// mdl.usda · Model I/O · libusd_ms · CVE-2026-112485
// 原语: OOB 读 · 进程内 · tier 2
// Primitive: OOB read · in-process · tier 2
//
// [zh] USDA 声明嵌套深度
// Model I/O 的修复载体为 libusd_ms 24.1.30 → 24.1.32：经 64 位检查的图像分配、Ptex log2 与页保护、USDA 声明嵌套上限、SdfZipFile
// 尺寸检查。ModelIO.dylib 自身不含任何修复。
//
// [en] USDA declaration nesting depth
// The fix carrier for Model I/O is libusd_ms 24.1.30 → 24.1.32: 64-bit checked image allocation,
// Ptex log2 and page guards, a USDA declaration nesting cap, and SdfZipFile size checks. ModelIO.dylib
// itself carries none of the fix.
// ── 判别 / oracle ──
// 2000 层嵌套的 def Xform。27.2 会在嵌套上限处拒绝，27.0 递归下去。
//
// 种子构建器（python，可直接运行）: CVE-2026-112485/CVE-2026-112485.py
// runnable python seed builder: CVE-2026-112485/CVE-2026-112485.py

import Foundation

// ── byte helpers — verbatim from Cinder27 Sources/Kit.swift ──
enum B {
    static func be16(_ v: UInt16) -> [UInt8] { [UInt8(v >> 8 & 0xff), UInt8(v & 0xff)] }
    static func le16(_ v: UInt16) -> [UInt8] { [UInt8(v & 0xff), UInt8(v >> 8 & 0xff)] }
    static func be32(_ v: UInt32) -> [UInt8] {
        [UInt8(v >> 24 & 0xff), UInt8(v >> 16 & 0xff), UInt8(v >> 8 & 0xff), UInt8(v & 0xff)]
    }
    static func le32(_ v: UInt32) -> [UInt8] {
        [UInt8(v & 0xff), UInt8(v >> 8 & 0xff), UInt8(v >> 16 & 0xff), UInt8(v >> 24 & 0xff)]
    }
    static func be64(_ v: UInt64) -> [UInt8] {
        (0..<8).map { UInt8((v >> (56 - UInt64($0) * 8)) & 0xff) }
    }
    static func le64(_ v: UInt64) -> [UInt8] {
        (0..<8).map { UInt8((v >> (UInt64($0) * 8)) & 0xff) }
    }
    static func both16(_ v: UInt16) -> [UInt8] { le16(v) + be16(v) }
    static func both32(_ v: UInt32) -> [UInt8] { le32(v) + be32(v) }
    static func ascii(_ s: String) -> [UInt8] { Array(s.utf8) }
}