fix(elf): validate declared file extents before provider admission

docs/installation.md

@@ -968,6 +968,19 @@ dossiers, instructions, recovered data types, measured load mappings, loaded
 memory bytes, and observed file offsets. Independent load-image attestation
 supports DOS MZ, explicitly selected COM, and explicit raw-binary imports;
 PE returns measurements with an unsupported attestation status.
+ELF target opening checks the declared program and section header tables and
+their file-backed ranges before selecting a provider. A declaration beyond EOF
+is refused with its range and the actual file size, including a file cut one
+byte short. This also refuses carved or deliberately damaged copies that retain
+out-of-file declarations; they are not presented as complete smaller programs.
+Files declaring no tables remain valid inputs, subject to the provider's lane.
+Inactive headers, zero-length ranges and `SHT_NOBITS` memory-only sections do
+not require stored payload bytes. Extended counts come from section zero.
+The check streams header records in chunks of at most 64 KiB; it does not decode
+section names, copy payloads or impose the metadata decoder's structural budget.
+Passing it establishes physical range consistency, not complete function
+discovery, loader validity or runtime behavior. Existing ISA/ABI checks remain
+separate, including the bounded recordless MIPS lane.
 Target admission preserves recognized PE/NE/LE/LX signatures separately from
 reader layout support. A Windows header overlapping the first 64 DOS-header
 bytes remains an unsupported layout in this release; it is not reported as an

src/application/BinaryTargetResolver.ts

@@ -31,6 +31,7 @@ import { AnalysisCancelledError } from "../domain/analysisErrorCore.js";
 import type { BinaryTarget } from "../domain/binaryTargetTypes.js";
 import { err, ok, type Result } from "../domain/result.js";
 import { readMipsElfMetadata } from "./MipsElfMetadata.js";
+import { validateElfDeclaredRanges } from "../domain/elfDeclaredRanges.js";
 import {
   resolveAppBundleExecutable,
   type ResolvedAppBundle,
@@ -852,6 +853,12 @@ const readExecutableMetadata = async (
       signatureEvidence,
     );
   }
+  if (bytes.length >= 4 && bytes.toString("hex", 0, 4) === "7f454c46")
+    return readElfMetadata(handle, bytes, {
+      fileSize,
+      hostArchitecture,
+      signal,
+    });
   const thin = await readThinMachoMetadata(handle, bytes, {
     fileSize,
     hostArchitecture,
@@ -881,11 +888,25 @@ const readExecutableMetadata = async (
       if (!framed.ok) return framed;
     }
   }
-  if (
-    !parsed.ok ||
-    parsed.value.architecture !== "mips" ||
-    parsed.value.mips.elfClass !== 32
-  )
+  return parsed;
+};
+
+/** ELF structure and family declarations share one descriptor before provider selection. */
+const readElfMetadata = async (
+  handle: FileHandle,
+  bytes: Buffer,
+  options: {
+    readonly fileSize: number;
+    readonly hostArchitecture: NodeJS.Architecture;
+    readonly signal?: AbortSignal | undefined;
+  },
+): Promise<Result<ExecutableMetadata, ExecutableMetadataFailure>> => {
+  const { fileSize, hostArchitecture, signal } = options;
+  const parsed = parseExecutableHeader(bytes, hostArchitecture, fileSize);
+  if (!parsed.ok || parsed.value.format !== "elf") return parsed;
+  const ranges = await readElfDeclaredRanges(handle, bytes, fileSize, signal);
+  if (!ranges.ok) return ranges;
+  if (parsed.value.architecture !== "mips" || parsed.value.mips.elfClass !== 32)
     return parsed;
   const declarations = await readMipsElfMetadata(
     handle,
@@ -909,6 +930,44 @@ const readExecutableMetadata = async (
   });
 };
 
+/** Borrow the admitted descriptor; every request is at most one 64 KiB table chunk. */
+const readElfDeclaredRanges = async (
+  handle: FileHandle,
+  prefix: Buffer,
+  fileSize: number,
+  signal?: AbortSignal,
+): Promise<Result<null, string>> => {
+  const ranges = validateElfDeclaredRanges(prefix, fileSize);
+  let next = ranges.next();
+  let window: Buffer | undefined;
+  while (!next.done) {
+    throwIfTargetResolutionCancelled(signal);
+    const { offset, size } = next.value;
+    let bytes: Buffer;
+    if (offset + size <= prefix.length)
+      bytes = prefix.subarray(offset, offset + size);
+    else {
+      window ??= Buffer.allocUnsafe(64 * 1024);
+      bytes = window.subarray(0, size);
+      let length = 0;
+      while (length < size) {
+        const read = await handle.read(
+          bytes,
+          length,
+          size - length,
+          offset + length,
+        );
+        throwIfTargetResolutionCancelled(signal);
+        if (read.bytesRead === 0) break;
+        length += read.bytesRead;
+      }
+      bytes = bytes.subarray(0, length);
+    }
+    next = ranges.next(bytes);
+  }
+  return next.value;
+};
+
 type ExecutableMetadataFailure =
   | string
   | {

src/domain/elfDeclaredRanges.ts

@@ -0,0 +1,271 @@
+import { readElfFixedHeader, type ElfFixedHeader } from "./elfFixedHeader.js";
+import { err, ok, type Result } from "./result.js";
+
+/** Positional source requests; the caller owns the descriptor and cancellation. */
+export interface ElfDeclarationRead {
+  readonly offset: number;
+  readonly size: number;
+}
+
+interface ElfDeclaredTable {
+  readonly offset: bigint;
+  readonly count: number;
+  readonly width: number;
+}
+
+export interface ElfTableDeclarations {
+  readonly header: ElfFixedHeader;
+  readonly programs: ElfDeclaredTable;
+  readonly sections: ElfDeclaredTable & { readonly namesIndex: number };
+}
+
+const reader = (bytes: Buffer, header: ElfFixedHeader) => {
+  const little = header.byteOrder === "little";
+  const u16 = (at: number) =>
+    little ? bytes.readUInt16LE(at) : bytes.readUInt16BE(at);
+  const u32 = (at: number) =>
+    little ? bytes.readUInt32LE(at) : bytes.readUInt32BE(at);
+  const word = (at: number) =>
+    header.elfClass === 32
+      ? BigInt(u32(at))
+      : little
+        ? bytes.readBigUInt64LE(at)
+        : bytes.readBigUInt64BE(at);
+  return { u16, u32, word };
+};
+
+/** Zero-sized/inactive declarations own no file bytes. Arithmetic stays exact. */
+const rangeFailure = (
+  label: string,
+  offset: bigint,
+  size: bigint,
+  fileSize: number,
+): string | undefined =>
+  size !== 0n && (offset > BigInt(fileSize) || size > BigInt(fileSize) - offset)
+    ? `truncated ELF ${label}: declared file range ${String(offset)}..${String(offset + size)} exceeds the ${String(fileSize)}-byte file`
+    : undefined;
+
+interface RawTableDeclaration {
+  readonly offset: bigint;
+  readonly count: bigint;
+  readonly width: number;
+}
+
+const tableFailure = (
+  kind: "program" | "section",
+  table: RawTableDeclaration,
+  header: ElfFixedHeader,
+  fileSize: number,
+): string | undefined => {
+  if (table.count === 0n) return undefined;
+  const wide = header.elfClass === 64;
+  const minimumWidth = kind === "program" ? (wide ? 56 : 32) : wide ? 64 : 40;
+  const label = `${kind} header table`;
+  if (table.width < minimumWidth) return `invalid ELF ${label} entry width`;
+  if (table.offset < BigInt(wide ? 64 : 52))
+    return `ELF ${label} overlaps the fixed header`;
+  return rangeFailure(
+    label,
+    table.offset,
+    table.count * BigInt(table.width),
+    fileSize,
+  );
+};
+
+interface TableCounts {
+  programCount: bigint;
+  sectionCount: bigint;
+  namesIndex: number;
+}
+
+const extendedCounts = (
+  first: Buffer,
+  header: ElfFixedHeader,
+  initial: TableCounts,
+): Result<TableCounts, string> => {
+  const wide = header.elfClass === 64;
+  if (first.length !== (wide ? 64 : 40))
+    return err("truncated ELF extended section-zero header");
+  const zero = reader(first, header);
+  if (zero.u32(4) !== 0)
+    return err(
+      "ELF extended numbering requires an inactive SHT_NULL section zero",
+    );
+  const counts = { ...initial };
+  if (counts.sectionCount === 0n) {
+    counts.sectionCount = zero.word(wide ? 32 : 20);
+    if (counts.sectionCount < 0xff00n)
+      return err("invalid ELF extended section count");
+  }
+  if (counts.namesIndex === 0xffff) {
+    counts.namesIndex = zero.u32(wide ? 40 : 24);
+    if (counts.namesIndex < 0xff00)
+      return err("invalid ELF extended section-name index");
+  }
+  if (counts.programCount === 0xffffn) {
+    counts.programCount = BigInt(zero.u32(wide ? 44 : 28));
+    if (counts.programCount < 0xffffn)
+      return err("invalid ELF extended program count");
+  }
+  return ok(counts);
+};
+
+const TABLE_FIELDS = {
+  32: {
+    programOffset: 28,
+    sectionOffset: 32,
+    programWidth: 42,
+    programCount: 44,
+    sectionWidth: 46,
+    sectionCount: 48,
+    namesIndex: 50,
+    sectionHeaderSize: 40,
+  },
+  64: {
+    programOffset: 32,
+    sectionOffset: 40,
+    programWidth: 54,
+    programCount: 56,
+    sectionWidth: 58,
+    sectionCount: 60,
+    namesIndex: 62,
+    sectionHeaderSize: 64,
+  },
+} as const;
+
+/** Canonical table declarations, including extended counts in inactive section zero. */
+export function* readElfTableDeclarations(
+  bytes: Buffer,
+  fileSize: number,
+): Generator<ElfDeclarationRead, Result<ElfTableDeclarations, string>, Buffer> {
+  const fixed = readElfFixedHeader(bytes, fileSize);
+  if (!fixed.ok) return fixed;
+  const header = fixed.value;
+  const r = reader(bytes, header);
+  const fields = TABLE_FIELDS[header.elfClass];
+  const programOffset = r.word(fields.programOffset);
+  const sectionOffset = r.word(fields.sectionOffset);
+  const programWidth = r.u16(fields.programWidth);
+  const sectionWidth = r.u16(fields.sectionWidth);
+  let programCount = BigInt(r.u16(fields.programCount));
+  let sectionCount = BigInt(r.u16(fields.sectionCount));
+  let namesIndex = r.u16(fields.namesIndex);
+  if (
+    sectionOffset === 0n &&
+    (sectionCount !== 0n || namesIndex !== 0 || programCount === 0xffffn)
+  )
+    return err("ELF section table is missing");
+  if (
+    sectionOffset !== 0n &&
+    (sectionCount === 0n || namesIndex === 0xffff || programCount === 0xffffn)
+  ) {
+    const failure = tableFailure(
+      "section",
+      { offset: sectionOffset, count: 1n, width: sectionWidth },
+      header,
+      fileSize,
+    );
+    if (failure !== undefined) return err(failure);
+    const first = yield {
+      offset: Number(sectionOffset),
+      size: fields.sectionHeaderSize,
+    };
+    const counts = extendedCounts(first, header, {
+      programCount,
+      sectionCount,
+      namesIndex,
+    });
+    if (!counts.ok) return counts;
+    ({ programCount, sectionCount, namesIndex } = counts.value);
+  }
+  for (const [kind, offset, count, width] of [
+    ["program", programOffset, programCount, programWidth],
+    ["section", sectionOffset, sectionCount, sectionWidth],
+  ] as const) {
+    const failure = tableFailure(
+      kind,
+      { offset, count, width },
+      header,
+      fileSize,
+    );
+    if (failure !== undefined) return err(failure);
+  }
+  if (sectionCount !== 0n && BigInt(namesIndex) >= sectionCount)
+    return err(
+      "ELF section-name index lies outside the declared section table",
+    );
+  // A validated table fits the host-sized file, so its record count is exact.
+  return ok({
+    header,
+    programs: {
+      offset: programOffset,
+      count: Number(programCount),
+      width: programWidth,
+    },
+    sections: {
+      offset: sectionOffset,
+      count: Number(sectionCount),
+      width: sectionWidth,
+      namesIndex,
+    },
+  });
+}
+
+/** Examine only header records; referenced payloads are range-checked, never copied. */
+function* inspectTableRanges(
+  kind: "program" | "section",
+  table: ElfDeclaredTable,
+  header: ElfFixedHeader,
+  fileSize: number,
+): Generator<ElfDeclarationRead, Result<null, string>, Buffer> {
+  const wide = header.elfClass === 64;
+  const perRead = Math.max(1, Math.floor((64 * 1024) / table.width));
+  for (let index = 0; index < table.count; index += perRead) {
+    const count = Math.min(perRead, table.count - index);
+    const size = count * table.width;
+    const bytes = yield {
+      offset: Number(table.offset) + index * table.width,
+      size,
+    };
+    if (bytes.length !== size) return err(`truncated ELF ${kind} header table`);
+    const r = reader(bytes, header);
+    for (let item = 0; item < count; item++) {
+      const at = item * table.width;
+      const type = r.u32(at + (kind === "program" ? 0 : 4));
+      if (type === 0 || (kind === "section" && type === 8)) continue;
+      const offset = r.word(
+        at + (kind === "program" ? (wide ? 8 : 4) : wide ? 24 : 16),
+      );
+      const length = r.word(
+        at + (kind === "program" ? (wide ? 32 : 16) : wide ? 32 : 20),
+      );
+      const failure = rangeFailure(
+        `${kind} ${String(index + item)}`,
+        offset,
+        length,
+        fileSize,
+      );
+      if (failure !== undefined) return err(failure);
+    }
+  }
+  return ok(null);
+}
+
+/** Physical extent admission, independent of section names, CPU lanes and decoder budgets. */
+export function* validateElfDeclaredRanges(
+  prefix: Buffer,
+  fileSize: number,
+): Generator<ElfDeclarationRead, Result<null, string>, Buffer> {
+  const declarations = yield* readElfTableDeclarations(prefix, fileSize);
+  if (!declarations.ok) return declarations;
+  const { header, programs, sections } = declarations.value;
+  for (const [kind, table] of [
+    ["program", programs],
+    ["section", sections],
+  ] as const) {
+    if (table.count === 0) continue;
+    const inspected = yield* inspectTableRanges(kind, table, header, fileSize);
+    if (!inspected.ok) return inspected;
+  }
+  return ok(null);
+}

src/native/metadata/NativeSectionDirectory.ts

@@ -1,4 +1,4 @@
-import { readElfFixedHeader } from "../../domain/elfFixedHeader.js";
+import { readElfTableDeclarations } from "../../domain/elfDeclaredRanges.js";
 import {
   BinaryFormatFailure,
   BinaryReader,
@@ -78,63 +78,26 @@ export function* readElfSectionDirectory(
   const prefix = yield request(fileSize, 0n, 16n);
   const headerSize = prefix[4] === 1 ? 52 : 64;
   const bytes = yield request(fileSize, 0n, BigInt(headerSize));
-  const parsed = readElfFixedHeader(bytes, fileSize);
+  const parsed = yield* readElfTableDeclarations(bytes, fileSize);
   if (!parsed.ok) return reject(parsed.error);
-  const { elfClass: bits, byteOrder, machine } = parsed.value;
+  const { header, programs, sections: sectionTable } = parsed.value;
+  const { elfClass: bits, byteOrder, machine } = header;
   const little = byteOrder === "little";
   const wide = bits === 64;
   const r = new BinaryReader(bytes, little);
-  const program_offset = r.word(wide ? 32 : 28, bits);
-  const sectionOffset = r.word(wide ? 40 : 32, bits);
-  const program_width = r.u16(wide ? 54 : 42);
-  const sectionWidth = r.u16(wide ? 58 : 46);
-  let program_count = r.u16(wide ? 56 : 44);
-  let count = r.u16(wide ? 60 : 48);
-  let namesIndex = r.u16(wide ? 62 : 50);
-  if (
-    (program_count !== 0 && program_offset < BigInt(headerSize)) ||
-    (sectionOffset !== 0n && sectionOffset < BigInt(headerSize))
-  )
-    reject("ELF header table overlaps the native header");
-  if (
-    sectionOffset === 0n &&
-    (count !== 0 || namesIndex !== 0 || program_count === 0xffff)
-  )
-    reject("ELF section table is missing");
-  if (
-    sectionOffset !== 0n &&
-    (count === 0 || namesIndex === 0xffff || program_count === 0xffff)
-  ) {
-    if (sectionWidth < (wide ? 64 : 40))
-      reject("ELF extended section header width is invalid");
-    const first = new BinaryReader(
-      yield request(fileSize, sectionOffset, BigInt(sectionWidth)),
-      little,
-    );
-    if (first.u32(4) !== 0)
-      reject(
-        "ELF initial section for extended numbering must have SHT_NULL type",
-      );
-    if (count === 0) {
-      const declared = first.word(wide ? 32 : 20, bits);
-      if (declared < 0xff00n) reject("ELF extended section count is invalid");
-      count = exact(declared);
-    }
-    if (namesIndex === 0xffff) {
-      namesIndex = first.u32(wide ? 40 : 24);
-      if (namesIndex < 0xff00)
-        reject("ELF extended section name index is below its reserved range");
-    }
-    if (program_count === 0xffff) {
-      program_count = first.u32(wide ? 44 : 28);
-      if (program_count < 0xffff)
-        reject("ELF extended program count is below its reserved range");
-    }
-  }
+  const {
+    offset: program_offset,
+    width: program_width,
+    count: program_count,
+  } = programs;
+  const {
+    offset: sectionOffset,
+    width: sectionWidth,
+    count,
+    namesIndex,
+  } = sectionTable;
   let has_dynamic_segment = false;
   if (program_count !== 0) {
-    if (program_width < (wide ? 56 : 32))
-      reject("ELF program header width is invalid");
     const programs = new BinaryReader(
       yield request(
         fileSize,
@@ -153,8 +116,6 @@ export function* readElfSectionDirectory(
   const sections: NativeSection[] = [];
   let section_names_limitation: string | undefined;
   if (count !== 0) {
-    if (sectionWidth < (wide ? 64 : 40) || namesIndex >= count)
-      reject("ELF section width or name-table index is invalid");
     const table = new BinaryReader(
       yield request(
         fileSize,

tests/boundary/filesystem/elfDeclaredRanges.test.ts

@@ -0,0 +1,159 @@
+import { createHash } from "node:crypto";
+import { readFile, writeFile } from "node:fs/promises";
+import { join } from "node:path";
+import { expect, it } from "vitest";
+import { parseBinaryTarget } from "../../../src/application/BinaryTargetResolver.js";
+import { elf } from "../../../src/domain/binaryTarget.fixture.js";
+import { createTestTempDirectory } from "../../fixtures/temporaryDirectory.js";
+
+const image = (bits: 32 | 64, little: boolean) => {
+  const bytes = Buffer.alloc(368);
+  const header = elf(bits === 32 ? 1 : 2, little ? 1 : 2, bits === 32 ? 3 : 62);
+  header.copy(bytes);
+  const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+  const u16 = (offset: number, value: number) =>
+    view.setUint16(offset, value, little);
+  const u32 = (offset: number, value: number) =>
+    view.setUint32(offset, value, little);
+  const word = (offset: number, value: bigint) =>
+    bits === 32
+      ? u32(offset, Number(value))
+      : view.setBigUint64(offset, value, little);
+  const wide = bits === 64;
+  const program = wide ? 64 : 52;
+  const programWidth = wide ? 56 : 32;
+  const sectionWidth = wide ? 64 : 40;
+  u16(16, 2);
+  word(wide ? 32 : 28, BigInt(program));
+  word(wide ? 40 : 32, 128n);
+  u16(wide ? 54 : 42, programWidth);
+  u16(wide ? 56 : 44, 1);
+  u16(wide ? 58 : 46, sectionWidth);
+  u16(wide ? 60 : 48, 2);
+  u32(program, 1); // PT_LOAD
+  word(program + (wide ? 8 : 4), 320n);
+  word(program + (wide ? 32 : 16), 16n);
+  word(program + (wide ? 40 : 20), 16n);
+  const section = 128 + sectionWidth;
+  u32(section + 4, 1); // SHT_PROGBITS
+  word(section + (wide ? 24 : 16), 352n);
+  word(section + (wide ? 32 : 20), 16n);
+  return {
+    bytes,
+    word,
+    u16,
+    u32,
+    program,
+    section,
+    programWidth,
+    sectionWidth,
+  };
+};
+
+const admit = async (bytes: Buffer) => {
+  const directory = await createTestTempDirectory("rea-elf-declared-ranges-");
+  const path = join(directory, "image.elf");
+  await writeFile(path, bytes);
+  const result = await parseBinaryTarget(path);
+  const digest = createHash("sha256").update(bytes).digest("hex");
+  expect(
+    createHash("sha256")
+      .update(await readFile(path))
+      .digest("hex"),
+  ).toBe(digest);
+  if (result.ok) expect(result.value.sha256).toBe(digest);
+  return result;
+};
+
+for (const bits of [32, 64] as const) {
+  for (const little of [true, false]) {
+    it(`refuses declared table and payload truncation before provider admission (ELF${bits} ${little ? "LE" : "BE"})`, async () => {
+      const fixture = image(bits, little);
+      expect((await admit(fixture.bytes)).ok).toBe(true);
+      for (const [length, declaration] of [
+        [fixture.program, "program header table"],
+        [fixture.program + fixture.programWidth - 1, "program header table"],
+        [128 + fixture.sectionWidth * 2 - 1, "section header table"],
+        [335, "program 0"],
+        [367, "section 1"],
+      ] as const) {
+        const result = await admit(fixture.bytes.subarray(0, length));
+        expect(result).toMatchObject({
+          ok: false,
+          error: {
+            constraint: "file_format_rejected",
+            reason: expect.stringContaining(`truncated ELF ${declaration}`),
+          },
+        });
+        if (result.ok) throw new Error("Expected a declared range refusal");
+        expect(result.error.reason).toContain(`${length}-byte file`);
+      }
+    });
+
+    it(`preserves absent tables and memory-only declarations (ELF${bits} ${little ? "LE" : "BE"})`, async () => {
+      expect(
+        (
+          await admit(
+            elf(bits === 32 ? 1 : 2, little ? 1 : 2, bits === 32 ? 3 : 62),
+          )
+        ).ok,
+      ).toBe(true);
+      const fixture = image(bits, little);
+      const wide = bits === 64;
+      const outside = wide ? 0xffffffffffffffffn : 0xffffffffn;
+      fixture.u32(fixture.section + 4, 8); // SHT_NOBITS owns memory, not file bytes.
+      fixture.word(fixture.section + (wide ? 24 : 16), outside);
+      fixture.word(fixture.section + (wide ? 32 : 20), outside);
+      fixture.word(fixture.program + (wide ? 8 : 4), outside);
+      fixture.word(fixture.program + (wide ? 32 : 16), 0n);
+      fixture.word(128 + (wide ? 24 : 16), outside); // Inactive section-zero fields.
+      fixture.word(128 + (wide ? 32 : 20), outside);
+      expect((await admit(fixture.bytes)).ok).toBe(true);
+    });
+
+    it(`keeps declared offsets exact when their sum exceeds host precision (ELF${bits} ${little ? "LE" : "BE"})`, async () => {
+      const fixture = image(bits, little);
+      const maximum = bits === 64 ? 0xffffffffffffffffn : 0xffffffffn;
+      fixture.word(fixture.program + (bits === 64 ? 8 : 4), maximum);
+      const result = await admit(fixture.bytes);
+      expect(result).toMatchObject({ ok: false });
+      if (result.ok) throw new Error("Expected an out-of-file range");
+      expect(result.error.reason).toContain(`${maximum}..${maximum + 16n}`);
+    });
+  }
+}
+
+it.each(["sections", "programs", "section names"] as const)(
+  "resolves valid extended %s numbering from bounded section zero",
+  async (kind) => {
+    const count =
+      kind === "programs" ? 0xffff : kind === "section names" ? 0xff01 : 0xff00;
+    const width = kind === "programs" ? 56 : 64;
+    const sectionAt = kind === "programs" ? 64 + count * width : 64;
+    const bytes = Buffer.alloc(
+      kind === "programs" ? sectionAt + 64 : sectionAt + count * width,
+    );
+    elf(2, 1, 62).copy(bytes);
+    bytes.writeBigUInt64LE(BigInt(sectionAt), 40);
+    bytes.writeUInt16LE(64, 58);
+    if (kind !== "programs") {
+      bytes.writeBigUInt64LE(BigInt(count), sectionAt + 32);
+      if (kind === "section names") {
+        bytes.writeUInt16LE(0xffff, 62);
+        bytes.writeUInt32LE(0xff00, sectionAt + 40);
+        bytes.writeUInt32LE(3, sectionAt + 0xff00 * width + 4);
+      }
+    } else {
+      bytes.writeBigUInt64LE(64n, 32);
+      bytes.writeUInt16LE(56, 54);
+      bytes.writeUInt16LE(0xffff, 56);
+      bytes.writeUInt16LE(1, 60);
+      bytes.writeUInt32LE(count, sectionAt + 44);
+    }
+    expect((await admit(bytes)).ok).toBe(true);
+    const truncated = await admit(bytes.subarray(0, bytes.length - 1));
+    expect(truncated).toMatchObject({ ok: false });
+    if (truncated.ok) throw new Error("Expected an extended table refusal");
+    expect(truncated.error.reason).toContain("truncated ELF");
+  },
+);

tests/boundary/filesystem/mipsSharedLoad.test.ts

@@ -52,10 +52,31 @@ const fixture = (little: boolean, count = 2): Buffer => {
   }
   return bytes;
 };
-const resolve = async (bytes: Buffer) => {
+const writeFixture = async (bytes: Buffer) => {
   const directory = await createTestTempDirectory("rea-mips-shared-test-");
   const path = join(directory, "shared.elf");
   await writeFile(path, bytes);
+  return path;
+};
+const inspectSource = async (path: string) => {
+  const handle = await open(path, "r");
+  try {
+    return await readMipsElfMetadata(
+      handle,
+      {
+        elfClass: 32,
+        byteOrder: "little",
+        type: 3,
+        flags: 0x74001005,
+      },
+      () => undefined,
+    );
+  } finally {
+    await handle.close();
+  }
+};
+const resolve = async (bytes: Buffer) => {
+  const path = await writeFixture(bytes);
   const result = await parseBinaryTarget(path);
   assert.ok(result.ok);
   assert.equal(result.value.kind, "executable");
@@ -201,16 +222,23 @@ it("does not treat uncaptured ABI declaration headers as an inspected absence",
   bytes.writeUInt32LE(bytes.length + 1, 32);
   bytes.writeUInt16LE(40, 46);
   bytes.writeUInt16LE(1, 48);
-  const target = await resolve(bytes);
-  assert.equal(target.mips.abiFlags, null);
-  assert.equal(target.mips.sharedLoad?.status, "unavailable");
+  const path = await writeFixture(bytes);
+  const admitted = await parseBinaryTarget(path);
+  assert.ok(!admitted.ok);
+  assert.match(admitted.error.reason, /truncated ELF section header table/u);
+  // The specialized inspector still retains unknown source facts if used on
+  // damaged evidence; normal target admission refuses its impossible extent.
+  const declarations = await inspectSource(path);
+  assert.ok(declarations.ok);
+  assert.equal(declarations.value.abiFlags, null);
+  assert.equal(declarations.value.sharedLoad?.status, "unavailable");
   assert.match(
-    ghidraMipsUnsupportedReason(target) ?? "",
-    /unavailable headers remain unknown/u,
+    declarations.value.limitations.join(" "),
+    /extends beyond the captured file/u,
   );
 });
 
-const malformed: [string, (bytes: Buffer) => void, RegExp][] = [
+const malformed: [string, (bytes: Buffer) => void, RegExp, boolean?][] = [
   [
     "overlapping load ranges",
     (b) => {
@@ -233,11 +261,13 @@ const malformed: [string, (bytes: Buffer) => void, RegExp][] = [
     "declared dynamic tail outside file",
     (b) => b.writeUInt32LE(b.length, 100),
     /beyond the file/u,
+    true,
   ],
   [
     "unavailable load bytes",
     (b) => b.writeUInt32LE(b.length + 1, 68),
     /PT_LOAD range/u,
+    true,
   ],
   ["missing terminator", (b) => b.writeUInt32LE(1, 280), /DT_NULL/u],
   [
@@ -268,9 +298,22 @@ const malformed: [string, (bytes: Buffer) => void, RegExp][] = [
 ];
 it.each(malformed)(
   "preserves useful partial header facts for %s",
-  async (_name, mutate, reason) => {
+  async (_name, mutate, reason, rejectsExtent) => {
     const bytes = fixture(true);
     mutate(bytes);
+    if (rejectsExtent) {
+      const path = await writeFixture(bytes);
+      const admitted = await parseBinaryTarget(path);
+      assert.ok(!admitted.ok);
+      assert.match(admitted.error.reason, /truncated ELF program \d/u);
+      const declarations = await inspectSource(path);
+      assert.ok(declarations.ok);
+      assert.equal(declarations.value.sharedLoad?.status, "unavailable");
+      if (declarations.value.sharedLoad?.status !== "unavailable")
+        throw new Error("Expected retained unknown relocation coverage");
+      assert.match(declarations.value.sharedLoad.reason, reason);
+      return;
+    }
     const target = await resolve(bytes);
     assert.equal(target.mips.flags, 0x74001005);
     assert.equal(target.mips.abiFlags, null);