From 5b3a82d621e75ef9198213d20081da8b28511403 Mon Sep 17 00:00:00 2001
From: Gusted <postmaster@gusted.xyz>
Date: Wed, 21 Feb 2024 22:18:44 +0100
Subject: [PATCH] [FEAT] Enable ambiguous character detection in configured
contexts
- The ambiguous character detection is an important security feature to
combat against sourcebase attacks (https://trojansource.codes/).
- However there are a few problems with the feature as it stands
today (i) it's apparantly an big performance hitter, it's twice as slow
as syntax highlighting (ii) it contains false positives, because it's
reporting valid problems but not valid within the context of a
programming language (ambiguous charachters in code comments being a
prime example) that can lead to security issues (iii) charachters from
certain languages always being marked as ambiguous. It's a lot of effort
to fix the aforementioned issues.
- Therefore, make it configurable in which context the ambiguous
character detection should be run, this avoids running detection in all
contexts such as file views, but still enable it in commits and pull
requests diffs where it matters the most. Ideally this also becomes an
per-repository setting, but the code architecture doesn't allow for a
clean implementation of that.
- Adds unit test.
- Adds integration tests to ensure that the contexts and instance-wide
is respected (and that ambigious charachter detection actually work in
different places).
- Ref: https://codeberg.org/forgejo/forgejo/pulls/2395#issuecomment-1575547
- Ref: https://codeberg.org/forgejo/forgejo/issues/564
---
modules/charset/escape.go | 22 +++++--
modules/charset/escape_test.go | 22 ++++++-
modules/setting/ui.go | 2 +
routers/web/repo/blame.go | 2 +-
routers/web/repo/setting/lfs.go | 2 +-
routers/web/repo/view.go | 6 +-
routers/web/repo/wiki.go | 2 +-
services/gitdiff/gitdiff.go | 4 +-
tests/integration/view_test.go | 104 ++++++++++++++++++++++++++++++++
9 files changed, 151 insertions(+), 15 deletions(-)
diff --git a/modules/charset/escape.go b/modules/charset/escape.go
index 92e417d1f7..ba0eb73a3a 100644
--- a/modules/charset/escape.go
+++ b/modules/charset/escape.go
@@ -10,6 +10,7 @@ package charset
import (
"html/template"
"io"
+ "slices"
"strings"
"code.gitea.io/gitea/modules/log"
@@ -20,16 +21,29 @@ import (
// RuneNBSP is the codepoint for NBSP
const RuneNBSP = 0xa0
+type escapeContext string
+
+// Keep this consistent with the documentation of [ui].SKIP_ESCAPE_CONTEXTS
+// Defines the different contexts that could be used to escape in.
+const (
+ // Wiki pages.
+ WikiContext escapeContext = "wiki"
+ // Rendered content (except markup), source code and blames.
+ FileviewContext escapeContext = "file-view"
+ // Commits or pull requet's diff.
+ DiffContext escapeContext = "diff"
+)
+
// EscapeControlHTML escapes the unicode control sequences in a provided html document
-func EscapeControlHTML(html template.HTML, locale translation.Locale, allowed ...rune) (escaped *EscapeStatus, output template.HTML) {
+func EscapeControlHTML(html template.HTML, locale translation.Locale, context escapeContext, allowed ...rune) (escaped *EscapeStatus, output template.HTML) {
sb := &strings.Builder{}
- escaped, _ = EscapeControlReader(strings.NewReader(string(html)), sb, locale, allowed...) // err has been handled in EscapeControlReader
+ escaped, _ = EscapeControlReader(strings.NewReader(string(html)), sb, locale, context, allowed...) // err has been handled in EscapeControlReader
return escaped, template.HTML(sb.String())
}
// EscapeControlReader escapes the unicode control sequences in a provided reader of HTML content and writer in a locale and returns the findings as an EscapeStatus
-func EscapeControlReader(reader io.Reader, writer io.Writer, locale translation.Locale, allowed ...rune) (escaped *EscapeStatus, err error) {
- if !setting.UI.AmbiguousUnicodeDetection {
+func EscapeControlReader(reader io.Reader, writer io.Writer, locale translation.Locale, context escapeContext, allowed ...rune) (escaped *EscapeStatus, err error) {
+ if !setting.UI.AmbiguousUnicodeDetection || slices.Contains(setting.UI.SkipEscapeContexts, string(context)) {
_, err = io.Copy(writer, reader)
return &EscapeStatus{}, err
}
diff --git a/modules/charset/escape_test.go b/modules/charset/escape_test.go
index a353ced631..7442a80d7f 100644
--- a/modules/charset/escape_test.go
+++ b/modules/charset/escape_test.go
@@ -4,6 +4,7 @@
package charset
import (
+ "html/template"
"strings"
"testing"
@@ -14,6 +15,8 @@ import (
"github.com/stretchr/testify/assert"
)
+var testContext = escapeContext("test")
+
type escapeControlTest struct {
name string
text string
@@ -159,7 +162,7 @@ func TestEscapeControlReader(t *testing.T) {
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
output := &strings.Builder{}
- status, err := EscapeControlReader(strings.NewReader(tt.text), output, &translation.MockLocale{})
+ status, err := EscapeControlReader(strings.NewReader(tt.text), output, &translation.MockLocale{}, testContext)
assert.NoError(t, err)
assert.Equal(t, tt.status, *status)
assert.Equal(t, tt.result, output.String())
@@ -169,9 +172,22 @@ func TestEscapeControlReader(t *testing.T) {
func TestSettingAmbiguousUnicodeDetection(t *testing.T) {
defer test.MockVariableValue(&setting.UI.AmbiguousUnicodeDetection, true)()
- _, out := EscapeControlHTML("a test", &translation.MockLocale{})
+
+ _, out := EscapeControlHTML("a test", &translation.MockLocale{}, testContext)
assert.EqualValues(t, `a<span class="escaped-code-point" data-escaped="[U+00A0]"><span class="char"> </span></span>test`, out)
setting.UI.AmbiguousUnicodeDetection = false
- _, out = EscapeControlHTML("a test", &translation.MockLocale{})
+ _, out = EscapeControlHTML("a test", &translation.MockLocale{}, testContext)
assert.EqualValues(t, `a test`, out)
}
+
+func TestAmbiguousUnicodeDetectionContext(t *testing.T) {
+ defer test.MockVariableValue(&setting.UI.SkipEscapeContexts, []string{"test"})()
+
+ input := template.HTML("a test")
+
+ _, out := EscapeControlHTML(input, &translation.MockLocale{}, escapeContext("not-test"))
+ assert.EqualValues(t, `a<span class="escaped-code-point" data-escaped="[U+00A0]"><span class="char"> </span></span>test`, out)
+
+ _, out = EscapeControlHTML(input, &translation.MockLocale{}, testContext)
+ assert.EqualValues(t, input, out)
+}
diff --git a/modules/setting/ui.go b/modules/setting/ui.go
index 02a213d478..47e1393ef3 100644
--- a/modules/setting/ui.go
+++ b/modules/setting/ui.go
@@ -38,6 +38,7 @@ var UI = struct {
PreferredTimestampTense string
AmbiguousUnicodeDetection bool
+ SkipEscapeContexts []string
Notification struct {
MinTimeout time.Duration
@@ -89,6 +90,7 @@ var UI = struct {
PreferredTimestampTense: "mixed",
AmbiguousUnicodeDetection: true,
+ SkipEscapeContexts: []string{},
Notification: struct {
MinTimeout time.Duration
diff --git a/routers/web/repo/blame.go b/routers/web/repo/blame.go
index d7c861c42b..dca963c8ef 100644
--- a/routers/web/repo/blame.go
+++ b/routers/web/repo/blame.go
@@ -279,7 +279,7 @@ func renderBlame(ctx *context.Context, blameParts []*git.BlamePart, commitNames
lexerName = lexerNameForLine
}
- br.EscapeStatus, br.Code = charset.EscapeControlHTML(line, ctx.Locale)
+ br.EscapeStatus, br.Code = charset.EscapeControlHTML(line, ctx.Locale, charset.FileviewContext)
rows = append(rows, br)
escapeStatus = escapeStatus.Or(br.EscapeStatus)
}
diff --git a/routers/web/repo/setting/lfs.go b/routers/web/repo/setting/lfs.go
index cd0f11d548..e360ae2b8c 100644
--- a/routers/web/repo/setting/lfs.go
+++ b/routers/web/repo/setting/lfs.go
@@ -307,7 +307,7 @@ func LFSFileGet(ctx *context.Context) {
// Building code view blocks with line number on server side.
escapedContent := &bytes.Buffer{}
- ctx.Data["EscapeStatus"], _ = charset.EscapeControlReader(rd, escapedContent, ctx.Locale)
+ ctx.Data["EscapeStatus"], _ = charset.EscapeControlReader(rd, escapedContent, ctx.Locale, charset.FileviewContext)
var output bytes.Buffer
lines := strings.Split(escapedContent.String(), "\n")
diff --git a/routers/web/repo/view.go b/routers/web/repo/view.go
index e48865a2f5..86977062cb 100644
--- a/routers/web/repo/view.go
+++ b/routers/web/repo/view.go
@@ -338,7 +338,7 @@ func renderReadmeFile(ctx *context.Context, subfolder string, readmeFile *git.Tr
log.Error("Read readme content failed: %v", err)
}
contentEscaped := template.HTMLEscapeString(util.UnsafeBytesToString(content))
- ctx.Data["EscapeStatus"], ctx.Data["FileContent"] = charset.EscapeControlHTML(template.HTML(contentEscaped), ctx.Locale)
+ ctx.Data["EscapeStatus"], ctx.Data["FileContent"] = charset.EscapeControlHTML(template.HTML(contentEscaped), ctx.Locale, charset.FileviewContext)
}
if !fInfo.isLFSFile && ctx.Repo.CanEnableEditor(ctx, ctx.Doer) {
@@ -572,7 +572,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry) {
status := &charset.EscapeStatus{}
statuses := make([]*charset.EscapeStatus, len(fileContent))
for i, line := range fileContent {
- statuses[i], fileContent[i] = charset.EscapeControlHTML(line, ctx.Locale)
+ statuses[i], fileContent[i] = charset.EscapeControlHTML(line, ctx.Locale, charset.FileviewContext)
status = status.Or(statuses[i])
}
ctx.Data["EscapeStatus"] = status
@@ -678,7 +678,7 @@ func markupRender(ctx *context.Context, renderCtx *markup.RenderContext, input i
go func() {
sb := &strings.Builder{}
// We allow NBSP here this is rendered
- escaped, _ = charset.EscapeControlReader(markupRd, sb, ctx.Locale, charset.RuneNBSP)
+ escaped, _ = charset.EscapeControlReader(markupRd, sb, ctx.Locale, charset.FileviewContext, charset.RuneNBSP)
output = template.HTML(sb.String())
close(done)
}()
diff --git a/routers/web/repo/wiki.go b/routers/web/repo/wiki.go
index 79f446ea88..157ebd4d5d 100644
--- a/routers/web/repo/wiki.go
+++ b/routers/web/repo/wiki.go
@@ -254,7 +254,7 @@ func renderViewPage(ctx *context.Context) (*git.Repository, *git.TreeEntry) {
done := make(chan struct{})
go func() {
// We allow NBSP here this is rendered
- escaped, _ = charset.EscapeControlReader(markupRd, buf, ctx.Locale, charset.RuneNBSP)
+ escaped, _ = charset.EscapeControlReader(markupRd, buf, ctx.Locale, charset.WikiContext, charset.RuneNBSP)
output = buf.String()
buf.Reset()
close(done)
diff --git a/services/gitdiff/gitdiff.go b/services/gitdiff/gitdiff.go
index 241d849c9f..715c5bf9b8 100644
--- a/services/gitdiff/gitdiff.go
+++ b/services/gitdiff/gitdiff.go
@@ -284,14 +284,14 @@ type DiffInline struct {
// DiffInlineWithUnicodeEscape makes a DiffInline with hidden unicode characters escaped
func DiffInlineWithUnicodeEscape(s template.HTML, locale translation.Locale) DiffInline {
- status, content := charset.EscapeControlHTML(s, locale)
+ status, content := charset.EscapeControlHTML(s, locale, charset.DiffContext)
return DiffInline{EscapeStatus: status, Content: content}
}
// DiffInlineWithHighlightCode makes a DiffInline with code highlight and hidden unicode characters escaped
func DiffInlineWithHighlightCode(fileName, language, code string, locale translation.Locale) DiffInline {
highlighted, _ := highlight.Code(fileName, language, code)
- status, content := charset.EscapeControlHTML(highlighted, locale)
+ status, content := charset.EscapeControlHTML(highlighted, locale, charset.DiffContext)
return DiffInline{EscapeStatus: status, Content: content}
}
diff --git a/tests/integration/view_test.go b/tests/integration/view_test.go
index f434446801..cd63304a91 100644
--- a/tests/integration/view_test.go
+++ b/tests/integration/view_test.go
@@ -5,8 +5,16 @@ package integration
import (
"net/http"
+ "net/url"
+ "strings"
"testing"
+ unit_model "code.gitea.io/gitea/models/unit"
+ "code.gitea.io/gitea/models/unittest"
+ user_model "code.gitea.io/gitea/models/user"
+ "code.gitea.io/gitea/modules/setting"
+ "code.gitea.io/gitea/modules/test"
+ files_service "code.gitea.io/gitea/services/repository/files"
"code.gitea.io/gitea/tests"
"github.com/stretchr/testify/assert"
@@ -25,3 +33,99 @@ func TestRenderFileSVGIsInImgTag(t *testing.T) {
assert.True(t, exists, "The SVG image should be in an <img> tag so that scripts in the SVG are not run")
assert.Equal(t, "/user2/repo2/raw/branch/master/line.svg", src)
}
+
+func TestAmbiguousCharacterDetection(t *testing.T) {
+ onGiteaRun(t, func(t *testing.T, u *url.URL) {
+ user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+ session := loginUser(t, user2.Name)
+
+ // Prepare the environments. File view, commit view (diff), wiki page.
+ repo, commitID, f := CreateDeclarativeRepo(t, user2, "",
+ []unit_model.Type{unit_model.TypeCode, unit_model.TypeWiki}, nil,
+ []*files_service.ChangeRepoFile{
+ {
+ Operation: "create",
+ TreePath: "test.sh",
+ ContentReader: strings.NewReader("Hello there!\nline western"),
+ },
+ },
+ )
+ defer f()
+
+ req := NewRequestWithValues(t, "POST", repo.Link()+"/wiki?action=new", map[string]string{
+ "_csrf": GetCSRF(t, session, repo.Link()+"/wiki?action=new"),
+ "title": "Normal",
+ "content": "Hello – Hello",
+ })
+ session.MakeRequest(t, req, http.StatusSeeOther)
+
+ assertCase := func(t *testing.T, fileContext, commitContext, wikiContext bool) {
+ t.Helper()
+
+ t.Run("File context", func(t *testing.T) {
+ defer tests.PrintCurrentTest(t)()
+
+ req := NewRequest(t, "GET", repo.Link()+"/src/branch/main/test.sh")
+ resp := session.MakeRequest(t, req, http.StatusOK)
+
+ htmlDoc := NewHTMLParser(t, resp.Body)
+ htmlDoc.AssertElement(t, ".unicode-escape-prompt", fileContext)
+ })
+ t.Run("Commit context", func(t *testing.T) {
+ defer tests.PrintCurrentTest(t)()
+
+ req := NewRequest(t, "GET", repo.Link()+"/commit/"+commitID)
+ resp := session.MakeRequest(t, req, http.StatusOK)
+
+ htmlDoc := NewHTMLParser(t, resp.Body)
+ htmlDoc.AssertElement(t, ".lines-escape .toggle-escape-button", commitContext)
+ })
+ t.Run("Wiki context", func(t *testing.T) {
+ defer tests.PrintCurrentTest(t)()
+
+ req := NewRequest(t, "GET", repo.Link()+"/wiki/Normal")
+ resp := session.MakeRequest(t, req, http.StatusOK)
+
+ htmlDoc := NewHTMLParser(t, resp.Body)
+ htmlDoc.AssertElement(t, ".unicode-escape-prompt", wikiContext)
+ })
+ }
+
+ t.Run("Enabled all context", func(t *testing.T) {
+ defer test.MockVariableValue(&setting.UI.SkipEscapeContexts, []string{})()
+
+ assertCase(t, true, true, true)
+ })
+
+ t.Run("Enabled file context", func(t *testing.T) {
+ defer test.MockVariableValue(&setting.UI.SkipEscapeContexts, []string{"diff", "wiki"})()
+
+ assertCase(t, true, false, false)
+ })
+
+ t.Run("Enabled commit context", func(t *testing.T) {
+ defer test.MockVariableValue(&setting.UI.SkipEscapeContexts, []string{"file-view", "wiki"})()
+
+ assertCase(t, false, true, false)
+ })
+
+ t.Run("Enabled wiki context", func(t *testing.T) {
+ defer test.MockVariableValue(&setting.UI.SkipEscapeContexts, []string{"file-view", "diff"})()
+
+ assertCase(t, false, false, true)
+ })
+
+ t.Run("No context", func(t *testing.T) {
+ defer test.MockVariableValue(&setting.UI.SkipEscapeContexts, []string{"file-view", "wiki", "diff"})()
+
+ assertCase(t, false, false, false)
+ })
+
+ t.Run("Disabled detection", func(t *testing.T) {
+ defer test.MockVariableValue(&setting.UI.SkipEscapeContexts, []string{})()
+ defer test.MockVariableValue(&setting.UI.AmbiguousUnicodeDetection, false)()
+
+ assertCase(t, false, false, false)
+ })
+ })
+}