view tests/test-contrib-check-code.t @ 36755:ff4bc0ab6740 stable

wireproto: check permissions when executing "batch" command (BC) (SEC)

For as long as the "batch" command has existed (introduced by
bd88561afb4b and first released as part of Mercurial 1.9), that command
(like most wire commands introduced after 2008) lacked an entry in
the hgweb permissions table. And since we don't verify permissions if
an entry is missing from the permissions table, this meant that
executing a command via "batch" would bypass all permissions
checks.

The security implications are significant: a Mercurial HTTP server
would allow writes via "batch" wire protocol commands as long as
the HTTP request were processed by Mercurial and the process running
the Mercurial HTTP server had write access to the repository. The
Mercurial defaults of servers being read-only and the various web.*
config options to define access control were bypassed.

In addition, "batch" could be used to exfiltrate data from servers
that were configured to not allow read access.

Both forms of permissions bypass could be mitigated to some extent
by using HTTP authentication. This would prevent HTTP requests from
hitting Mercurial's server logic. However, any authenticated request
would still be able to bypass permissions checks via "batch" commands.

The easiest exploit was to send "pushkey" commands via "batch" and
modify the state of bookmarks, phases, and obsolescence markers.
However, I suspect a well-crafted HTTP request could trick the server
into running the "unbundle" wire protocol command, effectively
performing a full `hg push` to create new changesets on the remote.

This commit plugs this gaping security hole by having the "batch"
command perform permissions checking on each sub-command that is
being batched. We do this by threading a permissions checking
callable all the way to the protocol handler. The threading is a
bit hacky from a code perspective. But it preserves API compatibility,
which is the proper thing to do on the stable branch.

One of the subtle things we do is assume that a command with an
undefined permission is a "push" command. This is the safest thing to
do from a security perspective: we don't want to take chances that
a command could perform a write even though the server is configured
to not allow writes.

As the test changes demonstrate, it is no longer possible to bypass
permissions via the "batch" wire protocol command.

.. bc::

   The "batch" wire protocol command now enforces permissions of
   each invoked sub-command. Wire protocol commands must define
   their operation type or the "batch" command will assume they
   can write data and will prevent their execution on HTTP servers
   unless the HTTP request method is POST, the server is configured
   to allow pushes, and the (possibly authenticated) HTTP user is
   authorized to perform a push.

  $ cat > correct.py <<EOF
  > def toto(arg1, arg2):
  >     del arg2
  >     return (5 + 6, 9)
  > EOF
  $ cat > wrong.py <<EOF
  > def toto( arg1, arg2):
  >     del(arg2)
  >     return ( 5+6, 9)
  > EOF
  $ cat > quote.py <<EOF
  > # let's use quote in comments
  > (''' ( 4x5 )
  > but """\\''' and finally''',
  > """let's fool checkpatch""", '1+2',
  > '"""', 42+1, """and
  > ( 4-1 ) """, "( 1+1 )\" and ")
  > a, '\\\\\\\\', "\\\\\\" x-2", "c-1"
  > EOF
  $ cat > classstyle.py <<EOF
  > class newstyle_class(object):
  >     pass
  > 
  > class oldstyle_class:
  >     pass
  > 
  > class empty():
  >     pass
  > 
  > no_class = 1:
  >     pass
  > EOF
  $ check_code="$TESTDIR"/../contrib/check-code.py
  $ "$check_code" ./wrong.py ./correct.py ./quote.py ./classstyle.py
  ./wrong.py:1:
   > def toto( arg1, arg2):
   gratuitous whitespace in () or []
  ./wrong.py:2:
   >     del(arg2)
   Python keyword is not a function
  ./wrong.py:3:
   >     return ( 5+6, 9)
   gratuitous whitespace in () or []
   missing whitespace in expression
  ./quote.py:5:
   > '"""', 42+1, """and
   missing whitespace in expression
  ./classstyle.py:4:
   > class oldstyle_class:
   old-style class, use class foo(object)
  ./classstyle.py:7:
   > class empty():
   class foo() creates old style object, use class foo(object)
  [1]
  $ cat > python3-compat.py << EOF
  > foo <> bar
  > reduce(lambda a, b: a + b, [1, 2, 3, 4])
  > dict(key=value)
  > EOF
  $ "$check_code" python3-compat.py
  python3-compat.py:1:
   > foo <> bar
   <> operator is not available in Python 3+, use !=
  python3-compat.py:2:
   > reduce(lambda a, b: a + b, [1, 2, 3, 4])
   reduce is not available in Python 3+
  python3-compat.py:3:
   > dict(key=value)
   dict() is different in Py2 and 3 and is slower than {}
  [1]

  $ cat > foo.c <<EOF
  > void narf() {
  > 	strcpy(foo, bar);
  > 	// strcpy_s is okay, but this comment is not
  > 	strcpy_s(foo, bar);
  > }
  > EOF
  $ "$check_code" ./foo.c
  ./foo.c:2:
   > 	strcpy(foo, bar);
   don't use strcpy, use strlcpy or memcpy
  ./foo.c:3:
   > 	// strcpy_s is okay, but this comment is not
   don't use //-style comments
  [1]

  $ cat > is-op.py <<EOF
  > # is-operator comparing number or string literal
  > x = None
  > y = x is 'foo'
  > y = x is "foo"
  > y = x is 5346
  > y = x is -6
  > y = x is not 'foo'
  > y = x is not "foo"
  > y = x is not 5346
  > y = x is not -6
  > EOF

  $ "$check_code" ./is-op.py
  ./is-op.py:3:
   > y = x is 'foo'
   object comparison with literal
  ./is-op.py:4:
   > y = x is "foo"
   object comparison with literal
  ./is-op.py:5:
   > y = x is 5346
   object comparison with literal
  ./is-op.py:6:
   > y = x is -6
   object comparison with literal
  ./is-op.py:7:
   > y = x is not 'foo'
   object comparison with literal
  ./is-op.py:8:
   > y = x is not "foo"
   object comparison with literal
  ./is-op.py:9:
   > y = x is not 5346
   object comparison with literal
  ./is-op.py:10:
   > y = x is not -6
   object comparison with literal
  [1]

  $ cat > for-nolineno.py <<EOF
  > except:
  > EOF
  $ "$check_code" for-nolineno.py --nolineno
  for-nolineno.py:0:
   > except:
   naked except clause
  [1]

  $ cat > warning.t <<EOF
  >   $ function warnonly {
  >   > }
  >   $ diff -N aaa
  >   $ function onwarn {}
  > EOF
  $ "$check_code" warning.t
  $ "$check_code" --warn warning.t
  warning.t:1:
   >   $ function warnonly {
   warning: don't use 'function', use old style
  warning.t:3:
   >   $ diff -N aaa
   warning: don't use 'diff -N'
  warning.t:4:
   >   $ function onwarn {}
   warning: don't use 'function', use old style
  [1]
  $ cat > error.t <<EOF
  >   $ [ foo == bar ]
  > EOF
  $ "$check_code" error.t
  error.t:1:
   >   $ [ foo == bar ]
   [ foo == bar ] is a bashism, use [ foo = bar ] instead
  [1]
  $ rm error.t
  $ cat > raise-format.py <<EOF
  > raise SomeException, message
  > # this next line is okay
  > raise SomeException(arg1, arg2)
  > EOF
  $ "$check_code" not-existing.py raise-format.py
  Skipping*not-existing.py* (glob)
  raise-format.py:1:
   > raise SomeException, message
   don't use old-style two-argument raise, use Exception(message)
  [1]

  $ cat <<EOF > tab.t
  > 	indent
  >   > 	heredoc
  > EOF
  $ "$check_code" tab.t
  tab.t:1:
   > 	indent
   don't use tabs to indent
  [1]
  $ rm tab.t

  $ cat > rst.py <<EOF
  > """problematic rst text
  > 
  > .. note::
  >     wrong
  > """
  > 
  > '''
  > 
  > .. note::
  > 
  >     valid
  > 
  > new text
  > 
  >     .. note::
  > 
  >         also valid
  > '''
  > 
  > """mixed
  > 
  > .. note::
  > 
  >   good
  > 
  >     .. note::
  >         plus bad
  > """
  > EOF
  $ $check_code -w rst.py
  rst.py:3:
   > .. note::
   warning: add two newlines after '.. note::'
  rst.py:26:
   >     .. note::
   warning: add two newlines after '.. note::'
  [1]

  $ cat > ./map-inside-gettext.py <<EOF
  > print(_("map inside gettext %s" % v))
  > 
  > print(_("concatenating " " by " " space %s" % v))
  > print(_("concatenating " + " by " + " '+' %s" % v))
  > 
  > print(_("mapping operation in different line %s"
  >         % v))
  > 
  > print(_(
  >         "leading spaces inside of '(' %s" % v))
  > EOF
  $ "$check_code" ./map-inside-gettext.py
  ./map-inside-gettext.py:1:
   > print(_("map inside gettext %s" % v))
   don't use % inside _()
  ./map-inside-gettext.py:3:
   > print(_("concatenating " " by " " space %s" % v))
   don't use % inside _()
  ./map-inside-gettext.py:4:
   > print(_("concatenating " + " by " + " '+' %s" % v))
   don't use % inside _()
  ./map-inside-gettext.py:6:
   > print(_("mapping operation in different line %s"
   don't use % inside _()
  ./map-inside-gettext.py:9:
   > print(_(
   don't use % inside _()
  [1]

web templates

  $ mkdir -p mercurial/templates
  $ cat > mercurial/templates/example.tmpl <<EOF
  > {desc}
  > {desc|escape}
  > {desc|firstline}
  > {desc|websub}
  > EOF

  $ "$check_code" --warnings mercurial/templates/example.tmpl
  mercurial/templates/example.tmpl:2:
   > {desc|escape}
   warning: follow desc keyword with either firstline or websub
  [1]

'string join across lines with no space' detection

  $ cat > stringjoin.py <<EOF
  > foo = (' foo'
  >        'bar foo.'
  >        'bar foo:'
  >        'bar foo@'
  >        'bar foo%'
  >        'bar foo*'
  >        'bar foo+'
  >        'bar foo-'
  >        'bar')
  > EOF

'missing _() in ui message' detection

  $ cat > uigettext.py <<EOF
  > ui.status("% 10s %05d % -3.2f %*s %%"
  >           # this use '\\\\' instead of '\\', because the latter in
  >           # heredoc on shell becomes just '\'
  >           '\\\\ \n \t \0'
  >           """12345
  >           """
  >           '''.:*+-=
  >           ''' "%-6d \n 123456 .:*+-= foobar")
  > EOF

superfluous pass

  $ cat > superfluous_pass.py <<EOF
  > # correct examples
  > if foo:
  >     pass
  > else:
  >     # comment-only line means still need pass
  >     pass
  > def nothing():
  >     pass
  > class empty(object):
  >     pass
  > if whatever:
  >     passvalue(value)
  > # bad examples
  > if foo:
  >     "foo"
  >     pass
  > else: # trailing comment doesn't fool checker
  >     wat()
  >     pass
  > def nothing():
  >     "docstring means no pass"
  >     pass
  > class empty(object):
  >     """multiline
  >     docstring also
  >     means no pass"""
  >     pass
  > EOF

(Checking multiple invalid files at once examines whether caching
translation table for repquote() works as expected or not. All files
should break rules depending on result of repquote(), in this case)

  $ "$check_code" stringjoin.py uigettext.py superfluous_pass.py
  stringjoin.py:1:
   > foo = (' foo'
   string join across lines with no space
  stringjoin.py:2:
   >        'bar foo.'
   string join across lines with no space
  stringjoin.py:3:
   >        'bar foo:'
   string join across lines with no space
  stringjoin.py:4:
   >        'bar foo@'
   string join across lines with no space
  stringjoin.py:5:
   >        'bar foo%'
   string join across lines with no space
  stringjoin.py:6:
   >        'bar foo*'
   string join across lines with no space
  stringjoin.py:7:
   >        'bar foo+'
   string join across lines with no space
  stringjoin.py:8:
   >        'bar foo-'
   string join across lines with no space
  uigettext.py:1:
   > ui.status("% 10s %05d % -3.2f %*s %%"
   missing _() in ui message (use () to hide false-positives)
  superfluous_pass.py:14:
   > if foo:
   omit superfluous pass
  superfluous_pass.py:17:
   > else: # trailing comment doesn't fool checker
   omit superfluous pass
  superfluous_pass.py:20:
   > def nothing():
   omit superfluous pass
  superfluous_pass.py:23:
   > class empty(object):
   omit superfluous pass
  [1]