view mercurial/fileset.py @ 36756:2ecb0fc535b1 stable

hgweb: always perform permissions checks on protocol commands (BC) (SEC)

Previously, the HTTP request handling code would only perform
permissions checking on a wire protocol command if that wire protocol
command defined its permissions / operation type. This meant that
commands (possibly provided by extensions) not defining their
operation type would bypass permissions check. This could lead
to exfiltration of data from servers and mutating repositories that
were supposed to be read-only.

This security issue has been present since the permissions table
was introduced by d3147b4e3e8a in 2008.

This commit changes the behavior of the HTTP server to always
perform permissions checking for protocol requests. If an
explicit permission for a wire protocol command is not defined,
the server assumes the command can be used for writing and
governs access accordingly.

.. bc::

   Wire protocol commands not defining their operation type in
   ``wireproto.PERMISSIONS`` are now assumed to be used for
   "push" operations and access control to run those commands
   is now enforced accordingly.

# fileset.py - file set queries for mercurial
#
# Copyright 2010 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import re

from .i18n import _
from . import (
    error,
    match as matchmod,
    merge,
    parser,
    pycompat,
    registrar,
    scmutil,
    util,
)

elements = {
    # token-type: binding-strength, primary, prefix, infix, suffix
    "(": (20, None, ("group", 1, ")"), ("func", 1, ")"), None),
    ":": (15, None, None, ("kindpat", 15), None),
    "-": (5, None, ("negate", 19), ("minus", 5), None),
    "not": (10, None, ("not", 10), None, None),
    "!": (10, None, ("not", 10), None, None),
    "and": (5, None, None, ("and", 5), None),
    "&": (5, None, None, ("and", 5), None),
    "or": (4, None, None, ("or", 4), None),
    "|": (4, None, None, ("or", 4), None),
    "+": (4, None, None, ("or", 4), None),
    ",": (2, None, None, ("list", 2), None),
    ")": (0, None, None, None, None),
    "symbol": (0, "symbol", None, None, None),
    "string": (0, "string", None, None, None),
    "end": (0, None, None, None, None),
}

keywords = {'and', 'or', 'not'}

globchars = ".*{}[]?/\\_"

def tokenize(program):
    pos, l = 0, len(program)
    program = pycompat.bytestr(program)
    while pos < l:
        c = program[pos]
        if c.isspace(): # skip inter-token whitespace
            pass
        elif c in "(),-:|&+!": # handle simple operators
            yield (c, None, pos)
        elif (c in '"\'' or c == 'r' and
              program[pos:pos + 2] in ("r'", 'r"')): # handle quoted strings
            if c == 'r':
                pos += 1
                c = program[pos]
                decode = lambda x: x
            else:
                decode = parser.unescapestr
            pos += 1
            s = pos
            while pos < l: # find closing quote
                d = program[pos]
                if d == '\\': # skip over escaped characters
                    pos += 2
                    continue
                if d == c:
                    yield ('string', decode(program[s:pos]), s)
                    break
                pos += 1
            else:
                raise error.ParseError(_("unterminated string"), s)
        elif c.isalnum() or c in globchars or ord(c) > 127:
            # gather up a symbol/keyword
            s = pos
            pos += 1
            while pos < l: # find end of symbol
                d = program[pos]
                if not (d.isalnum() or d in globchars or ord(d) > 127):
                    break
                pos += 1
            sym = program[s:pos]
            if sym in keywords: # operator keywords
                yield (sym, None, s)
            else:
                yield ('symbol', sym, s)
            pos -= 1
        else:
            raise error.ParseError(_("syntax error"), pos)
        pos += 1
    yield ('end', None, pos)

def parse(expr):
    p = parser.parser(elements)
    tree, pos = p.parse(tokenize(expr))
    if pos != len(expr):
        raise error.ParseError(_("invalid token"), pos)
    return tree

def getsymbol(x):
    if x and x[0] == 'symbol':
        return x[1]
    raise error.ParseError(_('not a symbol'))

def getstring(x, err):
    if x and (x[0] == 'string' or x[0] == 'symbol'):
        return x[1]
    raise error.ParseError(err)

def _getkindpat(x, y, allkinds, err):
    kind = getsymbol(x)
    pat = getstring(y, err)
    if kind not in allkinds:
        raise error.ParseError(_("invalid pattern kind: %s") % kind)
    return '%s:%s' % (kind, pat)

def getpattern(x, allkinds, err):
    if x and x[0] == 'kindpat':
        return _getkindpat(x[1], x[2], allkinds, err)
    return getstring(x, err)

def getset(mctx, x):
    if not x:
        raise error.ParseError(_("missing argument"))
    return methods[x[0]](mctx, *x[1:])

def stringset(mctx, x):
    m = mctx.matcher([x])
    return [f for f in mctx.subset if m(f)]

def kindpatset(mctx, x, y):
    return stringset(mctx, _getkindpat(x, y, matchmod.allpatternkinds,
                                       _("pattern must be a string")))

def andset(mctx, x, y):
    return getset(mctx.narrow(getset(mctx, x)), y)

def orset(mctx, x, y):
    # needs optimizing
    xl = getset(mctx, x)
    yl = getset(mctx, y)
    return xl + [f for f in yl if f not in xl]

def notset(mctx, x):
    s = set(getset(mctx, x))
    return [r for r in mctx.subset if r not in s]

def minusset(mctx, x, y):
    xl = getset(mctx, x)
    yl = set(getset(mctx, y))
    return [f for f in xl if f not in yl]

def negateset(mctx, x):
    raise error.ParseError(_("can't use negate operator in this context"))

def listset(mctx, a, b):
    raise error.ParseError(_("can't use a list in this context"),
                           hint=_('see hg help "filesets.x or y"'))

# symbols are callable like:
#  fun(mctx, x)
# with:
#  mctx - current matchctx instance
#  x - argument in tree form
symbols = {}

# filesets using matchctx.status()
_statuscallers = set()

# filesets using matchctx.existing()
_existingcallers = set()

predicate = registrar.filesetpredicate()

@predicate('modified()', callstatus=True)
def modified(mctx, x):
    """File that is modified according to :hg:`status`.
    """
    # i18n: "modified" is a keyword
    getargs(x, 0, 0, _("modified takes no arguments"))
    s = set(mctx.status().modified)
    return [f for f in mctx.subset if f in s]

@predicate('added()', callstatus=True)
def added(mctx, x):
    """File that is added according to :hg:`status`.
    """
    # i18n: "added" is a keyword
    getargs(x, 0, 0, _("added takes no arguments"))
    s = set(mctx.status().added)
    return [f for f in mctx.subset if f in s]

@predicate('removed()', callstatus=True)
def removed(mctx, x):
    """File that is removed according to :hg:`status`.
    """
    # i18n: "removed" is a keyword
    getargs(x, 0, 0, _("removed takes no arguments"))
    s = set(mctx.status().removed)
    return [f for f in mctx.subset if f in s]

@predicate('deleted()', callstatus=True)
def deleted(mctx, x):
    """Alias for ``missing()``.
    """
    # i18n: "deleted" is a keyword
    getargs(x, 0, 0, _("deleted takes no arguments"))
    s = set(mctx.status().deleted)
    return [f for f in mctx.subset if f in s]

@predicate('missing()', callstatus=True)
def missing(mctx, x):
    """File that is missing according to :hg:`status`.
    """
    # i18n: "missing" is a keyword
    getargs(x, 0, 0, _("missing takes no arguments"))
    s = set(mctx.status().deleted)
    return [f for f in mctx.subset if f in s]

@predicate('unknown()', callstatus=True)
def unknown(mctx, x):
    """File that is unknown according to :hg:`status`. These files will only be
    considered if this predicate is used.
    """
    # i18n: "unknown" is a keyword
    getargs(x, 0, 0, _("unknown takes no arguments"))
    s = set(mctx.status().unknown)
    return [f for f in mctx.subset if f in s]

@predicate('ignored()', callstatus=True)
def ignored(mctx, x):
    """File that is ignored according to :hg:`status`. These files will only be
    considered if this predicate is used.
    """
    # i18n: "ignored" is a keyword
    getargs(x, 0, 0, _("ignored takes no arguments"))
    s = set(mctx.status().ignored)
    return [f for f in mctx.subset if f in s]

@predicate('clean()', callstatus=True)
def clean(mctx, x):
    """File that is clean according to :hg:`status`.
    """
    # i18n: "clean" is a keyword
    getargs(x, 0, 0, _("clean takes no arguments"))
    s = set(mctx.status().clean)
    return [f for f in mctx.subset if f in s]

def func(mctx, a, b):
    funcname = getsymbol(a)
    if funcname in symbols:
        enabled = mctx._existingenabled
        mctx._existingenabled = funcname in _existingcallers
        try:
            return symbols[funcname](mctx, b)
        finally:
            mctx._existingenabled = enabled

    keep = lambda fn: getattr(fn, '__doc__', None) is not None

    syms = [s for (s, fn) in symbols.items() if keep(fn)]
    raise error.UnknownIdentifier(funcname, syms)

def getlist(x):
    if not x:
        return []
    if x[0] == 'list':
        return getlist(x[1]) + [x[2]]
    return [x]

def getargs(x, min, max, err):
    l = getlist(x)
    if len(l) < min or len(l) > max:
        raise error.ParseError(err)
    return l

@predicate('binary()', callexisting=True)
def binary(mctx, x):
    """File that appears to be binary (contains NUL bytes).
    """
    # i18n: "binary" is a keyword
    getargs(x, 0, 0, _("binary takes no arguments"))
    return [f for f in mctx.existing() if mctx.ctx[f].isbinary()]

@predicate('exec()', callexisting=True)
def exec_(mctx, x):
    """File that is marked as executable.
    """
    # i18n: "exec" is a keyword
    getargs(x, 0, 0, _("exec takes no arguments"))
    return [f for f in mctx.existing() if mctx.ctx.flags(f) == 'x']

@predicate('symlink()', callexisting=True)
def symlink(mctx, x):
    """File that is marked as a symlink.
    """
    # i18n: "symlink" is a keyword
    getargs(x, 0, 0, _("symlink takes no arguments"))
    return [f for f in mctx.existing() if mctx.ctx.flags(f) == 'l']

@predicate('resolved()')
def resolved(mctx, x):
    """File that is marked resolved according to :hg:`resolve -l`.
    """
    # i18n: "resolved" is a keyword
    getargs(x, 0, 0, _("resolved takes no arguments"))
    if mctx.ctx.rev() is not None:
        return []
    ms = merge.mergestate.read(mctx.ctx.repo())
    return [f for f in mctx.subset if f in ms and ms[f] == 'r']

@predicate('unresolved()')
def unresolved(mctx, x):
    """File that is marked unresolved according to :hg:`resolve -l`.
    """
    # i18n: "unresolved" is a keyword
    getargs(x, 0, 0, _("unresolved takes no arguments"))
    if mctx.ctx.rev() is not None:
        return []
    ms = merge.mergestate.read(mctx.ctx.repo())
    return [f for f in mctx.subset if f in ms and ms[f] == 'u']

@predicate('hgignore()')
def hgignore(mctx, x):
    """File that matches the active .hgignore pattern.
    """
    # i18n: "hgignore" is a keyword
    getargs(x, 0, 0, _("hgignore takes no arguments"))
    ignore = mctx.ctx.repo().dirstate._ignore
    return [f for f in mctx.subset if ignore(f)]

@predicate('portable()')
def portable(mctx, x):
    """File that has a portable name. (This doesn't include filenames with case
    collisions.)
    """
    # i18n: "portable" is a keyword
    getargs(x, 0, 0, _("portable takes no arguments"))
    checkwinfilename = util.checkwinfilename
    return [f for f in mctx.subset if checkwinfilename(f) is None]

@predicate('grep(regex)', callexisting=True)
def grep(mctx, x):
    """File contains the given regular expression.
    """
    try:
        # i18n: "grep" is a keyword
        r = re.compile(getstring(x, _("grep requires a pattern")))
    except re.error as e:
        raise error.ParseError(_('invalid match pattern: %s') % e)
    return [f for f in mctx.existing() if r.search(mctx.ctx[f].data())]

def _sizetomax(s):
    try:
        s = s.strip().lower()
        for k, v in util._sizeunits:
            if s.endswith(k):
                # max(4k) = 5k - 1, max(4.5k) = 4.6k - 1
                n = s[:-len(k)]
                inc = 1.0
                if "." in n:
                    inc /= 10 ** len(n.split(".")[1])
                return int((float(n) + inc) * v) - 1
        # no extension, this is a precise value
        return int(s)
    except ValueError:
        raise error.ParseError(_("couldn't parse size: %s") % s)

def sizematcher(x):
    """Return a function(size) -> bool from the ``size()`` expression"""

    # i18n: "size" is a keyword
    expr = getstring(x, _("size requires an expression")).strip()
    if '-' in expr: # do we have a range?
        a, b = expr.split('-', 1)
        a = util.sizetoint(a)
        b = util.sizetoint(b)
        return lambda x: x >= a and x <= b
    elif expr.startswith("<="):
        a = util.sizetoint(expr[2:])
        return lambda x: x <= a
    elif expr.startswith("<"):
        a = util.sizetoint(expr[1:])
        return lambda x: x < a
    elif expr.startswith(">="):
        a = util.sizetoint(expr[2:])
        return lambda x: x >= a
    elif expr.startswith(">"):
        a = util.sizetoint(expr[1:])
        return lambda x: x > a
    elif expr[0].isdigit or expr[0] == '.':
        a = util.sizetoint(expr)
        b = _sizetomax(expr)
        return lambda x: x >= a and x <= b
    raise error.ParseError(_("couldn't parse size: %s") % expr)

@predicate('size(expression)', callexisting=True)
def size(mctx, x):
    """File size matches the given expression. Examples:

    - size('1k') - files from 1024 to 2047 bytes
    - size('< 20k') - files less than 20480 bytes
    - size('>= .5MB') - files at least 524288 bytes
    - size('4k - 1MB') - files from 4096 bytes to 1048576 bytes
    """
    m = sizematcher(x)
    return [f for f in mctx.existing() if m(mctx.ctx[f].size())]

@predicate('encoding(name)', callexisting=True)
def encoding(mctx, x):
    """File can be successfully decoded with the given character
    encoding. May not be useful for encodings other than ASCII and
    UTF-8.
    """

    # i18n: "encoding" is a keyword
    enc = getstring(x, _("encoding requires an encoding name"))

    s = []
    for f in mctx.existing():
        d = mctx.ctx[f].data()
        try:
            d.decode(enc)
        except LookupError:
            raise error.Abort(_("unknown encoding '%s'") % enc)
        except UnicodeDecodeError:
            continue
        s.append(f)

    return s

@predicate('eol(style)', callexisting=True)
def eol(mctx, x):
    """File contains newlines of the given style (dos, unix, mac). Binary
    files are excluded, files with mixed line endings match multiple
    styles.
    """

    # i18n: "eol" is a keyword
    enc = getstring(x, _("eol requires a style name"))

    s = []
    for f in mctx.existing():
        d = mctx.ctx[f].data()
        if util.binary(d):
            continue
        if (enc == 'dos' or enc == 'win') and '\r\n' in d:
            s.append(f)
        elif enc == 'unix' and re.search('(?<!\r)\n', d):
            s.append(f)
        elif enc == 'mac' and re.search('\r(?!\n)', d):
            s.append(f)
    return s

@predicate('copied()')
def copied(mctx, x):
    """File that is recorded as being copied.
    """
    # i18n: "copied" is a keyword
    getargs(x, 0, 0, _("copied takes no arguments"))
    s = []
    for f in mctx.subset:
        if f in mctx.ctx:
            p = mctx.ctx[f].parents()
            if p and p[0].path() != f:
                s.append(f)
    return s

@predicate('revs(revs, pattern)')
def revs(mctx, x):
    """Evaluate set in the specified revisions. If the revset match multiple
    revs, this will return file matching pattern in any of the revision.
    """
    # i18n: "revs" is a keyword
    r, x = getargs(x, 2, 2, _("revs takes two arguments"))
    # i18n: "revs" is a keyword
    revspec = getstring(r, _("first argument to revs must be a revision"))
    repo = mctx.ctx.repo()
    revs = scmutil.revrange(repo, [revspec])

    found = set()
    result = []
    for r in revs:
        ctx = repo[r]
        for f in getset(mctx.switch(ctx, _buildstatus(ctx, x)), x):
            if f not in found:
                found.add(f)
                result.append(f)
    return result

@predicate('status(base, rev, pattern)')
def status(mctx, x):
    """Evaluate predicate using status change between ``base`` and
    ``rev``. Examples:

    - ``status(3, 7, added())`` - matches files added from "3" to "7"
    """
    repo = mctx.ctx.repo()
    # i18n: "status" is a keyword
    b, r, x = getargs(x, 3, 3, _("status takes three arguments"))
    # i18n: "status" is a keyword
    baseerr = _("first argument to status must be a revision")
    baserevspec = getstring(b, baseerr)
    if not baserevspec:
        raise error.ParseError(baseerr)
    reverr = _("second argument to status must be a revision")
    revspec = getstring(r, reverr)
    if not revspec:
        raise error.ParseError(reverr)
    basenode, node = scmutil.revpair(repo, [baserevspec, revspec])
    basectx = repo[basenode]
    ctx = repo[node]
    return getset(mctx.switch(ctx, _buildstatus(ctx, x, basectx=basectx)), x)

@predicate('subrepo([pattern])')
def subrepo(mctx, x):
    """Subrepositories whose paths match the given pattern.
    """
    # i18n: "subrepo" is a keyword
    getargs(x, 0, 1, _("subrepo takes at most one argument"))
    ctx = mctx.ctx
    sstate = sorted(ctx.substate)
    if x:
        pat = getpattern(x, matchmod.allpatternkinds,
                         # i18n: "subrepo" is a keyword
                         _("subrepo requires a pattern or no arguments"))
        fast = not matchmod.patkind(pat)
        if fast:
            def m(s):
                return (s == pat)
        else:
            m = matchmod.match(ctx.repo().root, '', [pat], ctx=ctx)
        return [sub for sub in sstate if m(sub)]
    else:
        return [sub for sub in sstate]

methods = {
    'string': stringset,
    'symbol': stringset,
    'kindpat': kindpatset,
    'and': andset,
    'or': orset,
    'minus': minusset,
    'negate': negateset,
    'list': listset,
    'group': getset,
    'not': notset,
    'func': func,
}

class matchctx(object):
    def __init__(self, ctx, subset, status=None):
        self.ctx = ctx
        self.subset = subset
        self._status = status
        self._existingenabled = False
    def status(self):
        return self._status
    def matcher(self, patterns):
        return self.ctx.match(patterns)
    def filter(self, files):
        return [f for f in files if f in self.subset]
    def existing(self):
        assert self._existingenabled, 'unexpected existing() invocation'
        if self._status is not None:
            removed = set(self._status[3])
            unknown = set(self._status[4] + self._status[5])
        else:
            removed = set()
            unknown = set()
        return (f for f in self.subset
                if (f in self.ctx and f not in removed) or f in unknown)
    def narrow(self, files):
        return matchctx(self.ctx, self.filter(files), self._status)
    def switch(self, ctx, status=None):
        subset = self.filter(_buildsubset(ctx, status))
        return matchctx(ctx, subset, status)

class fullmatchctx(matchctx):
    """A match context where any files in any revisions should be valid"""

    def __init__(self, ctx, status=None):
        subset = _buildsubset(ctx, status)
        super(fullmatchctx, self).__init__(ctx, subset, status)
    def switch(self, ctx, status=None):
        return fullmatchctx(ctx, status)

# filesets using matchctx.switch()
_switchcallers = [
    'revs',
    'status',
]

def _intree(funcs, tree):
    if isinstance(tree, tuple):
        if tree[0] == 'func' and tree[1][0] == 'symbol':
            if tree[1][1] in funcs:
                return True
            if tree[1][1] in _switchcallers:
                # arguments won't be evaluated in the current context
                return False
        for s in tree[1:]:
            if _intree(funcs, s):
                return True
    return False

def _buildsubset(ctx, status):
    if status:
        subset = []
        for c in status:
            subset.extend(c)
        return subset
    else:
        return list(ctx.walk(ctx.match([])))

def getfileset(ctx, expr):
    tree = parse(expr)
    return getset(fullmatchctx(ctx, _buildstatus(ctx, tree)), tree)

def _buildstatus(ctx, tree, basectx=None):
    # do we need status info?

    # temporaty boolean to simplify the next conditional
    purewdir = ctx.rev() is None and basectx is None

    if (_intree(_statuscallers, tree) or
        # Using matchctx.existing() on a workingctx requires us to check
        # for deleted files.
        (purewdir and _intree(_existingcallers, tree))):
        unknown = _intree(['unknown'], tree)
        ignored = _intree(['ignored'], tree)

        r = ctx.repo()
        if basectx is None:
            basectx = ctx.p1()
        return r.status(basectx, ctx,
                        unknown=unknown, ignored=ignored, clean=True)
    else:
        return None

def prettyformat(tree):
    return parser.prettyformat(tree, ('string', 'symbol'))

def loadpredicate(ui, extname, registrarobj):
    """Load fileset predicates from specified registrarobj
    """
    for name, func in registrarobj._table.iteritems():
        symbols[name] = func
        if func._callstatus:
            _statuscallers.add(name)
        if func._callexisting:
            _existingcallers.add(name)

# load built-in predicates explicitly to setup _statuscallers/_existingcallers
loadpredicate(None, None, predicate)

# tell hggettext to extract docstrings from these functions:
i18nfunctions = symbols.values()