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/*
* flags.go - File which contains all the flags used by the application. This
* includes both global flags and command specific flags. When applicable, it
* also includes the default values.
*
* Copyright 2017 Google Inc.
* Author: Joe Richey (joerichey@google.com)
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package main
import (
"fmt"
"log"
"os/user"
"regexp"
"time"
"github.com/google/fscrypt/actions"
"github.com/google/fscrypt/cmd"
"github.com/google/fscrypt/security"
"github.com/google/fscrypt/util"
)
// Bool flags: used to switch some behavior on or off
var (
legacyFlag = &cmd.BoolFlag{
Name: "legacy",
Usage: `Configure fscrypt to support older kernels.`,
Default: true,
}
skipUnlockFlag = &cmd.BoolFlag{
Name: "skip-unlock",
Usage: "Leave the directory in a locked state after setup.",
}
dropCachesFlag = &cmd.BoolFlag{
Name: "drop-caches",
Usage: `After purging the keys from the keyring, drop the
associated caches for the purge to take effect.`,
Default: true,
}
)
// Option flags: used to specify options instead of being prompted for them
var (
timeTargetFlag = &cmd.DurationFlag{
Name: "time",
ArgName: "time",
Usage: `Set the global options so that passphrase hashing takes
<time> long.`,
Default: 1 * time.Second,
}
sourceFlag = &cmd.StringFlag{
Name: "source",
ArgName: "source",
Usage: `New protectors will have type <source> (one of
pam_passphrase, custom_passphrase, or raw_key).`,
}
nameFlag = &cmd.StringFlag{
Name: "name",
ArgName: "name",
Usage: "Use <name> as the name for a new protector.",
}
keyFileFlag = &cmd.StringFlag{
Name: "key",
ArgName: "path",
Usage: "Use the file at <path> as the protector key.",
}
userFlag = &cmd.StringFlag{
Name: "user",
ArgName: "username",
Usage: `Specify which user should be used for login passphrases
or to which user's keyring keys should be provisioned.`,
}
mountpointIDArg = usedMountpointArg.ArgName + ":id"
protectorFlag = &cmd.StringFlag{
Name: "protector",
ArgName: mountpointIDArg,
Usage: fmt.Sprintf(`An existing protector on %s with hexadecimal
id <id>.`, usedMountpointArg),
}
unlockWithFlag = &cmd.StringFlag{
Name: "unlock-with",
ArgName: mountpointIDArg,
Usage: fmt.Sprintf(`The protector that should be used to unlock
the policy specified with %s.`, policyFlag),
}
policyFlag = &cmd.StringFlag{
Name: "policy",
ArgName: mountpointIDArg,
Usage: fmt.Sprintf(`An existing policy on %s with hexadecimal id
<id>.`, usedMountpointArg),
}
)
// The first group corresponds to the mountpoint string. The second group
// corresponds to the hexideciamal descriptor.
var idFlagRegex = regexp.MustCompile("^([[:print:]]+):([[:alnum:]]+)$")
func matchMetadataFlag(flagValue string) (mountpoint, descriptor string, err error) {
matches := idFlagRegex.FindStringSubmatch(flagValue)
if matches == nil {
return "", "", fmt.Errorf("flag value %q does not have format %q",
flagValue, mountpointIDArg)
}
log.Printf("parsed flag: mountpoint=%q descriptor=%s", matches[1], matches[2])
return matches[1], matches[2], nil
}
// parseMetadataFlag takes the value of either protectorFlag or policyFlag
// formatted as MOUNTPOINT:DESCRIPTOR, and returns a context for the mountpoint
// and a string for the descriptor.
func parseMetadataFlag(flagValue string, target *user.User) (*actions.Context, string, error) {
mountpoint, descriptor, err := matchMetadataFlag(flagValue)
if err != nil {
return nil, "", err
}
ctx, err := actions.NewContextFromMountpoint(mountpoint, target)
return ctx, descriptor, err
}
// getProtectorFromFlag gets an existing locked protector from protectorFlag.
func getProtectorFromFlag(flagValue string, target *user.User) (*actions.Protector, error) {
ctx, descriptor, err := parseMetadataFlag(flagValue, target)
if err != nil {
return nil, err
}
return actions.GetProtector(ctx, descriptor)
}
// getPolicyFromFlag gets an existing locked policy from policyFlag.
func getPolicyFromFlag(flagValue string, target *user.User) (*actions.Policy, error) {
ctx, descriptor, err := parseMetadataFlag(flagValue, target)
if err != nil {
return nil, err
}
return actions.GetPolicy(ctx, descriptor)
}
// parseUserFlag returns the user specified by userFlag or the current effective
// user if the flag value is missing. If the effective user is root, however, a
// user must specified in the flag. If checkKeyring is true, we also make sure
// there are no problems accessing the user keyring.
func parseUserFlag(checkKeyring bool) (targetUser *user.User, err error) {
if userFlag.Value != "" {
if targetUser, err = user.Lookup(userFlag.Value); err != nil {
return nil, err
}
} else {
targetID := util.CurrentUserID()
if targetID == 0 {
return nil, ErrSpecifyUser
}
targetUser = util.GetUser(targetID)
}
if checkKeyring {
if _, err = security.UserKeyringID(targetUser, true); err != nil {
return nil, err
}
}
return targetUser, nil
}
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