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|
package hst
import (
"errors"
"strconv"
"time"
"hakurei.app/container/check"
)
const Tmp = "/.hakurei"
var AbsTmp = check.MustAbs(Tmp)
const (
// WaitDelayDefault is used when WaitDelay has its zero value.
WaitDelayDefault = 5 * time.Second
// WaitDelayMax is used if WaitDelay exceeds its value.
WaitDelayMax = 30 * time.Second
// IdentityMin is the minimum value of [Config.Identity]. This is enforced by cmd/hsu.
IdentityMin = 0
// IdentityMax is the maximum value of [Config.Identity]. This is enforced by cmd/hsu.
IdentityMax = 9999
// ShimExitRequest is returned when the priv side process requests shim exit.
ShimExitRequest = 254
// ShimExitOrphan is returned when the shim is orphaned before priv side delivers a signal.
ShimExitOrphan = 3
)
type (
// Config configures an application container, implemented in internal/app.
Config struct {
// Reverse-DNS style configured arbitrary identifier string.
// Passed to wayland security-context-v1 and used as part of defaults in dbus session proxy.
ID string `json:"id"`
// System services to make available in the container.
Enablements *Enablements `json:"enablements,omitempty"`
// Session D-Bus proxy configuration.
// If set to nil, session bus proxy assume built-in defaults.
SessionBus *BusConfig `json:"session_bus,omitempty"`
// System D-Bus proxy configuration.
// If set to nil, system bus proxy is disabled.
SystemBus *BusConfig `json:"system_bus,omitempty"`
// Direct access to wayland socket, no attempt is made to attach security-context-v1
// and the bare socket is made available to the container.
DirectWayland bool `json:"direct_wayland,omitempty"`
// Extra acl update ops to perform before setuid.
ExtraPerms []*ExtraPermConfig `json:"extra_perms,omitempty"`
// Numerical application id, passed to hsu, used to derive init user namespace credentials.
Identity int `json:"identity"`
// Init user namespace supplementary groups inherited by all container processes.
Groups []string `json:"groups"`
// High level configuration applied to the underlying [container.Params].
Container *ContainerConfig `json:"container"`
}
// ContainerConfig describes the container configuration to be applied to an underlying [container.Params].
ContainerConfig struct {
// Container UTS namespace hostname.
Hostname string `json:"hostname,omitempty"`
// Duration in nanoseconds to wait for after interrupting the initial process.
// Defaults to [WaitDelayDefault] if less than or equals to zero,
// or [WaitDelayMax] if greater than [WaitDelayMax].
WaitDelay time.Duration `json:"wait_delay,omitempty"`
// Emit Flatpak-compatible seccomp filter programs.
SeccompCompat bool `json:"seccomp_compat,omitempty"`
// Allow ptrace and friends.
Devel bool `json:"devel,omitempty"`
// Allow userns creation and container setup syscalls.
Userns bool `json:"userns,omitempty"`
// Share host net namespace.
HostNet bool `json:"host_net,omitempty"`
// Share abstract unix socket scope.
HostAbstract bool `json:"host_abstract,omitempty"`
// Allow dangerous terminal I/O (faking input).
Tty bool `json:"tty,omitempty"`
// Allow multiarch.
Multiarch bool `json:"multiarch,omitempty"`
// Initial process environment variables.
Env map[string]string `json:"env"`
/* Map target user uid to privileged user uid in the container user namespace.
Some programs fail to connect to dbus session running as a different uid,
this option works around it by mapping priv-side caller uid in container. */
MapRealUID bool `json:"map_real_uid"`
// Mount /dev/ from the init mount namespace as-is in the container mount namespace.
Device bool `json:"device,omitempty"`
/* Container mount points.
If the first element targets /, it is inserted early and excluded from path hiding. */
Filesystem []FilesystemConfigJSON `json:"filesystem"`
// String used as the username of the emulated user, validated against the default NAME_REGEX from adduser.
// Defaults to passwd name of target uid or chronos.
Username string `json:"username,omitempty"`
// Pathname of shell in the container filesystem to use for the emulated user.
Shell *check.Absolute `json:"shell"`
// Directory in the container filesystem to enter and use as the home directory of the emulated user.
Home *check.Absolute `json:"home"`
// Pathname to executable file in the container filesystem.
Path *check.Absolute `json:"path,omitempty"`
// Final args passed to the initial program.
Args []string `json:"args"`
}
)
var (
// ErrConfigNull is returned by [Config.Validate] for an invalid configuration that contains a null value for any
// field that must not be null.
ErrConfigNull = errors.New("unexpected null in config")
// ErrIdentityBounds is returned by [Config.Validate] for an out of bounds [Config.Identity] value.
ErrIdentityBounds = errors.New("identity out of bounds")
)
// Validate checks [Config] and returns [AppError] if an invalid value is encountered.
func (config *Config) Validate() error {
if config == nil {
return &AppError{Step: "validate configuration", Err: ErrConfigNull,
Msg: "invalid configuration"}
}
// this is checked again in hsu
if config.Identity < IdentityMin || config.Identity > IdentityMax {
return &AppError{Step: "validate configuration", Err: ErrIdentityBounds,
Msg: "identity " + strconv.Itoa(config.Identity) + " out of range"}
}
if err := config.SessionBus.CheckInterfaces("session"); err != nil {
return err
}
if err := config.SystemBus.CheckInterfaces("system"); err != nil {
return err
}
if config.Container == nil {
return &AppError{Step: "validate configuration", Err: ErrConfigNull,
Msg: "configuration missing container state"}
}
if config.Container.Home == nil {
return &AppError{Step: "validate configuration", Err: ErrConfigNull,
Msg: "container configuration missing path to home directory"}
}
if config.Container.Shell == nil {
return &AppError{Step: "validate configuration", Err: ErrConfigNull,
Msg: "container configuration missing path to shell"}
}
if config.Container.Path == nil {
return &AppError{Step: "validate configuration", Err: ErrConfigNull,
Msg: "container configuration missing path to initial program"}
}
return nil
}
// ExtraPermConfig describes an acl update op.
type ExtraPermConfig struct {
Ensure bool `json:"ensure,omitempty"`
Path *check.Absolute `json:"path"`
Read bool `json:"r,omitempty"`
Write bool `json:"w,omitempty"`
Execute bool `json:"x,omitempty"`
}
func (e *ExtraPermConfig) String() string {
if e == nil || e.Path == nil {
return "<invalid>"
}
buf := make([]byte, 0, 5+len(e.Path.String()))
buf = append(buf, '-', '-', '-')
if e.Ensure {
buf = append(buf, '+')
}
buf = append(buf, ':')
buf = append(buf, []byte(e.Path.String())...)
if e.Read {
buf[0] = 'r'
}
if e.Write {
buf[1] = 'w'
}
if e.Execute {
buf[2] = 'x'
}
return string(buf)
}
|
