hugo/resources/resource_spec.go
Bjørn Erik Pedersen f4389e48ce
Add some basic security policies with sensible defaults
This ommmit contains some security hardening measures for the Hugo build runtime.

There are some rarely used features in Hugo that would be good to have disabled by default. One example would be the "external helpers".

For `asciidoctor` and some others we use Go's `os/exec` package to start a new process.

These are a predefined set of binary names, all loaded from `PATH` and with a predefined set of arguments. Still, if you don't use `asciidoctor` in your project, you might as well have it turned off.

You can configure your own in the new `security` configuration section, but the defaults are configured to create a minimal amount of site breakage. And if that do happen, you will get clear instructions in the loa about what to do.

The default configuration is listed below. Note that almost all of these options are regular expression _whitelists_ (a string or a slice); the value `none` will block all.

```toml
[security]
  enableInlineShortcodes = false
  [security.exec]
    allow = ['^dart-sass-embedded$', '^go$', '^npx$', '^postcss$']
    osEnv = ['(?i)^(PATH|PATHEXT|APPDATA|TMP|TEMP|TERM)$']

  [security.funcs]
    getenv = ['^HUGO_']

  [security.http]
    methods = ['(?i)GET|POST']
    urls = ['.*']
```
2021-12-16 09:40:22 +01:00

339 lines
8.3 KiB
Go

// Copyright 2019 The Hugo Authors. All rights reserved.
//
// 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 resources
import (
"errors"
"fmt"
"mime"
"os"
"path"
"path/filepath"
"strings"
"sync"
"github.com/gohugoio/hugo/resources/jsconfig"
"github.com/gohugoio/hugo/common/herrors"
"github.com/gohugoio/hugo/common/hexec"
"github.com/gohugoio/hugo/config"
"github.com/gohugoio/hugo/identity"
"github.com/gohugoio/hugo/helpers"
"github.com/gohugoio/hugo/hugofs"
"github.com/gohugoio/hugo/resources/postpub"
"github.com/gohugoio/hugo/cache/filecache"
"github.com/gohugoio/hugo/common/loggers"
"github.com/gohugoio/hugo/media"
"github.com/gohugoio/hugo/output"
"github.com/gohugoio/hugo/resources/images"
"github.com/gohugoio/hugo/resources/page"
"github.com/gohugoio/hugo/resources/resource"
"github.com/gohugoio/hugo/tpl"
"github.com/spf13/afero"
)
func NewSpec(
s *helpers.PathSpec,
fileCaches filecache.Caches,
incr identity.Incrementer,
logger loggers.Logger,
errorHandler herrors.ErrorSender,
execHelper *hexec.Exec,
outputFormats output.Formats,
mimeTypes media.Types) (*Spec, error) {
imgConfig, err := images.DecodeConfig(s.Cfg.GetStringMap("imaging"))
if err != nil {
return nil, err
}
imaging, err := images.NewImageProcessor(imgConfig)
if err != nil {
return nil, err
}
if incr == nil {
incr = &identity.IncrementByOne{}
}
if logger == nil {
logger = loggers.NewErrorLogger()
}
permalinks, err := page.NewPermalinkExpander(s)
if err != nil {
return nil, err
}
rs := &Spec{
PathSpec: s,
Logger: logger,
ErrorSender: errorHandler,
imaging: imaging,
ExecHelper: execHelper,
incr: incr,
MediaTypes: mimeTypes,
OutputFormats: outputFormats,
Permalinks: permalinks,
BuildConfig: config.DecodeBuild(s.Cfg),
FileCaches: fileCaches,
PostBuildAssets: &PostBuildAssets{
PostProcessResources: make(map[string]postpub.PostPublishedResource),
JSConfigBuilder: jsconfig.NewBuilder(),
},
imageCache: newImageCache(
fileCaches.ImageCache(),
s,
),
}
rs.ResourceCache = newResourceCache(rs)
return rs, nil
}
type Spec struct {
*helpers.PathSpec
MediaTypes media.Types
OutputFormats output.Formats
Logger loggers.Logger
ErrorSender herrors.ErrorSender
TextTemplates tpl.TemplateParseFinder
Permalinks page.PermalinkExpander
BuildConfig config.Build
// Holds default filter settings etc.
imaging *images.ImageProcessor
ExecHelper *hexec.Exec
incr identity.Incrementer
imageCache *imageCache
ResourceCache *ResourceCache
FileCaches filecache.Caches
// Assets used after the build is done.
// This is shared between all sites.
*PostBuildAssets
}
type PostBuildAssets struct {
postProcessMu sync.RWMutex
PostProcessResources map[string]postpub.PostPublishedResource
JSConfigBuilder *jsconfig.Builder
}
func (r *Spec) New(fd ResourceSourceDescriptor) (resource.Resource, error) {
return r.newResourceFor(fd)
}
func (r *Spec) CacheStats() string {
r.imageCache.mu.RLock()
defer r.imageCache.mu.RUnlock()
s := fmt.Sprintf("Cache entries: %d", len(r.imageCache.store))
count := 0
for k := range r.imageCache.store {
if count > 5 {
break
}
s += "\n" + k
count++
}
return s
}
func (r *Spec) ClearCaches() {
r.imageCache.clear()
r.ResourceCache.clear()
}
func (r *Spec) DeleteBySubstring(s string) {
r.imageCache.deleteIfContains(s)
}
func (s *Spec) String() string {
return "spec"
}
// TODO(bep) clean up below
func (r *Spec) newGenericResource(sourceFs afero.Fs,
targetPathBuilder func() page.TargetPaths,
osFileInfo os.FileInfo,
sourceFilename,
baseFilename string,
mediaType media.Type) *genericResource {
return r.newGenericResourceWithBase(
sourceFs,
nil,
nil,
targetPathBuilder,
osFileInfo,
sourceFilename,
baseFilename,
mediaType,
)
}
func (r *Spec) newGenericResourceWithBase(
sourceFs afero.Fs,
openReadSeekerCloser resource.OpenReadSeekCloser,
targetPathBaseDirs []string,
targetPathBuilder func() page.TargetPaths,
osFileInfo os.FileInfo,
sourceFilename,
baseFilename string,
mediaType media.Type) *genericResource {
if osFileInfo != nil && osFileInfo.IsDir() {
panic(fmt.Sprintf("dirs not supported resource types: %v", osFileInfo))
}
// This value is used both to construct URLs and file paths, but start
// with a Unix-styled path.
baseFilename = helpers.ToSlashTrimLeading(baseFilename)
fpath, fname := path.Split(baseFilename)
resourceType := mediaType.MainType
pathDescriptor := &resourcePathDescriptor{
baseTargetPathDirs: helpers.UniqueStringsReuse(targetPathBaseDirs),
targetPathBuilder: targetPathBuilder,
relTargetDirFile: dirFile{dir: fpath, file: fname},
}
var fim hugofs.FileMetaInfo
if osFileInfo != nil {
fim = osFileInfo.(hugofs.FileMetaInfo)
}
gfi := &resourceFileInfo{
fi: fim,
openReadSeekerCloser: openReadSeekerCloser,
sourceFs: sourceFs,
sourceFilename: sourceFilename,
h: &resourceHash{},
}
g := &genericResource{
resourceFileInfo: gfi,
resourcePathDescriptor: pathDescriptor,
mediaType: mediaType,
resourceType: resourceType,
spec: r,
params: make(map[string]interface{}),
name: baseFilename,
title: baseFilename,
resourceContent: &resourceContent{},
}
return g
}
func (r *Spec) newResource(sourceFs afero.Fs, fd ResourceSourceDescriptor) (resource.Resource, error) {
fi := fd.FileInfo
var sourceFilename string
if fd.OpenReadSeekCloser != nil {
} else if fd.SourceFilename != "" {
var err error
fi, err = sourceFs.Stat(fd.SourceFilename)
if err != nil {
if os.IsNotExist(err) {
return nil, nil
}
return nil, err
}
sourceFilename = fd.SourceFilename
} else {
sourceFilename = fd.SourceFile.Filename()
}
if fd.RelTargetFilename == "" {
fd.RelTargetFilename = sourceFilename
}
ext := strings.ToLower(filepath.Ext(fd.RelTargetFilename))
mimeType, suffixInfo, found := r.MediaTypes.GetFirstBySuffix(strings.TrimPrefix(ext, "."))
// TODO(bep) we need to handle these ambiguous types better, but in this context
// we most likely want the application/xml type.
if suffixInfo.Suffix == "xml" && mimeType.SubType == "rss" {
mimeType, found = r.MediaTypes.GetByType("application/xml")
}
if !found {
// A fallback. Note that mime.TypeByExtension is slow by Hugo standards,
// so we should configure media types to avoid this lookup for most
// situations.
mimeStr := mime.TypeByExtension(ext)
if mimeStr != "" {
mimeType, _ = media.FromStringAndExt(mimeStr, ext)
}
}
gr := r.newGenericResourceWithBase(
sourceFs,
fd.OpenReadSeekCloser,
fd.TargetBasePaths,
fd.TargetPaths,
fi,
sourceFilename,
fd.RelTargetFilename,
mimeType)
if mimeType.MainType == "image" {
imgFormat, ok := images.ImageFormatFromExt(ext)
if ok {
ir := &imageResource{
Image: images.NewImage(imgFormat, r.imaging, nil, gr),
baseResource: gr,
}
ir.root = ir
return newResourceAdapter(gr.spec, fd.LazyPublish, ir), nil
}
}
return newResourceAdapter(gr.spec, fd.LazyPublish, gr), nil
}
func (r *Spec) newResourceFor(fd ResourceSourceDescriptor) (resource.Resource, error) {
if fd.OpenReadSeekCloser == nil {
if fd.SourceFile != nil && fd.SourceFilename != "" {
return nil, errors.New("both SourceFile and AbsSourceFilename provided")
} else if fd.SourceFile == nil && fd.SourceFilename == "" {
return nil, errors.New("either SourceFile or AbsSourceFilename must be provided")
}
}
if fd.RelTargetFilename == "" {
fd.RelTargetFilename = fd.Filename()
}
if len(fd.TargetBasePaths) == 0 {
// If not set, we publish the same resource to all hosts.
fd.TargetBasePaths = r.MultihostTargetBasePaths
}
return r.newResource(fd.Fs, fd)
}