gitea/modules/setting/markup.go
Alexander Scheel 1bf9e44bda
Fix sanitizer config - multiple rules (#11133)
In #9888, it was reported that my earlier pull request #9075 didn't quite function as expected. I was quite hopeful the `ValuesWithShadow()` worked as expected (and, I thought my testing showed it did) but I guess not. @zeripath proposed an alternative syntax which I like:

```ini
[markup.sanitizer.1]
ELEMENT=a
ALLOW_ATTR=target
REGEXP=something
[markup.sanitizer.2]
ELEMENT=a
ALLOW_ATTR=target
REGEXP=something
```

This was quite easy to adopt into the existing code. I've done so in a semi-backwards-compatible manner:

 - The value from `.Value()` is used for each element.
 - We parse `[markup.sanitizer]` and all `[markup.sanitizer.*]` sections and add them as rules.

This means that existing configs will load one rule (not all rules). It also means people can use string identifiers (`[markup.sanitiser.KaTeX]`) if they prefer, instead of numbered ones.

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>
2020-04-29 12:34:59 +01:00

134 lines
3.4 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package setting
import (
"regexp"
"strings"
"code.gitea.io/gitea/modules/log"
"gopkg.in/ini.v1"
)
// ExternalMarkupParsers represents the external markup parsers
var (
ExternalMarkupParsers []MarkupParser
ExternalSanitizerRules []MarkupSanitizerRule
)
// MarkupParser defines the external parser configured in ini
type MarkupParser struct {
Enabled bool
MarkupName string
Command string
FileExtensions []string
IsInputFile bool
}
// MarkupSanitizerRule defines the policy for whitelisting attributes on
// certain elements.
type MarkupSanitizerRule struct {
Element string
AllowAttr string
Regexp *regexp.Regexp
}
func newMarkup() {
for _, sec := range Cfg.Section("markup").ChildSections() {
name := strings.TrimPrefix(sec.Name(), "markup.")
if name == "" {
log.Warn("name is empty, markup " + sec.Name() + "ignored")
continue
}
if name == "sanitizer" || strings.HasPrefix(name, "sanitizer.") {
newMarkupSanitizer(name, sec)
} else {
newMarkupRenderer(name, sec)
}
}
}
func newMarkupSanitizer(name string, sec *ini.Section) {
haveElement := sec.HasKey("ELEMENT")
haveAttr := sec.HasKey("ALLOW_ATTR")
haveRegexp := sec.HasKey("REGEXP")
if !haveElement && !haveAttr && !haveRegexp {
log.Warn("Skipping empty section: markup.%s.", name)
return
}
if !haveElement || !haveAttr || !haveRegexp {
log.Error("Missing required keys from markup.%s. Must have all three of ELEMENT, ALLOW_ATTR, and REGEXP defined!", name)
return
}
elements := sec.Key("ELEMENT").Value()
allowAttrs := sec.Key("ALLOW_ATTR").Value()
regexpStr := sec.Key("REGEXP").Value()
if regexpStr == "" {
rule := MarkupSanitizerRule{
Element: elements,
AllowAttr: allowAttrs,
Regexp: nil,
}
ExternalSanitizerRules = append(ExternalSanitizerRules, rule)
return
}
// Validate when parsing the config that this is a valid regular
// expression. Then we can use regexp.MustCompile(...) later.
compiled, err := regexp.Compile(regexpStr)
if err != nil {
log.Error("In module.%s: REGEXP (%s) at definition %d failed to compile: %v", regexpStr, name, err)
return
}
rule := MarkupSanitizerRule{
Element: elements,
AllowAttr: allowAttrs,
Regexp: compiled,
}
ExternalSanitizerRules = append(ExternalSanitizerRules, rule)
}
func newMarkupRenderer(name string, sec *ini.Section) {
extensionReg := regexp.MustCompile(`\.\w`)
extensions := sec.Key("FILE_EXTENSIONS").Strings(",")
var exts = make([]string, 0, len(extensions))
for _, extension := range extensions {
if !extensionReg.MatchString(extension) {
log.Warn(sec.Name() + " file extension " + extension + " is invalid. Extension ignored")
} else {
exts = append(exts, extension)
}
}
if len(exts) == 0 {
log.Warn(sec.Name() + " file extension is empty, markup " + name + " ignored")
return
}
command := sec.Key("RENDER_COMMAND").MustString("")
if command == "" {
log.Warn(" RENDER_COMMAND is empty, markup " + name + " ignored")
return
}
ExternalMarkupParsers = append(ExternalMarkupParsers, MarkupParser{
Enabled: sec.Key("ENABLED").MustBool(false),
MarkupName: name,
FileExtensions: exts,
Command: command,
IsInputFile: sec.Key("IS_INPUT_FILE").MustBool(false),
})
}