Add max_offset parameter to configure hardcoded offset limit

When parsing large images warnings are raised if they go beyond
an hardcoded and fixed value. This is often not enough for many
use cases, such as parsing a large Unified Kernel Image.

Add a parameter, defaulting to the previous value.

Fixes #396

pefile.py

@@ -2350,6 +2350,10 @@ class PE:
     whole PE structure. The "full_load" method can be used to parse
     the missing data at a later stage.
 
+    Warnings will be raised during parsing if a section is larger and/or
+    at a higher offset than the limit configured by the 'max_offset'
+    parameter, which defaults to '0x10000000'.
+
     Basic headers information will be available in the attributes:
 
     DOS_HEADER
@@ -2897,6 +2901,7 @@ def __init__(
         fast_load=None,
         max_symbol_exports=MAX_SYMBOL_EXPORT_COUNT,
         max_repeated_symbol=120,
+        max_offset=0x10000000,
     ):
         self.max_symbol_exports = max_symbol_exports
         self.max_repeated_symbol = max_repeated_symbol
@@ -2938,7 +2943,7 @@ def __init__(
 
         fast_load = fast_load if fast_load is not None else globals()["fast_load"]
         try:
-            self.__parse__(name, data, fast_load)
+            self.__parse__(name, data, fast_load, max_offset)
         except:
             self.close()
             raise
@@ -3010,7 +3015,7 @@ def __unpack_data_with_bitfields__(self, format, data, file_offset):
 
         return structure
 
-    def __parse__(self, fname, data, fast_load):
+    def __parse__(self, fname, data, fast_load, max_offset):
         """Parse a Portable Executable file.
 
         Loads a PE file, parsing all its structures and making them available
@@ -3310,7 +3315,7 @@ def __parse__(self, fname, data, fast_load):
             ):
                 break
 
-        offset = self.parse_sections(sections_offset)
+        offset = self.parse_sections(sections_offset, max_offset)
 
         # There could be a problem if there are no raw data sections
         # greater than 0
@@ -3544,7 +3549,7 @@ def write(self, filename=None):
         with open(filename, "wb+") as f:
             f.write(new_file_data)
 
-    def parse_sections(self, offset):
+    def parse_sections(self, offset, max_offset=0x10000000):
         """Fetch the PE file sections.
 
         The sections will be readily available in the "sections" attribute.
@@ -3557,6 +3562,10 @@ def parse_sections(self, offset):
         section instance.
 
         Refer to the SectionStructure class for additional info.
+
+        The method will raise a warning if a section is larger and/or at
+        a higher offset than the limit configured by the 'max_offset'
+        parameter.
         """
 
         self.sections = []
@@ -3606,11 +3615,11 @@ def parse_sections(self, offset):
                     "the end of the file."
                 )
 
-            if section.Misc_VirtualSize > 0x10000000:
+            if section.Misc_VirtualSize > max_offset:
                 simultaneous_errors += 1
                 self.__warnings.append(
                     f"Suspicious value found parsing section {i}. VirtualSize is "
-                    "extremely large > 256MiB."
+                    f"extremely large > {max_offset} bytes."
                 )
 
             if (
@@ -3619,12 +3628,12 @@ def parse_sections(self, offset):
                     self.OPTIONAL_HEADER.SectionAlignment,
                     self.OPTIONAL_HEADER.FileAlignment,
                 )
-                > 0x10000000
+                > max_offset
             ):
                 simultaneous_errors += 1
                 self.__warnings.append(
                     f"Suspicious value found parsing section {i}. VirtualAddress is "
-                    "beyond 0x10000000."
+                    f"beyond {max_offset}."
                 )
 
             if (