llvm · drodriguez · Jan 8, 2025 · Sep 13, 2024
diff --git a/llvm/lib/ObjCopy/MachO/MachOLayoutBuilder.cpp b/llvm/lib/ObjCopy/MachO/MachOLayoutBuilder.cpp
@@ -116,6 +116,11 @@ uint64_t MachOLayoutBuilder::layoutSegments() {
   const bool IsObjectFile =
       O.Header.FileType == MachO::HeaderFileType::MH_OBJECT;
   uint64_t Offset = IsObjectFile ? (HeaderSize + O.Header.SizeOfCmds) : 0;
+  if (O.EncryptionInfoCommandIndex) {
+    // If we are emitting an encryptable binary, our load commands must have a
+    // separate (non-encrypted) page to themselves.
+    Offset = alignToPowerOf2(HeaderSize + O.Header.SizeOfCmds, PageSize);
+  }
   for (LoadCommand &LC : O.LoadCommands) {
     auto &MLC = LC.MachOLoadCommand;
     StringRef Segname;

diff --git a/llvm/lib/ObjCopy/MachO/MachOObject.cpp b/llvm/lib/ObjCopy/MachO/MachOObject.cpp
@@ -85,6 +85,10 @@ void Object::updateLoadCommandIndexes() {
     case MachO::LC_DYLD_EXPORTS_TRIE:
       ExportsTrieCommandIndex = Index;
       break;
+    case MachO::LC_ENCRYPTION_INFO:
+    case MachO::LC_ENCRYPTION_INFO_64:
+      EncryptionInfoCommandIndex = Index;
+      break;
     }
   }
 }

diff --git a/llvm/lib/ObjCopy/MachO/MachOObject.h b/llvm/lib/ObjCopy/MachO/MachOObject.h
@@ -340,6 +340,9 @@ struct Object {
   /// The index of the LC_SEGMENT or LC_SEGMENT_64 load command
   /// corresponding to the __TEXT segment.
   std::optional<size_t> TextSegmentCommandIndex;
+  /// The index of the LC_ENCRYPTION_INFO or LC_ENCRYPTION_INFO_64 load command
+  /// if present.
+  std::optional<size_t> EncryptionInfoCommandIndex;
 
   BumpPtrAllocator Alloc;
   StringSaver NewSectionsContents;

diff --git a/llvm/lib/ObjCopy/MachO/MachOReader.cpp b/llvm/lib/ObjCopy/MachO/MachOReader.cpp
@@ -184,6 +184,10 @@ Error MachOReader::readLoadCommands(Object &O) const {
     case MachO::LC_DYLD_CHAINED_FIXUPS:
       O.ChainedFixupsCommandIndex = O.LoadCommands.size();
       break;
+    case MachO::LC_ENCRYPTION_INFO:
+    case MachO::LC_ENCRYPTION_INFO_64:
+      O.EncryptionInfoCommandIndex = O.LoadCommands.size();
+      break;
     }
 #define HANDLE_LOAD_COMMAND(LCName, LCValue, LCStruct)                         \
   case MachO::LCName:                                                          \

diff --git a/llvm/test/tools/llvm-objcopy/MachO/strip-with-encryption-info.test b/llvm/test/tools/llvm-objcopy/MachO/strip-with-encryption-info.test
@@ -0,0 +1,217 @@
+# RUN: rm -rf %t && mkdir %t
+# RUN: yaml2obj %s -o %t/original
+# RUN: llvm-strip --strip-all %t/original -o %t/stripped
+# RUN: llvm-readobj --macho-segment %t/stripped | FileCheck %s
+
+# CHECK-LABEL: Name: __PAGEZERO
+# CHECK:       fileoff: 16384
+
+# CHECK-LABEL: Name: __TEXT
+# CHECK:       fileoff: 16384
+
+# The YAML below is the following code
+# int main(int argc, char **argv) { return 0; }
+# Compiled on macOS against the macOS SDK and passing `-Wl,-encryptable`
+# Contents are removed, since they are not important for the test. We need a
+# small text segment (smaller than a page).
+--- !mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x100000C
+  cpusubtype:      0x0
+  filetype:        0x2
+  ncmds:           15
+  sizeofcmds:      696
+  flags:           0x200085
+  reserved:        0x0
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         72
+    segname:         __PAGEZERO
+    vmaddr:          0
+    vmsize:          4294967296
+    fileoff:         0
+    filesize:        0
+    maxprot:         0
+    initprot:        0
+    nsects:          0
+    flags:           0
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         232
+    segname:         __TEXT
+    vmaddr:          4294967296
+    vmsize:          32768
+    fileoff:         0
+    filesize:        32768
+    maxprot:         5
+    initprot:        5
+    nsects:          2
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x100004000
+        size:            32
+        offset:          0x4000
+        align:           2
+        reloff:          0x0
+        nreloc:          0
+        flags:           0x80000400
+        reserved1:       0x0
+        reserved2:       0x0
+        reserved3:       0x0
+      - sectname:        __unwind_info
+        segname:         __TEXT
+        addr:            0x100004020
+        size:            4152
+        offset:          0x4020
+        align:           2
+        reloff:          0x0
+        nreloc:          0
+        flags:           0x0
+        reserved1:       0x0
+        reserved2:       0x0
+        reserved3:       0x0
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         72
+    segname:         __LINKEDIT
+    vmaddr:          4295000064
+    vmsize:          592
+    fileoff:         32768
+    filesize:        592
+    maxprot:         1
+    initprot:        1
+    nsects:          0
+    flags:           0
+  - cmd:             LC_DYLD_CHAINED_FIXUPS
+    cmdsize:         16
+    dataoff:         32768
+    datasize:        48
+  - cmd:             LC_DYLD_EXPORTS_TRIE
+    cmdsize:         16
+    dataoff:         32816
+    datasize:        48
+  - cmd:             LC_SYMTAB
+    cmdsize:         24
+    symoff:          32872
+    nsyms:           2
+    stroff:          32904
+    strsize:         32
+  - cmd:             LC_DYSYMTAB
+    cmdsize:         80
+    ilocalsym:       0
+    nlocalsym:       0
+    iextdefsym:      0
+    nextdefsym:      2
+    iundefsym:       2
+    nundefsym:       0
+    tocoff:          0
+    ntoc:            0
+    modtaboff:       0
+    nmodtab:         0
+    extrefsymoff:    0
+    nextrefsyms:     0
+    indirectsymoff:  0
+    nindirectsyms:   0
+    extreloff:       0
+    nextrel:         0
+    locreloff:       0
+    nlocrel:         0
+  - cmd:             LC_ENCRYPTION_INFO_64
+    cmdsize:         24
+    cryptoff:        16384
+    cryptsize:       16384
+    cryptid:         0
+    pad:             0
+  - cmd:             LC_LOAD_DYLINKER
+    cmdsize:         32
+    name:            12
+    Content:         '/usr/lib/dyld'
+    ZeroPadBytes:    7
+  - cmd:             LC_UUID
+    cmdsize:         24
+    uuid:            4C4C4447-5555-3144-A18A-01E9EB7E7D92
+  - cmd:             LC_BUILD_VERSION
+    cmdsize:         32
+    platform:        1
+    minos:           983040
+    sdk:             983552
+    ntools:          1
+    Tools:
+      - tool:            4
+        version:         1310720
+  - cmd:             LC_MAIN
+    cmdsize:         24
+    entryoff:        16384
+    stacksize:       0
+  - cmd:             LC_FUNCTION_STARTS
+    cmdsize:         16
+    dataoff:         32864
+    datasize:        8
+  - cmd:             LC_DATA_IN_CODE
+    cmdsize:         16
+    dataoff:         32872
+    datasize:        0
+  - cmd:             LC_CODE_SIGNATURE
+    cmdsize:         16
+    dataoff:         32944
+    datasize:        416
+LinkEditData:
+  ExportTrie:
+    TerminalSize:    0
+    NodeOffset:      0
+    Name:            ''
+    Flags:           0x0
+    Address:         0x0
+    Other:           0x0
+    ImportName:      ''
+    Children:
+      - TerminalSize:    0
+        NodeOffset:      5
+        Name:            _
+        Flags:           0x0
+        Address:         0x0
+        Other:           0x0
+        ImportName:      ''
+        Children:
+          - TerminalSize:    4
+            NodeOffset:      33
+            Name:            main
+            Flags:           0x0
+            Address:         0x4000
+            Other:           0x0
+            ImportName:      ''
+          - TerminalSize:    2
+            NodeOffset:      39
+            Name:            _mh_execute_header
+            Flags:           0x0
+            Address:         0x0
+            Other:           0x0
+            ImportName:      ''
+  NameList:
+    - n_strx:          2
+      n_type:          0xF
+      n_sect:          1
+      n_desc:          0
+      n_value:         4294983680
+    - n_strx:          8
+      n_type:          0xF
+      n_sect:          1
+      n_desc:          16
+      n_value:         4294967296
+  StringTable:
+    - ' '
+    - _main
+    - __mh_execute_header
+    - ''
+    - ''
+    - ''
+    - ''
+  FunctionStarts:  [ 0x4000 ]
+  ChainedFixups:   [ 0x0, 0x0, 0x0, 0x0, 0x20, 0x0, 0x0, 0x0, 0x30, 0x0, 
+                     0x0, 0x0, 0x30, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 
+                     0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 
+                     0x0, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 
+                     0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 ]
+...
+