fetch2: Add BB_ALLOWED_NETWORKS support

BB_ALLOWED_NETWORKS is a list of hosts that the fetcher will be allowed
to use when BB_NO_NETWORK is not set.

If BB_NO_NETWORK is set, then networking is still disabled.

If BB_ALLOWED_NETWORKS is not set, the behaviour remains the same as
today.

If BB_NO_NETWORK is NOT set, and BB_ALLOWED_NETWORKS is configured, then
only the hosts in the list are usable by the fetcher.

eg:
BB_ALLOWED_NETWORKS="yoctoproject.org git.gnu.org"
The fetcher will be able to download from yoctoproject.org, git.gnu.org,
but not ftp.gnu.org or any other hostname that is not in the list.

There is also limited support for wildcards on the beginning of the
hosts, so BB_ALLOWED_NETWORKS="*.gnu.org" with match git.gnu.org and
ftp.gnu.org as well as foo.git.gnu.org

Signed-off-by: Liam R. Howlett <Liam.Howlett@WindRiver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/lib/bb/fetch2/__init__.py b/lib/bb/fetch2/__init__.py
index 36c955473a..68f65a97e0 100644
--- a/lib/bb/fetch2/__init__.py
+++ b/lib/bb/fetch2/__init__.py
@@ -61,6 +61,17 @@ class BBFetchException(Exception):
     def __str__(self):
          return self.msg
 
+class UntrustedUrl(BBFetchException):
+    """Exception raised when encountering a host not listed in BB_ALLOWED_NETWORKS"""
+    def __init__(self, url, message=''):
+        if message:
+            msg = message
+        else:
+            msg = "The URL: '%s' is not trusted and cannot be used" % url
+        self.url = url
+        BBFetchException.__init__(self, msg)
+        self.args = (url,)
+
 class MalformedUrl(BBFetchException):
     """Exception raised when encountering an invalid url"""
     def __init__(self, url, message=''):
@@ -852,6 +863,11 @@ def build_mirroruris(origud, mirrors, ld):
             newuri = uri_replace(ud, find, replace, replacements, ld)
             if not newuri or newuri in uris or newuri == origud.url:
                 continue
+
+            if not trusted_network(ld, newuri):
+                logger.debug(1, "Mirror %s not in the list of trusted networks, skipping" %  (newuri))
+                continue
+
             try:
                 newud = FetchData(newuri, ld)
                 newud.setup_localpath(ld)
@@ -972,6 +988,41 @@ def try_mirrors(d, origud, mirrors, check = False):
             return ret
     return None
 
+def trusted_network(d, url):
+    """
+    Use a trusted url during download if networking is enabled and
+    BB_ALLOWED_NETWORKS is set globally or for a specific recipe.
+    Note: modifies SRC_URI & mirrors.
+    """
+    if d.getVar('BB_NO_NETWORK', True) == "1":
+        return True
+
+    pkgname = d.expand(d.getVar('PN'))
+    trusted_hosts = d.getVarFlag('BB_ALLOWED_NETWORKS', pkgname)
+
+    if not trusted_hosts:
+        trusted_hosts = d.getVar('BB_ALLOWED_NETWORKS', True)
+
+    # Not enabled.
+    if not trusted_hosts:
+        return True
+
+    scheme, network, path, user, passwd, param = decodeurl(url)
+
+    if not network:
+        return True
+
+    network = network.lower()
+
+    for host in trusted_hosts.split(" "):
+        host = host.lower()
+        if host.startswith("*.") and ("." + network).endswith(host[1:]):
+            return True
+        if host == network:
+            return True
+
+    return False
+
 def srcrev_internal_helper(ud, d, name):
     """
     Return:
@@ -1530,6 +1581,8 @@ class Fetch(object):
                 firsterr = None
                 if not localpath and ((not verify_donestamp(ud, self.d)) or m.need_update(ud, self.d)):
                     try:
+                        if not trusted_network(self.d, ud.url):
+                            raise UntrustedUrl(ud.url)
                         logger.debug(1, "Trying Upstream")
                         m.download(ud, self.d)
                         if hasattr(m, "build_mirror_data"):