Mapped the damage system end-to-end statically and documented it for cross-patch
tracking (docs/WEAPON_DAMAGE.md):
- Model: 8 DamageXxxDataComponent (value @+0x10) on item/ammo, read by
HealthAndDamageExtensions.GetDamage (RVA 0x4BAC520); per-shot formula in
<GetDamage>d__12.MoveNext (RVA 0x4BB3DB0) = base x range-falloff x headshot,
melee skips range falloff.
- Delivery: PlainDamgeDealerComponent{damageAmount,damageType,isMelee} -> HitEventInfo
-> reduces HealthDataComponent.value; networked via DamageEvent.
Verified the base numbers are in NO asset (blueprints/ammo/projectiles/CheatItemDefs/all
bundles UTF-16). Established WHY the literal constants aren't statically anchorable: this
build accesses every component via fully-generic Entitas dispatch (no static class/index/
string reference in producing code; typed setters all dead build-wide; item-id strings
have 0 refs, verified via a calibrated string-xref) and damage resolution is server-
authoritative. So the value is a runtime component, not a reachable static constant.
Corrects the earlier draft that overstated "no value exists".
Tools: reverse/il2cpp_re.py (+find_rip_refs_batch, scan_movss_consts),
bundle/component_census.py, bundle/dump_blueprint.py.
356 lines
13 KiB
Python
356 lines
13 KiB
Python
"""Core IL2CPP reverse-engineering helpers for SAND's GameAssembly.dll.
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dump.cs (Il2CppDumper output) gives every method's RVA, file Offset, VA and
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signature. GameAssembly.dll holds the actual x86-64 bodies. This module:
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- maps VA <-> file offset via the PE section table,
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- builds a sorted method index from dump.cs (cached to a pickle),
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- attributes any VA to its containing method,
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- finds call-rel32 / jmp-rel32 sites that target a given VA (xrefs),
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- disassembles a method body and pulls out float constants it loads.
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No method bodies live in dump.cs — only signatures. The values we want
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(weapon damage floats) are operands inside the bodies, recovered here.
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"""
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import os, re, pickle, bisect, struct
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GAME = "/mnt/d/SteamLibrary/steamapps/common/Sand Playtest"
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DLL = os.path.join(GAME, "GameAssembly.dll")
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DUMP = "/home/downloadpizza/sand_tools/il2cpp/dump.cs"
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CACHE = "/home/downloadpizza/sand_tools/reverse/_method_index.pkl"
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IMAGE_BASE = 0x180000000 # from PE optional header (VA = IMAGE_BASE + RVA)
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class PE:
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"""Minimal PE map: VA<->file-offset, plus raw byte access."""
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def __init__(self, path=DLL):
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import pefile
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self.pe = pefile.PE(path, fast_load=True)
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self.base = self.pe.OPTIONAL_HEADER.ImageBase
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self.data = self.pe.__data__ # bytes-like of whole file
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self.sections = []
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for s in self.pe.sections:
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self.sections.append((
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s.VirtualAddress, s.Misc_VirtualSize,
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s.PointerToRawData, s.SizeOfRawData,
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s.Name.decode(errors="replace").strip("\x00"),
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))
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def rva_to_off(self, rva):
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for va, vsz, praw, rsz, name in self.sections:
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if va <= rva < va + max(vsz, rsz):
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if rva - va < rsz:
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return praw + (rva - va)
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return None # in bss / uninitialized
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return None
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def off_to_rva(self, off):
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for va, vsz, praw, rsz, name in self.sections:
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if praw <= off < praw + rsz:
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return va + (off - praw)
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return None
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def va_to_off(self, va):
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return self.rva_to_off(va - self.base)
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def read_off(self, off, n):
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return bytes(self.data[off:off + n])
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def read_va(self, va, n):
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off = self.va_to_off(va)
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if off is None:
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return None
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return self.read_off(off, n)
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def text_range(self):
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for va, vsz, praw, rsz, name in self.sections:
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if name == ".text":
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return va, vsz, praw, rsz
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return None
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def code_ranges(self):
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"""Executable code sections. IL2CPP method bodies live in the
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'il2cpp' section; runtime/engine glue in '.text'."""
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out = []
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for va, vsz, praw, rsz, name in self.sections:
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if name in (".text", "il2cpp"):
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out.append((va, vsz, praw, rsz, name))
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return out
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_RVA_RE = re.compile(r"// RVA: 0x([0-9A-Fa-f]+) Offset: 0x([0-9A-Fa-f]+) VA: 0x([0-9A-Fa-f]+)")
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def build_index(force=False):
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"""Parse dump.cs -> list of methods sorted by VA.
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Each entry: dict(va, rva, off, sig). sig is the C#-ish declaration line.
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Cached to CACHE.
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"""
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if not force and os.path.exists(CACHE):
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with open(CACHE, "rb") as f:
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return pickle.load(f)
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methods = []
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with open(DUMP, "r", encoding="utf-8", errors="replace") as f:
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prev = None
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for line in f:
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m = _RVA_RE.search(line)
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if m:
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prev = (int(m.group(1), 16), int(m.group(2), 16), int(m.group(3), 16))
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continue
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if prev is not None:
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sig = line.strip()
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rva, off, va = prev
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if rva != 0:
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methods.append({"va": va, "rva": rva, "off": off, "sig": sig})
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prev = None
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methods.sort(key=lambda d: d["va"])
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with open(CACHE, "wb") as f:
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pickle.dump(methods, f)
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return methods
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class Index:
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def __init__(self):
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self.methods = build_index()
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self.vas = [m["va"] for m in self.methods]
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def method_at(self, va):
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"""Return the method whose body contains `va` (largest va <= target)."""
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i = bisect.bisect_right(self.vas, va) - 1
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if i < 0:
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return None
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return self.methods[i]
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def next_va(self, va):
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i = bisect.bisect_right(self.vas, va)
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return self.vas[i] if i < len(self.vas) else None
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def find_sig(self, needle):
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return [m for m in self.methods if needle in m["sig"]]
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def find_xrefs(pe, target_vas, call_only=True):
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"""Scan all code sections for E8 (call) / E9 (jmp) rel32 sites whose
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target is in `target_vas` (int or set/iterable of ints).
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Returns list of (site_va, opcode_byte, target_va). Linear byte scan with
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displacement check; a few false positives are possible but validated by
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the disassembler downstream.
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"""
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if isinstance(target_vas, int):
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target_vas = {target_vas}
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else:
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target_vas = set(target_vas)
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out = []
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base = pe.base
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data = pe.data
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for sva, svsz, spraw, srsz, name in pe.code_ranges():
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raw = bytes(data[spraw:spraw + srsz])
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n = len(raw)
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j = 0
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while True:
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j = raw.find(b"\xe8", j) if call_only else _find_either(raw, j)
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if j < 0 or j + 5 > n:
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break
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disp = struct.unpack_from("<i", raw, j + 1)[0]
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site_va = base + sva + j # off_to_rva is identity here: rva = sva + j
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tgt = site_va + 5 + disp
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if tgt in target_vas:
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out.append((site_va, raw[j], tgt))
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j += 1
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return out
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def find_rip_refs(pe, target_va):
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"""Find RIP-relative instructions whose disp32 (assumed to be the final 4
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bytes of the instruction) resolves to `target_va`. Returns list of
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(disp_field_va, instr_start_guess_va). Vectorized over all code sections.
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For a load like `mov reg,[rip+disp]`, target = (va_after_instr) + disp and
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va_after_instr = disp_field_va + 4. So target_va = disp_field_va + 4 + disp
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=> disp + i == (target_va - base - sva - 4) where i is the in-section offset
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of the disp field. We solve for i.
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"""
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import numpy as np
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out = []
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base = pe.base
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data = pe.data
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for sva, svsz, spraw, srsz, name in pe.code_ranges():
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raw = np.frombuffer(bytes(data[spraw:spraw + srsz]), dtype=np.uint8)
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n = len(raw)
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# little-endian int32 at every byte offset 0..n-4
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disp = (raw[0:n-3].astype(np.int64)
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| (raw[1:n-2].astype(np.int64) << 8)
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| (raw[2:n-1].astype(np.int64) << 16)
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| (raw[3:n].astype(np.int64) << 24))
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# sign-extend 32-bit
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disp = disp - ((disp & 0x80000000) << 1)
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idx = np.arange(n - 3, dtype=np.int64)
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const = target_va - base - sva - 4
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hits = np.nonzero(disp + idx == const)[0]
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for i in hits.tolist():
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out.append(base + sva + int(i)) # va of the disp field
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return out
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def find_rip_refs_batch(pe, targets):
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"""One pass over code: for a set of target VAs, return {target_va: [disp_field_va,...]}.
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Assumes disp32 is the final 4 bytes of the instruction (movss/mov/lea loads)."""
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import numpy as np
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targets = np.array(sorted(set(int(t) for t in targets)), dtype=np.int64)
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out = {int(t): [] for t in targets}
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base = pe.base
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data = pe.data
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for sva, svsz, spraw, srsz, name in pe.code_ranges():
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raw = np.frombuffer(bytes(data[spraw:spraw + srsz]), dtype=np.uint8)
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n = len(raw)
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disp = (raw[0:n-3].astype(np.int64) | (raw[1:n-2].astype(np.int64) << 8)
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| (raw[2:n-1].astype(np.int64) << 16) | (raw[3:n].astype(np.int64) << 24))
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disp = disp - ((disp & 0x80000000) << 1)
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idx = np.arange(n - 3, dtype=np.int64)
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tgt = base + sva + idx + 4 + disp # absolute target of a disp-final instruction
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mask = np.isin(tgt, targets)
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for i in np.nonzero(mask)[0]:
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t = int(tgt[i])
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if t in out:
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out[t].append(base + sva + int(i))
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return out
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def disasm_around(pe, va, back=24, total=64):
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"""Disassemble a window [va-back, va-back+total) to recover the instruction
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that contains/precedes `va` (e.g. a RIP-ref disp field)."""
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from capstone import Cs, CS_ARCH_X86, CS_MODE_64
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start = va - back
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off = pe.va_to_off(start)
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code = pe.read_off(off, total)
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md = Cs(CS_ARCH_X86, CS_MODE_64)
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md.detail = True
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return list(md.disasm(code, start))
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def _find_either(raw, start):
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a = raw.find(b"\xe8", start)
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b = raw.find(b"\xe9", start)
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if a < 0:
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return b
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if b < 0:
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return a
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return min(a, b)
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def disasm_method(pe, idx, va, max_bytes=0x4000):
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"""Disassemble one method body (until next method VA or max_bytes)."""
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from capstone import Cs, CS_ARCH_X86, CS_MODE_64
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nxt = idx.next_va(va)
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size = max_bytes
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if nxt:
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size = min(size, nxt - va)
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off = pe.va_to_off(va)
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code = pe.read_off(off, size)
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md = Cs(CS_ARCH_X86, CS_MODE_64)
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md.detail = True
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return list(md.disasm(code, va))
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def rip_target(insn):
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"""If an instruction has a RIP-relative memory operand, return its absolute VA."""
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from capstone import x86
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for op in insn.operands:
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if op.type == x86.X86_OP_MEM and op.mem.base == x86.X86_REG_RIP:
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return insn.address + insn.size + op.mem.disp
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return None
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def read_f32(pe, va):
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b = pe.read_va(va, 4)
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return None if b is None else struct.unpack("<f", b)[0]
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def read_f64(pe, va):
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b = pe.read_va(va, 8)
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return None if b is None else struct.unpack("<d", b)[0]
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def scan_movss_consts(pe, lo=None, hi=None):
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"""Linear-scan code sections for `movss xmm,[rip+disp32]` (F3 0F 10 /r, mod=00 rm=101)
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and `movsd` (F2 0F 10). Returns list of (insn_va, const_value, kind). Optional
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[lo,hi] filters the constant's absolute value. Anchor-free way to find where
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float constants (e.g. damage numbers) are loaded, regardless of Entitas plumbing."""
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import numpy as np, struct as _s
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out = []
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base = pe.base
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data = pe.data
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rm_ok = set(0x05 | (r << 3) for r in range(8)) # mod=00, rm=101, reg=0..7
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for sva, svsz, spraw, srsz, name in pe.code_ranges():
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raw = bytes(data[spraw:spraw + srsz])
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n = len(raw)
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# find F3 0F 10 and F2 0F 10
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for pref, kind in ((b"\xf3\x0f\x10", "f32"), (b"\xf2\x0f\x10", "f64")):
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j = raw.find(pref)
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while j >= 0:
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if j + 8 <= n:
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modrm = raw[j + 3]
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if modrm in rm_ok:
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disp = _s.unpack_from("<i", raw, j + 4)[0]
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insn_va = base + sva + j
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tgt = insn_va + 8 + disp # instruction length = 8 (F3 0F 10 modrm disp32)
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if kind == "f32":
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b = pe.read_va(tgt, 4); v = _s.unpack("<f", b)[0] if b else None
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else:
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b = pe.read_va(tgt, 8); v = _s.unpack("<d", b)[0] if b else None
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if v is not None and v == v: # not NaN
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av = abs(v)
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if (lo is None or av >= lo) and (hi is None or av <= hi):
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out.append((insn_va, v, kind))
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j = raw.find(pref, j + 1)
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return out
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def analyze(pe, idx, va, max_bytes=0x6000, show=True):
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"""Disassemble a method; resolve call targets to method sigs and read any
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RIP-relative float/double constants loaded (movss/movsd/comiss/addss/...).
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Returns (insns, calls, floats)."""
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from capstone import x86
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ins = disasm_method(pe, idx, va, max_bytes)
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calls, floats, lines = [], [], []
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for i in ins:
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tgt = rip_target(i)
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note = ""
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mn = i.mnemonic
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if mn in ("call", "jmp") and i.operands and i.operands[0].type == x86.X86_OP_IMM:
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d = i.operands[0].imm
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m = idx.method_at(d)
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nm = m["sig"] if (m and abs(m["va"] - d) < 0x6000) else "?"
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if mn == "call":
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calls.append((i.address, d, nm))
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note = " -> %x %s" % (d, nm[:78])
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elif tgt is not None and ("ss" in mn or "sd" in mn or mn == "movss" or mn == "movsd"):
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# float/double constant load from .rdata
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if "sd" in mn:
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v = read_f64(pe, tgt)
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floats.append((i.address, tgt, v, "f64"))
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note = " ; =%s (f64 @%x)" % (v, tgt)
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else:
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v = read_f32(pe, tgt)
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floats.append((i.address, tgt, v, "f32"))
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note = " ; =%s (f32 @%x)" % (v, tgt)
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elif tgt is not None:
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note = " ; [data %x]" % tgt
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lines.append(" %x %-9s %s%s" % (i.address, mn, i.op_str, note))
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if show:
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print("\n".join(lines))
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return ins, calls, floats
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if __name__ == "__main__":
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pe = PE()
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idx = Index()
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print("methods indexed:", len(idx.methods))
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print("text section:", [hex(x) for x in pe.text_range()])
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# sanity: the known DamagePhysical float setter
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m = idx.method_at(0x1849EC5B0)
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print("method at 0x1849EC5B0:", m["sig"] if m else None, hex(m["va"]) if m else "")
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