Harden Windows package paths (T-605)

core/catalog/parser.go

@@ -9,12 +9,12 @@ import (
 	"fmt"
 	"io"
 	"net/url"
-	"path"
 	"regexp"
 	"strings"
 	"time"
 
 	"softbox.local/core/domain"
+	"softbox.local/core/internal/safepath"
 )
 
 var (
@@ -163,8 +163,12 @@ func validateApp(app App) error {
 	if len(app.Architectures) == 0 {
 		return invalidField("architectures", "must not be empty")
 	}
-	if !validSafeRelativePath(app.EntryEXE) {
-		return invalidField("entry_exe", "must be a safe relative path")
+	if err := safepath.ValidateRelative(app.EntryEXE); err != nil {
+		return invalidField(
+			"entry_exe",
+			"must be a safe Windows relative path: %v",
+			err,
+		)
 	}
 	if len(app.Packages) == 0 {
 		return invalidField("packages", "must not be empty")
@@ -261,18 +265,6 @@ func validateHTTPSURL(value string) error {
 	return nil
 }
 
-func validSafeRelativePath(value string) bool {
-	if value == "" || strings.Contains(value, `\`) || strings.Contains(value, ":") {
-		return false
-	}
-	cleaned := path.Clean(value)
-	return cleaned == value &&
-		cleaned != "." &&
-		!strings.HasPrefix(cleaned, "/") &&
-		cleaned != ".." &&
-		!strings.HasPrefix(cleaned, "../")
-}
-
 func invalidField(field, format string, values ...any) error {
 	return fmt.Errorf(
 		"%w: %s: %s",

core/catalog/parser_test.go

@@ -70,6 +70,45 @@ func TestParserRejectsDuplicateAppIDAndPackageMismatch(t *testing.T) {
 	}
 }
 
+func TestParserRejectsUnsafeWindowsEntrypoints(t *testing.T) {
+	for _, entrypoint := range []string{
+		".. /escape.exe",
+		"bin./App.exe",
+		"App.exe.",
+		"App.exe ",
+		" App.exe",
+		"NUL",
+		"con.txt",
+		"bad?.exe",
+		`bin\App.exe`,
+	} {
+		t.Run(entrypoint, func(t *testing.T) {
+			manifest := validManifestForTest()
+			manifest.Apps[0].EntryEXE = entrypoint
+			_, err := parseSignedManifestForTest(t, manifest, ChannelModern)
+			if !errors.Is(err, ErrInvalidManifest) {
+				t.Fatalf("Parse() error = %v, want %v", err, ErrInvalidManifest)
+			}
+		})
+	}
+}
+
+func TestParserAcceptsUnicodeNestedEntrypoint(t *testing.T) {
+	manifest := validManifestForTest()
+	manifest.Apps[0].EntryEXE = "工具/解析器.exe"
+	parsed, err := parseSignedManifestForTest(t, manifest, ChannelModern)
+	if err != nil {
+		t.Fatalf("Parse() error = %v", err)
+	}
+	if parsed.Apps[0].EntryEXE != manifest.Apps[0].EntryEXE {
+		t.Fatalf(
+			"EntryEXE = %q, want %q",
+			parsed.Apps[0].EntryEXE,
+			manifest.Apps[0].EntryEXE,
+		)
+	}
+}
+
 func signedFixture(t *testing.T, name string) (Verifier, []byte) {
 	t.Helper()
 	publicKey, privateKey := catalogTestKey()

core/installer/extractor.go

@@ -7,10 +7,10 @@ import (
 	"io"
 	"math"
 	"os"
-	"path"
 	"path/filepath"
 	"strings"
-	"unicode/utf8"
+
+	"softbox.local/core/internal/safepath"
 )
 
 var (
@@ -45,6 +45,7 @@ type plannedEntry struct {
 	file        *zip.File
 	archivePath string
 	outputPath  string
+	targetPath  string
 	directory   bool
 }
 
@@ -85,11 +86,19 @@ func (extractor Extractor) extract(
 	if err != nil {
 		return ExtractResult{}, err
 	}
+	destinationRoot, entrypointPath, err := planOutputPaths(
+		destination,
+		normalizedEntrypoint,
+		plan,
+	)
+	if err != nil {
+		return ExtractResult{}, err
+	}
 
-	if err := os.MkdirAll(filepath.Dir(destination), 0o700); err != nil {
+	if err := os.MkdirAll(filepath.Dir(destinationRoot), 0o700); err != nil {
 		return ExtractResult{}, fmt.Errorf("create staging parent: %w", err)
 	}
-	if err := os.Mkdir(destination, 0o700); err != nil {
+	if err := os.Mkdir(destinationRoot, 0o700); err != nil {
 		if os.IsExist(err) {
 			return ExtractResult{}, ErrDestinationExists
 		}
@@ -98,23 +107,22 @@ func (extractor Extractor) extract(
 	complete := false
 	defer func() {
 		if !complete {
-			_ = os.RemoveAll(destination)
+			_ = os.RemoveAll(destinationRoot)
 		}
 	}()
 
 	var written int64
 	for _, entry := range plan {
-		target := filepath.Join(destination, filepath.FromSlash(entry.outputPath))
 		if entry.directory {
 			if entry.outputPath == "" {
 				continue
 			}
-			if err := os.MkdirAll(target, 0o700); err != nil {
+			if err := os.MkdirAll(entry.targetPath, 0o700); err != nil {
 				return ExtractResult{}, fmt.Errorf("create staging directory: %w", err)
 			}
 			continue
 		}
-		if err := os.MkdirAll(filepath.Dir(target), 0o700); err != nil {
+		if err := os.MkdirAll(filepath.Dir(entry.targetPath), 0o700); err != nil {
 			return ExtractResult{}, fmt.Errorf("create staging file parent: %w", err)
 		}
 
@@ -126,7 +134,11 @@ func (extractor Extractor) extract(
 		if entry.file.Mode().Perm()&0o111 != 0 {
 			mode = 0o700
 		}
-		output, err := os.OpenFile(target, os.O_CREATE|os.O_EXCL|os.O_WRONLY, mode)
+		output, err := os.OpenFile(
+			entry.targetPath,
+			os.O_CREATE|os.O_EXCL|os.O_WRONLY,
+			mode,
+		)
 		if err != nil {
 			source.Close()
 			return ExtractResult{}, fmt.Errorf("create staging file: %w", err)
@@ -166,14 +178,52 @@ func (extractor Extractor) extract(
 	}
 
 	result.Bytes = written
-	result.EntrypointPath = filepath.Join(
-		destination,
-		filepath.FromSlash(normalizedEntrypoint),
-	)
+	result.EntrypointPath = entrypointPath
 	complete = true
 	return result, nil
 }
 
+func planOutputPaths(
+	destination string,
+	entrypoint string,
+	plan []plannedEntry,
+) (string, string, error) {
+	if destination == "" {
+		return "", "", fmt.Errorf("%w: staging destination is empty", ErrPathEscape)
+	}
+	destinationRoot, err := filepath.Abs(destination)
+	if err != nil {
+		return "", "", fmt.Errorf("%w: resolve staging destination: %v", ErrPathEscape, err)
+	}
+	destinationRoot = filepath.Clean(destinationRoot)
+	for index := range plan {
+		if plan[index].outputPath == "" {
+			plan[index].targetPath = destinationRoot
+			continue
+		}
+		target, err := safepath.JoinUnder(destinationRoot, plan[index].outputPath)
+		if err != nil {
+			return "", "", fmt.Errorf(
+				"%w: output %q: %v",
+				ErrPathEscape,
+				plan[index].outputPath,
+				err,
+			)
+		}
+		plan[index].targetPath = target
+	}
+	entrypointPath, err := safepath.JoinUnder(destinationRoot, entrypoint)
+	if err != nil {
+		return "", "", fmt.Errorf(
+			"%w: entrypoint %q: %v",
+			ErrEntrypointInvalid,
+			entrypoint,
+			err,
+		)
+	}
+	return destinationRoot, entrypointPath, nil
+}
+
 func (extractor Extractor) preflight(
 	archive *zip.Reader,
 	entrypoint string,
@@ -200,7 +250,7 @@ func (extractor Extractor) preflight(
 		if err != nil {
 			return nil, err
 		}
-		folded := strings.ToLower(normalized)
+		folded := safepath.CollisionKey(normalized)
 		if previous, exists := seenPaths[folded]; exists {
 			return nil, fmt.Errorf(
 				"%w: %q conflicts with %q",
@@ -305,47 +355,22 @@ func validateArchiveEntry(file *zip.File) (string, bool, error) {
 }
 
 func normalizeArchivePath(name string) (string, bool, error) {
-	if name == "" || !utf8.ValidString(name) || strings.ContainsRune(name, '\x00') {
-		return "", false, fmt.Errorf("%w: invalid entry name", ErrPathEscape)
-	}
-	if strings.Contains(name, `\`) || strings.Contains(name, ":") {
-		return "", false, fmt.Errorf("%w: %q", ErrPathEscape, name)
-	}
 	directory := strings.HasSuffix(name, "/")
 	trimmed := strings.TrimSuffix(name, "/")
-	if trimmed == "" || path.IsAbs(trimmed) || strings.HasPrefix(trimmed, "/") {
-		return "", false, fmt.Errorf("%w: %q", ErrPathEscape, name)
+	if err := safepath.ValidateRelative(trimmed); err != nil {
+		return "", false, fmt.Errorf("%w: %q: %v", ErrPathEscape, name, err)
 	}
-	cleaned := path.Clean(trimmed)
-	if cleaned != trimmed ||
-		cleaned == "." ||
-		cleaned == ".." ||
-		strings.HasPrefix(cleaned, "../") {
-		return "", false, fmt.Errorf("%w: %q", ErrPathEscape, name)
-	}
-	return cleaned, directory, nil
+	return trimmed, directory, nil
 }
 
 func normalizeEntrypoint(entrypoint string) (string, error) {
-	if entrypoint == "" ||
-		!utf8.ValidString(entrypoint) ||
-		strings.ContainsRune(entrypoint, '\x00') ||
-		strings.Contains(entrypoint, `\`) ||
-		strings.Contains(entrypoint, ":") ||
-		strings.HasSuffix(entrypoint, "/") ||
-		path.IsAbs(entrypoint) {
+	if err := safepath.ValidateRelative(entrypoint); err != nil {
+		return "", fmt.Errorf("%w: %q: %v", ErrEntrypointInvalid, entrypoint, err)
+	}
+	if entrypoint == "payload" || strings.HasPrefix(entrypoint, "payload/") {
 		return "", fmt.Errorf("%w: %q", ErrEntrypointInvalid, entrypoint)
 	}
-	cleaned := path.Clean(entrypoint)
-	if cleaned != entrypoint ||
-		cleaned == "." ||
-		cleaned == ".." ||
-		strings.HasPrefix(cleaned, "../") ||
-		cleaned == "payload" ||
-		strings.HasPrefix(cleaned, "payload/") {
-		return "", fmt.Errorf("%w: %q", ErrEntrypointInvalid, entrypoint)
-	}
-	return cleaned, nil
+	return entrypoint, nil
 }
 
 func exceedsCompressionRatio(uncompressed, compressed uint64, maximum float64) bool {

core/installer/extractor_test.go

@@ -83,6 +83,70 @@ func TestExtractorRejectsAttackArchives(t *testing.T) {
 			limits:     testLimits(),
 			wantErr:    ErrPathEscape,
 		},
+		{
+			name: "Windows normalized dot dot traversal",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/.. /escape.exe", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
+		{
+			name: "trailing period",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/evil.exe.", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
+		{
+			name: "trailing space",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/evil.exe ", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
+		{
+			name: "leading space",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/ evil.exe", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
+		{
+			name: "reserved device",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/NUL.txt", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
+		{
+			name: "reserved device with space before extension",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/NUL .txt", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
+		{
+			name: "reserved device superscript",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/COM¹.log", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
+		{
+			name: "forbidden Windows character",
+			entries: appendEntries(base,
+				testZIPEntry{name: "payload/evil?.exe", body: []byte("x")}),
+			entrypoint: "App.exe",
+			limits:     testLimits(),
+			wantErr:    ErrPathEscape,
+		},
 		{
 			name: "backslash traversal",
 			entries: appendEntries(base,
@@ -127,6 +191,17 @@ func TestExtractorRejectsAttackArchives(t *testing.T) {
 			limits:     testLimits(),
 			wantErr:    ErrDuplicateEntry,
 		},
+		{
+			name: "Unicode folded duplicate",
+			entries: []testZIPEntry{
+				{name: "app.json", body: []byte(`{}`)},
+				{name: "payload/K.exe", body: []byte("one")},
+				{name: "payload/K.exe", body: []byte("two")},
+			},
+			entrypoint: "K.exe",
+			limits:     testLimits(),
+			wantErr:    ErrDuplicateEntry,
+		},
 		{
 			name: "unexpected top level entry",
 			entries: appendEntries(base,
@@ -184,7 +259,8 @@ func TestExtractorRejectsAttackArchives(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			archivePath := writeTestZIP(t, test.entries)
-			destination := filepath.Join(t.TempDir(), "staging")
+			root := t.TempDir()
+			destination := filepath.Join(root, "staging")
 			extractor := mustExtractor(t, test.limits)
 
 			_, err := extractor.ExtractFile(archivePath, destination, test.entrypoint)
@@ -194,6 +270,9 @@ func TestExtractorRejectsAttackArchives(t *testing.T) {
 			if _, statErr := os.Stat(destination); !os.IsNotExist(statErr) {
 				t.Fatalf("rejected archive left staging, stat error = %v", statErr)
 			}
+			if _, statErr := os.Stat(filepath.Join(root, "escape.exe")); !os.IsNotExist(statErr) {
+				t.Fatalf("rejected archive wrote outside staging, stat error = %v", statErr)
+			}
 		})
 	}
 }
@@ -210,6 +289,12 @@ func TestExtractorRejectsInvalidEntrypoints(t *testing.T) {
 		{entrypoint: "../App.exe", wantErr: ErrEntrypointInvalid},
 		{entrypoint: "/App.exe", wantErr: ErrEntrypointInvalid},
 		{entrypoint: `..\App.exe`, wantErr: ErrEntrypointInvalid},
+		{entrypoint: ".. /App.exe", wantErr: ErrEntrypointInvalid},
+		{entrypoint: "App.exe.", wantErr: ErrEntrypointInvalid},
+		{entrypoint: "App.exe ", wantErr: ErrEntrypointInvalid},
+		{entrypoint: " App.exe", wantErr: ErrEntrypointInvalid},
+		{entrypoint: "NUL", wantErr: ErrEntrypointInvalid},
+		{entrypoint: "bad?.exe", wantErr: ErrEntrypointInvalid},
 		{entrypoint: "payload/App.exe", wantErr: ErrEntrypointInvalid},
 		{entrypoint: "Missing.exe", wantErr: ErrEntrypointMissing},
 	}
@@ -229,6 +314,27 @@ func TestExtractorRejectsInvalidEntrypoints(t *testing.T) {
 	}
 }
 
+func TestExtractorAcceptsUnicodeNestedPaths(t *testing.T) {
+	archivePath := writeTestZIP(t, []testZIPEntry{
+		{name: "app.json", body: []byte(`{}`)},
+		{name: "payload/工具/解析器.exe", body: []byte("executable")},
+		{name: "payload/资源/说明.txt", body: []byte("说明")},
+	})
+	destination := filepath.Join(t.TempDir(), "staging")
+	extractor := mustExtractor(t, testLimits())
+
+	result, err := extractor.ExtractFile(archivePath, destination, "工具/解析器.exe")
+	if err != nil {
+		t.Fatalf("ExtractFile() error = %v", err)
+	}
+	if result.Files != 2 {
+		t.Fatalf("Files = %d, want 2", result.Files)
+	}
+	if _, err := os.Stat(result.EntrypointPath); err != nil {
+		t.Fatalf("entrypoint stat error = %v", err)
+	}
+}
+
 func TestExtractorRejectsExistingDestination(t *testing.T) {
 	archivePath := writeTestZIP(t, []testZIPEntry{
 		{name: "app.json", body: []byte(`{}`)},

core/installer/extractor_windows_test.go

@@ -0,0 +1,32 @@
+//go:build windows
+
+package installer
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestExtractorRejectsWindowsNormalizedEscapeOnNativeFilesystem(t *testing.T) {
+	archivePath := writeTestZIP(t, []testZIPEntry{
+		{name: "app.json", body: []byte(`{}`)},
+		{name: "payload/App.exe", body: []byte("ok")},
+		{name: "payload/.. /escape.exe", body: []byte("escape")},
+	})
+	root := t.TempDir()
+	destination := filepath.Join(root, "staging")
+	extractor := mustExtractor(t, testLimits())
+
+	_, err := extractor.ExtractFile(archivePath, destination, "App.exe")
+	if !errors.Is(err, ErrPathEscape) {
+		t.Fatalf("ExtractFile() error = %v, want %v", err, ErrPathEscape)
+	}
+	if _, statErr := os.Stat(destination); !os.IsNotExist(statErr) {
+		t.Fatalf("rejected archive left staging, stat error = %v", statErr)
+	}
+	if _, statErr := os.Stat(filepath.Join(root, "escape.exe")); !os.IsNotExist(statErr) {
+		t.Fatalf("archive escaped staging, stat error = %v", statErr)
+	}
+}

core/internal/safepath/path.go

@@ -0,0 +1,167 @@
+// Package safepath validates package-controlled paths before they reach the
+// Windows filesystem.
+package safepath
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+var (
+	ErrInvalidRelativePath = errors.New("invalid Windows relative path")
+	ErrOutsideRoot         = errors.New("path is outside the managed root")
+)
+
+// ValidateRelative accepts a canonical, slash-separated relative path that
+// names a file or directory below a managed root.
+func ValidateRelative(value string) error {
+	return validate(value, false)
+}
+
+// ValidateWorkingDirectory accepts "." or a canonical relative directory.
+func ValidateWorkingDirectory(value string) error {
+	return validate(value, true)
+}
+
+func validate(value string, allowCurrent bool) error {
+	if value == "." && allowCurrent {
+		return nil
+	}
+	if value == "" {
+		return invalid("path is empty")
+	}
+	if !utf8.ValidString(value) {
+		return invalid("path is not valid UTF-8")
+	}
+	if strings.HasPrefix(value, "/") || path.IsAbs(value) {
+		return invalid("absolute paths are forbidden")
+	}
+	if strings.ContainsRune(value, '\\') {
+		return invalid("backslashes are forbidden")
+	}
+	if cleaned := path.Clean(value); cleaned != value {
+		return invalid("path is not canonical")
+	}
+
+	segments := strings.Split(value, "/")
+	for _, segment := range segments {
+		if err := validateSegment(segment); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func validateSegment(segment string) error {
+	if segment == "" {
+		return invalid("empty path segment")
+	}
+	if segment == "." || segment == ".." {
+		return invalid("relative dot segment")
+	}
+	if strings.HasPrefix(segment, " ") ||
+		strings.HasSuffix(segment, " ") ||
+		strings.HasSuffix(segment, ".") {
+		return invalid("path segment uses a Windows-trimmed character")
+	}
+	for _, character := range segment {
+		if unicode.IsControl(character) || strings.ContainsRune(`<>:"\|?*`, character) {
+			return invalid("path segment contains a Windows-forbidden character")
+		}
+	}
+	if isReservedDeviceName(segment) {
+		return invalid("path segment is a reserved Windows device name")
+	}
+	return nil
+}
+
+func isReservedDeviceName(segment string) bool {
+	base := segment
+	if dot := strings.IndexRune(base, '.'); dot >= 0 {
+		base = base[:dot]
+	}
+	base = strings.TrimRight(base, " ")
+	upper := strings.ToUpper(base)
+	switch upper {
+	case "CON", "PRN", "AUX", "NUL", "CLOCK$", "CONIN$", "CONOUT$":
+		return true
+	}
+	if len(upper) == 4 {
+		prefix := upper[:3]
+		digit := upper[3]
+		if (prefix == "COM" || prefix == "LPT") && digit >= '1' && digit <= '9' {
+			return true
+		}
+	}
+	if len([]rune(upper)) == 4 {
+		runes := []rune(upper)
+		prefix := string(runes[:3])
+		digit := runes[3]
+		if (prefix == "COM" || prefix == "LPT") &&
+			(digit == '\u00b9' || digit == '\u00b2' || digit == '\u00b3') {
+			return true
+		}
+	}
+	return false
+}
+
+// CollisionKey returns a stable Unicode simple-fold key for case-insensitive
+// duplicate detection. Callers should validate the path first.
+func CollisionKey(value string) string {
+	var builder strings.Builder
+	builder.Grow(len(value))
+	for _, character := range value {
+		builder.WriteRune(foldRune(character))
+	}
+	return builder.String()
+}
+
+func foldRune(character rune) rune {
+	smallest := character
+	for next := unicode.SimpleFold(character); next != character; next = unicode.SimpleFold(next) {
+		if next < smallest {
+			smallest = next
+		}
+	}
+	return smallest
+}
+
+// JoinUnder joins a validated relative path below root and verifies the
+// resulting native path remains lexically contained by that root.
+func JoinUnder(root, relative string) (string, error) {
+	if root == "" {
+		return "", fmt.Errorf("%w: root is empty", ErrOutsideRoot)
+	}
+	if err := ValidateRelative(relative); err != nil {
+		return "", err
+	}
+	absoluteRoot, err := filepath.Abs(root)
+	if err != nil {
+		return "", fmt.Errorf("%w: resolve root: %v", ErrOutsideRoot, err)
+	}
+	absoluteRoot = filepath.Clean(absoluteRoot)
+	target := filepath.Clean(filepath.Join(
+		absoluteRoot,
+		filepath.FromSlash(relative),
+	))
+	relativeTarget, err := filepath.Rel(absoluteRoot, target)
+	if err != nil {
+		return "", fmt.Errorf("%w: compare target: %v", ErrOutsideRoot, err)
+	}
+	if relativeTarget == ".." ||
+		filepath.IsAbs(relativeTarget) ||
+		strings.HasPrefix(relativeTarget, ".."+string(os.PathSeparator)) {
+		return "", fmt.Errorf("%w: %q", ErrOutsideRoot, relative)
+	}
+	return target, nil
+}
+
+func invalid(reason string) error {
+	return fmt.Errorf("%w: %s", ErrInvalidRelativePath, reason)
+}

core/internal/safepath/path_test.go

@@ -0,0 +1,138 @@
+package safepath
+
+import (
+	"errors"
+	"path/filepath"
+	"testing"
+)
+
+func TestValidateRelative(t *testing.T) {
+	valid := []string{
+		"JsonParser.exe",
+		"bin/JsonParser.exe",
+		"工具/解析器.exe",
+		".config/settings.json",
+		"name..txt",
+		"folder with spaces/read me.txt",
+	}
+	for _, value := range valid {
+		t.Run("valid_"+value, func(t *testing.T) {
+			if err := ValidateRelative(value); err != nil {
+				t.Fatalf("ValidateRelative(%q) error = %v", value, err)
+			}
+		})
+	}
+
+	invalid := []string{
+		"",
+		".",
+		"..",
+		"../escape.exe",
+		"a/../escape.exe",
+		"./App.exe",
+		"a//App.exe",
+		"a/",
+		"/App.exe",
+		"//server/share/App.exe",
+		`C:/App.exe`,
+		`C:App.exe`,
+		`bin\App.exe`,
+		"bad\x00name.exe",
+		"bad\nname.exe",
+		"bad<name.exe",
+		"bad>name.exe",
+		`bad"name.exe`,
+		"bad|name.exe",
+		"bad?name.exe",
+		"bad*name.exe",
+		"folder./App.exe",
+		"folder /App.exe",
+		" App.exe",
+		"folder/ App.exe",
+		"App.exe.",
+		"App.exe ",
+		"CON",
+		"con.txt",
+		"PRN.json",
+		"AUX",
+		"NUL.bin",
+		"NUL .bin",
+		"COM1",
+		"com9.log",
+		"LPT1",
+		"lpt9.txt",
+		"COM¹",
+		"LPT³.log",
+		"CLOCK$",
+		"CONIN$",
+		"CONOUT$",
+	}
+	for _, value := range invalid {
+		t.Run("invalid_"+value, func(t *testing.T) {
+			err := ValidateRelative(value)
+			if !errors.Is(err, ErrInvalidRelativePath) {
+				t.Fatalf(
+					"ValidateRelative(%q) error = %v, want %v",
+					value,
+					err,
+					ErrInvalidRelativePath,
+				)
+			}
+		})
+	}
+}
+
+func TestValidateWorkingDirectory(t *testing.T) {
+	for _, value := range []string{".", "bin", "资源/运行目录"} {
+		if err := ValidateWorkingDirectory(value); err != nil {
+			t.Fatalf("ValidateWorkingDirectory(%q) error = %v", value, err)
+		}
+	}
+	for _, value := range []string{"", "..", "bin.", "NUL"} {
+		if err := ValidateWorkingDirectory(value); !errors.Is(err, ErrInvalidRelativePath) {
+			t.Fatalf(
+				"ValidateWorkingDirectory(%q) error = %v, want %v",
+				value,
+				err,
+				ErrInvalidRelativePath,
+			)
+		}
+	}
+}
+
+func TestCollisionKeyUsesUnicodeSimpleFold(t *testing.T) {
+	tests := [][2]string{
+		{"App.EXE", "app.exe"},
+		{"K.exe", "K.exe"},
+		{"Σ.txt", "ς.txt"},
+	}
+	for _, values := range tests {
+		if CollisionKey(values[0]) != CollisionKey(values[1]) {
+			t.Fatalf(
+				"CollisionKey(%q) != CollisionKey(%q)",
+				values[0],
+				values[1],
+			)
+		}
+	}
+}
+
+func TestJoinUnder(t *testing.T) {
+	root := filepath.Join(t.TempDir(), "staging")
+	target, err := JoinUnder(root, "bin/App.exe")
+	if err != nil {
+		t.Fatalf("JoinUnder() error = %v", err)
+	}
+	want := filepath.Join(root, "bin", "App.exe")
+	if target != want {
+		t.Fatalf("JoinUnder() = %q, want %q", target, want)
+	}
+
+	for _, value := range []string{"../escape.exe", ".. /escape.exe", "/escape.exe"} {
+		_, err := JoinUnder(root, value)
+		if !errors.Is(err, ErrInvalidRelativePath) &&
+			!errors.Is(err, ErrOutsideRoot) {
+			t.Fatalf("JoinUnder(%q) error = %v", value, err)
+		}
+	}
+}

core/storage/installed_app.go

@@ -7,13 +7,12 @@ import (
 	"fmt"
 	"io"
 	"os"
-	"path"
 	"path/filepath"
 	"regexp"
-	"strings"
 	"sync"
 
 	"softbox.local/core/domain"
+	"softbox.local/core/internal/safepath"
 )
 
 const (
@@ -281,12 +280,13 @@ func (record InstalledApp) validate() error {
 
 	seenPaths := make(map[string]struct{}, len(record.Files))
 	for index, installedFile := range record.Files {
-		if !validInstalledPath(installedFile.Path) {
+		if err := safepath.ValidateRelative(installedFile.Path); err != nil {
 			return fmt.Errorf(
-				"%w: files[%d].path=%q",
+				"%w: files[%d].path=%q: %v",
 				ErrInstalledAppInvalid,
 				index,
 				installedFile.Path,
+				err,
 			)
 		}
 		if installedFile.Size < 0 {
@@ -304,7 +304,7 @@ func (record InstalledApp) validate() error {
 				index,
 			)
 		}
-		foldedPath := strings.ToLower(installedFile.Path)
+		foldedPath := safepath.CollisionKey(installedFile.Path)
 		if _, exists := seenPaths[foldedPath]; exists {
 			return fmt.Errorf(
 				"%w: duplicate file path %q",
@@ -317,18 +317,6 @@ func (record InstalledApp) validate() error {
 	return nil
 }
 
-func validInstalledPath(value string) bool {
-	if value == "" || strings.Contains(value, `\`) || strings.Contains(value, ":") {
-		return false
-	}
-	cleaned := path.Clean(value)
-	return cleaned == value &&
-		cleaned != "." &&
-		!strings.HasPrefix(cleaned, "/") &&
-		cleaned != ".." &&
-		!strings.HasPrefix(cleaned, "../")
-}
-
 func requireRealDirectory(directory string) error {
 	info, err := os.Lstat(directory)
 	if err != nil {

core/storage/installed_app_test.go

@@ -74,6 +74,42 @@ func TestInstalledAppStoreRejectsInvalidRecords(t *testing.T) {
 				record.Files[0].Path = "../escape.exe"
 			},
 		},
+		{
+			name: "Windows normalized escape",
+			mutate: func(record *InstalledApp) {
+				record.Files[0].Path = ".. /escape.exe"
+			},
+		},
+		{
+			name: "trailing period",
+			mutate: func(record *InstalledApp) {
+				record.Files[0].Path = "JsonParser.exe."
+			},
+		},
+		{
+			name: "trailing space",
+			mutate: func(record *InstalledApp) {
+				record.Files[0].Path = "JsonParser.exe "
+			},
+		},
+		{
+			name: "leading space",
+			mutate: func(record *InstalledApp) {
+				record.Files[0].Path = " JsonParser.exe"
+			},
+		},
+		{
+			name: "reserved device",
+			mutate: func(record *InstalledApp) {
+				record.Files[0].Path = "NUL.txt"
+			},
+		},
+		{
+			name: "forbidden Windows character",
+			mutate: func(record *InstalledApp) {
+				record.Files[0].Path = "Json?Parser.exe"
+			},
+		},
 		{
 			name: "invalid hash",
 			mutate: func(record *InstalledApp) {
@@ -103,6 +139,22 @@ func TestInstalledAppStoreRejectsInvalidRecords(t *testing.T) {
 	}
 }
 
+func TestInstalledAppStoreAcceptsUnicodeNestedPath(t *testing.T) {
+	record := validInstalledApp()
+	record.Files[0].Path = "工具/解析器.exe"
+	store := NewInstalledAppStore(filepath.Join(t.TempDir(), "apps"))
+	if err := store.Write(record); err != nil {
+		t.Fatalf("Write() error = %v", err)
+	}
+	loaded, found, err := store.Read(record.ID)
+	if err != nil {
+		t.Fatalf("Read() error = %v", err)
+	}
+	if !found || loaded.Files[0].Path != record.Files[0].Path {
+		t.Fatalf("Read() = %#v, found=%t", loaded, found)
+	}
+}
+
 func TestInstalledAppStoreRejectsUnknownFieldsAndIDMismatch(t *testing.T) {
 	appsRoot := filepath.Join(t.TempDir(), "apps")
 	appRoot := filepath.Join(appsRoot, "json-parser")