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Add max_offset parameter to configure hardcoded offset limit #460

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Add max_offset parameter to configure hardcoded offset limit #460

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25 changes: 17 additions & 8 deletions pefile.py
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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.
Expand All @@ -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 = []
Expand Down Expand Up @@ -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 (
Expand All @@ -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 (
Expand Down