feat(compartment-mapper): parseArchive return hash

endojs · Feb 19, 2022 · 1306c7d · 1306c7d
1 parent 4204058
commit 1306c7d
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Showing 4 changed files with 29 additions and 10 deletions.
diff --git a/packages/compartment-mapper/NEWS.md b/packages/compartment-mapper/NEWS.md
@@ -1,5 +1,12 @@
 User-visible changes to the compartment mapper:
 
+# Next release
+
+- The `parseArchive` function returns a promise for an archive.  If provided a
+  `computeSha512`, regardless of whether provided `expectedSha512`, the archive
+  will have a `sha512` property computed from the parsed archive, for
+  the purpose of verifying integrity.
+
 # 0.5.3 (2021-12-08)
 
 - The `node-powers.js` module now exports `makeReadPowers` and

diff --git a/packages/compartment-mapper/README.md b/packages/compartment-mapper/README.md
@@ -116,6 +116,9 @@ Use `parseArchive` to construct a runner from the bytes of an archive.
 The `loadArchive` and `parseArchive` functions return an `Application`
 object with an `import({ globals?, modules? })` method.
 
+`loadArchive` and `parseArchive` do not run the archived program,
+so they can be used to check the hash of a program without running it.
+
 # Package Descriptors
 
 The compartment mapper uses [Compartments], one for each Node.js package your

diff --git a/packages/compartment-mapper/src/import-archive.js b/packages/compartment-mapper/src/import-archive.js
@@ -150,13 +150,16 @@ export const parseArchive = async (
   const archive = await readZip(archiveBytes, archiveLocation);
   const compartmentMapBytes = await archive.read('compartment-map.json');
 
+  let sha512;
+  if (computeSha512 !== undefined) {
+    sha512 = computeSha512(compartmentMapBytes);
+  }
   if (expectedSha512 !== undefined) {
-    if (computeSha512 === undefined) {
+    if (sha512 === undefined) {
       throw new Error(
         `Cannot verify expectedSha512 without also providing computeSha512, for archive ${archiveLocation}`,
       );
     }
-    const sha512 = computeSha512(compartmentMapBytes);
     if (sha512 !== expectedSha512) {
       throw new Error(
         `Archive compartment map failed a SHA-512 integrity check, expected ${expectedSha512}, got ${sha512}, for archive ${archiveLocation}`,
@@ -205,7 +208,7 @@ export const parseArchive = async (
     return compartment.import(moduleSpecifier);
   };
 
-  return { import: execute };
+  return { import: execute, sha512 };
 };
 
 /**

diff --git a/packages/compartment-mapper/test/scaffold.js b/packages/compartment-mapper/test/scaffold.js
@@ -184,7 +184,7 @@ export function scaffold(
   });
 
   test(`${name} / makeArchive / parseArchive / hashArchive consistency`, async t => {
-    t.plan(0);
+    t.plan(1);
     await setup();
 
     const expectedSha512 = await hashLocation(readPowers, fixture, {
@@ -198,12 +198,18 @@ export function scaffold(
     });
 
     const { computeSha512 } = readPowers;
-    await parseArchive(archiveBytes, 'memory:app.agar', {
-      modules,
-      dev: true,
-      computeSha512,
-      expectedSha512,
-    });
+    const { sha512: computedSha512 } = await parseArchive(
+      archiveBytes,
+      'memory:app.agar',
+      {
+        modules,
+        dev: true,
+        computeSha512,
+        expectedSha512,
+      },
+    );
+
+    t.is(computedSha512, expectedSha512);
   });
 
   test(`${name} / makeArchive / parseArchive, but with sha512 corruption of a compartment map`, async t => {