From 1d9c211eedd75087fa3a110b2daf972031e29be4 Mon Sep 17 00:00:00 2001
From: Kornel Pal <kornelpal@gmail.com>
Date: Wed, 22 Dec 2021 03:00:17 +0100
Subject: [PATCH] PE: Make imports in decompressor stub optional

---
 src/p_w32pe.cpp  | 25 ++++++++++++++-----------
 src/p_w64pep.cpp | 25 ++++++++++++++-----------
 src/pefile.cpp   |  5 ++++-
 3 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/src/p_w32pe.cpp b/src/p_w32pe.cpp
index 6a346935..8003ac5f 100644
--- a/src/p_w32pe.cpp
+++ b/src/p_w32pe.cpp
@@ -168,7 +168,7 @@ void PackW32Pe::buildLoader(const Filter *ft)
         addLoader("CLEARSTACK", nullptr);
     addLoader("PEMAIN21", nullptr);
     //NEW: last loader sections split up to insert TLS callback handler - Stefan Widmann
-    addLoader(ih.entry ? "PEDOJUMP" : "PERETURN", nullptr);
+    addLoader(ih.entry || !ilinker ? "PEDOJUMP" : "PERETURN", nullptr);
 
     //NEW: TLS callback support PART 2, the callback handler - Stefan Widmann
     if(use_tls_callbacks)
@@ -232,16 +232,19 @@ void PackW32Pe::defineSymbols(unsigned ncsection, unsigned upxsection,
     }
     linker->defineSymbol("reloc_delt", 0u - (unsigned) ih.imagebase - rvamin);
     linker->defineSymbol("start_of_relocs", crelocs);
-    if (!isdll)
-        linker->defineSymbol("ExitProcess", 0u-rvamin +
-                             ilinkerGetAddress("kernel32.dll", "ExitProcess"));
-    linker->defineSymbol("GetProcAddress", 0u-rvamin +
-                         ilinkerGetAddress("kernel32.dll", "GetProcAddress"));
-    linker->defineSymbol("kernel32_ordinals", myimport);
-    linker->defineSymbol("LoadLibraryA", 0u-rvamin +
-                         ilinkerGetAddress("kernel32.dll", "LoadLibraryA"));
-    linker->defineSymbol("start_of_imports", myimport);
-    linker->defineSymbol("compressed_imports", cimports);
+
+    if (ilinker) {
+        if (!isdll)
+            linker->defineSymbol("ExitProcess", 0u-rvamin +
+                                 ilinkerGetAddress("kernel32.dll", "ExitProcess"));
+        linker->defineSymbol("GetProcAddress", 0u-rvamin +
+                             ilinkerGetAddress("kernel32.dll", "GetProcAddress"));
+        linker->defineSymbol("kernel32_ordinals", myimport);
+        linker->defineSymbol("LoadLibraryA", 0u-rvamin +
+                             ilinkerGetAddress("kernel32.dll", "LoadLibraryA"));
+        linker->defineSymbol("start_of_imports", myimport);
+        linker->defineSymbol("compressed_imports", cimports);
+    }
 
     defineDecompressorSymbols();
     linker->defineSymbol("filter_buffer_start", ih.codebase - rvamin);
diff --git a/src/p_w64pep.cpp b/src/p_w64pep.cpp
index bb509a9e..8a36d5e8 100644
--- a/src/p_w64pep.cpp
+++ b/src/p_w64pep.cpp
@@ -167,7 +167,7 @@ void PackW64Pep::buildLoader(const Filter *ft)
 
     if (ih.entry && isdll)
         addLoader("PEISDLL9");
-    addLoader(ih.entry ? "PEDOJUMP" : "PERETURN", nullptr);
+    addLoader(ih.entry || !ilinker ? "PEDOJUMP" : "PERETURN", nullptr);
 
     //NEW: TLS callback support PART 2, the callback handler - Stefan Widmann
     if(use_tls_callbacks)
@@ -227,16 +227,19 @@ void PackW64Pep::defineSymbols(unsigned ncsection, unsigned upxsection,
                              ilinkerGetAddress("kernel32.dll", "VirtualProtect"));
     }
     linker->defineSymbol("start_of_relocs", crelocs);
-    if (!isdll)
-        linker->defineSymbol("ExitProcess",
-                             ilinkerGetAddress("kernel32.dll", "ExitProcess"));
-    linker->defineSymbol("GetProcAddress",
-                         ilinkerGetAddress("kernel32.dll", "GetProcAddress"));
-    linker->defineSymbol("kernel32_ordinals", myimport);
-    linker->defineSymbol("LoadLibraryA",
-                         ilinkerGetAddress("kernel32.dll", "LoadLibraryA"));
-    linker->defineSymbol("start_of_imports", myimport);
-    linker->defineSymbol("compressed_imports", cimports);
+
+    if (ilinker) {
+        if (!isdll)
+            linker->defineSymbol("ExitProcess",
+                                 ilinkerGetAddress("kernel32.dll", "ExitProcess"));
+        linker->defineSymbol("GetProcAddress",
+                             ilinkerGetAddress("kernel32.dll", "GetProcAddress"));
+        linker->defineSymbol("kernel32_ordinals", myimport);
+        linker->defineSymbol("LoadLibraryA",
+                             ilinkerGetAddress("kernel32.dll", "LoadLibraryA"));
+        linker->defineSymbol("start_of_imports", myimport);
+        linker->defineSymbol("compressed_imports", cimports);
+    }
 
     if (M_IS_LZMA(ph.method))
     {
diff --git a/src/pefile.cpp b/src/pefile.cpp
index 86ebdd62..9a27d425 100644
--- a/src/pefile.cpp
+++ b/src/pefile.cpp
@@ -867,6 +867,9 @@ void PeFile::processImports2(unsigned myimport, unsigned) // pass 2
 {
     COMPILE_TIME_ASSERT(sizeof(import_desc) == 20);
 
+    if (!ilinker)
+        return;
+
     ilinker->relocate_import(myimport);
     int len;
     oimpdlls = ilinker->getLoader(&len);
@@ -2540,7 +2543,7 @@ void PeFile::pack0(OutputFile *fo, ht &ih, ht &oh,
         callProcessRelocs(rel, ic);
 
     processImports2(ic, getProcessImportParam(upxsection));
-    ODADDR(PEDIR_IMPORT) = ic;
+    ODADDR(PEDIR_IMPORT) = soimpdlls ? ic : 0;
     ODSIZE(PEDIR_IMPORT) = soimpdlls;
     ic += soimpdlls;