Fix sanitizer config - multiple rules

custom/conf/app.ini.sample

@@ -963,8 +963,10 @@ SHOW_FOOTER_VERSION = true
 ; Show template execution time in the footer
 SHOW_FOOTER_TEMPLATE_LOAD_TIME = true
 
-[markup.sanitizer]
-; The following keys can be used multiple times to define sanitation policy rules.
+[markup.sanitizer.1]
+; The following keys can appear once to define a sanitation policy rule.
+; This section can appear with an incremenented number to define multiple rules.
+; e.g., [markup.sanitizer.1] -> [markup.sanitizer.2]
 ;ELEMENT = span
 ;ALLOW_ATTR = class
 ;REGEXP = ^(info|warning|error)$

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -646,7 +646,7 @@ Two special environment variables are passed to the render command:
 Gitea supports customizing the sanitization policy for rendered HTML. The example below will support KaTeX output from pandoc.
 
 ```ini
-[markup.sanitizer]
+[markup.sanitizer.TeX]
 ; Pandoc renders TeX segments as <span>s with the "math" class, optionally
 ; with "inline" or "display" classes depending on context.
 ELEMENT = span
@@ -658,7 +658,41 @@ REGEXP = ^\s*((math(\s+|$)|inline(\s+|$)|display(\s+|$)))+
  - `ALLOW_ATTR`: The attribute this policy allows. Must be non-empty.
  - `REGEXP`: A regex to match the contents of the attribute against. Must be present but may be empty for unconditional whitelisting of this attribute.
 
-You may redefine `ELEMENT`, `ALLOW_ATTR`, and `REGEXP` multiple times; each time all three are defined is a single policy entry.
+**Note**: The above section naming policy is new; previously the section was `[markup.sanitizer]` and keys could be redefined.
+Now, a unique identifier must appear in the section name (e.g., `[markup.sanitizer.TeX]`) in order to parse multiple rules.
+This was changed because the implementation with the ini parser used was flawed; the following configs were indistinguishable after parsing:
+
+```ini
+[markup.sanitizer]
+ELEMENT = a
+ALLOW_ATTR = target
+REGEXP = $1
+ELEMENT = a
+ALLOW_ATTR = rel
+REGEXP = $2
+ELEMENT = img
+ALLOW_ATTR = src
+REGEXP = $3
+```
+
+and
+
+```ini
+[markup.sanitizer]
+ELEMENT = a
+ALLOW_ATTR = target
+REGEXP = $1
+ELEMENT = img
+ALLOW_ATTR = rel
+REGEXP = $2
+ELEMENT = img
+ALLOW_ATTR = src
+REGEXP = $3
+```
+
+Because of limitations in the ini library, we are unable to automatically migrate configurations.
+
+We will still parse the first rule from a `[markup.sanitizer]` section if present, but multiple rules must be manually migrated.
 
 ## Time (`time`)
 

docs/content/doc/advanced/external-renderers.en-us.md

@@ -73,7 +73,7 @@ IS_INPUT_FILE = false
 If your external markup relies on additional classes and attributes on the generated HTML elements, you might need to enable custom sanitizer policies. Gitea uses the [`bluemonday`](https://godoc.org/github.com/microcosm-cc/bluemonday) package as our HTML sanitizier. The example below will support [KaTeX](https://katex.org/) output from [`pandoc`](https://pandoc.org/).
 
 ```ini
-[markup.sanitizer]
+[markup.sanitizer.TeX]
 ; Pandoc renders TeX segments as <span>s with the "math" class, optionally
 ; with "inline" or "display" classes depending on context.
 ELEMENT = span
@@ -86,6 +86,11 @@ FILE_EXTENSIONS = .md,.markdown
 RENDER_COMMAND = pandoc -f markdown -t html --katex
 ```
 
-You may redefine `ELEMENT`, `ALLOW_ATTR`, and `REGEXP` multiple times; each time all three are defined is a single policy entry. All three must be defined, but `REGEXP` may be blank to allow unconditional whitelisting of that attribute.
+You must define `ELEMENT`, `ALLOW_ATTR`, and `REGEXP` in each section.
+
+To define multiple entries, define different section names (e.g., `[markup.sanitizer.1]` and `[markup.sanitizer.2]`).
+These can be numbers, identifying names, or anything else.
 
 Once your configuration changes have been made, restart Gitea to have changes take effect.
+
+**Note**: The above section numbering policy is new; previously the section was `[markup.sanitizer]` and keys could be redefined.

modules/setting/markup.go

@@ -44,7 +44,7 @@ func newMarkup() {
  continue
  }
 
- if name == "sanitizer" {
+ if name == "sanitizer" || strings.HasPrefix(name, "sanitizer.") {
  newMarkupSanitizer(name, sec)
  } else {
  newMarkupRenderer(name, sec)
@@ -67,44 +67,36 @@ func newMarkupSanitizer(name string, sec *ini.Section) {
  return
  }
 
- elements := sec.Key("ELEMENT").ValueWithShadows()
- allowAttrs := sec.Key("ALLOW_ATTR").ValueWithShadows()
- regexps := sec.Key("REGEXP").ValueWithShadows()
+ elements := sec.Key("ELEMENT").Value()
+ allowAttrs := sec.Key("ALLOW_ATTR").Value()
+ regexpStr := sec.Key("REGEXP").Value()
 
- if len(elements) != len(allowAttrs) ||
- len(elements) != len(regexps) {
- log.Error("All three keys in markup.%s (ELEMENT, ALLOW_ATTR, REGEXP) must be defined the same number of times! Got %d, %d, and %d respectively.", name, len(elements), len(allowAttrs), len(regexps))
+ if regexpStr == "" {
+ rule := MarkupSanitizerRule{
+ Element: elements,
+ AllowAttr: allowAttrs,
+ Regexp: nil,
+ }
+
+ ExternalSanitizerRules = append(ExternalSanitizerRules, rule)
  return
  }
 
- ExternalSanitizerRules = make([]MarkupSanitizerRule, 0, len(elements))
-
- for index, pattern := range regexps {
- if pattern == "" {
- rule := MarkupSanitizerRule{
- Element: elements[index],
- AllowAttr: allowAttrs[index],
- Regexp: nil,
- }
- ExternalSanitizerRules = append(ExternalSanitizerRules, rule)
- continue
- }
-
- // Validate when parsing the config that this is a valid regular
- // expression. Then we can use regexp.MustCompile(...) later.
- compiled, err := regexp.Compile(pattern)
- if err != nil {
- log.Error("In module.%s: REGEXP at definition %d failed to compile: %v", name, index+1, err)
- continue
- }
+ // 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[index],
- AllowAttr: allowAttrs[index],
- Regexp: compiled,
- }
- ExternalSanitizerRules = append(ExternalSanitizerRules, rule)
+ rule := MarkupSanitizerRule{
+ Element: elements,
+ AllowAttr: allowAttrs,
+ Regexp: compiled,
  }
+
+ ExternalSanitizerRules = append(ExternalSanitizerRules, rule)
 }
 
 func newMarkupRenderer(name string, sec *ini.Section) {