hugo/markup/converter/converter.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

136 lines
3.6 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 converter
import (
"bytes"
"github.com/gohugoio/hugo/common/hexec"
"github.com/gohugoio/hugo/common/loggers"
"github.com/gohugoio/hugo/config"
"github.com/gohugoio/hugo/identity"
"github.com/gohugoio/hugo/markup/converter/hooks"
"github.com/gohugoio/hugo/markup/markup_config"
"github.com/gohugoio/hugo/markup/tableofcontents"
"github.com/spf13/afero"
)
// ProviderConfig configures a new Provider.
type ProviderConfig struct {
MarkupConfig markup_config.Config
Cfg config.Provider // Site config
ContentFs afero.Fs
Logger loggers.Logger
Exec *hexec.Exec
Highlight func(code, lang, optsStr string) (string, error)
}
// ProviderProvider creates converter providers.
type ProviderProvider interface {
New(cfg ProviderConfig) (Provider, error)
}
// Provider creates converters.
type Provider interface {
New(ctx DocumentContext) (Converter, error)
Name() string
}
// NewProvider creates a new Provider with the given name.
func NewProvider(name string, create func(ctx DocumentContext) (Converter, error)) Provider {
return newConverter{
name: name,
create: create,
}
}
type newConverter struct {
name string
create func(ctx DocumentContext) (Converter, error)
}
func (n newConverter) New(ctx DocumentContext) (Converter, error) {
return n.create(ctx)
}
func (n newConverter) Name() string {
return n.name
}
var NopConverter = new(nopConverter)
type nopConverter int
func (nopConverter) Convert(ctx RenderContext) (Result, error) {
return &bytes.Buffer{}, nil
}
func (nopConverter) Supports(feature identity.Identity) bool {
return false
}
// Converter wraps the Convert method that converts some markup into
// another format, e.g. Markdown to HTML.
type Converter interface {
Convert(ctx RenderContext) (Result, error)
Supports(feature identity.Identity) bool
}
// Result represents the minimum returned from Convert.
type Result interface {
Bytes() []byte
}
// DocumentInfo holds additional information provided by some converters.
type DocumentInfo interface {
AnchorSuffix() string
}
// TableOfContentsProvider provides the content as a ToC structure.
type TableOfContentsProvider interface {
TableOfContents() tableofcontents.Root
}
// AnchorNameSanitizer tells how a converter sanitizes anchor names.
type AnchorNameSanitizer interface {
SanitizeAnchorName(s string) string
}
// Bytes holds a byte slice and implements the Result interface.
type Bytes []byte
// Bytes returns itself
func (b Bytes) Bytes() []byte {
return b
}
// DocumentContext holds contextual information about the document to convert.
type DocumentContext struct {
Document interface{} // May be nil. Usually a page.Page
DocumentID string
DocumentName string
Filename string
ConfigOverrides map[string]interface{}
}
// RenderContext holds contextual information about the content to render.
type RenderContext struct {
Src []byte
RenderTOC bool
RenderHooks hooks.Renderers
}
var FeatureRenderHooks = identity.NewPathIdentity("markup", "renderingHooks")