wireprotoserver: ensure that output stream gets flushed on exception
Previously flush was happening due to Python finalizer being run on
`BufferedWriter`. With upgrade to Python 3.11 this started randomly
failing.
My guess is that the finalizer on the raw `FileIO` object may
be running before the finalizer of `BufferedWriter` has a chance to run.
At any rate, since we're not relying on finalizers in the happy case
we should also not rely on them in case of exception.
import base64
import hashlib
from mercurial.hgweb import common
from mercurial import node
def parse_keqv_list(req, l):
"""Parse list of key=value strings where keys are not duplicated."""
parsed = {}
for elt in l:
k, v = elt.split(b'=', 1)
if v[0:1] == b'"' and v[-1:] == b'"':
v = v[1:-1]
parsed[k] = v
return parsed
class digestauthserver:
def __init__(self):
self._user_hashes = {}
def gethashers(self):
def _md5sum(x):
m = hashlib.md5()
m.update(x)
return node.hex(m.digest())
h = _md5sum
kd = lambda s, d, h=h: h(b"%s:%s" % (s, d))
return h, kd
def adduser(self, user, password, realm):
h, kd = self.gethashers()
a1 = h(b'%s:%s:%s' % (user, realm, password))
self._user_hashes[(user, realm)] = a1
def makechallenge(self, realm):
# We aren't testing the protocol here, just that the bytes make the
# proper round trip. So hardcoded seems fine.
nonce = b'064af982c5b571cea6450d8eda91c20d'
return b'realm="%s", nonce="%s", algorithm=MD5, qop="auth"' % (
realm,
nonce,
)
def checkauth(self, req, header):
log = req.rawenv[b'wsgi.errors']
h, kd = self.gethashers()
resp = parse_keqv_list(req, header.split(b', '))
if resp.get(b'algorithm', b'MD5').upper() != b'MD5':
log.write(b'Unsupported algorithm: %s' % resp.get(b'algorithm'))
raise common.ErrorResponse(
common.HTTP_FORBIDDEN, b"unknown algorithm"
)
user = resp[b'username']
realm = resp[b'realm']
nonce = resp[b'nonce']
ha1 = self._user_hashes.get((user, realm))
if not ha1:
log.write(b'No hash found for user/realm "%s/%s"' % (user, realm))
raise common.ErrorResponse(common.HTTP_FORBIDDEN, b"bad user")
qop = resp.get(b'qop', b'auth')
if qop != b'auth':
log.write(b"Unsupported qop: %s" % qop)
raise common.ErrorResponse(common.HTTP_FORBIDDEN, b"bad qop")
cnonce, ncvalue = resp.get(b'cnonce'), resp.get(b'nc')
if not cnonce or not ncvalue:
log.write(b'No cnonce (%s) or ncvalue (%s)' % (cnonce, ncvalue))
raise common.ErrorResponse(common.HTTP_FORBIDDEN, b"no cnonce")
a2 = b'%s:%s' % (req.method, resp[b'uri'])
noncebit = b"%s:%s:%s:%s:%s" % (nonce, ncvalue, cnonce, qop, h(a2))
respdig = kd(ha1, noncebit)
if respdig != resp[b'response']:
log.write(
b'User/realm "%s/%s" gave %s, but expected %s'
% (user, realm, resp[b'response'], respdig)
)
return False
return True
digest = digestauthserver()
def perform_authentication(hgweb, req, op):
auth = req.headers.get(b'Authorization')
if req.headers.get(b'X-HgTest-AuthType') == b'Digest':
if not auth:
challenge = digest.makechallenge(b'mercurial')
raise common.ErrorResponse(
common.HTTP_UNAUTHORIZED,
b'who',
[(b'WWW-Authenticate', b'Digest %s' % challenge)],
)
if not digest.checkauth(req, auth[7:]):
raise common.ErrorResponse(common.HTTP_FORBIDDEN, b'no')
return
if not auth:
raise common.ErrorResponse(
common.HTTP_UNAUTHORIZED,
b'who',
[(b'WWW-Authenticate', b'Basic Realm="mercurial"')],
)
if base64.b64decode(auth.split()[1]).split(b':', 1) != [b'user', b'pass']:
raise common.ErrorResponse(common.HTTP_FORBIDDEN, b'no')
def extsetup(ui):
common.permhooks.insert(0, perform_authentication)
digest.adduser(b'user', b'pass', b'mercurial')