view tests/test-rebase-mq.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]
  > rebase=
  > mq=
  > 
  > [mq]
  > plain=true
  > 
  > [alias]
  > tglog = log -G --template "{rev}: {node|short} '{desc}' tags: {tags}\n"
  > EOF


  $ hg init a
  $ cd a
  $ hg qinit -c

  $ echo c1 > f
  $ hg add f
  $ hg ci -m C1

  $ echo r1 > f
  $ hg ci -m R1

  $ hg up -q 0

  $ hg qnew f.patch -d '1 0'
  $ echo mq1 > f
  $ hg qref -m P0

  $ hg qnew f2.patch
  $ echo mq2 > f
  $ hg qref -m P1 -d '2 0'

  $ hg tglog
  @  3: 929394423cd3 'P1' tags: f2.patch qtip tip
  |
  o  2: 3504f44bffc0 'P0' tags: f.patch qbase
  |
  | o  1: bac9ed9960d8 'R1' tags:
  |/
  o  0: 36f36ddbca61 'C1' tags: qparent
  

Rebase - try to rebase on an applied mq patch:

  $ hg rebase -s 1 -d 3
  abort: cannot rebase onto an applied mq patch
  [255]

Rebase - same thing, but mq patch is default dest:

  $ hg up -q 1
  $ hg rebase
  abort: cannot rebase onto an applied mq patch
  [255]
  $ hg up -q qtip

Rebase - generate a conflict:

  $ hg rebase -s 2 -d 1
  rebasing 2:3504f44bffc0 "P0" (f.patch qbase)
  merging f
  warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Fix the 1st conflict:

  $ echo mq1r1 > f
  $ hg resolve -m f
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase -c
  rebasing 2:3504f44bffc0 "P0" (f.patch qbase)
  rebasing 3:929394423cd3 "P1" (f2.patch qtip tip)
  merging f
  warning: conflicts while merging f! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Fix the 2nd conflict:

  $ echo mq1r1mq2 > f
  $ hg resolve -m f
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase -c
  already rebased 2:3504f44bffc0 "P0" (f.patch qbase) as ebe9914c0d1c
  rebasing 3:929394423cd3 "P1" (f2.patch qtip)
  saved backup bundle to $TESTTMP/a/.hg/strip-backup/3504f44bffc0-30595b40-rebase.hg

  $ hg tglog
  @  3: 462012cf340c 'P1' tags: f2.patch qtip tip
  |
  o  2: ebe9914c0d1c 'P0' tags: f.patch qbase
  |
  o  1: bac9ed9960d8 'R1' tags: qparent
  |
  o  0: 36f36ddbca61 'C1' tags:
  
  $ hg up -q qbase

  $ cat f
  mq1r1

  $ cat .hg/patches/f.patch
  # HG changeset patch
  # User test
  # Date 1 0
  #      Thu Jan 01 00:00:01 1970 +0000
  # Node ID ebe9914c0d1c3f60096e952fa4dbb3d377dea3ab
  # Parent  bac9ed9960d8992bcad75864a879fa76cadaf1b0
  P0
  
  diff -r bac9ed9960d8 -r ebe9914c0d1c f
  --- a/f	Thu Jan 01 00:00:00 1970 +0000
  +++ b/f	Thu Jan 01 00:00:01 1970 +0000
  @@ -1,1 +1,1 @@
  -r1
  +mq1r1

Update to qtip:

  $ hg up -q qtip

  $ cat f
  mq1r1mq2

  $ cat .hg/patches/f2.patch
  # HG changeset patch
  # User test
  # Date 2 0
  #      Thu Jan 01 00:00:02 1970 +0000
  # Node ID 462012cf340c97d44d62377c985a423f6bb82f07
  # Parent  ebe9914c0d1c3f60096e952fa4dbb3d377dea3ab
  P1
  
  diff -r ebe9914c0d1c -r 462012cf340c f
  --- a/f	Thu Jan 01 00:00:01 1970 +0000
  +++ b/f	Thu Jan 01 00:00:02 1970 +0000
  @@ -1,1 +1,1 @@
  -mq1r1
  +mq1r1mq2

Adding one git-style patch and one normal:

  $ hg qpop -a
  popping f2.patch
  popping f.patch
  patch queue now empty

  $ rm -fr .hg/patches
  $ hg qinit -c

  $ hg up -q 0

  $ hg qnew --git f_git.patch -d '3 0'
  $ echo mq1 > p
  $ hg add p
  $ hg qref --git -m 'P0 (git)'

  $ hg qnew f.patch -d '4 0'
  $ echo mq2 > p
  $ hg qref -m P1
  $ hg qci -m 'save patch state'

  $ hg qseries -s
  f_git.patch: P0 (git)
  f.patch: P1

  $ hg -R .hg/patches manifest
  .hgignore
  f.patch
  f_git.patch
  series

  $ cat .hg/patches/f_git.patch
  Date: 3 0
  
  P0 (git)
  
  diff --git a/p b/p
  new file mode 100644
  --- /dev/null
  +++ b/p
  @@ -0,0 +1,1 @@
  +mq1

  $ cat .hg/patches/f.patch
  Date: 4 0
  
  P1
  
  diff -r ???????????? p (glob)
  --- a/p	??? ??? ?? ??:??:?? ???? ????? (glob)
  +++ b/p	??? ??? ?? ??:??:?? ???? ????? (glob)
  @@ -1,1 +1,1 @@
  -mq1
  +mq2


Rebase the applied mq patches:

  $ hg rebase -s 2 -d 1
  rebasing 2:0c587ffcb480 "P0 (git)" (f_git.patch qbase)
  rebasing 3:c7f18665e4bc "P1" (f.patch qtip tip)
  saved backup bundle to $TESTTMP/a/.hg/strip-backup/0c587ffcb480-0ea5695f-rebase.hg

  $ hg qci -m 'save patch state'

  $ hg qseries -s
  f_git.patch: P0 (git)
  f.patch: P1

  $ hg -R .hg/patches manifest
  .hgignore
  f.patch
  f_git.patch
  series

  $ cat .hg/patches/f_git.patch
  # HG changeset patch
  # User test
  # Date 3 0
  #      Thu Jan 01 00:00:03 1970 +0000
  # Node ID 12d9f6a3bbe560dee50c7c454d434add7fb8e837
  # Parent  bac9ed9960d8992bcad75864a879fa76cadaf1b0
  P0 (git)
  
  diff --git a/p b/p
  new file mode 100644
  --- /dev/null
  +++ b/p
  @@ -0,0 +1,1 @@
  +mq1

  $ cat .hg/patches/f.patch
  # HG changeset patch
  # User test
  # Date 4 0
  #      Thu Jan 01 00:00:04 1970 +0000
  # Node ID c77a2661c64c60d82f63c4f7aefd95b3a948a557
  # Parent  12d9f6a3bbe560dee50c7c454d434add7fb8e837
  P1
  
  diff -r 12d9f6a3bbe5 -r c77a2661c64c p
  --- a/p	Thu Jan 01 00:00:03 1970 +0000
  +++ b/p	Thu Jan 01 00:00:04 1970 +0000
  @@ -1,1 +1,1 @@
  -mq1
  +mq2

  $ cd ..

Rebase with guards

  $ hg init foo
  $ cd foo
  $ echo a > a
  $ hg ci -Am a
  adding a

Create mq repo with guarded patches foo and bar and empty patch:

  $ hg qinit
  $ echo guarded > guarded
  $ hg add guarded
  $ hg qnew guarded
  $ hg qnew empty-important -m 'important commit message' -d '1 0'
  $ echo bar > bar
  $ hg add bar
  $ hg qnew bar -d '2 0'
  $ echo foo > foo
  $ hg add foo
  $ hg qnew foo
  $ hg qpop -a
  popping foo
  popping bar
  popping empty-important
  popping guarded
  patch queue now empty
  $ hg qguard guarded +guarded
  $ hg qguard bar +baz
  $ hg qguard foo +baz
  $ hg qselect baz
  number of unguarded, unapplied patches has changed from 1 to 3
  $ hg qpush bar
  applying empty-important
  patch empty-important is empty
  applying bar
  now at: bar

  $ hg qguard -l
  guarded: +guarded
  empty-important: unguarded
  bar: +baz
  foo: +baz

  $ hg tglog
  @  2: 4f44b861d38c 'imported patch bar' tags: bar qtip tip
  |
  o  1: 0aaf4c3af7eb 'important commit message' tags: empty-important qbase
  |
  o  0: cb9a9f314b8b 'a' tags: qparent
  
Create new head to rebase bar onto:

  $ hg up -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo b > b
  $ hg add b
  $ hg ci -m b
  created new head
  $ hg up -C 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo a >> a
  $ hg qref

  $ hg tglog
  @  3: d526d4536ed6 '[mq]: bar' tags: bar qtip tip
  |
  | o  2: d2ae7f538514 'b' tags:
  | |
  o |  1: 0aaf4c3af7eb 'important commit message' tags: empty-important qbase
  |/
  o  0: cb9a9f314b8b 'a' tags: qparent
  

Rebase bar (make sure series order is preserved and empty-important also is
removed from the series):

  $ hg qseries
  guarded
  empty-important
  bar
  foo
  $ [ -f .hg/patches/empty-important ]
  $ hg -q rebase -d 2
  note: rebase of 1:0aaf4c3af7eb created no changes to commit
  $ hg qseries
  guarded
  bar
  foo
  $ [ -f .hg/patches/empty-important ]
  [1]

  $ hg qguard -l
  guarded: +guarded
  bar: +baz
  foo: +baz

  $ hg tglog
  @  2: 477d948bb2af '[mq]: bar' tags: bar qbase qtip tip
  |
  o  1: d2ae7f538514 'b' tags: qparent
  |
  o  0: cb9a9f314b8b 'a' tags:
  
  $ cd ..