sslutil: calculate host fingerprints from additional algorithms

Currently, we only support defining host fingerprints with SHA-1.
A future patch will introduce support for defining fingerprints
using other hashing algorithms. In preparation for that, we
rewrite the fingerprint verification code to support multiple
fingerprints, namely SHA-256 and SHA-512 fingerprints.

We still only display the SHA-1 fingerprint. We'll have to revisit
this code once we support defining fingerprints with other hash
functions.

As part of this, I snuck in a change to use range() instead of
xrange() because xrange() isn't necessary for such small values.

mercurial/sslutil.py

@@ -327,13 +327,18 b' def validatesocket(sock, strict=False):'
 
     # If a certificate fingerprint is pinned, use it and only it to
     # validate the remote cert.
-    peerfingerprint = util.sha1(peercert).hexdigest()
-    nicefingerprint = ":".join([peerfingerprint[x:x + 2]
-        for x in xrange(0, len(peerfingerprint), 2)])
+    peerfingerprints = {
+        'sha1': util.sha1(peercert).hexdigest(),
+        'sha256': util.sha256(peercert).hexdigest(),
+        'sha512': util.sha512(peercert).hexdigest(),
+    }
+    nicefingerprint = ':'.join([peerfingerprints['sha1'][x:x + 2]
+        for x in range(0, len(peerfingerprints['sha1']), 2)])
+
     if settings['certfingerprints']:
         fingerprintmatch = False
         for hash, fingerprint in settings['certfingerprints']:
-            if peerfingerprint.lower() == fingerprint:
+            if peerfingerprints[hash].lower() == fingerprint:
                 fingerprintmatch = True
                 break
         if not fingerprintmatch: