tests/blackbox-readonly-dispatch.py

dispatch: protect against malicious 'hg serve --stdio' invocations (sec)

Some shared-ssh installations assume that 'hg serve --stdio' is a safe
command to run for minimally trusted users. Unfortunately, the messy
implementation of argument parsing here meant that trying to access a
repo named '--debugger' would give the user a pdb prompt, thereby
sidestepping any hoped-for sandboxing. Serving repositories over HTTP(S)
is unaffected.

We're not currently hardening any subcommands other than 'serve'. If
your service exposes other commands to users with arbitrary repository
names, it is imperative that you defend against repository names of
'--debugger' and anything starting with '--config'.

The read-only mode of hg-ssh stopped working because it provided its hook
configuration to "hg serve --stdio" via --config parameter. This is banned for
security reasons now. This patch switches it to directly call ui.setconfig().
If your custom hosting infrastructure relies on passing --config to
"hg serve --stdio", you'll need to find a different way to get that configuration
into Mercurial, either by using ui.setconfig() as hg-ssh does in this patch,
or by placing an hgrc file someplace where Mercurial will read it.

[e-mail] provided some extra fixes for the dispatch code and
for hg-ssh in places that I overlooked.

from __future__ import absolute_import, print_function
import os
from mercurial import (
    dispatch,
)

def testdispatch(cmd):
    """Simple wrapper around dispatch.dispatch()

    Prints command and result value, but does not handle quoting.
    """
    print("running: %s" % (cmd,))
    req = dispatch.request(cmd.split())
    result = dispatch.dispatch(req)
    print("result: %r" % (result,))

# create file 'foo', add and commit
f = open('foo', 'wb')
f.write('foo\n')
f.close()
testdispatch("add foo")
testdispatch("commit -m commit1 -d 2000-01-01 foo")

# append to file 'foo' and commit
f = open('foo', 'ab')
f.write('bar\n')
f.close()
# remove blackbox.log directory (proxy for readonly log file)
os.rmdir(".hg/blackbox.log")
# replace it with the real blackbox.log file
os.rename(".hg/blackbox.log-", ".hg/blackbox.log")
testdispatch("commit -m commit2 -d 2000-01-02 foo")

# check 88803a69b24 (fancyopts modified command table)
testdispatch("log -r 0")
testdispatch("log -r tip")