forgejo/modules/templates/helper.go
Mathieu Fenniak f93d2cb261 ci: detect and prevent empty case statements in Go code (#11593)
One of the security patches released 2026-03-09 [fixed a vulnerability](d1c7b04d09) caused by a misapplication of Go `case` statements, where the implementation would have been correct if Go `case` statements automatically fall through to the next case block, but they do not.  This PR adds a semgrep rule which detects any empty `case` statement and raises an error, in order to prevent this coding mistake in the future.

For example, code like this will now trigger a build error:
```go
	switch setting.Protocol {
	case setting.HTTPUnix:
	case setting.FCGI:
	case setting.FCGIUnix:
	default:
		defaultLocalURL := string(setting.Protocol) + "://"
	}
```

Example error:
```
    cmd/web.go
   ❯❯❱ semgrep.config.forgejo-switch-empty-case
          switch has a case block with no content. This is treated as "break" by Go, but developers may
          confuse it for "fallthrough".  To fix this error, disambiguate by using "break" or
          "fallthrough".

          279┆ switch setting.Protocol {
          280┆ case setting.HTTPUnix:
          281┆ case setting.FCGI:
          282┆ case setting.FCGIUnix:
          283┆ default:
          284┆   defaultLocalURL := string(setting.Protocol) + "://"
          285┆   if setting.HTTPAddr == "0.0.0.0" {
          286┆           defaultLocalURL += "localhost"
          287┆   } else {
          288┆           defaultLocalURL += setting.HTTPAddr
```

As described in the error output, this error can be fixed by explicitly listing `break` (the real Go behaviour, to do nothing in the block), or by listing `fallthrough` (if the intent was to fall through).

All existing code triggering this detection has been changed to `break` (or, rarely, irrelevant cases have been removed), which should maintain the same code functionality.  While performing this fixup, a light analysis was performed on each case and they *appeared* correct, but with ~65 cases I haven't gone into extreme depth.

Tests are present for the semgrep rule in `.semgrep/tests/go.go`.

## Checklist

The [contributor guide](https://forgejo.org/docs/next/contributor/) contains information that will be helpful to first time contributors. There also are a few [conditions for merging Pull Requests in Forgejo repositories](https://codeberg.org/forgejo/governance/src/branch/main/PullRequestsAgreement.md). You are also welcome to join the [Forgejo development chatroom](https://matrix.to/#/#forgejo-development:matrix.org).

### Documentation

- [ ] I created a pull request [to the documentation](https://codeberg.org/forgejo/docs) to explain to Forgejo users how to use this change.
- [x] I did not document these changes and I do not expect someone else to do it.

### Release notes

- [ ] This change will be noticed by a Forgejo user or admin (feature, bug fix, performance, etc.). I suggest to include a release note for this change.
- [x] This change is not visible to a Forgejo user or admin (refactor, dependency upgrade, etc.). I think there is no need to add a release note for this change.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11593
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: Mathieu Fenniak <mathieu@fenniak.net>
Co-committed-by: Mathieu Fenniak <mathieu@fenniak.net>
2026-03-10 02:50:28 +01:00

297 lines
9 KiB
Go

// Copyright 2024 The Forgejo Authors. All rights reserved.
// Copyright 2018 The Gitea Authors. All rights reserved.
// Copyright 2014 The Gogs Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package templates
import (
"bytes"
"context"
"fmt"
"html"
"html/template"
"net/url"
"slices"
"strings"
"time"
user_model "forgejo.org/models/user"
"forgejo.org/modules/base"
"forgejo.org/modules/markup"
"forgejo.org/modules/setting"
"forgejo.org/modules/svg"
"forgejo.org/modules/templates/eval"
"forgejo.org/modules/util"
"forgejo.org/services/gitdiff"
)
// NewFuncMap returns functions for injecting to templates
func NewFuncMap() template.FuncMap {
return map[string]any{
"ctx": func() any { return nil }, // template context function
"ExecuteTemplate": func(ctx context.Context, tmplName string, args any) template.HTML {
h := HTMLRenderer()
tmpl, err := h.TemplateLookup(tmplName, ctx)
if err != nil {
panic("Template not found: " + tmplName)
}
buf := bytes.Buffer{}
if err := tmpl.Execute(&buf, args); err != nil {
panic("Error while executing template")
}
// We can safely return this as `template.HTML` as html/template will
// already make sure it's sanitized.
return template.HTML(buf.String())
},
"DumpVar": dumpVar,
// -----------------------------------------------------------------
// html/template related functions
"dict": dict, // it's lowercase because this name has been widely used. Our other functions should have uppercase names.
"Eval": Eval,
"TrustHTML": TrustHTML,
"HTMLFormat": HTMLFormat,
"HTMLEscape": HTMLEscape,
"QueryEscape": QueryEscape,
"JSEscape": JSEscapeSafe,
"SanitizeHTML": SanitizeHTML,
"URLJoin": util.URLJoin,
"DotEscape": DotEscape,
"PathEscape": url.PathEscape,
"PathEscapeSegments": util.PathEscapeSegments,
// utils
"StringUtils": NewStringUtils,
"SliceUtils": NewSliceUtils,
"JsonUtils": NewJsonUtils,
"DateUtils": NewDateUtils,
// -----------------------------------------------------------------
// svg / avatar / icon / color
"svg": svg.RenderHTML,
"EntryIcon": base.EntryIcon,
"MigrationIcon": MigrationIcon,
"ActionIcon": ActionIcon,
"SortArrow": SortArrow,
"ContrastColor": util.ContrastColor,
// -----------------------------------------------------------------
// time / number / format
"FileSize": FileSizePanic,
"CountFmt": base.FormatNumberSI,
"Sec2Time": util.SecToTime,
"LoadTimes": func(startTime time.Time) string {
return fmt.Sprint(time.Since(startTime).Nanoseconds()/1e6) + "ms"
},
// for backward compatibility only, do not use them anymore
"TimeSince": timeSinceLegacy,
"TimeSinceUnix": timeSinceLegacy,
"DateTime": dateTimeLegacy,
// -----------------------------------------------------------------
// setting
"AppName": func() string {
return setting.AppName
},
"AppSlogan": func() string {
return setting.AppSlogan
},
"AppDisplayName": func() string {
return setting.AppDisplayName
},
"AppSubUrl": func() string {
return setting.AppSubURL
},
"AssetUrlPrefix": func() string {
return setting.StaticURLPrefix + "/assets"
},
"AppUrl": func() string {
// The usage of AppUrl should be avoided as much as possible,
// because the AppURL(ROOT_URL) may not match user's visiting site and the ROOT_URL in app.ini may be incorrect.
// And it's difficult for Gitea to guess absolute URL correctly with zero configuration,
// because Gitea doesn't know whether the scheme is HTTP or HTTPS unless the reverse proxy could tell Gitea.
return setting.AppURL
},
"AppVer": func() string {
return setting.AppVer
},
"AppVerNoMetadata": func() string {
version, _, _ := strings.Cut(setting.AppVer, "+")
return version
},
"AppDomain": func() string { // documented in mail-templates.md
return setting.Domain
},
"RepoFlagsEnabled": func() bool {
return setting.Repository.EnableFlags
},
"AssetVersion": func() string {
return setting.AssetVersion
},
"DefaultShowFullName": func() bool {
return setting.UI.DefaultShowFullName
},
"ShowFooterTemplateLoadTime": func() bool {
return setting.Other.ShowFooterTemplateLoadTime
},
"ShowFooterPoweredBy": func() bool {
return setting.Other.ShowFooterPoweredBy
},
"AllowedReactions": func() []string {
return setting.UI.Reactions
},
"CustomEmojis": func() []string {
return setting.UI.CustomEmojis
},
"MetaAuthor": func() string {
return setting.UI.Meta.Author
},
"MetaDescription": func() string {
return setting.UI.Meta.Description
},
"MetaKeywords": func() string {
return setting.UI.Meta.Keywords
},
"EnableTimetracking": func() bool {
return setting.Service.EnableTimetracking
},
"DisableGitHooks": func() bool {
return setting.DisableGitHooks
},
"DisableWebhooks": func() bool {
return setting.DisableWebhooks
},
"DisableImportLocal": func() bool {
return !setting.ImportLocalPaths
},
"ThemeName": func(user *user_model.User) string {
if user == nil || user.Theme == "" {
return setting.UI.DefaultTheme
}
return user.Theme
},
"NotificationSettings": func() map[string]any {
return map[string]any{
"MinTimeout": int(setting.UI.Notification.MinTimeout / time.Millisecond),
"TimeoutStep": int(setting.UI.Notification.TimeoutStep / time.Millisecond),
"MaxTimeout": int(setting.UI.Notification.MaxTimeout / time.Millisecond),
"EventSourceUpdateTime": int(setting.UI.Notification.EventSourceUpdateTime / time.Millisecond),
}
},
"MermaidMaxSourceCharacters": func() int {
return setting.MermaidMaxSourceCharacters
},
"FederationEnabled": func() bool {
return setting.Federation.Enabled
},
// -----------------------------------------------------------------
// render
"RenderCommitMessage": RenderCommitMessage,
"RenderCommitMessageLinkSubject": RenderCommitMessageLinkSubject,
"RenderCommitBody": RenderCommitBody,
"RenderCodeBlock": RenderCodeBlock,
"RenderIssueTitle": RenderIssueTitle,
"RenderRefIssueTitle": RenderRefIssueTitle,
"RenderEmoji": RenderEmoji,
"ReactionToEmoji": ReactionToEmoji,
"RenderMarkdownToHtml": RenderMarkdownToHtml,
"RenderLabel": RenderLabel,
"RenderLabels": RenderLabels,
"RenderUser": RenderUser,
"RenderReviewRequest": RenderReviewRequest,
// -----------------------------------------------------------------
// misc
"ShortSha": base.ShortSha,
"ActionContent2Commits": ActionContent2Commits,
"IsMultilineCommitMessage": IsMultilineCommitMessage,
"CommentMustAsDiff": gitdiff.CommentMustAsDiff,
"MirrorRemoteAddress": mirrorRemoteAddress,
"FilenameIsImage": FilenameIsImage,
"TabSizeClass": TabSizeClass,
}
}
func HTMLFormat(s string, rawArgs ...any) template.HTML {
args := slices.Clone(rawArgs)
for i, v := range args {
switch v := v.(type) {
case nil, bool, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, template.HTML:
// for most basic types (including template.HTML which is safe), just do nothing and use it
break
case string:
args[i] = template.HTMLEscapeString(v)
case fmt.Stringer:
args[i] = template.HTMLEscapeString(v.String())
default:
args[i] = template.HTMLEscapeString(fmt.Sprint(v))
}
}
return template.HTML(fmt.Sprintf(s, args...))
}
// TrustHTML render raw as HTML
func TrustHTML(s any) template.HTML {
switch v := s.(type) {
case string:
return template.HTML(v)
case template.HTML:
return v
}
panic(fmt.Sprintf("unexpected type %T", s))
}
// SanitizeHTML sanitizes the input by pre-defined markdown rules
func SanitizeHTML(s string) template.HTML {
return template.HTML(markup.Sanitize(s))
}
func HTMLEscape(s any) template.HTML {
switch v := s.(type) {
case string:
return template.HTML(html.EscapeString(v))
case template.HTML:
return v
}
panic(fmt.Sprintf("unexpected type %T", s))
}
func JSEscapeSafe(s string) template.HTML {
return template.HTML(template.JSEscapeString(s))
}
func QueryEscape(s string) template.URL {
return template.URL(url.QueryEscape(s))
}
// DotEscape wraps a dots in names with ZWJ [U+200D] in order to prevent autolinkers from detecting these as urls
func DotEscape(raw string) string {
return strings.ReplaceAll(raw, ".", "\u200d.\u200d")
}
// Eval the expression and return the result, see the comment of eval.Expr for details.
// To use this helper function in templates, pass each token as a separate parameter.
//
// {{ $int64 := Eval $var "+" 1 }}
// {{ $float64 := Eval $var "+" 1.0 }}
//
// Golang's template supports comparable int types, so the int64 result can be used in later statements like {{if lt $int64 10}}
func Eval(tokens ...any) (any, error) {
n, err := eval.Expr(tokens...)
return n.Value, err
}
func FileSizePanic(s int64) string {
panic("Usage of FileSize in templates is deprecated in Forgejo. Locale.TrSize should be used instead.")
}