The new updates system, relies on gh-pages, secured by RSA, uses external web servers

devscripts/transition_helper_exe/youtube-dl.py

@@ -2,17 +2,48 @@
 
 import sys, os
 import urllib2
+import json, hashlib
+
+def rsa_verify(message, signature, key):
+    from struct import pack
+    from hashlib import sha256
+    from sys import version_info
+    def b(x):
+        if version_info[0] == 2: return x
+        else: return x.encode('latin1')
+    assert(type(message) == type(b('')))
+    block_size = 0
+    n = key[0]
+    while n:
+        block_size += 1
+        n >>= 8
+    signature = pow(int(signature, 16), key[1], key[0])
+    raw_bytes = []
+    while signature:
+        raw_bytes.insert(0, pack("B", signature & 0xFF))
+        signature >>= 8
+    signature = (block_size - len(raw_bytes)) * b('\x00') + b('').join(raw_bytes)
+    if signature[0:2] != b('\x00\x01'): return False
+    signature = signature[2:]
+    if not b('\x00') in signature: return False
+    signature = signature[signature.index(b('\x00'))+1:]
+    if not signature.startswith(b('\x30\x31\x30\x0D\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x01\x05\x00\x04\x20')): return False
+    signature = signature[19:]
+    if signature != sha256(message).digest(): return False
+    return True
 
 sys.stderr.write(u'Hi! We changed distribution method and now youtube-dl needs to update itself one more time.\n')
 sys.stderr.write(u'This will only happen once. Simply press enter to go on. Sorry for the trouble!\n')
-sys.stderr.write(u'The new location of the binaries is https://github.com/rg3/youtube-dl/downloads, not the git repository.\n\n')
+sys.stderr.write(u'From now on, get the binaries from http://rg3.github.com/youtube-dl/download.html, not from the git repository.\n\n')
 
 raw_input()
 
 filename = sys.argv[0]
 
-API_URL = "https://api.github.com/repos/rg3/youtube-dl/downloads"
-EXE_URL = "https://github.com/downloads/rg3/youtube-dl/youtube-dl.exe"
+UPDATE_URL = "http://rg3.github.com/youtube-dl/update/"
+VERSION_URL = UPDATE_URL + 'LATEST_VERSION'
+JSON_URL = UPDATE_URL + 'versions.json'
+UPDATES_RSA_KEY = (0x9d60ee4d8f805312fdb15a62f87b95bd66177b91df176765d13514a0f1754bcd2057295c5b6f1d35daa6742c3ffc9a82d3e118861c207995a8031e151d863c9927e304576bc80692bc8e094896fcf11b66f3e29e04e3a71e9a11558558acea1840aec37fc396fb6b65dc81a1c4144e03bd1c011de62e3f1357b327d08426fe93, 65537)
 
 if not os.access(filename, os.W_OK):
     sys.exit('ERROR: no write permissions on %s' % filename)
@@ -23,13 +54,35 @@ if not os.access(directory, os.W_OK):
     sys.exit('ERROR: no write permissions on %s' % directory)
 
 try:
-    urlh = urllib2.urlopen(EXE_URL)
+    versions_info = urllib2.urlopen(JSON_URL).read().decode('utf-8')
+    versions_info = json.loads(versions_info)
+except:
+    sys.exit(u'ERROR: can\'t obtain versions info. Please try again later.')
+if not 'signature' in versions_info:
+    sys.exit(u'ERROR: the versions file is not signed or corrupted. Aborting.')
+signature = versions_info['signature']
+del versions_info['signature']
+if not rsa_verify(json.dumps(versions_info, sort_keys=True), signature, UPDATES_RSA_KEY):
+    sys.exit(u'ERROR: the versions file signature is invalid. Aborting.')
+
+version = versions_info['versions'][versions_info['latest']]
+
+try:
+    urlh = urllib2.urlopen(version['exe'][0])
     newcontent = urlh.read()
     urlh.close()
+except (IOError, OSError) as err:
+    sys.exit('ERROR: unable to download latest version')
+
+newcontent_hash = hashlib.sha256(newcontent).hexdigest()
+if newcontent_hash != version['exe'][1]:
+    sys.exit(u'ERROR: the downloaded file hash does not match. Aborting.')
+
+try:
     with open(exe + '.new', 'wb') as outf:
         outf.write(newcontent)
 except (IOError, OSError) as err:
-    sys.exit('ERROR: unable to download latest version')
+    sys.exit(u'ERROR: unable to write the new version')
 
 try:
     bat = os.path.join(directory, 'youtube-dl-updater.bat')