM;
	return VbTryLoadKernelImpl(ctx, disk_flags, 0, 0, kparams);
}

test_mockable
vb2_error_t VbTryLoadMiniOsKernel(struct vb2_context *ctx,
				  uint32_t minios_flags,
				  VbSelectAndLoadKernelParams *kparams)
{
	VB2_TRY(VbTryLoadKernelImpl(ctx, VB_DISK_FLAG_FIXED, 1, minios_flags,
				    kparams));
	ctx->flags |= VB2_CONTEXT_DISABLE_TPM;
	return VB2_SUCCESS;
}