From 3a30f12019a9e0aacc3946d436a2fce1887d89a5 Mon Sep 17 00:00:00 2001
From: nganhkhoa <mail.nganhkhoa@gmail.com>
Date: Fri, 2 Jun 2023 15:24:43 +0700
Subject: [PATCH] support for LC_DYLD_INFO_ONLY strip

---
 macho-go/pkg/ios/macho/dyld_info.go | 19 +++++----------
 macho-go/pkg/ios/macho/edit.go      | 36 +++++++++++++++++++++++++----
 2 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/macho-go/pkg/ios/macho/dyld_info.go b/macho-go/pkg/ios/macho/dyld_info.go
index 5053f36..c5e7bb4 100644
--- a/macho-go/pkg/ios/macho/dyld_info.go
+++ b/macho-go/pkg/ios/macho/dyld_info.go
@@ -98,19 +98,6 @@ func (mc *MachoContext) CollectBindSymbolsModern() []*ImportSymbol {
 
 // Old convention using LC_DYLD_INFO_ONLY section and bytecode runner
 func (mc *MachoContext) CollectBindSymbolsLegacy() []*ImportSymbol {
-	// // clear this whole section to 0x00 BIND_OPCODE_DONE
-	// dummy := []byte{
-	// 	0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
-	// 	0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
-	// }
-	// // make LINK EDIT section writable
-	// // mc.file.WriteAt([]byte{0x03}, int64(0x3f8))
-	// // set number of symbols to 0
-	// mc.file.WriteAt([]byte{0, 0, 0, 0}, int64(0x444))
-	// mc.file.WriteAt([]byte{0, 0, 0, 0}, int64(0x44c))
-	// mc.file.WriteAt([]byte{0, 0, 0, 0}, int64(0x48c))
-	// mc.file.WriteAt(dummy, int64(start))
-
   noLazy := (func() []*ImportSymbol {
     start := mc.dyldinfo.bind_off
     size := mc.dyldinfo.bind_size
@@ -187,6 +174,7 @@ func (mc *MachoContext) readBindStream(buf *bytes.Buffer, typ string) []*ImportS
 					"symbol": sym.name,
 				}).Trace("Bind")
 				sym.name = ""
+        sym.address += 8
 			}
 			offset += 1
 			break
@@ -241,7 +229,12 @@ func (mc *MachoContext) readBindStream(buf *bytes.Buffer, typ string) []*ImportS
 			offset += br
 			break
 
+    case BIND_OPCODE_SET_TYPE_IMM:
+      fmt.Println("// symbol type", imm)
+      break
+
 		default:
+      fmt.Println("BIND OPCODE NOT SUPPORTED", op, imm)
 			break
 		}
 	}
diff --git a/macho-go/pkg/ios/macho/edit.go b/macho-go/pkg/ios/macho/edit.go
index 1938c9a..9f4d48e 100644
--- a/macho-go/pkg/ios/macho/edit.go
+++ b/macho-go/pkg/ios/macho/edit.go
@@ -280,7 +280,31 @@ func (mc *MachoContext) RemoveBindSymbols() {
 	}
 }
 
-func (mc *MachoContext) removeBindSymbolsModern() {}
+func (mc *MachoContext) removeBindSymbolsModern() {
+  calculateHash := func(name string) uint32 {
+    var h uint32 = 0x811c9dc5
+    for _, s := range name {
+      h ^= uint32(s)
+      h *= 0x01000193
+    }
+    return h
+  }
+
+  // due to some limitations when design this tool
+  // we write the c code to stdout lol
+  fmt.Println("struct imported_symbol {const char* name; const char* lib; uint32_t hash; uint64_t address;};")
+  fmt.Println("struct imported_symbol imported_table[] = {")
+  count := 0
+  for _, symbol := range mc.CollectBindSymbols() {
+    count += 1
+    dylib_hash := calculateHash(symbol.Dylib())
+    fmt.Printf("{\"%s\", \"%s\", 0x%x, 0x%x},\n",
+      symbol.Name(), symbol.Dylib(), dylib_hash, symbol.Address());
+    mc.file.WriteAt(make([]byte, 8), int64(symbol.file_address))
+  }
+  fmt.Println("};")
+  fmt.Printf("uint32_t nimports = %d;\n", count);
+}
 
 func (mc *MachoContext) removeBindSymbolsLegacy() {
   start := mc.dyldinfo.lazy_bind_off
@@ -300,7 +324,7 @@ func (mc *MachoContext) removeBindSymbolsLegacy() {
 
   // due to some limitations when design this tool
   // we write the c code to stdout lol
-  fmt.Println("struct imported_symbol {const char* name; const char* lib; uint32_t hash; uint64_t address;};")
+  fmt.Println("struct imported_symbol {const char* name; const char* lib; uint32_t hash; int segment_i; uint64_t offset;};")
   fmt.Println("struct imported_symbol imported_table[] = {")
   count := 0
   for _, symbol := range mc.CollectBindSymbols() {
@@ -309,8 +333,12 @@ func (mc *MachoContext) removeBindSymbolsLegacy() {
     }
     count += 1
     dylib_hash := calculateHash(symbol.Dylib())
-    fmt.Printf("{\"%s\", \"%s\", 0x%x, 0x%x},\n",
-      symbol.Name(), symbol.Dylib(), dylib_hash, symbol.Address());
+    seg := mc.segments[symbol.segment]
+    offset := symbol.address - seg.Vmaddr()
+
+    fmt.Printf("{\"%s\", \"%s\", 0x%x, 0x%x, 0x%x},\n",
+      symbol.Name(), symbol.Dylib(), dylib_hash, symbol.segment, offset);
+    mc.file.WriteAt(make([]byte, 8), int64(seg.Fileoff() + offset))
   }
   fmt.Println("};")
   fmt.Printf("uint32_t nimports = %d;\n", count);