42 lines
2.1 KiB
Swift
42 lines
2.1 KiB
Swift
// iio.tiff.direntry · ImageIO · TIFFReadDirEntry*Array · CVE-2026-112488
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// 原语: OOB 写 · 进程内 · tier 2
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// Primitive: OOB write · in-process · tier 2
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//
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// [zh] TIFF 目录项分配 32 位截断
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// 输出分配的大小以 lsl w0, count, #log2(elemsize) 计算，属 32 位截断。当 count = 0x20000000 且元素宽度为 8 字节时，分配结果回绕为 0，
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// 而逐元素转换循环仍执行 count 次写入。27.2 改用 _TIFFCheckMalloc_type 的 64 位检查尺寸。
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//
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// [en] TIFF directory entry allocation 32-bit truncation
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// The output allocation size is computed as lsl w0, count, #log2(elemsize) — a 32-bit truncation.
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// With count = 0x20000000 and 8-byte elements the allocation wraps to zero while the per-element
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// conversion loop still performs count writes. iOS 27.2 switches to _TIFFCheckMalloc_type's 64-bit
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// checked size.
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// ── 判别 / oracle ──
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// 该原语的成立条件是 count×elemsize 跨越 2^32。本模块以一个 0x20000000 的 SBYTE 数组触发分配器，观察其返回空指针（干净拒绝）还是返回远小于请求的块（截断成立）。
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import Foundation
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// ── byte helpers — verbatim from Cinder27 Sources/Kit.swift ──
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enum B {
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static func be16(_ v: UInt16) -> [UInt8] { [UInt8(v >> 8 & 0xff), UInt8(v & 0xff)] }
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static func le16(_ v: UInt16) -> [UInt8] { [UInt8(v & 0xff), UInt8(v >> 8 & 0xff)] }
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static func be32(_ v: UInt32) -> [UInt8] {
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[UInt8(v >> 24 & 0xff), UInt8(v >> 16 & 0xff), UInt8(v >> 8 & 0xff), UInt8(v & 0xff)]
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}
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static func le32(_ v: UInt32) -> [UInt8] {
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[UInt8(v & 0xff), UInt8(v >> 8 & 0xff), UInt8(v >> 16 & 0xff), UInt8(v >> 24 & 0xff)]
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}
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static func be64(_ v: UInt64) -> [UInt8] {
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(0..<8).map { UInt8((v >> (56 - UInt64($0) * 8)) & 0xff) }
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}
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static func le64(_ v: UInt64) -> [UInt8] {
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(0..<8).map { UInt8((v >> (UInt64($0) * 8)) & 0xff) }
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}
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static func both16(_ v: UInt16) -> [UInt8] { le16(v) + be16(v) }
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static func both32(_ v: UInt32) -> [UInt8] { le32(v) + be32(v) }
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static func ascii(_ s: String) -> [UInt8] { Array(s.utf8) }
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}
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