92 lines
3.1 KiB
Diff
92 lines
3.1 KiB
Diff
|
From cfd61f6958a46d5e9687f87caf04c94680382a9f Mon Sep 17 00:00:00 2001
|
||
|
|
From: Nicolas Frayer <nfrayer@redhat.com>
|
||
|
|
Date: Wed, 1 Feb 2023 12:13:45 +0100
|
||
|
|
Subject: [PATCH] generate_binary: Add NX COMPAT flag manually when genpeimg
|
||
|
|
missing
|
||
|
|
|
||
|
|
When genpeimg or python3-pefile is missing, add the NX COMPAT flag
|
||
|
|
manually by setting bit8 of the DllCharacteristics in the optional
|
||
|
|
header, clear the TimeDateStamp and update the checksum.
|
||
|
|
---
|
||
|
|
efi/generate_binary.py | 50 ++++++++++++++++++++++++++++++++++++++++--
|
||
|
|
1 file changed, 48 insertions(+), 2 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/efi/generate_binary.py b/efi/generate_binary.py
|
||
|
|
index 7b802e7..10ab0b3 100755
|
||
|
|
--- a/efi/generate_binary.py
|
||
|
|
+++ b/efi/generate_binary.py
|
||
|
|
@@ -10,6 +10,13 @@
|
||
|
|
import subprocess
|
||
|
|
import sys
|
||
|
|
import argparse
|
||
|
|
+import os
|
||
|
|
+import struct
|
||
|
|
+
|
||
|
|
+COFF_HDR_OFFSET = 0x80
|
||
|
|
+OPTIONALHDR_CHECKSUM = COFF_HDR_OFFSET + 0x58
|
||
|
|
+OPTIONALHDR_DLLCHARACTERISTICS = COFF_HDR_OFFSET + 0x5E
|
||
|
|
+PEHEADER_TIMEDATASTAMP = COFF_HDR_OFFSET + 0x8
|
||
|
|
|
||
|
|
|
||
|
|
def _run_objcopy(args):
|
||
|
|
@@ -66,6 +73,27 @@ def _run_genpeimg(args):
|
||
|
|
sys.exit(1)
|
||
|
|
|
||
|
|
|
||
|
|
+def generate_checksum(data):
|
||
|
|
+ checksum_offset: int = OPTIONALHDR_CHECKSUM
|
||
|
|
+ checksum: int = 0
|
||
|
|
+ remainder: int = len(data) % 4
|
||
|
|
+ data_len: int = len(data) + ((4 - remainder) * (remainder != 0))
|
||
|
|
+ for i in range(int(data_len / 4)):
|
||
|
|
+ if i == int(checksum_offset / 4):
|
||
|
|
+ continue
|
||
|
|
+ if i + 1 == (int(data_len / 4)) and remainder:
|
||
|
|
+ dword = struct.unpack("I", data[i * 4 :] + (b"\0" * (4 - remainder)))[0]
|
||
|
|
+ else:
|
||
|
|
+ dword = struct.unpack("I", data[i * 4 : i * 4 + 4])[0]
|
||
|
|
+ checksum += dword
|
||
|
|
+ if checksum >= 2**32:
|
||
|
|
+ checksum = (checksum & 0xFFFFFFFF) + (checksum >> 32)
|
||
|
|
+ checksum = (checksum & 0xFFFF) + (checksum >> 16)
|
||
|
|
+ checksum = checksum + (checksum >> 16)
|
||
|
|
+ checksum = checksum & 0xFFFF
|
||
|
|
+ return checksum + len(data)
|
||
|
|
+
|
||
|
|
+
|
||
|
|
def _add_nx_pefile(args):
|
||
|
|
# unnecessary if we have genpeimg
|
||
|
|
if args.genpeimg:
|
||
|
|
@@ -73,8 +101,26 @@ def _add_nx_pefile(args):
|
||
|
|
try:
|
||
|
|
import pefile
|
||
|
|
except ImportError:
|
||
|
|
- print("Unable to add NX support to binaries without genpeimg or python3-pefile")
|
||
|
|
- sys.exit(1)
|
||
|
|
+ print("Adding NX support manually to the binary")
|
||
|
|
+ with open(args.outfile, "r+b") as fh:
|
||
|
|
+ buf = bytearray(fh.read(os.path.getsize(args.outfile)))
|
||
|
|
+ fh.seek(0)
|
||
|
|
+ DllCharacteristics = struct.unpack_from(
|
||
|
|
+ "<H", buf, OPTIONALHDR_DLLCHARACTERISTICS
|
||
|
|
+ )[0]
|
||
|
|
+ DllCharacteristics |= 0x100
|
||
|
|
+ struct.pack_into(
|
||
|
|
+ "<H", buf, OPTIONALHDR_DLLCHARACTERISTICS, DllCharacteristics
|
||
|
|
+ )
|
||
|
|
+
|
||
|
|
+ # set the timestamp to 0
|
||
|
|
+ struct.pack_into("<I", buf, PEHEADER_TIMEDATASTAMP, 0x0)
|
||
|
|
+
|
||
|
|
+ # as we have set the NX COMPAT bit, regenerate the checksum
|
||
|
|
+ struct.pack_into("<I", buf, OPTIONALHDR_CHECKSUM, generate_checksum(buf))
|
||
|
|
+ fh.write(buf)
|
||
|
|
+
|
||
|
|
+ return
|
||
|
|
|
||
|
|
pe = pefile.PE(args.outfile)
|
||
|
|
pe.OPTIONAL_HEADER.DllCharacteristics |= pefile.DLL_CHARACTERISTICS[
|
||
|
|
--
|
||
|
|
2.39.1
|
||
|
|
|