diff --git a/VULNERABILITY_REPORT.md b/VULNERABILITY_REPORT.md index 8f17bf3..9f2bde9 100644 --- a/VULNERABILITY_REPORT.md +++ b/VULNERABILITY_REPORT.md @@ -97,21 +97,43 @@ Should the Gigacage be bypassed or its base address leaked, this vulnerability e ## 6. Remediation Recommendations -We recommend the immediate implementation of **Checked Arithmetic** in the following components: +### 6.1 Implementation of Checked Arithmetic +The root cause—an integer overflow during memory offset calculation—must be addressed by implementing checked arithmetic within the JavaScriptCore runtime. We recommend replacing standard multiplication with compiler-intrinsic overflow checks to ensure that any `byteOffset` exceeding the 32-bit boundary is caught before memory access is attempted. + +**Target Components:** - `Source/JavaScriptCore/runtime/JSArrayBufferView.cpp` - `Source/JavaScriptCore/runtime/JSDataView.cpp` -**Proposed Fix:** -Utilize compiler intrinsics to detect overflows during offset calculation: - +**Proposed Fix (C++):** ```cpp +// Utilize compiler intrinsics to detect 32-bit overflows size_t byteOffset; if (__builtin_mul_overflow(static_cast(index), m_elementSize, &byteOffset)) { + return throwOverflowError(); // Prevent execution from reaching the Gigacage +} + +// Ensure the end-of-range does not wrap +size_t endOffset; +if (__builtin_add_overflow(byteOffset, m_elementSize, &endOffset)) { return throwOverflowError(); } ``` + +### 6.2 Technical Justification from Crash Telemetry + +The necessity of this fix is confirmed by the provided crash logs (Incidents 50371BD6 and F8D6F487). The telemetry data reveals: + +- **Hardware-Level Enforcement:** The current reliance on the Gigacage (Namespace 31) results in an `EXC_GUARD` violation. While effective at preventing RCE, this is a "fail-safe" rather than a primary validation, leading to a persistent Denial of Service. +- **Consistent Failure Point:** The identical crash frame at `0x22DB0E96C` across both MobileSafari and SafariViewService indicates the flaw is centrally located within the shared WebKit binary (`uuid: af25fa78...`). +- **Systemic Vulnerability:** The presence of the same exception in SafariViewService confirms that the vulnerability affects all third-party applications utilizing `WKWebView` on iOS 26.2. + + +### 6.3 JIT Compiler Hardening + +In addition to runtime checks, the WebAssembly JIT compiler must be updated to ensure that 32-bit integer arithmetic (`i32`) does not elide bounds checks when calculating effective addresses. The compiler should emit explicit check-and-branch instructions where an `i32.add` could result in a wrapped offset that bypasses standard bounds-checking logic. + --- ## 7. Supporting Evidence @@ -124,10 +146,9 @@ if (__builtin_mul_overflow(static_cast(index), m_elementSize, &byteOffse All logs demonstrate an identical crash offset (`0xADD7476C`) and namespace 31 violation, confirming 100% reproducibility across various process roles. - +--- # End of Report ---- - **Primary Contact:** Joseph Goydish II