# HG changeset patch # User Gregory Szorc # Date 2017-03-10 04:33:29 # Node ID f819aa9dbbf947d32905076f9e461ef695906cad # Parent 718a57e95a897f4ac407ae3733a7d41e87354acb sslutil: issue warning when [hostfingerprint] is used Mercurial 3.9 added the [hostsecurity] section, which is better than [hostfingerprints] in every way. One of the ways that [hostsecurity] is better is that it supports SHA-256 and SHA-512 fingerprints, not just SHA-1 fingerprints. The world is moving away from SHA-1 because it is borderline secure. Mercurial should be part of that movement. This patch adds a warning when a valid SHA-1 fingerprint from the [hostfingerprints] section is being used. The warning informs users to switch to [hostsecurity]. It even prints the config option they should set. It uses the SHA-256 fingerprint because recommending a SHA-1 fingerprint in 2017 would be ill-advised. The warning will print itself on every connection to a server until it is fixed. There is no way to suppress the warning. I admit this is annoying. But given the security implications of sticking with SHA-1, I think this is justified. If this patch is accepted, I'll likely send a follow-up to start warning on SHA-1 certificates in [hostsecurity] as well. Then sometime down the road, we can drop support for SHA-1 fingerprints. Credit for this idea comes from timeless in issue 5466. diff --git a/mercurial/sslutil.py b/mercurial/sslutil.py --- a/mercurial/sslutil.py +++ b/mercurial/sslutil.py @@ -815,6 +815,16 @@ def validatesocket(sock): if peerfingerprints[hash].lower() == fingerprint: ui.debug('%s certificate matched fingerprint %s:%s\n' % (host, hash, fmtfingerprint(fingerprint))) + if settings['legacyfingerprint']: + ui.warn(_('(SHA-1 fingerprint for %s found in legacy ' + '[hostfingerprints] section; ' + 'if you trust this fingerprint, set the ' + 'following config value in [hostsecurity] and ' + 'remove the old one from [hostfingerprints] ' + 'to upgrade to a more secure SHA-256 ' + 'fingerprint: ' + '%s.fingerprints=%s)\n') % ( + host, host, nicefingerprint)) return # Pinned fingerprint didn't match. This is a fatal error. diff --git a/tests/test-https.t b/tests/test-https.t --- a/tests/test-https.t +++ b/tests/test-https.t @@ -382,6 +382,7 @@ Fingerprints - works without cacerts (hostfingerprints) $ hg -R copy-pull id https://localhost:$HGPORT/ --insecure --config hostfingerprints.localhost=ec:d8:7c:d6:b3:86:d0:4f:c1:b8:b4:1c:9d:8f:5e:16:8e:ef:1c:03 warning: connecting to localhost using legacy security technology (TLS 1.0); see https://mercurial-scm.org/wiki/SecureConnections for more info (?) + (SHA-1 fingerprint for localhost found in legacy [hostfingerprints] section; if you trust this fingerprint, set the following config value in [hostsecurity] and remove the old one from [hostfingerprints] to upgrade to a more secure SHA-256 fingerprint: localhost.fingerprints=sha256:20:de:b3:ad:b4:cd:a5:42:f0:74:41:1c:a2:70:1e:da:6e:c0:5c:16:9e:e7:22:0f:f1:b7:e5:6e:e4:92:af:7e) 5fed3813f7f5 - works without cacerts (hostsecurity) @@ -396,6 +397,7 @@ Fingerprints - multiple fingerprints specified and first matches $ hg --config 'hostfingerprints.localhost=ecd87cd6b386d04fc1b8b41c9d8f5e168eef1c03, deadbeefdeadbeefdeadbeefdeadbeefdeadbeef' -R copy-pull id https://localhost:$HGPORT/ --insecure warning: connecting to localhost using legacy security technology (TLS 1.0); see https://mercurial-scm.org/wiki/SecureConnections for more info (?) + (SHA-1 fingerprint for localhost found in legacy [hostfingerprints] section; if you trust this fingerprint, set the following config value in [hostsecurity] and remove the old one from [hostfingerprints] to upgrade to a more secure SHA-256 fingerprint: localhost.fingerprints=sha256:20:de:b3:ad:b4:cd:a5:42:f0:74:41:1c:a2:70:1e:da:6e:c0:5c:16:9e:e7:22:0f:f1:b7:e5:6e:e4:92:af:7e) 5fed3813f7f5 $ hg --config 'hostsecurity.localhost:fingerprints=sha1:ecd87cd6b386d04fc1b8b41c9d8f5e168eef1c03, sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbeef' -R copy-pull id https://localhost:$HGPORT/ @@ -405,6 +407,7 @@ Fingerprints - multiple fingerprints specified and last matches $ hg --config 'hostfingerprints.localhost=deadbeefdeadbeefdeadbeefdeadbeefdeadbeef, ecd87cd6b386d04fc1b8b41c9d8f5e168eef1c03' -R copy-pull id https://localhost:$HGPORT/ --insecure warning: connecting to localhost using legacy security technology (TLS 1.0); see https://mercurial-scm.org/wiki/SecureConnections for more info (?) + (SHA-1 fingerprint for localhost found in legacy [hostfingerprints] section; if you trust this fingerprint, set the following config value in [hostsecurity] and remove the old one from [hostfingerprints] to upgrade to a more secure SHA-256 fingerprint: localhost.fingerprints=sha256:20:de:b3:ad:b4:cd:a5:42:f0:74:41:1c:a2:70:1e:da:6e:c0:5c:16:9e:e7:22:0f:f1:b7:e5:6e:e4:92:af:7e) 5fed3813f7f5 $ hg --config 'hostsecurity.localhost:fingerprints=sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbeef, sha1:ecd87cd6b386d04fc1b8b41c9d8f5e168eef1c03' -R copy-pull id https://localhost:$HGPORT/ @@ -436,6 +439,7 @@ Fingerprints - ignores that certificate doesn't match hostname $ hg -R copy-pull id https://$LOCALIP:$HGPORT/ --config hostfingerprints.$LOCALIP=ecd87cd6b386d04fc1b8b41c9d8f5e168eef1c03 warning: connecting to $LOCALIP using legacy security technology (TLS 1.0); see https://mercurial-scm.org/wiki/SecureConnections for more info (?) + (SHA-1 fingerprint for $LOCALIP found in legacy [hostfingerprints] section; if you trust this fingerprint, set the following config value in [hostsecurity] and remove the old one from [hostfingerprints] to upgrade to a more secure SHA-256 fingerprint: $LOCALIP.fingerprints=sha256:20:de:b3:ad:b4:cd:a5:42:f0:74:41:1c:a2:70:1e:da:6e:c0:5c:16:9e:e7:22:0f:f1:b7:e5:6e:e4:92:af:7e) 5fed3813f7f5 Ports used by next test. Kill servers. @@ -574,6 +578,7 @@ Test https with cacert and fingerprint t $ http_proxy=http://localhost:$HGPORT1/ hg -R copy-pull pull https://localhost:$HGPORT/ --config hostfingerprints.localhost=ecd87cd6b386d04fc1b8b41c9d8f5e168eef1c03 --trace pulling from https://*:$HGPORT/ (glob) warning: connecting to localhost using legacy security technology (TLS 1.0); see https://mercurial-scm.org/wiki/SecureConnections for more info (?) + (SHA-1 fingerprint for localhost found in legacy [hostfingerprints] section; if you trust this fingerprint, set the following config value in [hostsecurity] and remove the old one from [hostfingerprints] to upgrade to a more secure SHA-256 fingerprint: localhost.fingerprints=sha256:20:de:b3:ad:b4:cd:a5:42:f0:74:41:1c:a2:70:1e:da:6e:c0:5c:16:9e:e7:22:0f:f1:b7:e5:6e:e4:92:af:7e) searching for changes no changes found