commit 1419b8997ec348092b2bd98fa3d596f491321c3a Author: Damian Johnson atagar@torproject.org Date: Fri Jun 10 18:39:24 2011 -0700

Fetching / validating lib dependencies via mirror

When needed we fetch torctl and cagraph (small library dependencies of arm) from a mirror on my site and verify their sha256 signatures against hardcoded values. Issue caught by Sebastian and rransom. --- src/prereq.py | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/src/prereq.py b/src/prereq.py index 93d9de3..ba1e988 100644 --- a/src/prereq.py +++ b/src/prereq.py @@ -5,8 +5,19 @@ Provides a warning and error code if python version isn't compatible. import os import sys import shutil +import urllib +import hashlib +import tarfile import tempfile

+# Library dependencies can be fetched on request. By default this is via +# the following mirrors with their sha256 signatures checked. +TORCTL_ARCHIVE = "http://www.atagar.com/arm/resources/deps/11-6-10/torctl.tar.gz" +TORCTL_SIG = "be583e53b2bccf09a7126c5271f9af5682447903b6ac92cf1cf78ca5b35273ed" +CAGRAPH_ARCHIVE = "http://www.atagar.com/arm/resources/deps/11-6-10/cagraph.tar.gz" +CAGRAPH_SIG = "1439acd40ce016f4329deb216d86f36a749e4b8bf73a313a757396af6f95310d" + +# optionally we can do an unverified fetch from the library's sources TORCTL_REPO = "git://git.torproject.org/pytorctl.git" CAGRAPH_TARBALL_URL = "http://cagraph.googlecode.com/files/cagraph-1.2.tar.gz" CAGRAPH_TARBALL_NAME = "cagraph-1.2.tar.gz" @@ -46,7 +57,7 @@ def promptTorCtlInstall():

# attempt to install TorCtl, printing the issue if unsuccessful try: - installTorCtl() + fetchLibrary(TORCTL_ARCHIVE, TORCTL_SIG)

if not isTorCtlAvailable(): raise IOError("Unable to install TorCtl, sorry") @@ -70,7 +81,7 @@ def promptCagraphInstall():

# attempt to install cagraph, printing the issue if unsuccessful try: - installCagraph() + fetchLibrary(CAGRAPH_ARCHIVE, CAGRAPH_SIG)

if not isCagraphAvailable(): raise IOError("Unable to install cagraph, sorry") @@ -81,6 +92,43 @@ def promptCagraphInstall(): print exc return False

+def fetchLibrary(url, sig): + """ + Downloads the given archive, verifies its signature, then installs the + library. This raises an IOError if any of these steps fail. + + Arguments: + url - url from which to fetch the gzipped tarball + sig - sha256 signature for the archive + """ + + tmpDir = tempfile.mkdtemp() + destination = tmpDir + "/" + url.split("/")[-1] + urllib.urlretrieve(url, destination) + + # checks the signature, reading the archive in 256-byte chunks + m = hashlib.sha256() + fd = open(destination, "rb") + + while True: + data = fd.read(256) + if not data: break + m.update(data) + + fd.close() + actualSig = m.hexdigest() + + if sig != actualSig: + raise IOError("Signature of the library is incorrect (got '%s' rather than '%s')" % (actualSig, sig)) + + # extracts the tarball + tarFd = tarfile.open(destination, 'r:gz') + tarFd.extractall("src/") + tarFd.close() + + # clean up the temporary contents (fails quietly if unsuccessful) + shutil.rmtree(destination, ignore_errors=True) + def installTorCtl(): """ Checks out the current git head release for TorCtl and bundles it with arm. @@ -110,8 +158,8 @@ def installTorCtl():

def installCagraph(): """ - Downloads and extracts the cagraph tarball. - This raises an IOError if unsuccessful. + Downloads and extracts the cagraph tarball. This raises an IOError if + unsuccessful. """

if isCagraphAvailable(): return @@ -119,7 +167,7 @@ def installCagraph(): tmpDir = tempfile.mkdtemp() tmpFilename = os.path.join(tmpDir, CAGRAPH_TARBALL_NAME)

- exitStatus = os.system("wget -P %s %s" % (tmpDir, CAGRAPH_TARBALL_URL)) + exitStatus = os.system("wget --quiet -P %s %s" % (tmpDir, CAGRAPH_TARBALL_URL)) if exitStatus: raise IOError("Unable to fetch cagraph from %s. Is wget installed?" % CAGRAPH_TARBALL_URL)

# the destination for cagraph will be our directory