From 1963a0a6d7398a426d0701f90a5bc796e32899ae Mon Sep 17 00:00:00 2001
From: salmonik <salmonik@tuta.io>
Date: Fri, 31 Jul 2026 02:55:10 +0200
Subject: feat(rsboot): initial commit — UEFI bootloader extracted from RNG
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---
 fix_pe_simple.py | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 fix_pe_simple.py

(limited to 'fix_pe_simple.py')

diff --git a/fix_pe_simple.py b/fix_pe_simple.py
new file mode 100644
index 0000000..77b1366
--- /dev/null
+++ b/fix_pe_simple.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""fix_pe_simple.py — PE header fixup for PIE-built UEFI bootloader
+
+The -fPIE-built bootloader uses only PC-relative addressing, so it needs
+zero absolute fixups.  This script just sets proper PE flags:
+
+  - ImageBase         (env IMAGE_BASE, default 0x10000000)
+  - Characteristics   = 0x022e (RELOCS_STRIPPED)
+  - DllChar           = 0x0160 (NX | DYNAMIC_BASE | HIGH_ENTROPY_VA)
+  - Clears .reloc DD  (no relocations needed)
+  - Clears checksum   (not signed)
+"""
+
+import struct, os, sys
+
+def fix_pe(path):
+    try:
+        with open(path, 'rb') as f:
+            d = bytearray(f.read())
+    except IOError as e:
+        print(f"  ERROR: cannot read {path}: {e}")
+        return False
+
+    po = struct.unpack('<I', d[0x3C:0x40])[0]
+    if d[po:po+4] != b'PE\x00\x00':
+        print(f"  Not a PE file")
+        return False
+
+    coff = po + 4
+    opt = po + 24
+
+    magic = struct.unpack('<H', d[opt:opt+2])[0]
+    if magic != 0x20b:
+        print(f"  Not PE32+")
+        return False
+
+    ib_env = os.environ.get('IMAGE_BASE', '0x10000000')
+    img_base = int(ib_env, 16) if ib_env.startswith('0x') else 0x10000000
+    struct.pack_into('<Q', d, opt+24, img_base)
+    struct.pack_into('<H', d, coff+18, 0x022e)
+    struct.pack_into('<H', d, opt+70, 0x0160)
+    struct.pack_into('<I', d, coff+8, 0)
+    struct.pack_into('<I', d, coff+12, 0)
+    struct.pack_into('<I', d, opt+64, 0)
+
+    dd = opt + 112
+    struct.pack_into('<II', d, dd + 5*8, 0, 0)
+
+    try:
+        with open(path, 'wb') as f:
+            f.write(d)
+    except IOError as e:
+        print(f"  ERROR: cannot write {path}: {e}")
+        return False
+
+    print(f"  Fixed: ImageBase={img_base:#010x} char=0x022e dll=0x0160 reloc=cleared")
+    return True
+
+if __name__ == '__main__':
+    if len(sys.argv) < 2:
+        print(f"Usage: IMAGE_BASE=0x... {sys.argv[0]} <pe-path>")
+        sys.exit(1)
+    if not fix_pe(sys.argv[1]):
+        sys.exit(1)
-- 
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