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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2020 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package main
import (
"errors"
"fmt"
"os"
"path/filepath"
"runtime"
"github.com/snapcore/snapd/asserts"
"github.com/snapcore/snapd/boot"
"github.com/snapcore/snapd/gadget"
"github.com/snapcore/snapd/logger"
"github.com/snapcore/snapd/osutil"
"github.com/snapcore/snapd/seed"
"github.com/snapcore/snapd/snap"
"github.com/snapcore/snapd/timings"
)
var (
osutilSetTime = osutil.SetTime
runtimeNumCPU = runtime.NumCPU
)
// initramfsMountsState helps tracking the state and progress
// of the mounting driving process.
type initramfsMountsState struct {
mode string
recoverySystem string
verifiedModel gadget.Model
seeds map[string]seed.Seed
}
var errRunModeNoImpliedRecoverySystem = errors.New("internal error: no implied recovery system in run mode")
// LoadSeed returns the seed for the recoverySystem.
// If recoverySystem is "" the implied one will be used (only for
// modes other than run).
func (mst *initramfsMountsState) LoadSeed(recoverySystem string) (seed.Seed, error) {
if recoverySystem == "" {
if mst.mode == "run" {
return nil, errRunModeNoImpliedRecoverySystem
}
recoverySystem = mst.recoverySystem
}
if mst.seeds == nil {
mst.seeds = make(map[string]seed.Seed)
}
foundSeed, hasSeed := mst.seeds[recoverySystem]
if hasSeed {
return foundSeed, nil
}
perf := timings.New(nil)
// get the current time to pass to ReadSystemEssentialAndBetterEarliestTime
// note that we trust the time we have from the system, because that time
// comes from either:
// * a RTC on the system that the kernel/systemd consulted and used to move
// time forward
// * systemd using a built-in timestamp from the initrd which was stamped
// when the initrd was built, giving a lower bound on the current time if
// the RTC does not have a battery or is otherwise unreliable, etc.
now := timeNow()
jobs := 1
if runtimeNumCPU() > 1 {
jobs = 2
}
seed20, newTrustedEarliestTime, err := seed.ReadSeedAndBetterEarliestTime(boot.InitramfsUbuntuSeedDir, recoverySystem, now, jobs, perf)
if err != nil {
return nil, err
}
// set the time on the system to move forward if it is in the future - never
// move the time backwards
if newTrustedEarliestTime.After(now) {
if err := osutilSetTime(newTrustedEarliestTime); err != nil {
// log the error but don't fail on it, we should be able to continue
// even if the time can't be moved forward
logger.Noticef("failed to move time forward from %s to %s: %v", now, newTrustedEarliestTime, err)
}
}
mst.seeds[recoverySystem] = seed20
return seed20, nil
}
// SetVerifiedBootModel sets the "verifiedModel" field. It should only
// be called after the model is verified. Either via a successful unlock
// of the encrypted data or after validating the seed in install/recover
// mode.
func (mst *initramfsMountsState) SetVerifiedBootModel(m gadget.Model) {
mst.verifiedModel = m
}
// UnverifiedBootModel returns the unverified model from the
// boot partition for run mode. The current and only use case
// is measuring the model for run mode. Otherwise no decisions
// should be based on an unverified model. Note that the model
// is verified at the time the key auth policy is computed.
func (mst *initramfsMountsState) UnverifiedBootModel() (*asserts.Model, error) {
if mst.mode != "run" {
return nil, fmt.Errorf("internal error: unverified boot model access is for limited run mode use")
}
mf, err := os.Open(filepath.Join(boot.InitramfsUbuntuBootDir, "device/model"))
if err != nil {
return nil, fmt.Errorf("cannot read model assertion: %v", err)
}
defer mf.Close()
ma, err := asserts.NewDecoder(mf).Decode()
if err != nil {
return nil, fmt.Errorf("cannot decode assertion: %v", err)
}
if ma.Type() != asserts.ModelType {
return nil, fmt.Errorf("unexpected assertion: %q", ma.Type().Name)
}
return ma.(*asserts.Model), nil
}
// EphemeralModeenvForModel generates a modeenv given the model and the snaps for the
// current mode and recovery system of the initramfsMountsState.
func (mst *initramfsMountsState) EphemeralModeenvForModel(model *asserts.Model, snaps map[snap.Type]*seed.Snap) (*boot.Modeenv, error) {
if mst.mode == "run" {
return nil, fmt.Errorf("internal error: initramfs should not write modeenv in run mode")
}
return &boot.Modeenv{
Mode: mst.mode,
RecoverySystem: mst.recoverySystem,
Base: snaps[snap.TypeBase].PlaceInfo().Filename(),
Gadget: snaps[snap.TypeGadget].PlaceInfo().Filename(),
Model: model.Model(),
BrandID: model.BrandID(),
Grade: string(model.Grade()),
// TODO:UC20: what about current kernel snaps, trusted boot assets and
// kernel command lines?
}, nil
}
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