changeset 29258:6315c1e14f75

sslutil: introduce a function for determining host-specific settings This patch marks the beginning of a series that introduces a new, more configurable, per-host security settings mechanism. Currently, we have global settings (like web.cacerts and the --insecure argument). We also have per-host settings via [hostfingerprints]. Global security settings are good for defaults, but they don't provide the amount of control often wanted. For example, an organization may want to require a particular CA is used for a particular hostname. [hostfingerprints] is nice. But it currently assumes SHA-1. Furthermore, there is no obvious place to put additional per-host settings. Subsequent patches will be introducing new mechanisms for defining security settings, some on a per-host basis. This commits starts the transition to that world by introducing the _hostsettings function. It takes a ui and hostname and returns a dict of security settings. Currently, it limits itself to returning host fingerprint info. We foreshadow the future support of non-SHA1 hashing algorithms for verifying the host fingerprint by making the "certfingerprints" key a list of tuples instead of a list of hashes. We add this dict to the hgstate property on the socket and use it during socket validation for checking fingerprints. There should be no change in behavior.
author Gregory Szorc <gregory.szorc@gmail.com>
date Sat, 28 May 2016 11:12:02 -0700
parents 9da137faaa9c
children ec247e8595f9
files mercurial/sslutil.py
diffstat 1 files changed, 22 insertions(+), 5 deletions(-) [+]
line wrap: on
line diff
--- a/mercurial/sslutil.py	Wed May 25 19:57:31 2016 -0700
+++ b/mercurial/sslutil.py	Sat May 28 11:12:02 2016 -0700
@@ -106,6 +106,23 @@
 
             return ssl.wrap_socket(socket, **args)
 
+def _hostsettings(ui, hostname):
+    """Obtain security settings for a hostname.
+
+    Returns a dict of settings relevant to that hostname.
+    """
+    s = {
+        # List of 2-tuple of (hash algorithm, hash).
+        'certfingerprints': [],
+    }
+
+    # Fingerprints from [hostfingerprints] are always SHA-1.
+    for fingerprint in ui.configlist('hostfingerprints', hostname, []):
+        fingerprint = fingerprint.replace(':', '').lower()
+        s['certfingerprints'].append(('sha1', fingerprint))
+
+    return s
+
 def _determinecertoptions(ui, host):
     """Determine certificate options for a connections.
 
@@ -217,6 +234,7 @@
     sslsocket._hgstate = {
         'caloaded': caloaded,
         'hostname': serverhostname,
+        'settings': _hostsettings(ui, serverhostname),
         'ui': ui,
     }
 
@@ -292,6 +310,7 @@
     """
     host = sock._hgstate['hostname']
     ui = sock._hgstate['ui']
+    settings = sock._hgstate['settings']
 
     try:
         peercert = sock.getpeercert(True)
@@ -305,15 +324,13 @@
 
     # If a certificate fingerprint is pinned, use it and only it to
     # validate the remote cert.
-    hostfingerprints = ui.configlist('hostfingerprints', host)
     peerfingerprint = util.sha1(peercert).hexdigest()
     nicefingerprint = ":".join([peerfingerprint[x:x + 2]
         for x in xrange(0, len(peerfingerprint), 2)])
-    if hostfingerprints:
+    if settings['certfingerprints']:
         fingerprintmatch = False
-        for hostfingerprint in hostfingerprints:
-            if peerfingerprint.lower() == \
-                    hostfingerprint.replace(':', '').lower():
+        for hash, fingerprint in settings['certfingerprints']:
+            if peerfingerprint.lower() == fingerprint:
                 fingerprintmatch = True
                 break
         if not fingerprintmatch: