view tests/test-show.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 >> $HGRCPATH << EOF
  > [extensions]
  > show =
  > EOF

No arguments shows available views

  $ hg init empty
  $ cd empty
  $ hg show
  available views:
  
  bookmarks -- bookmarks and their associated changeset
  stack -- current line of work
  work -- changesets that aren't finished
  
  abort: no view requested
  (use "hg show VIEW" to choose a view)
  [255]

`hg help show` prints available views

  $ hg help show
  hg show VIEW
  
  show various repository information
  
      A requested view of repository data is displayed.
  
      If no view is requested, the list of available views is shown and the
      command aborts.
  
      Note:
         There are no backwards compatibility guarantees for the output of this
         command. Output may change in any future Mercurial release.
  
         Consumers wanting stable command output should specify a template via
         "-T/--template".
  
      List of available views:
  
      bookmarks   bookmarks and their associated changeset
  
      stack       current line of work
  
      work        changesets that aren't finished
  
  (use 'hg help -e show' to show help for the show extension)
  
  options:
  
   -T --template TEMPLATE display with template
  
  (some details hidden, use --verbose to show complete help)

Unknown view prints error

  $ hg show badview
  abort: unknown view: badview
  (run "hg show" to see available views)
  [255]

HGPLAIN results in abort

  $ HGPLAIN=1 hg show bookmarks
  abort: must specify a template in plain mode
  (invoke with -T/--template to control output format)
  [255]

But not if a template is specified

  $ HGPLAIN=1 hg show bookmarks -T '{bookmark}\n'
  (no bookmarks set)

  $ cd ..

bookmarks view with no bookmarks prints empty message

  $ hg init books
  $ cd books
  $ touch f0
  $ hg -q commit -A -m initial

  $ hg show bookmarks
  (no bookmarks set)

bookmarks view shows bookmarks in an aligned table

  $ echo book1 > f0
  $ hg commit -m 'commit for book1'
  $ echo book2 > f0
  $ hg commit -m 'commit for book2'

  $ hg bookmark -r 1 book1
  $ hg bookmark a-longer-bookmark

  $ hg show bookmarks
  * a-longer-bookmark    7b57
    book1                b757

A custom bookmarks template works

  $ hg show bookmarks -T '{node} {bookmark} {active}\n'
  7b5709ab64cbc34da9b4367b64afff47f2c4ee83 a-longer-bookmark True
  b757f780b8ffd71267c6ccb32e0882d9d32a8cc0 book1 False

bookmarks JSON works

  $ hg show bookmarks -T json
  [
   {
    "active": true,
    "bookmark": "a-longer-bookmark",
    "longestbookmarklen": 17,
    "node": "7b5709ab64cbc34da9b4367b64afff47f2c4ee83",
    "nodelen": 4
   },
   {
    "active": false,
    "bookmark": "book1",
    "longestbookmarklen": 17,
    "node": "b757f780b8ffd71267c6ccb32e0882d9d32a8cc0",
    "nodelen": 4
   }
  ]

JSON works with no bookmarks

  $ hg book -d a-longer-bookmark
  $ hg book -d book1
  $ hg show bookmarks -T json
  [
  ]

commands.show.aliasprefix aliases values to `show <view>`

  $ hg --config commands.show.aliasprefix=s sbookmarks
  (no bookmarks set)

  $ hg --config commands.show.aliasprefix=sh shwork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

  $ hg --config commands.show.aliasprefix='s sh' swork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

  $ hg --config commands.show.aliasprefix='s sh' shwork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

The aliases don't appear in `hg config`

  $ hg --config commands.show.aliasprefix=s config alias
  [1]

Doesn't overwrite existing alias

  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s swork
  changeset:   2:7b5709ab64cb
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit for book2
  

  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s config alias
  alias.swork=log -r .

  $ cd ..