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// Copyright 2018 Google Inc.
//
// 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 cmd
import (
"fmt"
"os"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/syndtr/gocapability/capability"
"gvisor.googlesource.com/gvisor/pkg/log"
)
// applyCaps applies the capabilities in the spec to the current thread.
//
// Note that it must be called with current thread locked.
func applyCaps(caps *specs.LinuxCapabilities) error {
setter, err := capability.NewPid2(os.Getpid())
if err != nil {
return err
}
if err := setter.Load(); err != nil {
return err
}
bounding, err := trimCaps(caps.Bounding, setter)
if err != nil {
return err
}
setter.Set(capability.BOUNDS, bounding...)
effective, err := trimCaps(caps.Effective, setter)
if err != nil {
return err
}
setter.Set(capability.EFFECTIVE, effective...)
permitted, err := trimCaps(caps.Permitted, setter)
if err != nil {
return err
}
setter.Set(capability.PERMITTED, permitted...)
inheritable, err := trimCaps(caps.Inheritable, setter)
if err != nil {
return err
}
setter.Set(capability.INHERITABLE, inheritable...)
ambient, err := trimCaps(caps.Ambient, setter)
if err != nil {
return err
}
setter.Set(capability.AMBIENT, ambient...)
return setter.Apply(capability.CAPS | capability.BOUNDS | capability.AMBS)
}
func trimCaps(names []string, setter capability.Capabilities) ([]capability.Cap, error) {
wantedCaps, err := capsFromNames(names)
if err != nil {
return nil, err
}
// Trim down capabilities that aren't possible to acquire.
var caps []capability.Cap
for _, c := range wantedCaps {
// Capability rules are more complicated than this, but this catches most
// problems with tests running with non-privileged user.
if setter.Get(capability.PERMITTED, c) {
caps = append(caps, c)
} else {
log.Warningf("Capability %q is not permitted, dropping it.", c)
}
}
return caps, nil
}
func capsFromNames(names []string) ([]capability.Cap, error) {
var caps []capability.Cap
for _, name := range names {
cap, ok := capFromName[name]
if !ok {
return nil, fmt.Errorf("invalid capability %q", name)
}
caps = append(caps, cap)
}
return caps, nil
}
var capFromName = map[string]capability.Cap{
"CAP_CHOWN": capability.CAP_CHOWN,
"CAP_DAC_OVERRIDE": capability.CAP_DAC_OVERRIDE,
"CAP_DAC_READ_SEARCH": capability.CAP_DAC_READ_SEARCH,
"CAP_FOWNER": capability.CAP_FOWNER,
"CAP_FSETID": capability.CAP_FSETID,
"CAP_KILL": capability.CAP_KILL,
"CAP_SETGID": capability.CAP_SETGID,
"CAP_SETUID": capability.CAP_SETUID,
"CAP_SETPCAP": capability.CAP_SETPCAP,
"CAP_LINUX_IMMUTABLE": capability.CAP_LINUX_IMMUTABLE,
"CAP_NET_BIND_SERVICE": capability.CAP_NET_BIND_SERVICE,
"CAP_NET_BROADCAST": capability.CAP_NET_BROADCAST,
"CAP_NET_ADMIN": capability.CAP_NET_ADMIN,
"CAP_NET_RAW": capability.CAP_NET_RAW,
"CAP_IPC_LOCK": capability.CAP_IPC_LOCK,
"CAP_IPC_OWNER": capability.CAP_IPC_OWNER,
"CAP_SYS_MODULE": capability.CAP_SYS_MODULE,
"CAP_SYS_RAWIO": capability.CAP_SYS_RAWIO,
"CAP_SYS_CHROOT": capability.CAP_SYS_CHROOT,
"CAP_SYS_PTRACE": capability.CAP_SYS_PTRACE,
"CAP_SYS_PACCT": capability.CAP_SYS_PACCT,
"CAP_SYS_ADMIN": capability.CAP_SYS_ADMIN,
"CAP_SYS_BOOT": capability.CAP_SYS_BOOT,
"CAP_SYS_NICE": capability.CAP_SYS_NICE,
"CAP_SYS_RESOURCE": capability.CAP_SYS_RESOURCE,
"CAP_SYS_TIME": capability.CAP_SYS_TIME,
"CAP_SYS_TTY_CONFIG": capability.CAP_SYS_TTY_CONFIG,
"CAP_MKNOD": capability.CAP_MKNOD,
"CAP_LEASE": capability.CAP_LEASE,
"CAP_AUDIT_WRITE": capability.CAP_AUDIT_WRITE,
"CAP_AUDIT_CONTROL": capability.CAP_AUDIT_CONTROL,
"CAP_SETFCAP": capability.CAP_SETFCAP,
"CAP_MAC_OVERRIDE": capability.CAP_MAC_OVERRIDE,
"CAP_MAC_ADMIN": capability.CAP_MAC_ADMIN,
"CAP_SYSLOG": capability.CAP_SYSLOG,
"CAP_WAKE_ALARM": capability.CAP_WAKE_ALARM,
"CAP_BLOCK_SUSPEND": capability.CAP_BLOCK_SUSPEND,
"CAP_AUDIT_READ": capability.CAP_AUDIT_READ,
}
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