view tests/test-strip-cross.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.

test stripping of filelogs where the linkrev doesn't always increase

  $ echo '[extensions]' >> $HGRCPATH
  $ echo 'strip =' >> $HGRCPATH
  $ hg init orig
  $ cd orig
  $ commit()
  > {
  >     hg up -qC null
  >     count=1
  >     for i in "$@"; do
  >         for f in $i; do
  >             echo $count > $f
  >         done
  >         count=`expr $count + 1`
  >     done
  >     hg commit -qAm "$*"
  > }

2 1 0 2 0 1 2

  $ commit '201 210'
  $ commit '102 120' '210'
  $ commit '021'
  $ commit '201' '021 120'
  $ commit '012 021' '102 201' '120 210'
  $ commit 'manifest-file'
  $ commit '102 120' '012 210' '021 201'
  $ commit '201 210' '021 120' '012 102'
  $ HGUSER=another-user; export HGUSER
  $ commit 'manifest-file'
  $ commit '012' 'manifest-file'
  $ cd ..
  $ hg clone -q -U -r -1 -r -2 -r -3 -r -4 -r -6 orig crossed
  $ cd crossed
  $ hg debugindex --manifest
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0     112  .....       0 6f105cbb914d 000000000000 000000000000 (re)
       1       112      56  .....       3 1b55917b3699 000000000000 000000000000 (re)
       2       168     123  .....       1 8f3d04e263e5 000000000000 000000000000 (re)
       3       291     122  .....       2 f0ef8726ac4f 000000000000 000000000000 (re)
       4       413      87  .....       4 0b76e38b4070 000000000000 000000000000 (re)

  $ for i in 012 021 102 120 201 210 manifest-file; do
  >     echo $i
  >     hg debugindex $i
  >     echo
  > done
  012
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       1 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       2 2661d26c6496 000000000000 000000000000 (re)
  
  021
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       2 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       1 2661d26c6496 000000000000 000000000000 (re)
  
  102
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       1 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       0 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       2 2661d26c6496 000000000000 000000000000 (re)
  
  120
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       1 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       2 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       0 2661d26c6496 000000000000 000000000000 (re)
  
  201
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       2 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       0 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       1 2661d26c6496 000000000000 000000000000 (re)
  
  210
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       2 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       1 5d9299349fc0 000000000000 000000000000 (re)
       2         6       3  .....       0 2661d26c6496 000000000000 000000000000 (re)
  
  manifest-file
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       3 b8e02f643373 000000000000 000000000000 (re)
       1         3       3  .....       4 5d9299349fc0 000000000000 000000000000 (re)
  
  $ cd ..
  $ for i in 0 1 2 3 4; do
  >     hg clone -q -U --pull crossed $i
  >     echo "% Trying to strip revision $i"
  >     hg --cwd $i strip $i
  >     echo "% Verifying"
  >     hg --cwd $i verify
  >     echo
  > done
  % Trying to strip revision 0
  saved backup bundle to $TESTTMP/0/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 15 total revisions
  
  % Trying to strip revision 1
  saved backup bundle to $TESTTMP/1/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 14 total revisions
  
  % Trying to strip revision 2
  saved backup bundle to $TESTTMP/2/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 14 total revisions
  
  % Trying to strip revision 3
  saved backup bundle to $TESTTMP/3/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 19 total revisions
  
  % Trying to strip revision 4
  saved backup bundle to $TESTTMP/4/.hg/strip-backup/*-backup.hg (glob)
  % Verifying
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  7 files, 4 changesets, 19 total revisions