disasm: Allow LE/LX without MZ header

mefistotelis · Jan 10, 2024 · 1a24de4 · 1a24de4
1 parent ed9c2a3
commit 1a24de4
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Showing 2 changed files with 50 additions and 17 deletions.
diff --git a/src/le.cpp b/src/le.cpp
@@ -59,6 +59,7 @@ class LinearExecutable::Loader
   vector<uint32_t> fixup_record_offsets;
 
 protected:
+  bool load_le_header_offset(void);
   bool load_header (void);
   bool load_object_table (void);
   bool load_object_header (ObjectHeader *hdr);
@@ -154,7 +155,7 @@ LinearExecutable::Loader::load (istream *is, const std::string &name)
 }
 
 bool
-LinearExecutable::Loader::load_header (void)
+LinearExecutable::Loader::load_le_header_offset(void)
 {
   char id[2];
   uint8_t byte;
@@ -166,6 +167,13 @@ LinearExecutable::Loader::load_header (void)
   if (!is->good ())
     return false;
 
+  // LE/LX header without MZ stub at start
+  if ((string (id, 2) == "LE") || (string (id, 2) == "LX"))
+    {
+      this->header_offset = 0;
+      return true;
+    }
+
   if (string (id, 2) != "MZ")
     {
       cerr << "Invalid MZ signature\n";
@@ -186,6 +194,25 @@ LinearExecutable::Loader::load_header (void)
   if (!read_le (is, &this->header_offset))
     return false;
 
+  return true;
+}
+
+bool
+LinearExecutable::Loader::load_header (void)
+{
+  char id[2];
+  uint8_t byte;
+  istream *is = this->is;
+  LinearExecutable *le = this->le;
+
+  is->seekg (0);
+  is->read (id, 2);
+  if (!is->good ())
+    return false;
+
+  if (!this->load_le_header_offset())
+    return false;
+
 #ifdef ENABLE_DEBUG
   print_variable (&cerr, 40, "header_offset", this->header_offset);
   cerr << "\n";
@@ -196,9 +223,9 @@ LinearExecutable::Loader::load_header (void)
   if (!is->good ())
     return false;
 
-  if (string (id, 2) != "LE")
+  if ((string (id, 2) != "LE") && (string (id, 2) != "LX"))
     {
-      cerr << "Invalid LE signature\n";
+      cerr << "Invalid LE signature at offset 0x" << std::hex << this->header_offset << std::endl;
       return false;
     }
 

diff --git a/src/le_disasm.cpp b/src/le_disasm.cpp
@@ -579,27 +579,33 @@ main (int argc, char **argv)
       return 1;
     }
 
-  ifs.open (argv[1], std::ios::binary);
-  if(!ifs.is_open())
-    {
-      std::cerr << "Error opening file: " << argv[1];
-      return 1;
-    }
+  try {
+
+    ifs.open (argv[1], std::ios::binary);
+    if(!ifs.is_open())
+      {
+        std::cerr << "Error opening file: " << argv[1];
+        return 1;
+      }
+
+    le = LinearExecutable::load (&ifs, argv[1]);
 
-  le = LinearExecutable::load (&ifs, argv[1]);
+    image = create_image (&ifs, le);
 
-  image = create_image (&ifs, le);
+    anal = Analyser (le, image);
 
-  anal = Analyser (le, image);
+    KnownFile::check(anal, le);
+    KnownFile::pre_anal_fixups_apply(anal);
 
-  KnownFile::check(anal, le);
-  KnownFile::pre_anal_fixups_apply(anal);
+    anal.run ();
 
-  anal.run ();
+    KnownFile::post_anal_fixups_apply(anal);
 
-  KnownFile::post_anal_fixups_apply(anal);
+    print_code (le, image, &anal);
 
-  print_code (le, image, &anal);
+  } catch (const std::exception &e) {
+    std::cerr << std::dec << e.what() << std::endl;
+  }
 
   delete image;
   delete le;