fix(asn1): preserve decoder capacity refusals

src/artifacts/pyinstaller/MarshalSubset.test.ts

@@ -20,11 +20,6 @@ it("reads a Python 3.9 reference-flagged PYZ table", () => {
   ]);
 });
 
-it("reads marshal one-byte string tags as Latin-1", () => {
-  for (const hex of ["6101000000e9", "4101000000e9", "7a01e9", "5a01e9"])
-    expect(readMarshalSubset(bytes(hex))).toEqual({ ok: true, value: "é" });
-});
-
 it("decodes CPython marshal Unicode with surrogatepass", () => {
   expect(
     readMarshalSubset(

src/artifacts/pyinstaller/MarshalSubset.ts

@@ -168,8 +168,14 @@ const readAsciiBytes = (
 ): Result<string, PyInstallerFailure> => {
   const bytes = readBytes(cursor, length);
   if (!bytes.ok) return bytes;
-  // These tags use CPython's one-byte Unicode constructor, not an ASCII check.
-  return ok(bytes.value.toString("latin1"));
+  if (bytes.value.some((byte) => byte > 0x7f))
+    return err(
+      pyInstallerFailure(
+        "format",
+        "PYZ marshal ASCII string contains a non-ASCII byte",
+      ),
+    );
+  return ok(bytes.value.toString("ascii"));
 };
 
 const readUtf8 = (

src/domain/apkSignature/apkV1SignatureBlock.test.ts

@@ -202,8 +202,9 @@ describe("v1 signature block (PKCS#7 SignedData)", () => {
     let nested: Uint8Array = Uint8Array.from([0x05, 0x00]);
     for (let i = 0; i < 64; i += 1) nested = indefinite(0x30, nested);
     expect(errorOf(nested)).toEqual({
-      kind: "malformed-pkcs7",
-      detail: "ASN.1 nesting exceeds 32 levels.",
+      kind: "budget-exceeded",
+      resource: "asn1-depth",
+      limit: 32,
     });
   });
 });
@@ -411,3 +412,42 @@ it.each([0, 1])(
     });
   },
 );
+
+it("keeps a valid constructed CMS content depth refusal distinct from malformed input", () => {
+  let content = tlv(0x04, Uint8Array.of(1));
+  const block = () =>
+    signedDataBlock({
+      certificates: [LEAF_CERTIFICATE],
+      signerInfos: [signerInfo({ names: LEAF_CERTIFICATE })],
+      encapsulatedContent: content,
+    });
+  expect(decodeV1SignatureBlock(block()).ok).toBe(true);
+  for (let depth = 0; depth < 40; depth += 1)
+    content = indefinite(0x24, content);
+  expect(errorOf(block())).toEqual({
+    kind: "budget-exceeded",
+    resource: "asn1-depth",
+    limit: 32,
+  });
+});
+
+it("preserves the canonical OID byte allowance for a valid unknown digest algorithm", () => {
+  const algorithm = tlv(
+    0x06,
+    Uint8Array.from([0x2a, ...Array<number>(64).fill(0)]),
+  );
+  expect(
+    errorOf(
+      signedDataBlock({
+        certificates: [LEAF_CERTIFICATE],
+        signerInfos: [
+          signerInfo({
+            names: LEAF_CERTIFICATE,
+            digestAlgorithmOid: algorithm,
+          }),
+        ],
+        digestAlgorithmOid: algorithm,
+      }),
+    ),
+  ).toEqual({ kind: "budget-exceeded", resource: "oid-bytes", limit: 64 });
+});

src/domain/apkSignature/apkV1SignatureBlock.ts

@@ -27,7 +27,10 @@ export type ApkV1BlockError =
       readonly resource:
         | "v1-block-certificates"
         | "v1-signer-infos"
-        | "asn1-elements";
+        | "asn1-elements"
+        | "asn1-depth"
+        | "oid-bytes"
+        | "oid-arc-bytes";
       readonly limit: number;
     };
 
@@ -98,11 +101,14 @@ class ApkBerReader {
       return this.#reader.read(at, limit, depth);
     } catch (cause: unknown) {
       if (!(cause instanceof Asn1BerFailure)) throw cause;
-      if (cause.kind === "budget-exceeded")
+      if (cause.constraint !== null)
         throw new BlockFailure({
           kind: "budget-exceeded",
-          resource: "asn1-elements",
-          limit: MAX_ASN1_ELEMENTS,
+          resource:
+            cause.constraint.resource === "nodes"
+              ? "asn1-elements"
+              : "asn1-depth",
+          limit: cause.constraint.limit,
         });
       throw malformed(cause.message);
     }
@@ -155,6 +161,13 @@ const expectOctetString = (
 const oidText = (content: Uint8Array): string => {
   const decoded = decodeAsn1Oid(content, { bytes: 64, arcBytes: 64 });
   if (decoded.ok) return decoded.value;
+  if (decoded.error.kind === "byte-limit" || decoded.error.kind === "arc-limit")
+    throw new BlockFailure({
+      kind: "budget-exceeded",
+      resource:
+        decoded.error.kind === "byte-limit" ? "oid-bytes" : "oid-arc-bytes",
+      limit: decoded.error.limit,
+    });
   if (decoded.error.kind === "truncated")
     throw malformed("object identifier is truncated");
   throw malformed(`object identifier of ${String(content.length)} bytes`);
@@ -188,6 +201,13 @@ const integerIdentityContents = (bytes: Uint8Array): Uint8Array => {
   return start === 0 ? bytes : bytes.subarray(start);
 };
 
+/** Optional identity interpretation may remain unknown while raw certificate identity survives. */
+const unavailableIdentityInterpretation = (cause: unknown): boolean =>
+  cause instanceof BlockFailure &&
+  (cause.error.kind === "malformed-pkcs7" ||
+    cause.error.resource === "oid-bytes" ||
+    cause.error.resource === "oid-arc-bytes");
+
 /**
  * RFC 5280 §7.1: RDN order matters; attributes in one SET do not. This
  * comparison profile admits ASCII PrintableString/UTF8String for common
@@ -237,8 +257,7 @@ const directoryNameKey = (name: Asn1BerNode): string | null => {
     }
     return JSON.stringify(rdns);
   } catch (cause) {
-    if (cause instanceof BlockFailure && cause.error.kind === "malformed-pkcs7")
-      return null;
+    if (unavailableIdentityInterpretation(cause)) return null;
     throw cause;
   }
 };
@@ -298,8 +317,7 @@ const certificateIdentity = (
       subjectKeyIdentifier,
     };
   } catch (cause: unknown) {
-    if (cause instanceof BlockFailure && cause.error.kind === "malformed-pkcs7")
-      return null;
+    if (unavailableIdentityInterpretation(cause)) return null;
     throw cause;
   }
 };

src/domain/asn1Ber.ts

@@ -11,11 +11,16 @@ export interface Asn1BerNode {
   readonly children: readonly Asn1BerNode[];
 }
 
+/** The fixed parser allowance that prevented examining more BER structure. */
+export interface Asn1BerConstraint {
+  readonly resource: "nodes" | "depth";
+  readonly limit: number;
+}
+
 export class Asn1BerFailure extends Error {
   constructor(
     message: string,
-    readonly kind: "malformed" | "budget-exceeded" = "malformed",
-    readonly limit: number | null = null,
+    readonly constraint: Asn1BerConstraint | null = null,
   ) {
     super(message);
     this.name = "Asn1BerFailure";
@@ -28,10 +33,9 @@ interface Budget {
 
 const fail = (
   message: string,
-  kind: Asn1BerFailure["kind"] = "malformed",
-  limit: number | null = null,
+  constraint: Asn1BerConstraint | null = null,
 ): never => {
-  throw new Asn1BerFailure(message, kind, limit);
+  throw new Asn1BerFailure(message, constraint);
 };
 
 /**
@@ -51,12 +55,14 @@ export class Asn1BerReader {
 
   read(offset = 0, end = this.bytes.length, depth = 0): Asn1BerNode {
     if (depth > this.maxDepth)
-      return fail(`ASN.1 nesting exceeds ${String(this.maxDepth)} levels.`);
+      return fail(`ASN.1 nesting exceeds ${String(this.maxDepth)} levels.`, {
+        resource: "depth",
+        limit: this.maxDepth,
+      });
     if (this.#budget.remaining <= 0)
       return fail(
         `ASN.1 value count exceeds the ${String(this.maxNodes)}-node budget.`,
-        "budget-exceeded",
-        this.maxNodes,
+        { resource: "nodes", limit: this.maxNodes },
       );
     this.#budget.remaining -= 1;
     if (offset >= end || offset + 2 > end)

src/native/pe/PeCertificateAsn1.ts

@@ -28,7 +28,12 @@ const OID_NAMES: Readonly<Record<string, string>> = {
 
 /** A fixed per-payload decoder allowance and its limit. */
 export interface PeCertificateDecodeAllowance {
-  readonly allowance: "asn1-nodes" | "decoded-text";
+  readonly allowance:
+    | "asn1-nodes"
+    | "asn1-depth"
+    | "decoded-text"
+    | "oid-bytes"
+    | "oid-arc-bytes";
   readonly limit: number;
 }
 
@@ -62,9 +67,15 @@ export const readAsn1 = (bytes: Buffer): Asn1BerNode => {
     if (cause instanceof Asn1BerFailure)
       throw new PeCertificateAsn1Failure(
         cause.message,
-        cause.kind === "budget-exceeded"
-          ? { allowance: "asn1-nodes", limit: cause.limit ?? ASN1_NODE_BUDGET }
-          : null,
+        cause.constraint === null
+          ? null
+          : {
+              allowance:
+                cause.constraint.resource === "nodes"
+                  ? "asn1-nodes"
+                  : "asn1-depth",
+              limit: cause.constraint.limit,
+            },
       );
     throw cause;
   }
@@ -112,12 +123,14 @@ export const decodeOid = (content: Buffer): string => {
     case "empty":
       return fail("Empty OBJECT IDENTIFIER.");
     case "byte-limit":
-      return fail(
+      throw new PeCertificateAsn1Failure(
         `OBJECT IDENTIFIER exceeds ${String(decoded.error.limit)} bytes.`,
+        { allowance: "oid-bytes", limit: decoded.error.limit },
       );
     case "arc-limit":
-      return fail(
+      throw new PeCertificateAsn1Failure(
         `OBJECT IDENTIFIER arc exceeds ${String(decoded.error.limit)} bytes.`,
+        { allowance: "oid-arc-bytes", limit: decoded.error.limit },
       );
     case "non-minimal":
       return fail("Non-minimal OBJECT IDENTIFIER component.");

src/native/pe/PeCertificatesProvider.test.ts

@@ -0,0 +1,132 @@
+import { writeFile } from "node:fs/promises";
+import { join } from "node:path";
+import { expect, it } from "vitest";
+import { createTestTempDirectory } from "../../../tests/fixtures/temporaryDirectory.js";
+import { repeatedCertificateSignedData } from "../../../tests/fixtures/peCertificateAllowance.js";
+import {
+  indefinite,
+  tlv,
+  signedDataBlock,
+  signerInfo,
+  LEAF_CERTIFICATE,
+} from "../../../tests/fixtures/apkSignature/v1SignatureBlock.js";
+import { inspectPeCertificatesInputSchema } from "../../domain/native/peCertificates.js";
+import {
+  AnalysisInputError,
+  AnalysisResourceConstraintError,
+} from "../../domain/analysisErrorCore.js";
+import { peCertificateFixture } from "./PeCertificates.fixture.js";
+import { PeCertificatesProvider } from "./PeCertificatesProvider.js";
+
+const encapsulated = (depth: number): Buffer => {
+  let content = tlv(0x04, Uint8Array.of(1));
+  for (let level = 0; level < depth; level += 1)
+    content = indefinite(0x24, content);
+  return Buffer.from(
+    signedDataBlock({
+      certificates: [LEAF_CERTIFICATE],
+      signerInfos: [signerInfo({ names: LEAF_CERTIFICATE })],
+      encapsulatedContent: content,
+    }),
+  );
+};
+
+const inspect = async (payload: Buffer) => {
+  const path = join(
+    await createTestTempDirectory("rea-pe-decoder-allowance-"),
+    "inert.exe",
+  );
+  await writeFile(path, peCertificateFixture(false, payload));
+  const provider = new PeCertificatesProvider();
+  try {
+    return await provider.inspect(
+      inspectPeCertificatesInputSchema.parse({ path }),
+    );
+  } finally {
+    await provider.close();
+  }
+};
+
+it.each([
+  {
+    name: "depth",
+    payload: () => encapsulated(40),
+    limits: { max_asn1_depth: 32 },
+    description: "32 nesting levels",
+  },
+  {
+    name: "nodes",
+    payload: () => repeatedCertificateSignedData(600),
+    limits: { max_asn1_values: 16_384 },
+    description: "16384 values",
+  },
+  {
+    name: "text",
+    payload: () => repeatedCertificateSignedData(350),
+    limits: { max_decoded_text_bytes: 65_536 },
+    description: "65536 bytes",
+  },
+])(
+  "reports the fixed $name allowance with its own resource and recovery",
+  async ({ payload, limits, description }) => {
+    const result = await inspect(payload());
+    expect(result.ok).toBe(false);
+    if (result.ok) throw new Error("Expected decoder refusal");
+    expect(result.error).toBeInstanceOf(AnalysisResourceConstraintError);
+    if (!(result.error instanceof AnalysisResourceConstraintError))
+      throw result.error;
+    expect(result.error.reportedLimits).toEqual(limits);
+    expect(result.error.retryable).toBe(false);
+    expect(result.error.fixedAllowance?.name).toContain(description);
+    expect(result.error.fixedAllowance?.name).toContain("no runtime override");
+  },
+);
+
+it("accepts shallower valid BER and keeps malformed BER an input failure", async () => {
+  expect((await inspect(encapsulated(1))).ok).toBe(true);
+  const malformed = await inspect(Buffer.from([0x30, 0x03, 0x05]));
+  expect(malformed.ok).toBe(false);
+  if (malformed.ok) throw new Error("Expected malformed input refusal");
+  expect(malformed.error).toBeInstanceOf(AnalysisInputError);
+});
+
+it.each([
+  {
+    name: "bytes",
+    content: Buffer.from([0x2a, ...Array<number>(256).fill(0)]),
+    limits: { max_oid_bytes: 256 },
+  },
+  {
+    name: "arc bytes",
+    content: Buffer.from([0x2a, 0x81, ...Array<number>(31).fill(0x80), 0]),
+    limits: { max_oid_arc_bytes: 32 },
+  },
+])(
+  "preserves the canonical OID $name allowance in a valid CMS algorithm",
+  async ({ content, limits }) => {
+    const algorithm = tlv(0x06, content);
+    const result = await inspect(
+      Buffer.from(
+        signedDataBlock({
+          certificates: [LEAF_CERTIFICATE],
+          signerInfos: [
+            signerInfo({
+              names: LEAF_CERTIFICATE,
+              digestAlgorithmOid: algorithm,
+            }),
+          ],
+          digestAlgorithmOid: algorithm,
+        }),
+      ),
+    );
+    expect(result.ok).toBe(false);
+    if (result.ok) throw new Error("Expected OID allowance refusal");
+    expect(result.error).toBeInstanceOf(AnalysisResourceConstraintError);
+    if (!(result.error instanceof AnalysisResourceConstraintError))
+      throw result.error;
+    expect(result.error.reportedLimits).toEqual(limits);
+    expect(result.error.retryable).toBe(false);
+    expect(result.error.fixedAllowance?.name).toContain("OBJECT IDENTIFIER");
+    expect(result.error.fixedAllowance?.name).toContain("no runtime override");
+  },
+);

src/native/pe/PeCertificatesProvider.ts

@@ -105,24 +105,40 @@ const inputBudgetRemediation = (
 const decoderAllowanceFailure = (
   cause: PeCertificateAsn1Failure,
   { allowance, limit }: PeCertificateDecodeAllowance,
-) =>
-  new AnalysisResourceConstraintError(
+) => {
+  const selected = {
+    "asn1-nodes": {
+      limits: { max_asn1_values: limit },
+      description: `The PE certificate ASN.1 allowance of ${String(limit)} values per PKCS#7 payload (this release has no runtime override)`,
+    },
+    "asn1-depth": {
+      limits: { max_asn1_depth: limit },
+      description: `The PE certificate ASN.1 allowance of ${String(limit)} nesting levels per PKCS#7 payload (this release has no runtime override)`,
+    },
+    "decoded-text": {
+      limits: { max_decoded_text_bytes: limit },
+      description: `The PE certificate decoded-text allowance of ${String(limit)} bytes per PKCS#7 payload (this release has no runtime override)`,
+    },
+    "oid-bytes": {
+      limits: { max_oid_bytes: limit },
+      description: `The PE certificate OBJECT IDENTIFIER allowance of ${String(limit)} bytes per OID (this release has no runtime override)`,
+    },
+    "oid-arc-bytes": {
+      limits: { max_oid_arc_bytes: limit },
+      description: `The PE certificate OBJECT IDENTIFIER allowance of ${String(limit)} bytes per base-128 arc (this release has no runtime override)`,
+    },
+  }[allowance];
+  return new AnalysisResourceConstraintError(
     OPERATION,
     "memory",
     `PKCS#7 signedData exceeds a fixed decoder allowance: ${cause.message}`,
-    allowance === "asn1-nodes"
-      ? { max_asn1_values: limit }
-      : { max_decoded_text_bytes: limit },
+    selected.limits,
     {
       cause,
-      ...fixedAllowanceOptions(
-        allowance === "asn1-nodes"
-          ? `The PE certificate ASN.1 allowance of ${String(limit)} values per PKCS#7 payload (this release has no runtime override)`
-          : `The PE certificate decoded-text allowance of ${String(limit)} bytes per PKCS#7 payload (this release has no runtime override)`,
-        "parser",
-      ),
+      ...fixedAllowanceOptions(selected.description, "parser"),
     },
   );
+};
 
 const peCertificatesFailurePrimary = (
   facts: ArtifactFilePrimaryFacts,

src/python/PythonPycParser.test.ts

@@ -407,30 +407,6 @@ it("charges long digits to the string budget and keeps large previews bounded",
   );
 });
 
-it("reads marshal one-byte string tags as Latin-1 with Unicode identity", () => {
-  for (const tag of [0x61, 0x41, 0x7a, 0x5a]) {
-    const encoded = Buffer.concat([
-      Buffer.from([tag]),
-      tag === 0x61 || tag === 0x41 ? u32(1) : Buffer.from([1]),
-      Buffer.from([0xe9]),
-    ]);
-    const sameUnicode = marshalUnicode(Buffer.from("é", "utf8"));
-    const set = Buffer.concat([
-      Buffer.from([0x3c]),
-      u32(2),
-      encoded,
-      sameUnicode,
-    ]);
-    const report = root(parse(withConsts([encoded, set])));
-    expect(report.consts[0]).toMatchObject({
-      kind: "str",
-      value: "é",
-      bytes: 1,
-    });
-    expect(report.consts[1]).toEqual({ kind: "set", length: 1 });
-  }
-});
-
 it("decodes marshal strings with CPython surrogatepass rules", () => {
   const report = parse(
     withConsts([marshalUnicode(Buffer.from("efbbbf73eda080efbbbf", "hex"))]),
@@ -1558,36 +1534,6 @@ it("hashes a long TYPE_REF tuple chain without recursing", () => {
   expect(pythonPycSchema.safeParse(report).success).toBe(true);
 });
 
-it("hashes shallow TYPE_REF code chains without using the JavaScript stack", () => {
-  const links = 3000;
-  const codes = Array.from({ length: links }, (_, index) =>
-    marshalCode("py311", {
-      flagged: true,
-      name: "f",
-      consts: index === 0 ? [Buffer.from([0x4e])] : [marshalRef(index - 1)],
-    }),
-  );
-  const bytes = Buffer.concat([
-    pythonPycHeader(3531),
-    marshalCode("py311", {
-      constsObject: Buffer.concat([
-        Buffer.from([0x28]),
-        u32(links + 1),
-        ...codes,
-        Buffer.from([0x3c]),
-        u32(1),
-        marshalRef(links - 1),
-      ]),
-    }),
-  ]);
-  const report = parseWith(bytes, { max_objects: 65_536 });
-  expect(root(report).consts.at(-1)).toEqual({ kind: "set", length: 1 });
-  expect(report.coverage).toMatchObject({
-    status: "complete",
-    code_objects: links + 1,
-  });
-});
-
 it("rejects code CPython treats as corrupt instead of complete coverage", () => {
   const file = (
     layout: "py37" | "py38" | "py311",

src/python/PythonPycParser.ts

@@ -332,7 +332,7 @@ class MarshalReader {
   readonly #codeKeys = new WeakMap<CodeNode, string>();
   readonly #codeIdentities = new WeakMap<CodeNode, number>();
   readonly #codeEquality = new WeakMap<CodeNode, CodeEquality>();
-  /** Completed Python hashability checks per code object. */
+  /** Python hashability per code object. False while that check is in progress. */
   readonly #codeHashable = new WeakMap<CodeNode, boolean>();
   /** Tuples whose items are still being read; CPython cannot hash them yet. */
   readonly #readingTuples = new WeakSet<MarshalValue>();
@@ -436,19 +436,13 @@ class MarshalReader {
         };
       case TYPE_INTERNED:
       case TYPE_UNICODE:
-        return this.string(
-          this.nonNegativeInt32("Marshal string length"),
-          "utf8",
-        );
+        return this.utf8(this.nonNegativeInt32("Marshal string length"), false);
       case TYPE_ASCII:
       case TYPE_ASCII_INTERNED:
-        return this.string(
-          this.nonNegativeInt32("Marshal string length"),
-          "latin1",
-        );
+        return this.utf8(this.nonNegativeInt32("Marshal string length"), true);
       case TYPE_SHORT_ASCII:
       case TYPE_SHORT_ASCII_INTERNED:
-        return this.string(this.u8(), "latin1");
+        return this.utf8(this.u8(), true);
       case TYPE_TUPLE:
         return this.sequenceValue(
           "tuple",
@@ -1315,70 +1309,13 @@ class MarshalReader {
   #isCodeHashable(node: CodeNode): boolean {
     const known = this.#codeHashable.get(node);
     if (known !== undefined) return known;
-    const frames: { value: MarshalValue; finish: boolean }[] = [
-      { value: { kind: "code", value: node }, finish: false },
-    ];
-    const gray = new Set<MarshalValue | CodeNode>();
-    const complete = new Set<MarshalValue>();
-    const reject = (): false => {
-      this.#codeHashable.set(node, false);
-      return false;
-    };
-    while (frames.length > 0) {
-      this.#takeKeyStep();
-      const frame = frames.pop()!;
-      const value = frame.value;
-      const identity = value.kind === "code" ? value.value : value;
-      if (frame.finish) {
-        gray.delete(identity);
-        if (value.kind === "code") {
-          const material =
-            this.#codeEquality.get(value.value) ??
-            malformed("Code object is missing equality material.");
-          // Child code checks are now complete, so the existing tuple key
-          // walker preserves its equality and expansion budgets without recursion.
-          const hashable =
-            this.#equalityKey(material.constsTuple, "hash") !== null;
-          this.#codeHashable.set(value.value, hashable);
-          if (!hashable) return reject();
-        } else complete.add(value);
-        continue;
-      }
-      if (value.kind === "code") {
-        const cached = this.#codeHashable.get(value.value);
-        if (cached === false) return reject();
-        if (cached === true) continue;
-      } else {
-        const cached = this.#keyCache.get(value);
-        if (cached === null) return reject();
-        if (cached !== undefined || complete.has(value)) continue;
-      }
-      if (
-        gray.has(identity) ||
-        this.#readingTuples.has(value) ||
-        value.kind === "list" ||
-        value.kind === "set" ||
-        value.kind === "dict" ||
-        value.kind === "null"
-      )
-        return reject();
-      const children =
-        value.kind === "code"
-          ? [
-              (
-                this.#codeEquality.get(value.value) ??
-                malformed("Code object is missing equality material.")
-              ).constsTuple,
-            ]
-          : value.kind === "tuple" || value.kind === "frozenset"
-            ? value.items
-            : [];
-      gray.add(identity);
-      frames.push({ value, finish: true });
-      for (let index = children.length - 1; index >= 0; index -= 1)
-        frames.push({ value: children[index]!, finish: false });
-    }
-    return true;
+    this.#codeHashable.set(node, false);
+    const material =
+      this.#codeEquality.get(node) ??
+      malformed("Code object is missing equality material.");
+    const hashable = this.#equalityKey(material.constsTuple, "hash") !== null;
+    this.#codeHashable.set(node, hashable);
+    return hashable;
   }
 
   #codeIdentity(node: CodeNode): number {
@@ -1555,20 +1492,17 @@ class MarshalReader {
     );
   }
 
-  string(length: number, encoding: "latin1" | "utf8"): MarshalValue {
+  utf8(length: number, ascii: boolean): MarshalValue {
     const bytes = this.blob(length);
-    if (encoding === "latin1") {
-      // CPython reads the ASCII-tagged forms as one-byte Unicode, even when
-      // high bytes appear. Identity must agree with the UTF-8 string form.
-      const value = bytes.toString("latin1");
+    if (ascii) {
+      if (bytes.some((byte) => byte > 0x7f))
+        malformed("Marshal ASCII string contains a non-ASCII byte.");
       return {
         kind: "str",
-        value,
+        value: bytes.toString("latin1"),
         previewEnd: Math.min(length, PYTHON_PYC_CONST_PREVIEW_LIMIT),
         bytes: length,
-        raw: bytes.some((byte) => byte > 0x7f)
-          ? Buffer.from(value, "utf8")
-          : bytes,
+        raw: bytes,
       };
     }
     const decoded = decodeMarshalUtf8(bytes, PYTHON_PYC_CONST_PREVIEW_LIMIT);

tests/fixtures/apkSignature/v1SignatureBlock.ts

@@ -230,12 +230,15 @@ export interface SignerInfoSpec {
    * from the certificate named by `names`.
    */
   readonly serial?: Uint8Array;
+  /** Complete digest algorithm OID TLV, including bounded-parser fixtures. */
+  readonly digestAlgorithmOid?: Uint8Array;
 }
 
 export const signerInfo = ({
   names,
   signature,
   serial,
+  digestAlgorithmOid,
 }: SignerInfoSpec): Uint8Array =>
   tlv(
     0x30,
@@ -244,7 +247,7 @@ export const signerInfo = ({
       names,
       serial === undefined ? undefined : tlv(0x02, serial),
     ),
-    algorithm(OID_SHA256),
+    tlv(0x30, digestAlgorithmOid ?? oid(OID_SHA256)),
     algorithm(OID_ECDSA_SHA256),
     signature ?? tlv(0x04, Uint8Array.from([1, 2, 3])),
   );
@@ -254,6 +257,8 @@ export const signedDataBlock = (options: {
   readonly certificates: readonly Uint8Array[];
   readonly signerInfos: readonly Uint8Array[];
   readonly contentType?: string;
+  readonly encapsulatedContent?: Uint8Array;
+  readonly digestAlgorithmOid?: Uint8Array;
 }): Uint8Array =>
   tlv(
     0x30,
@@ -263,8 +268,14 @@ export const signedDataBlock = (options: {
       tlv(
         0x30,
         integer(1),
-        tlv(0x31, algorithm(OID_SHA256)),
-        tlv(0x30, oid("1.2.840.113549.1.7.1")),
+        tlv(0x31, tlv(0x30, options.digestAlgorithmOid ?? oid(OID_SHA256))),
+        tlv(
+          0x30,
+          oid("1.2.840.113549.1.7.1"),
+          ...(options.encapsulatedContent === undefined
+            ? []
+            : [tlv(0xa0, options.encapsulatedContent)]),
+        ),
         tlv(0xa0, ...options.certificates),
         tlv(0x31, ...options.signerInfos),
       ),