fix(objc): add support for reading UTF-16 encoded CFStrings #78

Author: blacktop

file.go

@@ -16,6 +16,7 @@ import (
 	"strings"
 	"sync"
 	"unicode"
+	"unicode/utf16"
 
 	"github.com/blacktop/go-dwarf"
 
@@ -1805,6 +1806,23 @@ func (f *File) GetCString(addr uint64) (string, error) {
 	return "", fmt.Errorf("%w at address %#x", ErrCStringNoTerminator, addr)
 }
 
+// getUTF16String reads a UTF-16LE encoded string at a given virtual address.
+// charCount is the number of UTF-16 code units (not bytes).
+func (f *File) getUTF16String(addr, charCount uint64) (string, error) {
+	if charCount == 0 {
+		return "", nil
+	}
+	buf := make([]byte, charCount*2)
+	if _, err := f.cr.ReadAtAddr(buf, addr); err != nil {
+		return "", fmt.Errorf("failed to read UTF-16 string at address %#x: %w", addr, err)
+	}
+	codes := make([]uint16, charCount)
+	for i := range codes {
+		codes[i] = f.ByteOrder.Uint16(buf[i*2:])
+	}
+	return string(utf16.Decode(codes)), nil
+}
+
 func (f *File) GetCStrings() (map[string]map[string]uint64, error) {
 	strs := make(map[string]map[string]uint64)
 

objc.go

@@ -1645,9 +1645,14 @@ func (f *File) GetCFStrings() ([]objc.CFString, error) {
 					//   return nullptr;
 					// cfs_characters = n_value;
 				}
-				cfstrings[idx].Name, err = f.GetCString(cfstrings[idx].Data)
+				// Check encoding from Info field and use appropriate string reader
+				if cfstrings[idx].CFString64Type.IsUTF16() {
+					cfstrings[idx].Name, err = f.getUTF16String(cfstrings[idx].Data, cfstrings[idx].Length)
+				} else {
+					cfstrings[idx].Name, err = f.GetCString(cfstrings[idx].Data)
+				}
 				if err != nil {
-					return nil, fmt.Errorf("failed to read cstring: %v", err)
+					return nil, fmt.Errorf("failed to read cfstring: %v", err)
 				}
 				if c, ok := f.objc[cfstrings[idx].IsaVMAddr]; ok {
 					cfstrings[idx].Class = c.(*objc.Class)

types/objc/objc.go

@@ -404,6 +404,23 @@ type CFString64Type struct {
 	Length    uint64 // number of non-NULL characters in above
 }
 
+// CFString encoding constants (derived from Info field)
+const (
+	CFStringEncodingMask    = 0x0FF0 // mask to extract encoding from Info field
+	CFStringEncodingASCII   = 0x07C8 // UTF-8/ASCII encoding
+	CFStringEncodingUnicode = 0x07D0 // UTF-16LE encoding
+)
+
+// Encoding returns the string encoding type from the CFString Info field
+func (c CFString64Type) Encoding() uint64 {
+	return c.Info & CFStringEncodingMask
+}
+
+// IsUTF16 returns true if the CFString uses UTF-16 encoding
+func (c CFString64Type) IsUTF16() bool {
+	return c.Encoding() == CFStringEncodingUnicode
+}
+
 const (
 	FAST_IS_SWIFT_LEGACY = 1 << 0 // < 5
 	FAST_IS_SWIFT_STABLE = 1 << 1 // 5.X