view tests/test-http-branchmap.t @ 29560:303e9300772a

sslutil: require TLS 1.1+ when supported

Currently, Mercurial will use TLS 1.0 or newer when connecting to
remote servers, selecting the highest TLS version supported by both
peers. On older Pythons, only TLS 1.0 is available. On newer Pythons,
TLS 1.1 and 1.2 should be available.

Security professionals recommend avoiding TLS 1.0 if possible.
PCI DSS 3.1 "strongly encourages" the use of TLS 1.2.

Known attacks like BEAST and POODLE exist against TLS 1.0 (although
mitigations are available and properly configured servers aren't
vulnerable).

I asked Eric Rescorla - Mozilla's resident crypto expert - whether
Mercurial should drop support for TLS 1.0. His response was
"if you can get away with it." Essentially, a number of servers on
the Internet don't support TLS 1.1+. This is why web browsers
continue to support TLS 1.0 despite desires from security experts.

This patch changes Mercurial's default behavior on modern Python
versions to require TLS 1.1+, thus avoiding known security issues
with TLS 1.0 and making Mercurial more secure by default. Rather
than drop TLS 1.0 support wholesale, we still allow TLS 1.0 to be
used if configured. This is a compromise solution - ideally we'd
disallow TLS 1.0. However, since we're not sure how many Mercurial
servers don't support TLS 1.1+ and we're not sure how much user
inconvenience this change will bring, I think it is prudent to ship
an escape hatch that still allows usage of TLS 1.0. In the default
case our users get better security. In the worst case, they are no
worse off than before this patch.

This patch has no effect when running on Python versions that don't
support TLS 1.1+.

As the added test shows, connecting to a server that doesn't
support TLS 1.1+ will display a warning message with a link to
our wiki, where we can guide people to configure their client to
allow less secure connections.

#require killdaemons

  $ hgserve() {
  >     hg serve -a localhost -p $HGPORT1 -d --pid-file=hg.pid \
  >       -E errors.log -v $@ > startup.log
  >     # Grepping hg serve stdout would hang on Windows
  >     grep -v 'listening at' startup.log
  >     cat hg.pid >> "$DAEMON_PIDS"
  > }
  $ hg init a
  $ hg --encoding utf-8 -R a branch æ
  marked working directory as branch \xc3\xa6 (esc)
  (branches are permanent and global, did you want a bookmark?)
  $ echo foo > a/foo
  $ hg -R a ci -Am foo
  adding foo
  $ hgserve -R a --config web.push_ssl=False --config web.allow_push=* --encoding latin1
  $ hg --encoding utf-8 clone http://localhost:$HGPORT1 b
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  updating to branch \xc3\xa6 (esc)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg --encoding utf-8 -R b log
  changeset:   0:867c11ce77b8
  branch:      \xc3\xa6 (esc)
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo
  
  $ echo bar >> b/foo
  $ hg -R b ci -m bar
  $ hg --encoding utf-8 -R b push
  pushing to http://localhost:$HGPORT1/
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  $ hg -R a --encoding utf-8 log
  changeset:   1:58e7c90d67cb
  branch:      \xc3\xa6 (esc)
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     bar
  
  changeset:   0:867c11ce77b8
  branch:      \xc3\xa6 (esc)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     foo
  
  $ killdaemons.py hg.pid

verify 7e7d56fe4833 (encoding fallback in branchmap to maintain compatibility with 1.3.x)

  $ cat <<EOF > oldhg
  > import sys
  > from mercurial import ui, hg, commands
  > 
  > class StdoutWrapper(object):
  >     def __init__(self, stdout):
  >         self._file = stdout
  > 
  >     def write(self, data):
  >         if data == '47\n':
  >             # latin1 encoding is one %xx (3 bytes) shorter
  >             data = '44\n'
  >         elif data.startswith('%C3%A6 '):
  >             # translate to latin1 encoding
  >             data = '%%E6 %s' % data[7:]
  >         self._file.write(data)
  > 
  >     def __getattr__(self, name):
  >         return getattr(self._file, name)
  > 
  > sys.stdout = StdoutWrapper(sys.stdout)
  > sys.stderr = StdoutWrapper(sys.stderr)
  > 
  > myui = ui.ui()
  > repo = hg.repository(myui, 'a')
  > commands.serve(myui, repo, stdio=True, cmdserver=False)
  > EOF
  $ echo baz >> b/foo
  $ hg -R b ci -m baz
  $ hg push -R b -e 'python oldhg' ssh://dummy/ --encoding latin1
  pushing to ssh://dummy/
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files