build: add hashes to the external binary downloader

script/external-binaries.json

@@ -4,37 +4,45 @@
   "binaries": [
     {
       "url": "Mantle.zip",
-      "platform": "darwin"
+      "platform": "darwin",
+      "sha": "f9865e115c03871b45d3a2d8734220cb147a02dace46c92f766ca5d3059281dd"
     },
     {
       "url": "ReactiveCocoa.zip",
-      "platform": "darwin"
+      "platform": "darwin",
+      "sha": "8ae85cd226fa4076472bfdfcda4745b5c7edf31fbe695868068eeaf62e7fa962"
     },
     {
       "url": "Squirrel.zip",
-      "platform": "darwin"
+      "platform": "darwin",
+      "sha": "e516fd5c24c0ad267fd854848b04be0552be977aa846fa7f3c65ef4618699511"
     },
     {
       "url": "directxsdk-ia32.zip",
       "platform": "win32",
-      "targetArch": "ia32"
+      "targetArch": "ia32",
+      "sha": "f777bd5ab524bf39c3bfc68ac2b3f95ff2136c92328cf63e857f399e849db037"
     },
     {
       "url": "directxsdk-x64.zip",
       "platform": "win32",
-      "targetArch": "x64"
+      "targetArch": "x64",
+      "sha": "46c1f8afb9180516013c39e8d73182a7f15f0ea89c61dc94f92605b4734d447b"
     },
     {
       "url": "sccache-darwin-x64.zip",
-      "platform": "darwin"
+      "platform": "darwin",
+      "sha": "3bfe114b49a15e4f15e2e3a9ee6699f1acdb89446badbaa4144869c72a7690ca"
     },
     {
       "url": "sccache-linux-x64.zip",
-      "platform": "linux"
+      "platform": "linux",
+      "sha": "dd379b494122f9e85bdae3597b02c67b0a46192f20f4f16cae3f1258a57b39dd"
     },
     {
       "url": "sccache-win32-x64.zip",
-      "platform": "win32"
+      "platform": "win32",
+      "sha": "b6a20fd1c2026f3792e7286bc768a7ebc261847b76449b49f55455e1f841fecd"
     }
   ]
 }

script/update-external-binaries.py

@@ -2,6 +2,7 @@
 
 import argparse
 import errno
+import hashlib
 import json
 import os
 
@@ -17,6 +18,7 @@ def parse_args():
 
   parser.add_argument('--base-url', required=False,
                       help="Base URL for all downloads")
+  parser.add_argument('--force', action='store_true', default=False, required=False)
 
   return parser.parse_args()
 
@@ -37,7 +39,7 @@ def main():
   output_dir = os.path.join(SOURCE_ROOT, 'external_binaries')
   version_file = os.path.join(output_dir, '.version')
 
-  if (is_updated(version_file, version)):
+  if (is_updated(version_file, version) and not args.force):
     return
 
   rm_rf(output_dir)
@@ -47,7 +49,7 @@ def main():
     if not binary_should_be_downloaded(binary):
       continue
 
-    temp_path = download_binary(base_url, version, binary['url'])
+    temp_path = download_binary(base_url, version, binary['url'], binary['sha'])
 
     # We assume that all binaries are in zip archives.
     extract_zip(temp_path, output_dir)
@@ -82,16 +84,31 @@ def binary_should_be_downloaded(binary):
   return True
 
 
-def download_binary(base_url, version, binary_url):
+def sha256(file_path):
+  hash_256 = hashlib.sha256()
+  with open(file_path, "rb") as f:
+      for chunk in iter(lambda: f.read(4096), b""):
+          hash_256.update(chunk)
+  return hash_256.hexdigest()
+
+
+def download_binary(base_url, version, binary_url, sha):
   full_url = '{0}/{1}/{2}'.format(base_url, version, binary_url)
-  temp_path = download_to_temp_dir(full_url, filename=binary_url)
+  temp_path = download_to_temp_dir(full_url, filename=binary_url, sha=sha)
   return temp_path
 
 
-def download_to_temp_dir(url, filename):
+def validate_sha(file_path, sha):
+  downloaded_sha = sha256(file_path)
+  if downloaded_sha != sha:
+    raise Exception("SHA for external binary file {} does not match expected '{}' != '{}'".format(file_path, downloaded_sha, sha))
+
+
+def download_to_temp_dir(url, filename, sha):
   download_dir = tempdir(prefix='electron-')
   file_path = os.path.join(download_dir, filename)
   download(text='Download ' + filename, url=url, path=file_path)
+  validate_sha(file_path, sha)
   return file_path