From ba5c77c9e52a89e705e60853e96a813bffad9949 Mon Sep 17 00:00:00 2001
From: John Reiser <jreiser@BitWagon.com>
Date: Sun, 14 Mar 2021 15:20:15 -0700
Subject: [PATCH] Reject if MZ and PE headers overlap

Overlap ('leanify', etc.) causes headaches.
https://github.com/upx/upx/issues/231
	modified:   p_w32pe.cpp
	modified:   p_w64pep.cpp
	modified:   pefile.cpp
---
 src/p_w32pe.cpp  | 5 +++--
 src/p_w64pep.cpp | 5 +++--
 src/pefile.cpp   | 8 ++++++++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/p_w32pe.cpp b/src/p_w32pe.cpp
index 28863230..b02d9e3b 100644
--- a/src/p_w32pe.cpp
+++ b/src/p_w32pe.cpp
@@ -276,9 +276,10 @@ void PackW32Pe::setOhDataBase(const pe_section_t *osection)
     oh.database = osection[2].vaddr;
 }
 
-void PackW32Pe::setOhHeaderSize(const pe_section_t *)
+void PackW32Pe::setOhHeaderSize(const pe_section_t *osection)
 {
-    oh.headersize = rvamin; // FIXME
+    (void)osection;
+    oh.headersize = rvamin;  // FIXME
 }
 
 void PackW32Pe::pack(OutputFile *fo)
diff --git a/src/p_w64pep.cpp b/src/p_w64pep.cpp
index 121d3287..4a35be51 100644
--- a/src/p_w64pep.cpp
+++ b/src/p_w64pep.cpp
@@ -266,9 +266,10 @@ void PackW64Pep::defineSymbols(unsigned ncsection, unsigned upxsection,
     linker->defineSymbol("START", upxsection);
 }
 
-void PackW64Pep::setOhHeaderSize(const pe_section_t *)
+void PackW64Pep::setOhHeaderSize(const pe_section_t *osection)
 {
-    oh.headersize = rvamin; // FIXME
+    (void)osection;
+    oh.headersize = rvamin;  // FIXME
 }
 
 void PackW64Pep::pack(OutputFile *fo)
diff --git a/src/pefile.cpp b/src/pefile.cpp
index 0bc5e53c..06b0cf9f 100644
--- a/src/pefile.cpp
+++ b/src/pefile.cpp
@@ -163,6 +163,13 @@ int PeFile::readFileHeader()
 
         if (h.mz == 'M' + 'Z'*256) // dos exe
         {
+            if (h.nexepos && h.nexepos < sizeof(exe_header_t)) {
+                // Overlapping MZ and PE headers by 'leanify', etc.
+                char buf[64]; snprintf(buf, sizeof(buf),
+                    "PE and MZ header overlap: %#x < %#x",
+                    (unsigned)h.nexepos, (unsigned)sizeof(exe_header_t));
+                throwCantPack(buf);
+            }
             unsigned const delta = (h.relocoffs >= 0x40)
                 ? h.nexepos // new format exe
                 : (h.p512*512+h.m512 - h.m512 ? 512 : h.nexepos);
@@ -3125,6 +3132,7 @@ void PeFile32::pack0(OutputFile *fo, unsigned subsystem_mask,
 {
     super::pack0<LE32>(fo, ih, oh, subsystem_mask,
                        default_imagebase, last_section_rsrc_only);
+    infoWarning("End of PeFile32::pack0");
 }
 
 void PeFile32::unpack(OutputFile *fo)