httppeer: detect redirect to URL without query string (issue5860)
197d10e157ce subtly changed the HTTP peer's handling of HTTP redirects.
Before that changeset, we instantiated an HTTP peer instance and
performed the capabilities lookup with that instance. The old code had
the following relevant properties:
1) The HTTP request layer would automatically follow HTTP redirects.
2) An encountered HTTP redirect would update a peer instance variable
pointing to the repo URL.
3) The peer would automagically perform a "capabilities" command
request if a caller requested capabilities but capabilities were
not yet defined.
The first HTTP request issued by a peer is for ?cmd=capabilities. If
the server responds with an HTTP redirect to a ?cmd=capabilities URL,
the HTTP request layer automatically followed it, retrieved a valid
capabilities response, and the peer's base URL was updated
automatically so subsequent requests used the proper URL. In other
words, things "just worked."
In the case where the server redirected to a URL without the
?cmd=capabilities query string, the HTTP request layer would follow
the redirect and likely encounter HTML. The peer's base URL would be
updated and the unexpected Content-Type would raise a RepoError. We
would catch RepoError and immediately call between() (testing the case
for pre 0.9.1 servers not supporting the "capabilities" command). e.g.
try:
inst._fetchcaps()
except error.RepoError:
inst.between([(nullid, nullid)])
between() would eventually call into _callstream(). And _callstream()
made a call to self.capable('httpheader'). capable() would call
self.capabilities(), which would see that no capabilities were set
(because HTML was returned for that request) and call the "capabilities"
command to fetch capabilities. Because the base URL had been updated
from the redirect, this 2nd "capabilities" command would succeed and
the client would immediately call "between," which would also succeed.
The legacy handshake succeeded. Only because "capabilities" was
successfully executed as a side effect did the peer recognize that it
was talking to a modern server. In other words, this all appeared to
work accidentally.
After 197d10e157ce, we stopped calling the "capabilities" command on
the peer instance. Instead, we made the request via a low-level opener,
detected the redirect as part of response handling code, and passed the
redirected URL into the constructed peer instance.
For cases where the redirected URL included the query string, this
"just worked." But for cases where the redirected URL stripped the query
string, we threw RepoError and because we removed the "between" handshake
fallback, we fell through to the "is a static HTTP repo" check and
performed an HTTP request for .hg/requires.
While 197d10e157ce was marked as backwards incompatible, the only
intended backwards incompatible behavior was not performing the
"between" fallback. It was not realized that the "between" command
had the side-effect of recovering from an errant redirect that
dropped the query string.
This commit restores the previous behavior and allows clients to
handle a redirect that drops the query string. In the case where
the request is redirected and the query string is dropped, we raise
a special case of RepoError. We then catch this special exception in
the handshake code and perform another "capabilities" request against
the redirected URL. If that works, all is well. Otherwise, we fall back
to the "is a static HTTP repo" check.
The new code is arguably better than before 197d10e157ce, as it is
explicit about the expected behavior and we avoid performing a
"between" request, saving a server round trip.
Differential Revision: https://phab.mercurial-scm.org/D3433
# Copyright 2005, 2006 Benoit Boissinot <benoit.boissinot@ens-lyon.org>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''commands to sign and verify changesets'''
from __future__ import absolute_import
import binascii
import os
import tempfile
from mercurial.i18n import _
from mercurial import (
cmdutil,
error,
match,
node as hgnode,
pycompat,
registrar,
)
from mercurial.utils import (
dateutil,
procutil,
)
cmdtable = {}
command = registrar.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
configtable = {}
configitem = registrar.configitem(configtable)
configitem('gpg', 'cmd',
default='gpg',
)
configitem('gpg', 'key',
default=None,
)
configitem('gpg', '.*',
default=None,
generic=True,
)
class gpg(object):
def __init__(self, path, key=None):
self.path = path
self.key = (key and " --local-user \"%s\"" % key) or ""
def sign(self, data):
gpgcmd = "%s --sign --detach-sign%s" % (self.path, self.key)
return procutil.filter(data, gpgcmd)
def verify(self, data, sig):
""" returns of the good and bad signatures"""
sigfile = datafile = None
try:
# create temporary files
fd, sigfile = tempfile.mkstemp(prefix="hg-gpg-", suffix=".sig")
fp = os.fdopen(fd, r'wb')
fp.write(sig)
fp.close()
fd, datafile = tempfile.mkstemp(prefix="hg-gpg-", suffix=".txt")
fp = os.fdopen(fd, r'wb')
fp.write(data)
fp.close()
gpgcmd = ("%s --logger-fd 1 --status-fd 1 --verify "
"\"%s\" \"%s\"" % (self.path, sigfile, datafile))
ret = procutil.filter("", gpgcmd)
finally:
for f in (sigfile, datafile):
try:
if f:
os.unlink(f)
except OSError:
pass
keys = []
key, fingerprint = None, None
for l in ret.splitlines():
# see DETAILS in the gnupg documentation
# filter the logger output
if not l.startswith("[GNUPG:]"):
continue
l = l[9:]
if l.startswith("VALIDSIG"):
# fingerprint of the primary key
fingerprint = l.split()[10]
elif l.startswith("ERRSIG"):
key = l.split(" ", 3)[:2]
key.append("")
fingerprint = None
elif (l.startswith("GOODSIG") or
l.startswith("EXPSIG") or
l.startswith("EXPKEYSIG") or
l.startswith("BADSIG")):
if key is not None:
keys.append(key + [fingerprint])
key = l.split(" ", 2)
fingerprint = None
if key is not None:
keys.append(key + [fingerprint])
return keys
def newgpg(ui, **opts):
"""create a new gpg instance"""
gpgpath = ui.config("gpg", "cmd")
gpgkey = opts.get(r'key')
if not gpgkey:
gpgkey = ui.config("gpg", "key")
return gpg(gpgpath, gpgkey)
def sigwalk(repo):
"""
walk over every sigs, yields a couple
((node, version, sig), (filename, linenumber))
"""
def parsefile(fileiter, context):
ln = 1
for l in fileiter:
if not l:
continue
yield (l.split(" ", 2), (context, ln))
ln += 1
# read the heads
fl = repo.file(".hgsigs")
for r in reversed(fl.heads()):
fn = ".hgsigs|%s" % hgnode.short(r)
for item in parsefile(fl.read(r).splitlines(), fn):
yield item
try:
# read local signatures
fn = "localsigs"
for item in parsefile(repo.vfs(fn), fn):
yield item
except IOError:
pass
def getkeys(ui, repo, mygpg, sigdata, context):
"""get the keys who signed a data"""
fn, ln = context
node, version, sig = sigdata
prefix = "%s:%d" % (fn, ln)
node = hgnode.bin(node)
data = node2txt(repo, node, version)
sig = binascii.a2b_base64(sig)
keys = mygpg.verify(data, sig)
validkeys = []
# warn for expired key and/or sigs
for key in keys:
if key[0] == "ERRSIG":
ui.write(_("%s Unknown key ID \"%s\"\n") % (prefix, key[1]))
continue
if key[0] == "BADSIG":
ui.write(_("%s Bad signature from \"%s\"\n") % (prefix, key[2]))
continue
if key[0] == "EXPSIG":
ui.write(_("%s Note: Signature has expired"
" (signed by: \"%s\")\n") % (prefix, key[2]))
elif key[0] == "EXPKEYSIG":
ui.write(_("%s Note: This key has expired"
" (signed by: \"%s\")\n") % (prefix, key[2]))
validkeys.append((key[1], key[2], key[3]))
return validkeys
@command("sigs", [], _('hg sigs'))
def sigs(ui, repo):
"""list signed changesets"""
mygpg = newgpg(ui)
revs = {}
for data, context in sigwalk(repo):
node, version, sig = data
fn, ln = context
try:
n = repo.lookup(node)
except KeyError:
ui.warn(_("%s:%d node does not exist\n") % (fn, ln))
continue
r = repo.changelog.rev(n)
keys = getkeys(ui, repo, mygpg, data, context)
if not keys:
continue
revs.setdefault(r, [])
revs[r].extend(keys)
for rev in sorted(revs, reverse=True):
for k in revs[rev]:
r = "%5d:%s" % (rev, hgnode.hex(repo.changelog.node(rev)))
ui.write("%-30s %s\n" % (keystr(ui, k), r))
@command("sigcheck", [], _('hg sigcheck REV'))
def sigcheck(ui, repo, rev):
"""verify all the signatures there may be for a particular revision"""
mygpg = newgpg(ui)
rev = repo.lookup(rev)
hexrev = hgnode.hex(rev)
keys = []
for data, context in sigwalk(repo):
node, version, sig = data
if node == hexrev:
k = getkeys(ui, repo, mygpg, data, context)
if k:
keys.extend(k)
if not keys:
ui.write(_("no valid signature for %s\n") % hgnode.short(rev))
return
# print summary
ui.write(_("%s is signed by:\n") % hgnode.short(rev))
for key in keys:
ui.write(" %s\n" % keystr(ui, key))
def keystr(ui, key):
"""associate a string to a key (username, comment)"""
keyid, user, fingerprint = key
comment = ui.config("gpg", fingerprint)
if comment:
return "%s (%s)" % (user, comment)
else:
return user
@command("sign",
[('l', 'local', None, _('make the signature local')),
('f', 'force', None, _('sign even if the sigfile is modified')),
('', 'no-commit', None, _('do not commit the sigfile after signing')),
('k', 'key', '',
_('the key id to sign with'), _('ID')),
('m', 'message', '',
_('use text as commit message'), _('TEXT')),
('e', 'edit', False, _('invoke editor on commit messages')),
] + cmdutil.commitopts2,
_('hg sign [OPTION]... [REV]...'))
def sign(ui, repo, *revs, **opts):
"""add a signature for the current or given revision
If no revision is given, the parent of the working directory is used,
or tip if no revision is checked out.
The ``gpg.cmd`` config setting can be used to specify the command
to run. A default key can be specified with ``gpg.key``.
See :hg:`help dates` for a list of formats valid for -d/--date.
"""
with repo.wlock():
return _dosign(ui, repo, *revs, **opts)
def _dosign(ui, repo, *revs, **opts):
mygpg = newgpg(ui, **opts)
opts = pycompat.byteskwargs(opts)
sigver = "0"
sigmessage = ""
date = opts.get('date')
if date:
opts['date'] = dateutil.parsedate(date)
if revs:
nodes = [repo.lookup(n) for n in revs]
else:
nodes = [node for node in repo.dirstate.parents()
if node != hgnode.nullid]
if len(nodes) > 1:
raise error.Abort(_('uncommitted merge - please provide a '
'specific revision'))
if not nodes:
nodes = [repo.changelog.tip()]
for n in nodes:
hexnode = hgnode.hex(n)
ui.write(_("signing %d:%s\n") % (repo.changelog.rev(n),
hgnode.short(n)))
# build data
data = node2txt(repo, n, sigver)
sig = mygpg.sign(data)
if not sig:
raise error.Abort(_("error while signing"))
sig = binascii.b2a_base64(sig)
sig = sig.replace("\n", "")
sigmessage += "%s %s %s\n" % (hexnode, sigver, sig)
# write it
if opts['local']:
repo.vfs.append("localsigs", sigmessage)
return
if not opts["force"]:
msigs = match.exact(repo.root, '', ['.hgsigs'])
if any(repo.status(match=msigs, unknown=True, ignored=True)):
raise error.Abort(_("working copy of .hgsigs is changed "),
hint=_("please commit .hgsigs manually"))
sigsfile = repo.wvfs(".hgsigs", "ab")
sigsfile.write(sigmessage)
sigsfile.close()
if '.hgsigs' not in repo.dirstate:
repo[None].add([".hgsigs"])
if opts["no_commit"]:
return
message = opts['message']
if not message:
# we don't translate commit messages
message = "\n".join(["Added signature for changeset %s"
% hgnode.short(n)
for n in nodes])
try:
editor = cmdutil.getcommiteditor(editform='gpg.sign',
**pycompat.strkwargs(opts))
repo.commit(message, opts['user'], opts['date'], match=msigs,
editor=editor)
except ValueError as inst:
raise error.Abort(pycompat.bytestr(inst))
def node2txt(repo, node, ver):
"""map a manifest into some text"""
if ver == "0":
return "%s\n" % hgnode.hex(node)
else:
raise error.Abort(_("unknown signature version"))