sslutil: abort when unable to verify peer connection (BC)
Previously, when we connected to a server and were unable to verify
its certificate against a trusted certificate authority we would
issue a warning and continue to connect. This is obviously not
great behavior because the x509 certificate model is based upon
trust of specific CAs. Failure to enforce that trust erodes security.
This behavior was defined several years ago when Python did not
support loading the system trusted CA store (Python 2.7.9's
backports of Python 3's improvements to the "ssl" module enabled
this).
This commit changes behavior when connecting to abort if the peer
certificate can't be validated. With an empty/default Mercurial
configuration, the peer certificate can be validated if Python is
able to load the system trusted CA store. Environments able to load
the system trusted CA store include:
* Python 2.7.9+ on most platforms and installations
* Python 2.7 distributions with a modern ssl module (e.g. RHEL7's
patched 2.7.5 package)
* Python shipped on OS X
Environments unable to load the system trusted CA store include:
* Python 2.6
* Python 2.7 on many existing Linux installs (because they don't
ship 2.7.9+ or haven't backported modern ssl module)
* Python 2.7.9+ on some installs where Python is unable to locate
the system CA store (this is hopefully rare)
Users of these Pythongs will need to configure Mercurial to load the
system CA store using web.cacerts. This should ideally be performed
by packagers (by setting web.cacerts in the global/system hgrc file).
Where Mercurial packagers aren't setting this, the linked URL in the
new abort message can contain instructions for users.
In the future, we may want to add more code for finding the system
CA store. For example, many Linux distributions have the CA store
at well-known locations (such as /etc/ssl/certs/ca-certificates.crt
in the case of Ubuntu). This will enable CA loading to "just work"
on more Python configurations and will be best for our users since
they won't have to change anything after upgrading to a Mercurial
with this patch.
We may also want to consider distributing a trusted CA store with
Mercurial. Although we should think long and hard about that because
most systems have a global CA store and Mercurial should almost
certainly use the same store used by everything else on the system.
#require serve ssl
Proper https client requires the built-in ssl from Python 2.6.
Make server certificates:
$ CERTSDIR="$TESTDIR/sslcerts"
$ cat "$CERTSDIR/priv.pem" "$CERTSDIR/pub.pem" >> server.pem
$ PRIV=`pwd`/server.pem
$ cat "$CERTSDIR/priv.pem" "$CERTSDIR/pub-not-yet.pem" > server-not-yet.pem
$ cat "$CERTSDIR/priv.pem" "$CERTSDIR/pub-expired.pem" > server-expired.pem
$ hg init test
$ cd test
$ echo foo>foo
$ mkdir foo.d foo.d/bAr.hg.d foo.d/baR.d.hg
$ echo foo>foo.d/foo
$ echo bar>foo.d/bAr.hg.d/BaR
$ echo bar>foo.d/baR.d.hg/bAR
$ hg commit -A -m 1
adding foo
adding foo.d/bAr.hg.d/BaR
adding foo.d/baR.d.hg/bAR
adding foo.d/foo
$ hg serve -p $HGPORT -d --pid-file=../hg0.pid --certificate=$PRIV
$ cat ../hg0.pid >> $DAEMON_PIDS
cacert not found
$ hg in --config web.cacerts=no-such.pem https://localhost:$HGPORT/
abort: could not find web.cacerts: no-such.pem
[255]
Test server address cannot be reused
#if windows
$ hg serve -p $HGPORT --certificate=$PRIV 2>&1
abort: cannot start server at ':$HGPORT':
[255]
#else
$ hg serve -p $HGPORT --certificate=$PRIV 2>&1
abort: cannot start server at ':$HGPORT': Address already in use
[255]
#endif
$ cd ..
Our test cert is not signed by a trusted CA. It should fail to verify if
we are able to load CA certs.
#if defaultcacerts
$ hg clone https://localhost:$HGPORT/ copy-pull
abort: error: *certificate verify failed* (glob)
[255]
#endif
Specifying a per-host certificate file that doesn't exist will abort
$ hg --config hostsecurity.localhost:verifycertsfile=/does/not/exist clone https://localhost:$HGPORT/
abort: path specified by hostsecurity.localhost:verifycertsfile does not exist: /does/not/exist
[255]
A malformed per-host certificate file will raise an error
$ echo baddata > badca.pem
$ hg --config hostsecurity.localhost:verifycertsfile=badca.pem clone https://localhost:$HGPORT/
abort: error: * (glob)
[255]
A per-host certificate mismatching the server will fail verification
$ hg --config hostsecurity.localhost:verifycertsfile="$CERTSDIR/client-cert.pem" clone https://localhost:$HGPORT/
abort: error: *certificate verify failed* (glob)
[255]
A per-host certificate matching the server's cert will be accepted
$ hg --config hostsecurity.localhost:verifycertsfile="$CERTSDIR/pub.pem" clone -U https://localhost:$HGPORT/ perhostgood1
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
A per-host certificate with multiple certs and one matching will be accepted
$ cat "$CERTSDIR/client-cert.pem" "$CERTSDIR/pub.pem" > perhost.pem
$ hg --config hostsecurity.localhost:verifycertsfile=perhost.pem clone -U https://localhost:$HGPORT/ perhostgood2
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
Defining both per-host certificate and a fingerprint will print a warning
$ hg --config hostsecurity.localhost:verifycertsfile="$CERTSDIR/pub.pem" --config hostsecurity.localhost:fingerprints=sha1:914f1aff87249c09b6859b88b1906d30756491ca clone -U https://localhost:$HGPORT/ caandfingerwarning
(hostsecurity.localhost:verifycertsfile ignored when host fingerprints defined; using host fingerprints for verification)
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
$ DISABLECACERTS="--config devel.disableloaddefaultcerts=true"
Inability to verify peer certificate will result in abort
$ hg clone https://localhost:$HGPORT/ copy-pull $DISABLECACERTS
abort: unable to verify security of localhost (no loaded CA certificates); refusing to connect
(see https://mercurial-scm.org/wiki/SecureConnections for how to configure Mercurial to avoid this error or set hostsecurity.localhost:fingerprints=sha256:62:09:97:2f:97:60:e3:65:8f:12:5d:78:9e:35:a1:36:7a:65:4b:0e:9f:ac:db:c3:bc:6e:b6:a3:c0:16:e0:30 to trust this server)
[255]
$ hg clone --insecure https://localhost:$HGPORT/ copy-pull
warning: connection security to localhost is disabled per current settings; communication is susceptible to eavesdropping and tampering
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
updating to branch default
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg verify -R copy-pull
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
4 files, 1 changesets, 4 total revisions
$ cd test
$ echo bar > bar
$ hg commit -A -d '1 0' -m 2
adding bar
$ cd ..
pull without cacert
$ cd copy-pull
$ echo '[hooks]' >> .hg/hgrc
$ echo "changegroup = printenv.py changegroup" >> .hg/hgrc
$ hg pull $DISABLECACERTS
pulling from https://localhost:$HGPORT/
abort: unable to verify security of localhost (no loaded CA certificates); refusing to connect
(see https://mercurial-scm.org/wiki/SecureConnections for how to configure Mercurial to avoid this error or set hostsecurity.localhost:fingerprints=sha256:62:09:97:2f:97:60:e3:65:8f:12:5d:78:9e:35:a1:36:7a:65:4b:0e:9f:ac:db:c3:bc:6e:b6:a3:c0:16:e0:30 to trust this server)
[255]
$ hg pull --insecure
pulling from https://localhost:$HGPORT/
warning: connection security to localhost is disabled per current settings; communication is susceptible to eavesdropping and tampering
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
changegroup hook: HG_NODE=5fed3813f7f5e1824344fdc9cf8f63bb662c292d HG_NODE_LAST=5fed3813f7f5e1824344fdc9cf8f63bb662c292d HG_SOURCE=pull HG_TXNID=TXN:* HG_URL=https://localhost:$HGPORT/ (glob)
(run 'hg update' to get a working copy)
$ cd ..
cacert configured in local repo
$ cp copy-pull/.hg/hgrc copy-pull/.hg/hgrc.bu
$ echo "[web]" >> copy-pull/.hg/hgrc
$ echo "cacerts=$CERTSDIR/pub.pem" >> copy-pull/.hg/hgrc
$ hg -R copy-pull pull --traceback
pulling from https://localhost:$HGPORT/
searching for changes
no changes found
$ mv copy-pull/.hg/hgrc.bu copy-pull/.hg/hgrc
cacert configured globally, also testing expansion of environment
variables in the filename
$ echo "[web]" >> $HGRCPATH
$ echo 'cacerts=$P/pub.pem' >> $HGRCPATH
$ P="$CERTSDIR" hg -R copy-pull pull
pulling from https://localhost:$HGPORT/
searching for changes
no changes found
$ P="$CERTSDIR" hg -R copy-pull pull --insecure
pulling from https://localhost:$HGPORT/
warning: connection security to localhost is disabled per current settings; communication is susceptible to eavesdropping and tampering
searching for changes
no changes found
cacert mismatch
$ hg -R copy-pull pull --config web.cacerts="$CERTSDIR/pub.pem" \
> https://127.0.0.1:$HGPORT/
pulling from https://127.0.0.1:$HGPORT/
abort: 127.0.0.1 certificate error: certificate is for localhost
(set hostsecurity.127.0.0.1:certfingerprints=sha256:62:09:97:2f:97:60:e3:65:8f:12:5d:78:9e:35:a1:36:7a:65:4b:0e:9f:ac:db:c3:bc:6e:b6:a3:c0:16:e0:30 config setting or use --insecure to connect insecurely)
[255]
$ hg -R copy-pull pull --config web.cacerts="$CERTSDIR/pub.pem" \
> https://127.0.0.1:$HGPORT/ --insecure
pulling from https://127.0.0.1:$HGPORT/
warning: connection security to 127.0.0.1 is disabled per current settings; communication is susceptible to eavesdropping and tampering
searching for changes
no changes found
$ hg -R copy-pull pull --config web.cacerts="$CERTSDIR/pub-other.pem"
pulling from https://localhost:$HGPORT/
abort: error: *certificate verify failed* (glob)
[255]
$ hg -R copy-pull pull --config web.cacerts="$CERTSDIR/pub-other.pem" \
> --insecure
pulling from https://localhost:$HGPORT/
warning: connection security to localhost is disabled per current settings; communication is susceptible to eavesdropping and tampering
searching for changes
no changes found
Test server cert which isn't valid yet
$ hg serve -R test -p $HGPORT1 -d --pid-file=hg1.pid --certificate=server-not-yet.pem
$ cat hg1.pid >> $DAEMON_PIDS
$ hg -R copy-pull pull --config web.cacerts="$CERTSDIR/pub-not-yet.pem" \
> https://localhost:$HGPORT1/
pulling from https://localhost:$HGPORT1/
abort: error: *certificate verify failed* (glob)
[255]
Test server cert which no longer is valid
$ hg serve -R test -p $HGPORT2 -d --pid-file=hg2.pid --certificate=server-expired.pem
$ cat hg2.pid >> $DAEMON_PIDS
$ hg -R copy-pull pull --config web.cacerts="$CERTSDIR/pub-expired.pem" \
> https://localhost:$HGPORT2/
pulling from https://localhost:$HGPORT2/
abort: error: *certificate verify failed* (glob)
[255]
Fingerprints
- works without cacerts (hostkeyfingerprints)
$ hg -R copy-pull id https://localhost:$HGPORT/ --insecure --config hostfingerprints.localhost=91:4f:1a:ff:87:24:9c:09:b6:85:9b:88:b1:90:6d:30:75:64:91:ca
5fed3813f7f5
- works without cacerts (hostsecurity)
$ hg -R copy-pull id https://localhost:$HGPORT/ --config hostsecurity.localhost:fingerprints=sha1:914f1aff87249c09b6859b88b1906d30756491ca
5fed3813f7f5
$ hg -R copy-pull id https://localhost:$HGPORT/ --config hostsecurity.localhost:fingerprints=sha256:62:09:97:2f:97:60:e3:65:8f:12:5d:78:9e:35:a1:36:7a:65:4b:0e:9f:ac:db:c3:bc:6e:b6:a3:c0:16:e0:30
5fed3813f7f5
- multiple fingerprints specified and first matches
$ hg --config 'hostfingerprints.localhost=914f1aff87249c09b6859b88b1906d30756491ca, deadbeefdeadbeefdeadbeefdeadbeefdeadbeef' -R copy-pull id https://localhost:$HGPORT/ --insecure
5fed3813f7f5
$ hg --config 'hostsecurity.localhost:fingerprints=sha1:914f1aff87249c09b6859b88b1906d30756491ca, sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbeef' -R copy-pull id https://localhost:$HGPORT/
5fed3813f7f5
- multiple fingerprints specified and last matches
$ hg --config 'hostfingerprints.localhost=deadbeefdeadbeefdeadbeefdeadbeefdeadbeef, 914f1aff87249c09b6859b88b1906d30756491ca' -R copy-pull id https://localhost:$HGPORT/ --insecure
5fed3813f7f5
$ hg --config 'hostsecurity.localhost:fingerprints=sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbeef, sha1:914f1aff87249c09b6859b88b1906d30756491ca' -R copy-pull id https://localhost:$HGPORT/
5fed3813f7f5
- multiple fingerprints specified and none match
$ hg --config 'hostfingerprints.localhost=deadbeefdeadbeefdeadbeefdeadbeefdeadbeef, aeadbeefdeadbeefdeadbeefdeadbeefdeadbeef' -R copy-pull id https://localhost:$HGPORT/ --insecure
abort: certificate for localhost has unexpected fingerprint 91:4f:1a:ff:87:24:9c:09:b6:85:9b:88:b1:90:6d:30:75:64:91:ca
(check hostfingerprint configuration)
[255]
$ hg --config 'hostsecurity.localhost:fingerprints=sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbeef, sha1:aeadbeefdeadbeefdeadbeefdeadbeefdeadbeef' -R copy-pull id https://localhost:$HGPORT/
abort: certificate for localhost has unexpected fingerprint sha1:91:4f:1a:ff:87:24:9c:09:b6:85:9b:88:b1:90:6d:30:75:64:91:ca
(check hostsecurity configuration)
[255]
- fails when cert doesn't match hostname (port is ignored)
$ hg -R copy-pull id https://localhost:$HGPORT1/ --config hostfingerprints.localhost=914f1aff87249c09b6859b88b1906d30756491ca
abort: certificate for localhost has unexpected fingerprint 28:ff:71:bf:65:31:14:23:ad:62:92:b4:0e:31:99:18:fc:83:e3:9b
(check hostfingerprint configuration)
[255]
- ignores that certificate doesn't match hostname
$ hg -R copy-pull id https://127.0.0.1:$HGPORT/ --config hostfingerprints.127.0.0.1=914f1aff87249c09b6859b88b1906d30756491ca
5fed3813f7f5
HGPORT1 is reused below for tinyproxy tests. Kill that server.
$ killdaemons.py hg1.pid
Prepare for connecting through proxy
$ tinyproxy.py $HGPORT1 localhost >proxy.log </dev/null 2>&1 &
$ while [ ! -f proxy.pid ]; do sleep 0; done
$ cat proxy.pid >> $DAEMON_PIDS
$ echo "[http_proxy]" >> copy-pull/.hg/hgrc
$ echo "always=True" >> copy-pull/.hg/hgrc
$ echo "[hostfingerprints]" >> copy-pull/.hg/hgrc
$ echo "localhost =" >> copy-pull/.hg/hgrc
Test unvalidated https through proxy
$ http_proxy=http://localhost:$HGPORT1/ hg -R copy-pull pull --insecure --traceback
pulling from https://localhost:$HGPORT/
warning: connection security to localhost is disabled per current settings; communication is susceptible to eavesdropping and tampering
searching for changes
no changes found
Test https with cacert and fingerprint through proxy
$ http_proxy=http://localhost:$HGPORT1/ hg -R copy-pull pull \
> --config web.cacerts="$CERTSDIR/pub.pem"
pulling from https://localhost:$HGPORT/
searching for changes
no changes found
$ http_proxy=http://localhost:$HGPORT1/ hg -R copy-pull pull https://127.0.0.1:$HGPORT/ --config hostfingerprints.127.0.0.1=914f1aff87249c09b6859b88b1906d30756491ca
pulling from https://127.0.0.1:$HGPORT/
searching for changes
no changes found
Test https with cert problems through proxy
$ http_proxy=http://localhost:$HGPORT1/ hg -R copy-pull pull \
> --config web.cacerts="$CERTSDIR/pub-other.pem"
pulling from https://localhost:$HGPORT/
abort: error: *certificate verify failed* (glob)
[255]
$ http_proxy=http://localhost:$HGPORT1/ hg -R copy-pull pull \
> --config web.cacerts="$CERTSDIR/pub-expired.pem" https://localhost:$HGPORT2/
pulling from https://localhost:$HGPORT2/
abort: error: *certificate verify failed* (glob)
[255]
$ killdaemons.py hg0.pid
#if sslcontext
Start patched hgweb that requires client certificates:
$ cat << EOT > reqclientcert.py
> import ssl
> from mercurial.hgweb import server
> class _httprequesthandlersslclientcert(server._httprequesthandlerssl):
> @staticmethod
> def preparehttpserver(httpserver, ssl_cert):
> sslcontext = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
> sslcontext.verify_mode = ssl.CERT_REQUIRED
> sslcontext.load_cert_chain(ssl_cert)
> # verify clients by server certificate
> sslcontext.load_verify_locations(ssl_cert)
> httpserver.socket = sslcontext.wrap_socket(httpserver.socket,
> server_side=True)
> server._httprequesthandlerssl = _httprequesthandlersslclientcert
> EOT
$ cd test
$ hg serve -p $HGPORT -d --pid-file=../hg0.pid --certificate=$PRIV \
> --config extensions.reqclientcert=../reqclientcert.py
$ cat ../hg0.pid >> $DAEMON_PIDS
$ cd ..
without client certificate:
$ P="$CERTSDIR" hg id https://localhost:$HGPORT/
abort: error: *handshake failure* (glob)
[255]
with client certificate:
$ cat << EOT >> $HGRCPATH
> [auth]
> l.prefix = localhost
> l.cert = $CERTSDIR/client-cert.pem
> l.key = $CERTSDIR/client-key.pem
> EOT
$ P="$CERTSDIR" hg id https://localhost:$HGPORT/ \
> --config auth.l.key="$CERTSDIR/client-key-decrypted.pem"
5fed3813f7f5
$ printf '1234\n' | env P="$CERTSDIR" hg id https://localhost:$HGPORT/ \
> --config ui.interactive=True --config ui.nontty=True
passphrase for */client-key.pem: 5fed3813f7f5 (glob)
$ env P="$CERTSDIR" hg id https://localhost:$HGPORT/
abort: error: * (glob)
[255]
#endif