view tests/test-trusted.py @ 46607:e9901d01d135

revlog: add a mechanism to verify expected file position before appending

If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.

The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)

When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.

For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.

This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.

Differential Revision: https://phab.mercurial-scm.org/D9952

# Since it's not easy to write a test that portably deals
# with files from different users/groups, we cheat a bit by
# monkey-patching some functions in the util module

from __future__ import absolute_import, print_function

import os
import sys

from mercurial import (
    error,
    pycompat,
    ui as uimod,
    util,
)
from mercurial.utils import stringutil

hgrc = os.environ['HGRCPATH']
f = open(hgrc, 'rb')
basehgrc = f.read()
f.close()


def _maybesysstr(v):
    if isinstance(v, bytes):
        return pycompat.sysstr(v)
    return pycompat.sysstr(stringutil.pprint(v))


def bprint(*args, **kwargs):
    print(
        *[_maybesysstr(a) for a in args],
        **{k: _maybesysstr(v) for k, v in kwargs.items()}
    )
    # avoid awkward interleaving with ui object's output
    sys.stdout.flush()


def testui(
    user=b'foo',
    group=b'bar',
    tusers=(),
    tgroups=(),
    cuser=b'foo',
    cgroup=b'bar',
    debug=False,
    silent=False,
    report=True,
):
    # user, group => owners of the file
    # tusers, tgroups => trusted users/groups
    # cuser, cgroup => user/group of the current process

    # write a global hgrc with the list of trusted users/groups and
    # some setting so that we can be sure it was read
    f = open(hgrc, 'wb')
    f.write(basehgrc)
    f.write(b'\n[paths]\n')
    f.write(b'global = /some/path\n\n')

    if tusers or tgroups:
        f.write(b'[trusted]\n')
        if tusers:
            f.write(b'users = %s\n' % b', '.join(tusers))
        if tgroups:
            f.write(b'groups = %s\n' % b', '.join(tgroups))
    f.close()

    # override the functions that give names to uids and gids
    def username(uid=None):
        if uid is None:
            return cuser
        return user

    util.username = username

    def groupname(gid=None):
        if gid is None:
            return b'bar'
        return group

    util.groupname = groupname

    def isowner(st):
        return user == cuser

    util.isowner = isowner

    # try to read everything
    # print '# File belongs to user %s, group %s' % (user, group)
    # print '# trusted users = %s; trusted groups = %s' % (tusers, tgroups)
    kind = (b'different', b'same')
    who = (b'', b'user', b'group', b'user and the group')
    trusted = who[(user in tusers) + 2 * (group in tgroups)]
    if trusted:
        trusted = b', but we trust the ' + trusted
    bprint(
        b'# %s user, %s group%s'
        % (kind[user == cuser], kind[group == cgroup], trusted)
    )

    u = uimod.ui.load()
    # disable the configuration registration warning
    #
    # the purpose of this test is to check the old behavior, not to validate the
    # behavior from registered item. so we silent warning related to unregisted
    # config.
    u.setconfig(b'devel', b'warn-config-unknown', False, b'test')
    u.setconfig(b'devel', b'all-warnings', False, b'test')
    u.setconfig(b'ui', b'debug', pycompat.bytestr(bool(debug)))
    u.setconfig(b'ui', b'report_untrusted', pycompat.bytestr(bool(report)))
    u.readconfig(b'.hg/hgrc')
    if silent:
        return u
    bprint(b'trusted')
    for name, path in u.configitems(b'paths'):
        bprint(b'   ', name, b'=', util.pconvert(path))
    bprint(b'untrusted')
    for name, path in u.configitems(b'paths', untrusted=True):
        bprint(b'.', end=b' ')
        u.config(b'paths', name)  # warning with debug=True
        bprint(b'.', end=b' ')
        u.config(b'paths', name, untrusted=True)  # no warnings
        bprint(name, b'=', util.pconvert(path))
    print()

    return u


os.mkdir(b'repo')
os.chdir(b'repo')
os.mkdir(b'.hg')
f = open(b'.hg/hgrc', 'wb')
f.write(b'[paths]\n')
f.write(b'local = /another/path\n\n')
f.close()

# print '# Everything is run by user foo, group bar\n'

# same user, same group
testui()
# same user, different group
testui(group=b'def')
# different user, same group
testui(user=b'abc')
# ... but we trust the group
testui(user=b'abc', tgroups=[b'bar'])
# different user, different group
testui(user=b'abc', group=b'def')
# ... but we trust the user
testui(user=b'abc', group=b'def', tusers=[b'abc'])
# ... but we trust the group
testui(user=b'abc', group=b'def', tgroups=[b'def'])
# ... but we trust the user and the group
testui(user=b'abc', group=b'def', tusers=[b'abc'], tgroups=[b'def'])
# ... but we trust all users
bprint(b'# we trust all users')
testui(user=b'abc', group=b'def', tusers=[b'*'])
# ... but we trust all groups
bprint(b'# we trust all groups')
testui(user=b'abc', group=b'def', tgroups=[b'*'])
# ... but we trust the whole universe
bprint(b'# we trust all users and groups')
testui(user=b'abc', group=b'def', tusers=[b'*'], tgroups=[b'*'])
# ... check that users and groups are in different namespaces
bprint(b"# we don't get confused by users and groups with the same name")
testui(user=b'abc', group=b'def', tusers=[b'def'], tgroups=[b'abc'])
# ... lists of user names work
bprint(b"# list of user names")
testui(
    user=b'abc',
    group=b'def',
    tusers=[b'foo', b'xyz', b'abc', b'bleh'],
    tgroups=[b'bar', b'baz', b'qux'],
)
# ... lists of group names work
bprint(b"# list of group names")
testui(
    user=b'abc',
    group=b'def',
    tusers=[b'foo', b'xyz', b'bleh'],
    tgroups=[b'bar', b'def', b'baz', b'qux'],
)

bprint(b"# Can't figure out the name of the user running this process")
testui(user=b'abc', group=b'def', cuser=None)

bprint(b"# prints debug warnings")
u = testui(user=b'abc', group=b'def', cuser=b'foo', debug=True)

bprint(b"# report_untrusted enabled without debug hides warnings")
u = testui(user=b'abc', group=b'def', cuser=b'foo', report=False)

bprint(b"# report_untrusted enabled with debug shows warnings")
u = testui(user=b'abc', group=b'def', cuser=b'foo', debug=True, report=False)

bprint(b"# ui.readconfig sections")
filename = b'foobar'
f = open(filename, 'wb')
f.write(b'[foobar]\n')
f.write(b'baz = quux\n')
f.close()
u.readconfig(filename, sections=[b'foobar'])
bprint(u.config(b'foobar', b'baz'))

print()
bprint(b"# read trusted, untrusted, new ui, trusted")
u = uimod.ui.load()
# disable the configuration registration warning
#
# the purpose of this test is to check the old behavior, not to validate the
# behavior from registered item. so we silent warning related to unregisted
# config.
u.setconfig(b'devel', b'warn-config-unknown', False, b'test')
u.setconfig(b'devel', b'all-warnings', False, b'test')
u.setconfig(b'ui', b'debug', b'on')
u.readconfig(filename)
u2 = u.copy()


def username(uid=None):
    return b'foo'


util.username = username
u2.readconfig(b'.hg/hgrc')
bprint(b'trusted:')
bprint(u2.config(b'foobar', b'baz'))
bprint(b'untrusted:')
bprint(u2.config(b'foobar', b'baz', untrusted=True))

print()
bprint(b"# error handling")


def assertraises(f, exc=error.Abort):
    try:
        f()
    except exc as inst:
        bprint(b'raised', inst.__class__.__name__)
    else:
        bprint(b'no exception?!')


bprint(b"# file doesn't exist")
os.unlink(b'.hg/hgrc')
assert not os.path.exists(b'.hg/hgrc')
testui(debug=True, silent=True)
testui(user=b'abc', group=b'def', debug=True, silent=True)

print()
bprint(b"# parse error")
f = open(b'.hg/hgrc', 'wb')
f.write(b'foo')
f.close()

try:
    testui(user=b'abc', group=b'def', silent=True)
except error.ConfigError as inst:
    bprint(inst.format())

try:
    testui(debug=True, silent=True)
except error.ConfigError as inst:
    bprint(inst.format())

print()
bprint(b'# access typed information')
with open(b'.hg/hgrc', 'wb') as f:
    f.write(
        b'''\
[foo]
sub=main
sub:one=one
sub:two=two
path=monty/python
bool=true
int=42
bytes=81mb
list=spam,ham,eggs
'''
    )
u = testui(user=b'abc', group=b'def', cuser=b'foo', silent=True)


def configpath(section, name, default=None, untrusted=False):
    path = u.configpath(section, name, default, untrusted)
    if path is None:
        return None
    return util.pconvert(path)


bprint(b'# suboptions, trusted and untrusted')
trusted = u.configsuboptions(b'foo', b'sub')
untrusted = u.configsuboptions(b'foo', b'sub', untrusted=True)
bprint(
    (trusted[0], sorted(trusted[1].items())),
    (untrusted[0], sorted(untrusted[1].items())),
)
bprint(b'# path, trusted and untrusted')
bprint(configpath(b'foo', b'path'), configpath(b'foo', b'path', untrusted=True))
bprint(b'# bool, trusted and untrusted')
bprint(
    u.configbool(b'foo', b'bool'), u.configbool(b'foo', b'bool', untrusted=True)
)
bprint(b'# int, trusted and untrusted')
bprint(
    u.configint(b'foo', b'int', 0),
    u.configint(b'foo', b'int', 0, untrusted=True),
)
bprint(b'# bytes, trusted and untrusted')
bprint(
    u.configbytes(b'foo', b'bytes', 0),
    u.configbytes(b'foo', b'bytes', 0, untrusted=True),
)
bprint(b'# list, trusted and untrusted')
bprint(
    u.configlist(b'foo', b'list', []),
    u.configlist(b'foo', b'list', [], untrusted=True),
)