hgweb.cgi

subrepo: set GIT_ALLOW_PROTOCOL to limit git clone protocols (SEC)

CVE-2016-3068 (1/1)

Git's git-remote-ext remote helper provides an ext:: URL scheme that
allows running arbitrary shell commands. This feature allows
implementing simple git smart transports with a single shell shell
command. However, git submodules could clone arbitrary URLs specified
in the .gitmodules file. This was reported as CVE-2015-7545 and fixed
in git v2.6.1.

However, if a user directly clones a malicious ext URL, the git client
will still run arbitrary shell commands.

Mercurial is similarly effected. Mercurial allows specifying git
repositories as subrepositories. Git ext:: URLs can be specified as
Mercurial subrepositories allowing arbitrary shell commands to be run
on `hg clone ...`.


The Mercurial community would like to thank Blake Burkhart for
reporting this issue. The description of the issue is copied from
Blake's report.

This commit changes submodules to pass the GIT_ALLOW_PROTOCOL env
variable to git commands  with the same list of allowed protocols that
git submodule is using.

When the GIT_ALLOW_PROTOCOL env variable is already set, we just pass it
to git without modifications.

#!/usr/bin/env python
#
# An example hgweb CGI script, edit as necessary
# See also https://mercurial-scm.org/wiki/PublishingRepositories

# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = "/path/to/repo/or/config"

# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
#import sys; sys.path.insert(0, "/path/to/python/lib")

# Uncomment to send python tracebacks to the browser if an error occurs:
#import cgitb; cgitb.enable()

from mercurial import demandimport; demandimport.enable()
from mercurial.hgweb import hgweb, wsgicgi
application = hgweb(config)
wsgicgi.launch(application)