test(linux): reject a wrong-architecture native binary at packaging time

Cross-building the arm64 slice on an x64 host silently packed an x86-64
`pty.node` -- the rebuild logged "Forcing native rebuild for linux-arm64" and
shipped the host's binary anyway. Every gate here inspects symbol versions,
which are perfectly valid on the wrong architecture, so nothing noticed.

Observed on a Raspberry Pi 5: the packaged app loaded, then failed with
"Failed to load native module: pty.node", and the launch contract reported
3 of 8 cases crashed rather than naming the cause. Swapping in the aarch64
`pty.node` took the same build to 8/8.

Compare ELF `e_machine` against the slice being packaged and fail with the
offending path. Checked before the glibc pass, because a wrong-architecture
binary's symbol versions are valid but meaningless and would send the reader
down the wrong path.

Release CI builds arm64 on a native runner, so this guards local and future
cross-builds rather than a shipped artifact.

config/electron-builder.config.cjs

@@ -242,7 +242,11 @@ module.exports = {
     // requiring GLIBC_2.34, crashing the app on startup on Ubuntu 20.04 (#9902).
     // Fail packaging if any bundled native binary exceeds the supported floor.
     if (context.electronPlatformName === 'linux') {
-      verifyLinuxGlibcFloor(context.appOutDir)
+      // Why the arch is passed: symbol-version checks pass happily on a wrong-architecture binary,
+      // so a cross-built slice could ship the host's pty.node and only fail at runtime.
+      verifyLinuxGlibcFloor(context.appOutDir, {
+        targetArch: { 1: 'x64', 3: 'arm64' }[context.arch]
+      })
     }
     const resourcesDir =
       context.electronPlatformName === 'darwin'

config/scripts/verify-linux-glibc-floor.cjs

@@ -164,6 +164,53 @@ function findMissingProviderDeps(importedSymbols, neededLibraries) {
   return missing
 }
 
+// ELF e_machine values for the Linux slices we package. Names match electron-builder's Arch enum.
+const ELF_MACHINE_BY_ARCH = Object.freeze({ x64: 0x3e, arm64: 0xb7 })
+const ARCH_BY_ELF_MACHINE = Object.freeze({ 0x3e: 'x64', 0xb7: 'arm64' })
+
+/**
+ * ELF `e_machine`, or null when the file is not a readable little-endian ELF.
+ *
+ * Why this is checked at all: cross-building an arm64 package on an x64 host can silently pack an
+ * x86-64 `pty.node` into the arm64 slice — the rebuild logs a forced arm64 rebuild and still ships
+ * the host's binary. Every other gate here inspects symbol versions, which are perfectly valid on
+ * the wrong architecture, so nothing noticed. Observed on a Raspberry Pi 5: the app loaded, then
+ * failed with "Failed to load native module: pty.node".
+ */
+function readElfMachine(filePath) {
+  let fd
+  try {
+    fd = openSync(filePath, 'r')
+    const header = Buffer.alloc(20)
+    if (readSync(fd, header, 0, 20, 0) !== 20) {
+      return null
+    }
+    // EI_DATA (offset 5) must be ELFDATA2LSB for a little-endian e_machine read.
+    if (header[5] !== 1) {
+      return null
+    }
+    return header.readUInt16LE(18)
+  } catch {
+    return null
+  } finally {
+    if (fd !== undefined) {
+      closeSync(fd)
+    }
+  }
+}
+
+function findArchViolation(filePath, targetArch) {
+  const expected = ELF_MACHINE_BY_ARCH[targetArch]
+  if (expected === undefined) {
+    return null
+  }
+  const machine = readElfMachine(filePath)
+  if (machine === null || machine === expected) {
+    return null
+  }
+  return { machine, actual: ARCH_BY_ELF_MACHINE[machine] ?? `0x${machine.toString(16)}` }
+}
+
 function isElfFile(filePath) {
   let fd
   try {
@@ -312,6 +359,7 @@ function readImportedSymbols(filePath, objdumpPath) {
  */
 function verifyLinuxGlibcFloor(rootDir, options = {}) {
   const binaries = collectNativeBinaries(rootDir)
+  const targetArch = options.targetArch
   if (binaries.length === 0) {
     console.log(`[verify-linux-glibc-floor] OK — no bundled native binaries under ${rootDir}`)
     return
@@ -327,6 +375,27 @@ function verifyLinuxGlibcFloor(rootDir, options = {}) {
     )
   }
 
+  // Why before the glibc pass: a wrong-architecture binary's symbol versions are valid but
+  // meaningless, so reporting a floor violation for it would send the reader down the wrong path.
+  const archOffenders = binaries
+    .map((filePath) => ({ filePath, violation: findArchViolation(filePath, targetArch) }))
+    .filter(({ violation }) => violation !== null)
+  if (archOffenders.length > 0) {
+    const detail = archOffenders
+      .map(
+        ({ filePath, violation }) =>
+          `  ${relative(rootDir, filePath) || filePath} is ${violation.actual}`
+      )
+      .join('\n')
+    throw new Error(
+      `[verify-linux-glibc-floor] ${archOffenders.length} bundled native binar` +
+        `${archOffenders.length === 1 ? 'y is' : 'ies are'} built for the wrong architecture ` +
+        `(target ${targetArch}), so the app will fail to load them at runtime:\n${detail}\n` +
+        'Cross-building a Linux slice can pack the host architecture despite a forced rebuild; ' +
+        'build this slice on a native runner.'
+    )
+  }
+
   const offenders = []
   for (const filePath of binaries) {
     const { versionNeeds, neededLibraries } = readDynamicInfo(filePath, objdumpPath)
@@ -375,6 +444,9 @@ function verifyLinuxGlibcFloor(rootDir, options = {}) {
 
 module.exports = {
   MIN_GLIBC,
+  ELF_MACHINE_BY_ARCH,
+  readElfMachine,
+  findArchViolation,
   VERSION_FLOORS,
   FLOOR_LABEL,
   RELOCATED_SYMBOL_PROVIDERS,

config/scripts/verify-linux-glibc-floor.test.mjs

@@ -6,6 +6,9 @@ import { describe, expect, it } from 'vitest'
 
 const require = createRequire(import.meta.url)
 const {
+  readElfMachine,
+  findArchViolation,
+  ELF_MACHINE_BY_ARCH,
   parseGlibcVersion,
   compareGlibcVersions,
   parseVersionNeeds,
@@ -321,3 +324,60 @@ describe.skipIf(process.platform === 'win32')('verifyLinuxGlibcFloor', () => {
     }
   })
 })
+
+/** Minimal little-endian 64-bit ELF header with the given e_machine. */
+function elfHeader(machine) {
+  const header = Buffer.alloc(64)
+  header.write('\x7fELF', 0, 'latin1')
+  header[4] = 2 // ELFCLASS64
+  header[5] = 1 // ELFDATA2LSB
+  header[6] = 1 // EV_CURRENT
+  header.writeUInt16LE(3, 16) // ET_DYN
+  header.writeUInt16LE(machine, 18)
+  return header
+}
+
+describe('bundled native binary architecture', () => {
+  it('reads e_machine from a little-endian ELF', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'orca-elf-arch-'))
+    const file = join(dir, 'pty.node')
+    await writeFile(file, elfHeader(ELF_MACHINE_BY_ARCH.arm64))
+    expect(readElfMachine(file)).toBe(ELF_MACHINE_BY_ARCH.arm64)
+    await rm(dir, { recursive: true, force: true })
+  })
+
+  // The observed failure: cross-building arm64 on an x64 host packed an x86-64 pty.node, whose
+  // symbol versions are valid, so every other gate here passed it.
+  it('flags an x86-64 binary in an arm64 slice', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'orca-elf-arch-'))
+    const file = join(dir, 'pty.node')
+    await writeFile(file, elfHeader(ELF_MACHINE_BY_ARCH.x64))
+    expect(findArchViolation(file, 'arm64')).toMatchObject({ actual: 'x64' })
+    await rm(dir, { recursive: true, force: true })
+  })
+
+  it('accepts a matching architecture', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'orca-elf-arch-'))
+    const file = join(dir, 'pty.node')
+    await writeFile(file, elfHeader(ELF_MACHINE_BY_ARCH.x64))
+    expect(findArchViolation(file, 'x64')).toBeNull()
+    await rm(dir, { recursive: true, force: true })
+  })
+
+  it('stays silent when no target architecture is supplied', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'orca-elf-arch-'))
+    const file = join(dir, 'pty.node')
+    await writeFile(file, elfHeader(ELF_MACHINE_BY_ARCH.x64))
+    expect(findArchViolation(file, undefined)).toBeNull()
+    await rm(dir, { recursive: true, force: true })
+  })
+
+  it('ignores a file that is not a readable little-endian ELF', async () => {
+    const dir = await mkdtemp(join(tmpdir(), 'orca-elf-arch-'))
+    const file = join(dir, 'not-elf.node')
+    await writeFile(file, Buffer.from('not an elf at all'))
+    expect(readElfMachine(file)).toBeNull()
+    expect(findArchViolation(file, 'arm64')).toBeNull()
+    await rm(dir, { recursive: true, force: true })
+  })
+})