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Merge pull request #1548 from AkihiroSuda/remove-libseccomp-dependency

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remove libseccomp cgo dependency
This commit is contained in:
Wei Fu 2020-07-30 23:30:04 +08:00 committed by GitHub
commit 8871d5cdf8
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GPG Key ID: 4AEE18F83AFDEB23
13 changed files with 208 additions and 1951 deletions
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47
pkg/seccomp/fixtures/proc_self_status Normal file
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@ -0,0 +1,47 @@
Name: cat
State: R (running)
Tgid: 19383
Ngid: 0
Pid: 19383
PPid: 19275
TracerPid: 0
Uid: 1000 1000 1000 1000
Gid: 1000 1000 1000 1000
FDSize: 256
Groups: 24 25 27 29 30 44 46 102 104 108 111 1000 1001
NStgid: 19383
NSpid: 19383
NSpgid: 19383
NSsid: 19275
VmPeak: 5944 kB
VmSize: 5944 kB
VmLck: 0 kB
VmPin: 0 kB
VmHWM: 744 kB
VmRSS: 744 kB
VmData: 324 kB
VmStk: 136 kB
VmExe: 48 kB
VmLib: 1776 kB
VmPTE: 32 kB
VmPMD: 12 kB
VmSwap: 0 kB
Threads: 1
SigQ: 0/30067
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000080
SigCgt: 0000000000000000
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 0000003fffffffff
CapAmb: 0000000000000000
Seccomp: 0
Cpus_allowed: f
Cpus_allowed_list: 0-3
Mems_allowed: 00000000,00000001
Mems_allowed_list: 0
voluntary_ctxt_switches: 0
nonvoluntary_ctxt_switches: 1

88
pkg/seccomp/seccomp_linux.go Normal file
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@ -0,0 +1,88 @@
/*
Copyright The containerd Authors.
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.
*/
/*
Copyright The runc Authors.
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 seccomp
import (
"bufio"
"os"
"strings"
"golang.org/x/sys/unix"
)
// IsEnabled returns if the kernel has been configured to support seccomp.
// From https://github.com/opencontainers/runc/blob/v1.0.0-rc91/libcontainer/seccomp/seccomp_linux.go#L86-L102
func IsEnabled() bool {
// Try to read from /proc/self/status for kernels > 3.8
s, err := parseStatusFile("/proc/self/status")
if err != nil {
// Check if Seccomp is supported, via CONFIG_SECCOMP.
if err := unix.Prctl(unix.PR_GET_SECCOMP, 0, 0, 0, 0); err != unix.EINVAL {
// Make sure the kernel has CONFIG_SECCOMP_FILTER.
if err := unix.Prctl(unix.PR_SET_SECCOMP, unix.SECCOMP_MODE_FILTER, 0, 0, 0); err != unix.EINVAL {
return true
}
}
return false
}
_, ok := s["Seccomp"]
return ok
}
// parseStatusFile is from https://github.com/opencontainers/runc/blob/v1.0.0-rc91/libcontainer/seccomp/seccomp_linux.go#L243-L268
func parseStatusFile(path string) (map[string]string, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
defer f.Close()
s := bufio.NewScanner(f)
status := make(map[string]string)
for s.Scan() {
text := s.Text()
parts := strings.Split(text, ":")
if len(parts) <= 1 {
continue
}
status[parts[0]] = parts[1]
}
if err := s.Err(); err != nil {
return nil, err
}
return status, nil
}

48
pkg/seccomp/seccomp_linux_test.go Normal file
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@ -0,0 +1,48 @@
/*
Copyright The containerd Authors.
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.
*/
/*
Copyright The runc Authors.
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 seccomp
import "testing"
// TestParseStatusFile is from https://github.com/opencontainers/runc/blob/v1.0.0-rc91/libcontainer/seccomp/seccomp_linux_test.go
func TestParseStatusFile(t *testing.T) {
s, err := parseStatusFile("fixtures/proc_self_status")
if err != nil {
t.Fatal(err)
}
if _, ok := s["Seccomp"]; !ok {
t.Fatal("expected to find 'Seccomp' in the map but did not.")
}
}

23
pkg/seccomp/seccomp_unsupported.go Normal file
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@ -0,0 +1,23 @@
// +build !linux
/*
Copyright The containerd Authors.
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 seccomp
func IsEnabled() bool {
return false
}

4
pkg/server/helpers_unix.go
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@ -32,8 +32,8 @@ import (
"github.com/containerd/containerd/log" "github.com/containerd/containerd/log"
"github.com/containerd/containerd/mount" "github.com/containerd/containerd/mount"
"github.com/containerd/cri/pkg/seccomp"
runcapparmor "github.com/opencontainers/runc/libcontainer/apparmor" runcapparmor "github.com/opencontainers/runc/libcontainer/apparmor"
runcseccomp "github.com/opencontainers/runc/libcontainer/seccomp"
"github.com/opencontainers/selinux/go-selinux/label" "github.com/opencontainers/selinux/go-selinux/label"
"github.com/pkg/errors" "github.com/pkg/errors"
"golang.org/x/sys/unix" "golang.org/x/sys/unix"
@ -146,7 +146,7 @@ func (c *criService) apparmorEnabled() bool {
} }
func (c *criService) seccompEnabled() bool { func (c *criService) seccompEnabled() bool {
return runcseccomp.IsEnabled() return seccomp.IsEnabled()
} }
// openLogFile opens/creates a container log file. // openLogFile opens/creates a container log file.

1
vendor.conf
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@ -71,7 +71,6 @@ github.com/json-iterator/go v1.1.9
github.com/modern-go/concurrent 1.0.3 github.com/modern-go/concurrent 1.0.3
github.com/modern-go/reflect2 v1.0.1 github.com/modern-go/reflect2 v1.0.1
github.com/pmezard/go-difflib v1.0.0 github.com/pmezard/go-difflib v1.0.0
github.com/seccomp/libseccomp-golang v0.9.1
github.com/stretchr/testify v1.4.0 github.com/stretchr/testify v1.4.0
golang.org/x/crypto bac4c82f69751a6dd76e702d54b3ceb88adab236 golang.org/x/crypto bac4c82f69751a6dd76e702d54b3ceb88adab236
golang.org/x/oauth2 858c2ad4c8b6c5d10852cb89079f6ca1c7309787 golang.org/x/oauth2 858c2ad4c8b6c5d10852cb89079f6ca1c7309787

77
vendor/github.com/opencontainers/runc/libcontainer/seccomp/config.go generated vendored
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@ -1,77 +0,0 @@
package seccomp
import (
"fmt"
"github.com/opencontainers/runc/libcontainer/configs"
)
var operators = map[string]configs.Operator{
"SCMP_CMP_NE": configs.NotEqualTo,
"SCMP_CMP_LT": configs.LessThan,
"SCMP_CMP_LE": configs.LessThanOrEqualTo,
"SCMP_CMP_EQ": configs.EqualTo,
"SCMP_CMP_GE": configs.GreaterThanOrEqualTo,
"SCMP_CMP_GT": configs.GreaterThan,
"SCMP_CMP_MASKED_EQ": configs.MaskEqualTo,
}
var actions = map[string]configs.Action{
"SCMP_ACT_KILL": configs.Kill,
"SCMP_ACT_ERRNO": configs.Errno,
"SCMP_ACT_TRAP": configs.Trap,
"SCMP_ACT_ALLOW": configs.Allow,
"SCMP_ACT_TRACE": configs.Trace,
"SCMP_ACT_LOG": configs.Log,
}
var archs = map[string]string{
"SCMP_ARCH_X86": "x86",
"SCMP_ARCH_X86_64": "amd64",
"SCMP_ARCH_X32": "x32",
"SCMP_ARCH_ARM": "arm",
"SCMP_ARCH_AARCH64": "arm64",
"SCMP_ARCH_MIPS": "mips",
"SCMP_ARCH_MIPS64": "mips64",
"SCMP_ARCH_MIPS64N32": "mips64n32",
"SCMP_ARCH_MIPSEL": "mipsel",
"SCMP_ARCH_MIPSEL64": "mipsel64",
"SCMP_ARCH_MIPSEL64N32": "mipsel64n32",
"SCMP_ARCH_PPC": "ppc",
"SCMP_ARCH_PPC64": "ppc64",
"SCMP_ARCH_PPC64LE": "ppc64le",
"SCMP_ARCH_S390": "s390",
"SCMP_ARCH_S390X": "s390x",
}
// ConvertStringToOperator converts a string into a Seccomp comparison operator.
// Comparison operators use the names they are assigned by Libseccomp's header.
// Attempting to convert a string that is not a valid operator results in an
// error.
func ConvertStringToOperator(in string) (configs.Operator, error) {
if op, ok := operators[in]; ok == true {
return op, nil
}
return 0, fmt.Errorf("string %s is not a valid operator for seccomp", in)
}
// ConvertStringToAction converts a string into a Seccomp rule match action.
// Actions use the names they are assigned in Libseccomp's header, though some
// (notable, SCMP_ACT_TRACE) are not available in this implementation and will
// return errors.
// Attempting to convert a string that is not a valid action results in an
// error.
func ConvertStringToAction(in string) (configs.Action, error) {
if act, ok := actions[in]; ok == true {
return act, nil
}
return 0, fmt.Errorf("string %s is not a valid action for seccomp", in)
}
// ConvertStringToArch converts a string into a Seccomp comparison arch.
func ConvertStringToArch(in string) (string, error) {
if arch, ok := archs[in]; ok == true {
return arch, nil
}
return "", fmt.Errorf("string %s is not a valid arch for seccomp", in)
}

268
vendor/github.com/opencontainers/runc/libcontainer/seccomp/seccomp_linux.go generated vendored
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@ -1,268 +0,0 @@
// +build linux,cgo,seccomp
package seccomp
import (
"bufio"
"errors"
"fmt"
"os"
"strings"
"github.com/opencontainers/runc/libcontainer/configs"
libseccomp "github.com/seccomp/libseccomp-golang"
"golang.org/x/sys/unix"
)
var (
actAllow = libseccomp.ActAllow
actTrap = libseccomp.ActTrap
actKill = libseccomp.ActKill
actTrace = libseccomp.ActTrace.SetReturnCode(int16(unix.EPERM))
actLog = libseccomp.ActLog
actErrno = libseccomp.ActErrno.SetReturnCode(int16(unix.EPERM))
)
const (
// Linux system calls can have at most 6 arguments
syscallMaxArguments int = 6
)
// Filters given syscalls in a container, preventing them from being used
// Started in the container init process, and carried over to all child processes
// Setns calls, however, require a separate invocation, as they are not children
// of the init until they join the namespace
func InitSeccomp(config *configs.Seccomp) error {
if config == nil {
return errors.New("cannot initialize Seccomp - nil config passed")
}
defaultAction, err := getAction(config.DefaultAction, nil)
if err != nil {
return errors.New("error initializing seccomp - invalid default action")
}
filter, err := libseccomp.NewFilter(defaultAction)
if err != nil {
return fmt.Errorf("error creating filter: %s", err)
}
// Add extra architectures
for _, arch := range config.Architectures {
scmpArch, err := libseccomp.GetArchFromString(arch)
if err != nil {
return fmt.Errorf("error validating Seccomp architecture: %s", err)
}
if err := filter.AddArch(scmpArch); err != nil {
return fmt.Errorf("error adding architecture to seccomp filter: %s", err)
}
}
// Unset no new privs bit
if err := filter.SetNoNewPrivsBit(false); err != nil {
return fmt.Errorf("error setting no new privileges: %s", err)
}
// Add a rule for each syscall
for _, call := range config.Syscalls {
if call == nil {
return errors.New("encountered nil syscall while initializing Seccomp")
}
if err = matchCall(filter, call); err != nil {
return err
}
}
if err = filter.Load(); err != nil {
return fmt.Errorf("error loading seccomp filter into kernel: %s", err)
}
return nil
}
// IsEnabled returns if the kernel has been configured to support seccomp.
func IsEnabled() bool {
// Try to read from /proc/self/status for kernels > 3.8
s, err := parseStatusFile("/proc/self/status")
if err != nil {
// Check if Seccomp is supported, via CONFIG_SECCOMP.
if err := unix.Prctl(unix.PR_GET_SECCOMP, 0, 0, 0, 0); err != unix.EINVAL {
// Make sure the kernel has CONFIG_SECCOMP_FILTER.
if err := unix.Prctl(unix.PR_SET_SECCOMP, unix.SECCOMP_MODE_FILTER, 0, 0, 0); err != unix.EINVAL {
return true
}
}
return false
}
_, ok := s["Seccomp"]
return ok
}
// Convert Libcontainer Action to Libseccomp ScmpAction
func getAction(act configs.Action, errnoRet *uint) (libseccomp.ScmpAction, error) {
switch act {
case configs.Kill:
return actKill, nil
case configs.Errno:
if errnoRet != nil {
return libseccomp.ActErrno.SetReturnCode(int16(*errnoRet)), nil
}
return actErrno, nil
case configs.Trap:
return actTrap, nil
case configs.Allow:
return actAllow, nil
case configs.Trace:
if errnoRet != nil {
return libseccomp.ActTrace.SetReturnCode(int16(*errnoRet)), nil
}
return actTrace, nil
case configs.Log:
return actLog, nil
default:
return libseccomp.ActInvalid, errors.New("invalid action, cannot use in rule")
}
}
// Convert Libcontainer Operator to Libseccomp ScmpCompareOp
func getOperator(op configs.Operator) (libseccomp.ScmpCompareOp, error) {
switch op {
case configs.EqualTo:
return libseccomp.CompareEqual, nil
case configs.NotEqualTo:
return libseccomp.CompareNotEqual, nil
case configs.GreaterThan:
return libseccomp.CompareGreater, nil
case configs.GreaterThanOrEqualTo:
return libseccomp.CompareGreaterEqual, nil
case configs.LessThan:
return libseccomp.CompareLess, nil
case configs.LessThanOrEqualTo:
return libseccomp.CompareLessOrEqual, nil
case configs.MaskEqualTo:
return libseccomp.CompareMaskedEqual, nil
default:
return libseccomp.CompareInvalid, errors.New("invalid operator, cannot use in rule")
}
}
// Convert Libcontainer Arg to Libseccomp ScmpCondition
func getCondition(arg *configs.Arg) (libseccomp.ScmpCondition, error) {
cond := libseccomp.ScmpCondition{}
if arg == nil {
return cond, errors.New("cannot convert nil to syscall condition")
}
op, err := getOperator(arg.Op)
if err != nil {
return cond, err
}
return libseccomp.MakeCondition(arg.Index, op, arg.Value, arg.ValueTwo)
}
// Add a rule to match a single syscall
func matchCall(filter *libseccomp.ScmpFilter, call *configs.Syscall) error {
if call == nil || filter == nil {
return errors.New("cannot use nil as syscall to block")
}
if len(call.Name) == 0 {
return errors.New("empty string is not a valid syscall")
}
// If we can't resolve the syscall, assume it's not supported on this kernel
// Ignore it, don't error out
callNum, err := libseccomp.GetSyscallFromName(call.Name)
if err != nil {
return nil
}
// Convert the call's action to the libseccomp equivalent
callAct, err := getAction(call.Action, call.ErrnoRet)
if err != nil {
return fmt.Errorf("action in seccomp profile is invalid: %s", err)
}
// Unconditional match - just add the rule
if len(call.Args) == 0 {
if err = filter.AddRule(callNum, callAct); err != nil {
return fmt.Errorf("error adding seccomp filter rule for syscall %s: %s", call.Name, err)
}
} else {
// If two or more arguments have the same condition,
// Revert to old behavior, adding each condition as a separate rule
argCounts := make([]uint, syscallMaxArguments)
conditions := []libseccomp.ScmpCondition{}
for _, cond := range call.Args {
newCond, err := getCondition(cond)
if err != nil {
return fmt.Errorf("error creating seccomp syscall condition for syscall %s: %s", call.Name, err)
}
argCounts[cond.Index] += 1
conditions = append(conditions, newCond)
}
hasMultipleArgs := false
for _, count := range argCounts {
if count > 1 {
hasMultipleArgs = true
break
}
}
if hasMultipleArgs {
// Revert to old behavior
// Add each condition attached to a separate rule
for _, cond := range conditions {
condArr := []libseccomp.ScmpCondition{cond}
if err = filter.AddRuleConditional(callNum, callAct, condArr); err != nil {
return fmt.Errorf("error adding seccomp rule for syscall %s: %s", call.Name, err)
}
}
} else {
// No conditions share same argument
// Use new, proper behavior
if err = filter.AddRuleConditional(callNum, callAct, conditions); err != nil {
return fmt.Errorf("error adding seccomp rule for syscall %s: %s", call.Name, err)
}
}
}
return nil
}
func parseStatusFile(path string) (map[string]string, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
defer f.Close()
s := bufio.NewScanner(f)
status := make(map[string]string)
for s.Scan() {
text := s.Text()
parts := strings.Split(text, ":")
if len(parts) <= 1 {
continue
}
status[parts[0]] = parts[1]
}
if err := s.Err(); err != nil {
return nil, err
}
return status, nil
}

24
vendor/github.com/opencontainers/runc/libcontainer/seccomp/seccomp_unsupported.go generated vendored
View File

@ -1,24 +0,0 @@
// +build !linux !cgo !seccomp
package seccomp
import (
"errors"
"github.com/opencontainers/runc/libcontainer/configs"
)
var ErrSeccompNotEnabled = errors.New("seccomp: config provided but seccomp not supported")
// InitSeccomp does nothing because seccomp is not supported.
func InitSeccomp(config *configs.Seccomp) error {
if config != nil {
return ErrSeccompNotEnabled
}
return nil
}
// IsEnabled returns false, because it is not supported.
func IsEnabled() bool {
return false
}

22
vendor/github.com/seccomp/libseccomp-golang/LICENSE generated vendored
View File

@ -1,22 +0,0 @@
Copyright (c) 2015 Matthew Heon <mheon@redhat.com>
Copyright (c) 2015 Paul Moore <pmoore@redhat.com>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

51
vendor/github.com/seccomp/libseccomp-golang/README generated vendored
View File

@ -1,51 +0,0 @@
libseccomp-golang: Go Language Bindings for the libseccomp Project
===============================================================================
https://github.com/seccomp/libseccomp-golang
https://github.com/seccomp/libseccomp
The libseccomp library provides an easy to use, platform independent, interface
to the Linux Kernel's syscall filtering mechanism. The libseccomp API is
designed to abstract away the underlying BPF based syscall filter language and
present a more conventional function-call based filtering interface that should
be familiar to, and easily adopted by, application developers.
The libseccomp-golang library provides a Go based interface to the libseccomp
library.
* Online Resources
The library source repository currently lives on GitHub at the following URLs:
-> https://github.com/seccomp/libseccomp-golang
-> https://github.com/seccomp/libseccomp
The project mailing list is currently hosted on Google Groups at the URL below,
please note that a Google account is not required to subscribe to the mailing
list.
-> https://groups.google.com/d/forum/libseccomp
Documentation is also available at:
-> https://godoc.org/github.com/seccomp/libseccomp-golang
* Installing the package
The libseccomp-golang bindings require at least Go v1.2.1 and GCC v4.8.4;
earlier versions may yield unpredictable results. If you meet these
requirements you can install this package using the command below:
$ go get github.com/seccomp/libseccomp-golang
* Testing the Library
A number of tests and lint related recipes are provided in the Makefile, if
you want to run the standard regression tests, you can excute the following:
$ make check
In order to execute the 'make lint' recipe the 'golint' tool is needed, it
can be found at:
-> https://github.com/golang/lint

935
vendor/github.com/seccomp/libseccomp-golang/seccomp.go generated vendored
View File

@ -1,935 +0,0 @@
// +build linux
// Public API specification for libseccomp Go bindings
// Contains public API for the bindings
// Package seccomp provides bindings for libseccomp, a library wrapping the Linux
// seccomp syscall. Seccomp enables an application to restrict system call use
// for itself and its children.
package seccomp
import (
"fmt"
"os"
"runtime"
"strings"
"sync"
"syscall"
"unsafe"
)
// C wrapping code
// #cgo pkg-config: libseccomp
// #include <stdlib.h>
// #include <seccomp.h>
import "C"
// Exported types
// VersionError denotes that the system libseccomp version is incompatible
// with this package.
type VersionError struct {
message string
minimum string
}
func (e VersionError) Error() string {
format := "Libseccomp version too low: "
if e.message != "" {
format += e.message + ": "
}
format += "minimum supported is "
if e.minimum != "" {
format += e.minimum + ": "
} else {
format += "2.2.0: "
}
format += "detected %d.%d.%d"
return fmt.Sprintf(format, verMajor, verMinor, verMicro)
}
// ScmpArch represents a CPU architecture. Seccomp can restrict syscalls on a
// per-architecture basis.
type ScmpArch uint
// ScmpAction represents an action to be taken on a filter rule match in
// libseccomp
type ScmpAction uint
// ScmpCompareOp represents a comparison operator which can be used in a filter
// rule
type ScmpCompareOp uint
// ScmpCondition represents a rule in a libseccomp filter context
type ScmpCondition struct {
Argument uint `json:"argument,omitempty"`
Op ScmpCompareOp `json:"operator,omitempty"`
Operand1 uint64 `json:"operand_one,omitempty"`
Operand2 uint64 `json:"operand_two,omitempty"`
}
// ScmpSyscall represents a Linux System Call
type ScmpSyscall int32
// Exported Constants
const (
// Valid architectures recognized by libseccomp
// PowerPC and S390(x) architectures are unavailable below library version
// v2.3.0 and will returns errors if used with incompatible libraries
// ArchInvalid is a placeholder to ensure uninitialized ScmpArch
// variables are invalid
ArchInvalid ScmpArch = iota
// ArchNative is the native architecture of the kernel
ArchNative ScmpArch = iota
// ArchX86 represents 32-bit x86 syscalls
ArchX86 ScmpArch = iota
// ArchAMD64 represents 64-bit x86-64 syscalls
ArchAMD64 ScmpArch = iota
// ArchX32 represents 64-bit x86-64 syscalls (32-bit pointers)
ArchX32 ScmpArch = iota
// ArchARM represents 32-bit ARM syscalls
ArchARM ScmpArch = iota
// ArchARM64 represents 64-bit ARM syscalls
ArchARM64 ScmpArch = iota
// ArchMIPS represents 32-bit MIPS syscalls
ArchMIPS ScmpArch = iota
// ArchMIPS64 represents 64-bit MIPS syscalls
ArchMIPS64 ScmpArch = iota
// ArchMIPS64N32 represents 64-bit MIPS syscalls (32-bit pointers)
ArchMIPS64N32 ScmpArch = iota
// ArchMIPSEL represents 32-bit MIPS syscalls (little endian)
ArchMIPSEL ScmpArch = iota
// ArchMIPSEL64 represents 64-bit MIPS syscalls (little endian)
ArchMIPSEL64 ScmpArch = iota
// ArchMIPSEL64N32 represents 64-bit MIPS syscalls (little endian,
// 32-bit pointers)
ArchMIPSEL64N32 ScmpArch = iota
// ArchPPC represents 32-bit POWERPC syscalls
ArchPPC ScmpArch = iota
// ArchPPC64 represents 64-bit POWER syscalls (big endian)
ArchPPC64 ScmpArch = iota
// ArchPPC64LE represents 64-bit POWER syscalls (little endian)
ArchPPC64LE ScmpArch = iota
// ArchS390 represents 31-bit System z/390 syscalls
ArchS390 ScmpArch = iota
// ArchS390X represents 64-bit System z/390 syscalls
ArchS390X ScmpArch = iota
)
const (
// Supported actions on filter match
// ActInvalid is a placeholder to ensure uninitialized ScmpAction
// variables are invalid
ActInvalid ScmpAction = iota
// ActKill kills the process
ActKill ScmpAction = iota
// ActTrap throws SIGSYS
ActTrap ScmpAction = iota
// ActErrno causes the syscall to return a negative error code. This
// code can be set with the SetReturnCode method
ActErrno ScmpAction = iota
// ActTrace causes the syscall to notify tracing processes with the
// given error code. This code can be set with the SetReturnCode method
ActTrace ScmpAction = iota
// ActAllow permits the syscall to continue execution
ActAllow ScmpAction = iota
// ActLog permits the syscall to continue execution after logging it.
// This action is only usable when libseccomp API level 3 or higher is
// supported.
ActLog ScmpAction = iota
)
const (
// These are comparison operators used in conditional seccomp rules
// They are used to compare the value of a single argument of a syscall
// against a user-defined constant
// CompareInvalid is a placeholder to ensure uninitialized ScmpCompareOp
// variables are invalid
CompareInvalid ScmpCompareOp = iota
// CompareNotEqual returns true if the argument is not equal to the
// given value
CompareNotEqual ScmpCompareOp = iota
// CompareLess returns true if the argument is less than the given value
CompareLess ScmpCompareOp = iota
// CompareLessOrEqual returns true if the argument is less than or equal
// to the given value
CompareLessOrEqual ScmpCompareOp = iota
// CompareEqual returns true if the argument is equal to the given value
CompareEqual ScmpCompareOp = iota
// CompareGreaterEqual returns true if the argument is greater than or
// equal to the given value
CompareGreaterEqual ScmpCompareOp = iota
// CompareGreater returns true if the argument is greater than the given
// value
CompareGreater ScmpCompareOp = iota
// CompareMaskedEqual returns true if the argument is equal to the given
// value, when masked (bitwise &) against the second given value
CompareMaskedEqual ScmpCompareOp = iota
)
// Helpers for types
// GetArchFromString returns an ScmpArch constant from a string representing an
// architecture
func GetArchFromString(arch string) (ScmpArch, error) {
if err := ensureSupportedVersion(); err != nil {
return ArchInvalid, err
}
switch strings.ToLower(arch) {
case "x86":
return ArchX86, nil
case "amd64", "x86-64", "x86_64", "x64":
return ArchAMD64, nil
case "x32":
return ArchX32, nil
case "arm":
return ArchARM, nil
case "arm64", "aarch64":
return ArchARM64, nil
case "mips":
return ArchMIPS, nil
case "mips64":
return ArchMIPS64, nil
case "mips64n32":
return ArchMIPS64N32, nil
case "mipsel":
return ArchMIPSEL, nil
case "mipsel64":
return ArchMIPSEL64, nil
case "mipsel64n32":
return ArchMIPSEL64N32, nil
case "ppc":
return ArchPPC, nil
case "ppc64":
return ArchPPC64, nil
case "ppc64le":
return ArchPPC64LE, nil
case "s390":
return ArchS390, nil
case "s390x":
return ArchS390X, nil
default:
return ArchInvalid, fmt.Errorf("cannot convert unrecognized string %q", arch)
}
}
// String returns a string representation of an architecture constant
func (a ScmpArch) String() string {
switch a {
case ArchX86:
return "x86"
case ArchAMD64:
return "amd64"
case ArchX32:
return "x32"
case ArchARM:
return "arm"
case ArchARM64:
return "arm64"
case ArchMIPS:
return "mips"
case ArchMIPS64:
return "mips64"
case ArchMIPS64N32:
return "mips64n32"
case ArchMIPSEL:
return "mipsel"
case ArchMIPSEL64:
return "mipsel64"
case ArchMIPSEL64N32:
return "mipsel64n32"
case ArchPPC:
return "ppc"
case ArchPPC64:
return "ppc64"
case ArchPPC64LE:
return "ppc64le"
case ArchS390:
return "s390"
case ArchS390X:
return "s390x"
case ArchNative:
return "native"
case ArchInvalid:
return "Invalid architecture"
default:
return fmt.Sprintf("Unknown architecture %#x", uint(a))
}
}
// String returns a string representation of a comparison operator constant
func (a ScmpCompareOp) String() string {
switch a {
case CompareNotEqual:
return "Not equal"
case CompareLess:
return "Less than"
case CompareLessOrEqual:
return "Less than or equal to"
case CompareEqual:
return "Equal"
case CompareGreaterEqual:
return "Greater than or equal to"
case CompareGreater:
return "Greater than"
case CompareMaskedEqual:
return "Masked equality"
case CompareInvalid:
return "Invalid comparison operator"
default:
return fmt.Sprintf("Unrecognized comparison operator %#x", uint(a))
}
}
// String returns a string representation of a seccomp match action
func (a ScmpAction) String() string {
switch a & 0xFFFF {
case ActKill:
return "Action: Kill Process"
case ActTrap:
return "Action: Send SIGSYS"
case ActErrno:
return fmt.Sprintf("Action: Return error code %d", (a >> 16))
case ActTrace:
return fmt.Sprintf("Action: Notify tracing processes with code %d",
(a >> 16))
case ActLog:
return "Action: Log system call"
case ActAllow:
return "Action: Allow system call"
default:
return fmt.Sprintf("Unrecognized Action %#x", uint(a))
}
}
// SetReturnCode adds a return code to a supporting ScmpAction, clearing any
// existing code Only valid on ActErrno and ActTrace. Takes no action otherwise.
// Accepts 16-bit return code as argument.
// Returns a valid ScmpAction of the original type with the new error code set.
func (a ScmpAction) SetReturnCode(code int16) ScmpAction {
aTmp := a & 0x0000FFFF
if aTmp == ActErrno || aTmp == ActTrace {
return (aTmp | (ScmpAction(code)&0xFFFF)<<16)
}
return a
}
// GetReturnCode returns the return code of an ScmpAction
func (a ScmpAction) GetReturnCode() int16 {
return int16(a >> 16)
}
// General utility functions
// GetLibraryVersion returns the version of the library the bindings are built
// against.
// The version is formatted as follows: Major.Minor.Micro
func GetLibraryVersion() (major, minor, micro uint) {
return verMajor, verMinor, verMicro
}
// GetApi returns the API level supported by the system.
// Returns a positive int containing the API level, or 0 with an error if the
// API level could not be detected due to the library being older than v2.4.0.
// See the seccomp_api_get(3) man page for details on available API levels:
// https://github.com/seccomp/libseccomp/blob/master/doc/man/man3/seccomp_api_get.3
func GetApi() (uint, error) {
return getApi()
}
// SetApi forcibly sets the API level. General use of this function is strongly
// discouraged.
// Returns an error if the API level could not be set. An error is always
// returned if the library is older than v2.4.0
// See the seccomp_api_get(3) man page for details on available API levels:
// https://github.com/seccomp/libseccomp/blob/master/doc/man/man3/seccomp_api_get.3
func SetApi(api uint) error {
return setApi(api)
}
// Syscall functions
// GetName retrieves the name of a syscall from its number.
// Acts on any syscall number.
// Returns either a string containing the name of the syscall, or an error.
func (s ScmpSyscall) GetName() (string, error) {
return s.GetNameByArch(ArchNative)
}
// GetNameByArch retrieves the name of a syscall from its number for a given
// architecture.
// Acts on any syscall number.
// Accepts a valid architecture constant.
// Returns either a string containing the name of the syscall, or an error.
// if the syscall is unrecognized or an issue occurred.
func (s ScmpSyscall) GetNameByArch(arch ScmpArch) (string, error) {
if err := sanitizeArch(arch); err != nil {
return "", err
}
cString := C.seccomp_syscall_resolve_num_arch(arch.toNative(), C.int(s))
if cString == nil {
return "", fmt.Errorf("could not resolve syscall name for %#x", int32(s))
}
defer C.free(unsafe.Pointer(cString))
finalStr := C.GoString(cString)
return finalStr, nil
}
// GetSyscallFromName returns the number of a syscall by name on the kernel's
// native architecture.
// Accepts a string containing the name of a syscall.
// Returns the number of the syscall, or an error if no syscall with that name
// was found.
func GetSyscallFromName(name string) (ScmpSyscall, error) {
if err := ensureSupportedVersion(); err != nil {
return 0, err
}
cString := C.CString(name)
defer C.free(unsafe.Pointer(cString))
result := C.seccomp_syscall_resolve_name(cString)
if result == scmpError {
return 0, fmt.Errorf("could not resolve name to syscall: %q", name)
}
return ScmpSyscall(result), nil
}
// GetSyscallFromNameByArch returns the number of a syscall by name for a given
// architecture's ABI.
// Accepts the name of a syscall and an architecture constant.
// Returns the number of the syscall, or an error if an invalid architecture is
// passed or a syscall with that name was not found.
func GetSyscallFromNameByArch(name string, arch ScmpArch) (ScmpSyscall, error) {
if err := ensureSupportedVersion(); err != nil {
return 0, err
}
if err := sanitizeArch(arch); err != nil {
return 0, err
}
cString := C.CString(name)
defer C.free(unsafe.Pointer(cString))
result := C.seccomp_syscall_resolve_name_arch(arch.toNative(), cString)
if result == scmpError {
return 0, fmt.Errorf("could not resolve name to syscall: %q on %v", name, arch)
}
return ScmpSyscall(result), nil
}
// MakeCondition creates and returns a new condition to attach to a filter rule.
// Associated rules will only match if this condition is true.
// Accepts the number the argument we are checking, and a comparison operator
// and value to compare to.
// The rule will match if argument $arg (zero-indexed) of the syscall is
// $COMPARE_OP the provided comparison value.
// Some comparison operators accept two values. Masked equals, for example,
// will mask $arg of the syscall with the second value provided (via bitwise
// AND) and then compare against the first value provided.
// For example, in the less than or equal case, if the syscall argument was
// 0 and the value provided was 1, the condition would match, as 0 is less
// than or equal to 1.
// Return either an error on bad argument or a valid ScmpCondition struct.
func MakeCondition(arg uint, comparison ScmpCompareOp, values ...uint64) (ScmpCondition, error) {
var condStruct ScmpCondition
if err := ensureSupportedVersion(); err != nil {
return condStruct, err
}
if comparison == CompareInvalid {
return condStruct, fmt.Errorf("invalid comparison operator")
} else if arg > 5 {
return condStruct, fmt.Errorf("syscalls only have up to 6 arguments (%d given)", arg)
} else if len(values) > 2 {
return condStruct, fmt.Errorf("conditions can have at most 2 arguments (%d given)", len(values))
} else if len(values) == 0 {
return condStruct, fmt.Errorf("must provide at least one value to compare against")
}
condStruct.Argument = arg
condStruct.Op = comparison
condStruct.Operand1 = values[0]
if len(values) == 2 {
condStruct.Operand2 = values[1]
} else {
condStruct.Operand2 = 0 // Unused
}
return condStruct, nil
}
// Utility Functions
// GetNativeArch returns architecture token representing the native kernel
// architecture
func GetNativeArch() (ScmpArch, error) {
if err := ensureSupportedVersion(); err != nil {
return ArchInvalid, err
}
arch := C.seccomp_arch_native()
return archFromNative(arch)
}
// Public Filter API
// ScmpFilter represents a filter context in libseccomp.
// A filter context is initially empty. Rules can be added to it, and it can
// then be loaded into the kernel.
type ScmpFilter struct {
filterCtx C.scmp_filter_ctx
valid bool
lock sync.Mutex
}
// NewFilter creates and returns a new filter context.
// Accepts a default action to be taken for syscalls which match no rules in
// the filter.
// Returns a reference to a valid filter context, or nil and an error if the
// filter context could not be created or an invalid default action was given.
func NewFilter(defaultAction ScmpAction) (*ScmpFilter, error) {
if err := ensureSupportedVersion(); err != nil {
return nil, err
}
if err := sanitizeAction(defaultAction); err != nil {
return nil, err
}
fPtr := C.seccomp_init(defaultAction.toNative())
if fPtr == nil {
return nil, fmt.Errorf("could not create filter")
}
filter := new(ScmpFilter)
filter.filterCtx = fPtr
filter.valid = true
runtime.SetFinalizer(filter, filterFinalizer)
// Enable TSync so all goroutines will receive the same rules
// If the kernel does not support TSYNC, allow us to continue without error
if err := filter.setFilterAttr(filterAttrTsync, 0x1); err != nil && err != syscall.ENOTSUP {
filter.Release()
return nil, fmt.Errorf("could not create filter - error setting tsync bit: %v", err)
}
return filter, nil
}
// IsValid determines whether a filter context is valid to use.
// Some operations (Release and Merge) render filter contexts invalid and
// consequently prevent further use.
func (f *ScmpFilter) IsValid() bool {
f.lock.Lock()
defer f.lock.Unlock()
return f.valid
}
// Reset resets a filter context, removing all its existing state.
// Accepts a new default action to be taken for syscalls which do not match.
// Returns an error if the filter or action provided are invalid.
func (f *ScmpFilter) Reset(defaultAction ScmpAction) error {
f.lock.Lock()
defer f.lock.Unlock()
if err := sanitizeAction(defaultAction); err != nil {
return err
} else if !f.valid {
return errBadFilter
}
retCode := C.seccomp_reset(f.filterCtx, defaultAction.toNative())
if retCode != 0 {
return syscall.Errno(-1 * retCode)
}
return nil
}
// Release releases a filter context, freeing its memory. Should be called after
// loading into the kernel, when the filter is no longer needed.
// After calling this function, the given filter is no longer valid and cannot
// be used.
// Release() will be invoked automatically when a filter context is garbage
// collected, but can also be called manually to free memory.
func (f *ScmpFilter) Release() {
f.lock.Lock()
defer f.lock.Unlock()
if !f.valid {
return
}
f.valid = false
C.seccomp_release(f.filterCtx)
}
// Merge merges two filter contexts.
// The source filter src will be released as part of the process, and will no
// longer be usable or valid after this call.
// To be merged, filters must NOT share any architectures, and all their
// attributes (Default Action, Bad Arch Action, and No New Privs bools)
// must match.
// The filter src will be merged into the filter this is called on.
// The architectures of the src filter not present in the destination, and all
// associated rules, will be added to the destination.
// Returns an error if merging the filters failed.
func (f *ScmpFilter) Merge(src *ScmpFilter) error {
f.lock.Lock()
defer f.lock.Unlock()
src.lock.Lock()
defer src.lock.Unlock()
if !src.valid || !f.valid {
return fmt.Errorf("one or more of the filter contexts is invalid or uninitialized")
}
// Merge the filters
retCode := C.seccomp_merge(f.filterCtx, src.filterCtx)
if syscall.Errno(-1*retCode) == syscall.EINVAL {
return fmt.Errorf("filters could not be merged due to a mismatch in attributes or invalid filter")
} else if retCode != 0 {
return syscall.Errno(-1 * retCode)
}
src.valid = false
return nil
}
// IsArchPresent checks if an architecture is present in a filter.
// If a filter contains an architecture, it uses its default action for
// syscalls which do not match rules in it, and its rules can match syscalls
// for that ABI.
// If a filter does not contain an architecture, all syscalls made to that
// kernel ABI will fail with the filter's default Bad Architecture Action
// (by default, killing the process).
// Accepts an architecture constant.
// Returns true if the architecture is present in the filter, false otherwise,
// and an error on an invalid filter context, architecture constant, or an
// issue with the call to libseccomp.
func (f *ScmpFilter) IsArchPresent(arch ScmpArch) (bool, error) {
f.lock.Lock()
defer f.lock.Unlock()
if err := sanitizeArch(arch); err != nil {
return false, err
} else if !f.valid {
return false, errBadFilter
}
retCode := C.seccomp_arch_exist(f.filterCtx, arch.toNative())
if syscall.Errno(-1*retCode) == syscall.EEXIST {
// -EEXIST is "arch not present"
return false, nil
} else if retCode != 0 {
return false, syscall.Errno(-1 * retCode)
}
return true, nil
}
// AddArch adds an architecture to the filter.
// Accepts an architecture constant.
// Returns an error on invalid filter context or architecture token, or an
// issue with the call to libseccomp.
func (f *ScmpFilter) AddArch(arch ScmpArch) error {
f.lock.Lock()
defer f.lock.Unlock()
if err := sanitizeArch(arch); err != nil {
return err
} else if !f.valid {
return errBadFilter
}
// Libseccomp returns -EEXIST if the specified architecture is already
// present. Succeed silently in this case, as it's not fatal, and the
// architecture is present already.
retCode := C.seccomp_arch_add(f.filterCtx, arch.toNative())
if retCode != 0 && syscall.Errno(-1*retCode) != syscall.EEXIST {
return syscall.Errno(-1 * retCode)
}
return nil
}
// RemoveArch removes an architecture from the filter.
// Accepts an architecture constant.
// Returns an error on invalid filter context or architecture token, or an
// issue with the call to libseccomp.
func (f *ScmpFilter) RemoveArch(arch ScmpArch) error {
f.lock.Lock()
defer f.lock.Unlock()
if err := sanitizeArch(arch); err != nil {
return err
} else if !f.valid {
return errBadFilter
}
// Similar to AddArch, -EEXIST is returned if the arch is not present
// Succeed silently in that case, this is not fatal and the architecture
// is not present in the filter after RemoveArch
retCode := C.seccomp_arch_remove(f.filterCtx, arch.toNative())
if retCode != 0 && syscall.Errno(-1*retCode) != syscall.EEXIST {
return syscall.Errno(-1 * retCode)
}
return nil
}
// Load loads a filter context into the kernel.
// Returns an error if the filter context is invalid or the syscall failed.
func (f *ScmpFilter) Load() error {
f.lock.Lock()
defer f.lock.Unlock()
if !f.valid {
return errBadFilter
}
if retCode := C.seccomp_load(f.filterCtx); retCode != 0 {
return syscall.Errno(-1 * retCode)
}
return nil
}
// GetDefaultAction returns the default action taken on a syscall which does not
// match a rule in the filter, or an error if an issue was encountered
// retrieving the value.
func (f *ScmpFilter) GetDefaultAction() (ScmpAction, error) {
action, err := f.getFilterAttr(filterAttrActDefault)
if err != nil {
return 0x0, err
}
return actionFromNative(action)
}
// GetBadArchAction returns the default action taken on a syscall for an
// architecture not in the filter, or an error if an issue was encountered
// retrieving the value.
func (f *ScmpFilter) GetBadArchAction() (ScmpAction, error) {
action, err := f.getFilterAttr(filterAttrActBadArch)
if err != nil {
return 0x0, err
}
return actionFromNative(action)
}
// GetNoNewPrivsBit returns the current state the No New Privileges bit will be set
// to on the filter being loaded, or an error if an issue was encountered
// retrieving the value.
// The No New Privileges bit tells the kernel that new processes run with exec()
// cannot gain more privileges than the process that ran exec().
// For example, a process with No New Privileges set would be unable to exec
// setuid/setgid executables.
func (f *ScmpFilter) GetNoNewPrivsBit() (bool, error) {
noNewPrivs, err := f.getFilterAttr(filterAttrNNP)
if err != nil {
return false, err
}
if noNewPrivs == 0 {
return false, nil
}
return true, nil
}
// GetLogBit returns the current state the Log bit will be set to on the filter
// being loaded, or an error if an issue was encountered retrieving the value.
// The Log bit tells the kernel that all actions taken by the filter, with the
// exception of ActAllow, should be logged.
// The Log bit is only usable when libseccomp API level 3 or higher is
// supported.
func (f *ScmpFilter) GetLogBit() (bool, error) {
log, err := f.getFilterAttr(filterAttrLog)
if err != nil {
api, apiErr := getApi()
if (apiErr != nil && api == 0) || (apiErr == nil && api < 3) {
return false, fmt.Errorf("getting the log bit is only supported in libseccomp 2.4.0 and newer with API level 3 or higher")
}
return false, err
}
if log == 0 {
return false, nil
}
return true, nil
}
// SetBadArchAction sets the default action taken on a syscall for an
// architecture not in the filter, or an error if an issue was encountered
// setting the value.
func (f *ScmpFilter) SetBadArchAction(action ScmpAction) error {
if err := sanitizeAction(action); err != nil {
return err
}
return f.setFilterAttr(filterAttrActBadArch, action.toNative())
}
// SetNoNewPrivsBit sets the state of the No New Privileges bit, which will be
// applied on filter load, or an error if an issue was encountered setting the
// value.
// Filters with No New Privileges set to 0 can only be loaded if the process
// has the CAP_SYS_ADMIN capability.
func (f *ScmpFilter) SetNoNewPrivsBit(state bool) error {
var toSet C.uint32_t = 0x0
if state {
toSet = 0x1
}
return f.setFilterAttr(filterAttrNNP, toSet)
}
// SetLogBit sets the state of the Log bit, which will be applied on filter
// load, or an error if an issue was encountered setting the value.
// The Log bit is only usable when libseccomp API level 3 or higher is
// supported.
func (f *ScmpFilter) SetLogBit(state bool) error {
var toSet C.uint32_t = 0x0
if state {
toSet = 0x1
}
err := f.setFilterAttr(filterAttrLog, toSet)
if err != nil {
api, apiErr := getApi()
if (apiErr != nil && api == 0) || (apiErr == nil && api < 3) {
return fmt.Errorf("setting the log bit is only supported in libseccomp 2.4.0 and newer with API level 3 or higher")
}
}
return err
}
// SetSyscallPriority sets a syscall's priority.
// This provides a hint to the filter generator in libseccomp about the
// importance of this syscall. High-priority syscalls are placed
// first in the filter code, and incur less overhead (at the expense of
// lower-priority syscalls).
func (f *ScmpFilter) SetSyscallPriority(call ScmpSyscall, priority uint8) error {
f.lock.Lock()
defer f.lock.Unlock()
if !f.valid {
return errBadFilter
}
if retCode := C.seccomp_syscall_priority(f.filterCtx, C.int(call),
C.uint8_t(priority)); retCode != 0 {
return syscall.Errno(-1 * retCode)
}
return nil
}
// AddRule adds a single rule for an unconditional action on a syscall.
// Accepts the number of the syscall and the action to be taken on the call
// being made.
// Returns an error if an issue was encountered adding the rule.
func (f *ScmpFilter) AddRule(call ScmpSyscall, action ScmpAction) error {
return f.addRuleGeneric(call, action, false, nil)
}
// AddRuleExact adds a single rule for an unconditional action on a syscall.
// Accepts the number of the syscall and the action to be taken on the call
// being made.
// No modifications will be made to the rule, and it will fail to add if it
// cannot be applied to the current architecture without modification.
// The rule will function exactly as described, but it may not function identically
// (or be able to be applied to) all architectures.
// Returns an error if an issue was encountered adding the rule.
func (f *ScmpFilter) AddRuleExact(call ScmpSyscall, action ScmpAction) error {
return f.addRuleGeneric(call, action, true, nil)
}
// AddRuleConditional adds a single rule for a conditional action on a syscall.
// Returns an error if an issue was encountered adding the rule.
// All conditions must match for the rule to match.
// There is a bug in library versions below v2.2.1 which can, in some cases,
// cause conditions to be lost when more than one are used. Consequently,
// AddRuleConditional is disabled on library versions lower than v2.2.1
func (f *ScmpFilter) AddRuleConditional(call ScmpSyscall, action ScmpAction, conds []ScmpCondition) error {
return f.addRuleGeneric(call, action, false, conds)
}
// AddRuleConditionalExact adds a single rule for a conditional action on a
// syscall.
// No modifications will be made to the rule, and it will fail to add if it
// cannot be applied to the current architecture without modification.
// The rule will function exactly as described, but it may not function identically
// (or be able to be applied to) all architectures.
// Returns an error if an issue was encountered adding the rule.
// There is a bug in library versions below v2.2.1 which can, in some cases,
// cause conditions to be lost when more than one are used. Consequently,
// AddRuleConditionalExact is disabled on library versions lower than v2.2.1
func (f *ScmpFilter) AddRuleConditionalExact(call ScmpSyscall, action ScmpAction, conds []ScmpCondition) error {
return f.addRuleGeneric(call, action, true, conds)
}
// ExportPFC output PFC-formatted, human-readable dump of a filter context's
// rules to a file.
// Accepts file to write to (must be open for writing).
// Returns an error if writing to the file fails.
func (f *ScmpFilter) ExportPFC(file *os.File) error {
f.lock.Lock()
defer f.lock.Unlock()
fd := file.Fd()
if !f.valid {
return errBadFilter
}
if retCode := C.seccomp_export_pfc(f.filterCtx, C.int(fd)); retCode != 0 {
return syscall.Errno(-1 * retCode)
}
return nil
}
// ExportBPF outputs Berkeley Packet Filter-formatted, kernel-readable dump of a
// filter context's rules to a file.
// Accepts file to write to (must be open for writing).
// Returns an error if writing to the file fails.
func (f *ScmpFilter) ExportBPF(file *os.File) error {
f.lock.Lock()
defer f.lock.Unlock()
fd := file.Fd()
if !f.valid {
return errBadFilter
}
if retCode := C.seccomp_export_bpf(f.filterCtx, C.int(fd)); retCode != 0 {
return syscall.Errno(-1 * retCode)
}
return nil
}

571
vendor/github.com/seccomp/libseccomp-golang/seccomp_internal.go generated vendored
View File

@ -1,571 +0,0 @@
// +build linux
// Internal functions for libseccomp Go bindings
// No exported functions
package seccomp
import (
"fmt"
"syscall"
)
// Unexported C wrapping code - provides the C-Golang interface
// Get the seccomp header in scope
// Need stdlib.h for free() on cstrings
// #cgo pkg-config: libseccomp
/*
#include <errno.h>
#include <stdlib.h>
#include <seccomp.h>
#if SCMP_VER_MAJOR < 2
#error Minimum supported version of Libseccomp is v2.2.0
#elif SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR < 2
#error Minimum supported version of Libseccomp is v2.2.0
#endif
#define ARCH_BAD ~0
const uint32_t C_ARCH_BAD = ARCH_BAD;
#ifndef SCMP_ARCH_PPC
#define SCMP_ARCH_PPC ARCH_BAD
#endif
#ifndef SCMP_ARCH_PPC64
#define SCMP_ARCH_PPC64 ARCH_BAD
#endif
#ifndef SCMP_ARCH_PPC64LE
#define SCMP_ARCH_PPC64LE ARCH_BAD
#endif
#ifndef SCMP_ARCH_S390
#define SCMP_ARCH_S390 ARCH_BAD
#endif
#ifndef SCMP_ARCH_S390X
#define SCMP_ARCH_S390X ARCH_BAD
#endif
const uint32_t C_ARCH_NATIVE = SCMP_ARCH_NATIVE;
const uint32_t C_ARCH_X86 = SCMP_ARCH_X86;
const uint32_t C_ARCH_X86_64 = SCMP_ARCH_X86_64;
const uint32_t C_ARCH_X32 = SCMP_ARCH_X32;
const uint32_t C_ARCH_ARM = SCMP_ARCH_ARM;
const uint32_t C_ARCH_AARCH64 = SCMP_ARCH_AARCH64;
const uint32_t C_ARCH_MIPS = SCMP_ARCH_MIPS;
const uint32_t C_ARCH_MIPS64 = SCMP_ARCH_MIPS64;
const uint32_t C_ARCH_MIPS64N32 = SCMP_ARCH_MIPS64N32;
const uint32_t C_ARCH_MIPSEL = SCMP_ARCH_MIPSEL;
const uint32_t C_ARCH_MIPSEL64 = SCMP_ARCH_MIPSEL64;
const uint32_t C_ARCH_MIPSEL64N32 = SCMP_ARCH_MIPSEL64N32;
const uint32_t C_ARCH_PPC = SCMP_ARCH_PPC;
const uint32_t C_ARCH_PPC64 = SCMP_ARCH_PPC64;
const uint32_t C_ARCH_PPC64LE = SCMP_ARCH_PPC64LE;
const uint32_t C_ARCH_S390 = SCMP_ARCH_S390;
const uint32_t C_ARCH_S390X = SCMP_ARCH_S390X;
#ifndef SCMP_ACT_LOG
#define SCMP_ACT_LOG 0x7ffc0000U
#endif
const uint32_t C_ACT_KILL = SCMP_ACT_KILL;
const uint32_t C_ACT_TRAP = SCMP_ACT_TRAP;
const uint32_t C_ACT_ERRNO = SCMP_ACT_ERRNO(0);
const uint32_t C_ACT_TRACE = SCMP_ACT_TRACE(0);
const uint32_t C_ACT_LOG = SCMP_ACT_LOG;
const uint32_t C_ACT_ALLOW = SCMP_ACT_ALLOW;
// The libseccomp SCMP_FLTATR_CTL_LOG member of the scmp_filter_attr enum was
// added in v2.4.0
#if (SCMP_VER_MAJOR < 2) || \
(SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR < 4)
#define SCMP_FLTATR_CTL_LOG _SCMP_FLTATR_MIN
#endif
const uint32_t C_ATTRIBUTE_DEFAULT = (uint32_t)SCMP_FLTATR_ACT_DEFAULT;
const uint32_t C_ATTRIBUTE_BADARCH = (uint32_t)SCMP_FLTATR_ACT_BADARCH;
const uint32_t C_ATTRIBUTE_NNP = (uint32_t)SCMP_FLTATR_CTL_NNP;
const uint32_t C_ATTRIBUTE_TSYNC = (uint32_t)SCMP_FLTATR_CTL_TSYNC;
const uint32_t C_ATTRIBUTE_LOG = (uint32_t)SCMP_FLTATR_CTL_LOG;
const int C_CMP_NE = (int)SCMP_CMP_NE;
const int C_CMP_LT = (int)SCMP_CMP_LT;
const int C_CMP_LE = (int)SCMP_CMP_LE;
const int C_CMP_EQ = (int)SCMP_CMP_EQ;
const int C_CMP_GE = (int)SCMP_CMP_GE;
const int C_CMP_GT = (int)SCMP_CMP_GT;
const int C_CMP_MASKED_EQ = (int)SCMP_CMP_MASKED_EQ;
const int C_VERSION_MAJOR = SCMP_VER_MAJOR;
const int C_VERSION_MINOR = SCMP_VER_MINOR;
const int C_VERSION_MICRO = SCMP_VER_MICRO;
#if SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR >= 3
unsigned int get_major_version()
{
return seccomp_version()->major;
}
unsigned int get_minor_version()
{
return seccomp_version()->minor;
}
unsigned int get_micro_version()
{
return seccomp_version()->micro;
}
#else
unsigned int get_major_version()
{
return (unsigned int)C_VERSION_MAJOR;
}
unsigned int get_minor_version()
{
return (unsigned int)C_VERSION_MINOR;
}
unsigned int get_micro_version()
{
return (unsigned int)C_VERSION_MICRO;
}
#endif
// The libseccomp API level functions were added in v2.4.0
#if (SCMP_VER_MAJOR < 2) || \
(SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR < 4)
const unsigned int seccomp_api_get(void)
{
// libseccomp-golang requires libseccomp v2.2.0, at a minimum, which
// supported API level 2. However, the kernel may not support API level
// 2 constructs which are the seccomp() system call and the TSYNC
// filter flag. Return the "reserved" value of 0 here to indicate that
// proper API level support is not available in libseccomp.
return 0;
}
int seccomp_api_set(unsigned int level)
{
return -EOPNOTSUPP;
}
#endif
typedef struct scmp_arg_cmp* scmp_cast_t;
void* make_arg_cmp_array(unsigned int length)
{
return calloc(length, sizeof(struct scmp_arg_cmp));
}
// Wrapper to add an scmp_arg_cmp struct to an existing arg_cmp array
void add_struct_arg_cmp(
struct scmp_arg_cmp* arr,
unsigned int pos,
unsigned int arg,
int compare,
uint64_t a,
uint64_t b
)
{
arr[pos].arg = arg;
arr[pos].op = compare;
arr[pos].datum_a = a;
arr[pos].datum_b = b;
return;
}
*/
import "C"
// Nonexported types
type scmpFilterAttr uint32
// Nonexported constants
const (
filterAttrActDefault scmpFilterAttr = iota
filterAttrActBadArch scmpFilterAttr = iota
filterAttrNNP scmpFilterAttr = iota
filterAttrTsync scmpFilterAttr = iota
filterAttrLog scmpFilterAttr = iota
)
const (
// An error return from certain libseccomp functions
scmpError C.int = -1
// Comparison boundaries to check for architecture validity
archStart ScmpArch = ArchNative
archEnd ScmpArch = ArchS390X
// Comparison boundaries to check for action validity
actionStart ScmpAction = ActKill
actionEnd ScmpAction = ActLog
// Comparison boundaries to check for comparison operator validity
compareOpStart ScmpCompareOp = CompareNotEqual
compareOpEnd ScmpCompareOp = CompareMaskedEqual
)
var (
// Error thrown on bad filter context
errBadFilter = fmt.Errorf("filter is invalid or uninitialized")
// Constants representing library major, minor, and micro versions
verMajor = uint(C.get_major_version())
verMinor = uint(C.get_minor_version())
verMicro = uint(C.get_micro_version())
)
// Nonexported functions
// Check if library version is greater than or equal to the given one
func checkVersionAbove(major, minor, micro uint) bool {
return (verMajor > major) ||
(verMajor == major && verMinor > minor) ||
(verMajor == major && verMinor == minor && verMicro >= micro)
}
// Ensure that the library is supported, i.e. >= 2.2.0.
func ensureSupportedVersion() error {
if !checkVersionAbove(2, 2, 0) {
return VersionError{}
}
return nil
}
// Get the API level
func getApi() (uint, error) {
api := C.seccomp_api_get()
if api == 0 {
return 0, fmt.Errorf("API level operations are not supported")
}
return uint(api), nil
}
// Set the API level
func setApi(api uint) error {
if retCode := C.seccomp_api_set(C.uint(api)); retCode != 0 {
if syscall.Errno(-1*retCode) == syscall.EOPNOTSUPP {
return fmt.Errorf("API level operations are not supported")
}
return fmt.Errorf("could not set API level: %v", retCode)
}
return nil
}
// Filter helpers
// Filter finalizer - ensure that kernel context for filters is freed
func filterFinalizer(f *ScmpFilter) {
f.Release()
}
// Get a raw filter attribute
func (f *ScmpFilter) getFilterAttr(attr scmpFilterAttr) (C.uint32_t, error) {
f.lock.Lock()
defer f.lock.Unlock()
if !f.valid {
return 0x0, errBadFilter
}
var attribute C.uint32_t
retCode := C.seccomp_attr_get(f.filterCtx, attr.toNative(), &attribute)
if retCode != 0 {
return 0x0, syscall.Errno(-1 * retCode)
}
return attribute, nil
}
// Set a raw filter attribute
func (f *ScmpFilter) setFilterAttr(attr scmpFilterAttr, value C.uint32_t) error {
f.lock.Lock()
defer f.lock.Unlock()
if !f.valid {
return errBadFilter
}
retCode := C.seccomp_attr_set(f.filterCtx, attr.toNative(), value)
if retCode != 0 {
return syscall.Errno(-1 * retCode)
}
return nil
}
// DOES NOT LOCK OR CHECK VALIDITY
// Assumes caller has already done this
// Wrapper for seccomp_rule_add_... functions
func (f *ScmpFilter) addRuleWrapper(call ScmpSyscall, action ScmpAction, exact bool, length C.uint, cond C.scmp_cast_t) error {
if length != 0 && cond == nil {
return fmt.Errorf("null conditions list, but length is nonzero")
}
var retCode C.int
if exact {
retCode = C.seccomp_rule_add_exact_array(f.filterCtx, action.toNative(), C.int(call), length, cond)
} else {
retCode = C.seccomp_rule_add_array(f.filterCtx, action.toNative(), C.int(call), length, cond)
}
if syscall.Errno(-1*retCode) == syscall.EFAULT {
return fmt.Errorf("unrecognized syscall %#x", int32(call))
} else if syscall.Errno(-1*retCode) == syscall.EPERM {
return fmt.Errorf("requested action matches default action of filter")
} else if syscall.Errno(-1*retCode) == syscall.EINVAL {
return fmt.Errorf("two checks on same syscall argument")
} else if retCode != 0 {
return syscall.Errno(-1 * retCode)
}
return nil
}
// Generic add function for filter rules
func (f *ScmpFilter) addRuleGeneric(call ScmpSyscall, action ScmpAction, exact bool, conds []ScmpCondition) error {
f.lock.Lock()
defer f.lock.Unlock()
if !f.valid {
return errBadFilter
}
if len(conds) == 0 {
if err := f.addRuleWrapper(call, action, exact, 0, nil); err != nil {
return err
}
} else {
// We don't support conditional filtering in library version v2.1
if !checkVersionAbove(2, 2, 1) {
return VersionError{
message: "conditional filtering is not supported",
minimum: "2.2.1",
}
}
argsArr := C.make_arg_cmp_array(C.uint(len(conds)))
if argsArr == nil {
return fmt.Errorf("error allocating memory for conditions")
}
defer C.free(argsArr)
for i, cond := range conds {
C.add_struct_arg_cmp(C.scmp_cast_t(argsArr), C.uint(i),
C.uint(cond.Argument), cond.Op.toNative(),
C.uint64_t(cond.Operand1), C.uint64_t(cond.Operand2))
}
if err := f.addRuleWrapper(call, action, exact, C.uint(len(conds)), C.scmp_cast_t(argsArr)); err != nil {
return err
}
}
return nil
}
// Generic Helpers
// Helper - Sanitize Arch token input
func sanitizeArch(in ScmpArch) error {
if in < archStart || in > archEnd {
return fmt.Errorf("unrecognized architecture %#x", uint(in))
}
if in.toNative() == C.C_ARCH_BAD {
return fmt.Errorf("architecture %v is not supported on this version of the library", in)
}
return nil
}
func sanitizeAction(in ScmpAction) error {
inTmp := in & 0x0000FFFF
if inTmp < actionStart || inTmp > actionEnd {
return fmt.Errorf("unrecognized action %#x", uint(inTmp))
}
if inTmp != ActTrace && inTmp != ActErrno && (in&0xFFFF0000) != 0 {
return fmt.Errorf("highest 16 bits must be zeroed except for Trace and Errno")
}
return nil
}
func sanitizeCompareOp(in ScmpCompareOp) error {
if in < compareOpStart || in > compareOpEnd {
return fmt.Errorf("unrecognized comparison operator %#x", uint(in))
}
return nil
}
func archFromNative(a C.uint32_t) (ScmpArch, error) {
switch a {
case C.C_ARCH_X86:
return ArchX86, nil
case C.C_ARCH_X86_64:
return ArchAMD64, nil
case C.C_ARCH_X32:
return ArchX32, nil
case C.C_ARCH_ARM:
return ArchARM, nil
case C.C_ARCH_NATIVE:
return ArchNative, nil
case C.C_ARCH_AARCH64:
return ArchARM64, nil
case C.C_ARCH_MIPS:
return ArchMIPS, nil
case C.C_ARCH_MIPS64:
return ArchMIPS64, nil
case C.C_ARCH_MIPS64N32:
return ArchMIPS64N32, nil
case C.C_ARCH_MIPSEL:
return ArchMIPSEL, nil
case C.C_ARCH_MIPSEL64:
return ArchMIPSEL64, nil
case C.C_ARCH_MIPSEL64N32:
return ArchMIPSEL64N32, nil
case C.C_ARCH_PPC:
return ArchPPC, nil
case C.C_ARCH_PPC64:
return ArchPPC64, nil
case C.C_ARCH_PPC64LE:
return ArchPPC64LE, nil
case C.C_ARCH_S390:
return ArchS390, nil
case C.C_ARCH_S390X:
return ArchS390X, nil
default:
return 0x0, fmt.Errorf("unrecognized architecture %#x", uint32(a))
}
}
// Only use with sanitized arches, no error handling
func (a ScmpArch) toNative() C.uint32_t {
switch a {
case ArchX86:
return C.C_ARCH_X86
case ArchAMD64:
return C.C_ARCH_X86_64
case ArchX32:
return C.C_ARCH_X32
case ArchARM:
return C.C_ARCH_ARM
case ArchARM64:
return C.C_ARCH_AARCH64
case ArchMIPS:
return C.C_ARCH_MIPS
case ArchMIPS64:
return C.C_ARCH_MIPS64
case ArchMIPS64N32:
return C.C_ARCH_MIPS64N32
case ArchMIPSEL:
return C.C_ARCH_MIPSEL
case ArchMIPSEL64:
return C.C_ARCH_MIPSEL64
case ArchMIPSEL64N32:
return C.C_ARCH_MIPSEL64N32
case ArchPPC:
return C.C_ARCH_PPC
case ArchPPC64:
return C.C_ARCH_PPC64
case ArchPPC64LE:
return C.C_ARCH_PPC64LE
case ArchS390:
return C.C_ARCH_S390
case ArchS390X:
return C.C_ARCH_S390X
case ArchNative:
return C.C_ARCH_NATIVE
default:
return 0x0
}
}
// Only use with sanitized ops, no error handling
func (a ScmpCompareOp) toNative() C.int {
switch a {
case CompareNotEqual:
return C.C_CMP_NE
case CompareLess:
return C.C_CMP_LT
case CompareLessOrEqual:
return C.C_CMP_LE
case CompareEqual:
return C.C_CMP_EQ
case CompareGreaterEqual:
return C.C_CMP_GE
case CompareGreater:
return C.C_CMP_GT
case CompareMaskedEqual:
return C.C_CMP_MASKED_EQ
default:
return 0x0
}
}
func actionFromNative(a C.uint32_t) (ScmpAction, error) {
aTmp := a & 0xFFFF
switch a & 0xFFFF0000 {
case C.C_ACT_KILL:
return ActKill, nil
case C.C_ACT_TRAP:
return ActTrap, nil
case C.C_ACT_ERRNO:
return ActErrno.SetReturnCode(int16(aTmp)), nil
case C.C_ACT_TRACE:
return ActTrace.SetReturnCode(int16(aTmp)), nil
case C.C_ACT_LOG:
return ActLog, nil
case C.C_ACT_ALLOW:
return ActAllow, nil
default:
return 0x0, fmt.Errorf("unrecognized action %#x", uint32(a))
}
}
// Only use with sanitized actions, no error handling
func (a ScmpAction) toNative() C.uint32_t {
switch a & 0xFFFF {
case ActKill:
return C.C_ACT_KILL
case ActTrap:
return C.C_ACT_TRAP
case ActErrno:
return C.C_ACT_ERRNO | (C.uint32_t(a) >> 16)
case ActTrace:
return C.C_ACT_TRACE | (C.uint32_t(a) >> 16)
case ActLog:
return C.C_ACT_LOG
case ActAllow:
return C.C_ACT_ALLOW
default:
return 0x0
}
}
// Internal only, assumes safe attribute
func (a scmpFilterAttr) toNative() uint32 {
switch a {
case filterAttrActDefault:
return uint32(C.C_ATTRIBUTE_DEFAULT)
case filterAttrActBadArch:
return uint32(C.C_ATTRIBUTE_BADARCH)
case filterAttrNNP:
return uint32(C.C_ATTRIBUTE_NNP)
case filterAttrTsync:
return uint32(C.C_ATTRIBUTE_TSYNC)
case filterAttrLog:
return uint32(C.C_ATTRIBUTE_LOG)
default:
return 0x0
}
}