view tests/test-import-bypass.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.

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "purge=" >> $HGRCPATH

  $ shortlog() {
  >     hg log -G --template '{rev}:{node|short} {author} {date|hgdate} - {branch} - {desc|firstline}\n'
  > }

Test --bypass with other options

  $ hg init repo-options
  $ cd repo-options
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ echo a >> a
  $ hg branch foo
  marked working directory as branch foo
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -Am changea
  $ hg export . > ../test.diff
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

Test importing an existing revision
(this also tests that "hg import" disallows combination of '--exact'
and '--edit')

  $ hg import --bypass --exact --edit ../test.diff
  abort: cannot use --exact with --edit
  [255]
  $ hg import --bypass --exact ../test.diff
  applying ../test.diff
  $ shortlog
  o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |
  o  0:07f494440405 test 0 0 - default - adda
  

Test failure without --exact

  $ hg import --bypass ../test.diff
  applying ../test.diff
  unable to find 'a' for patching
  (use '--prefix' to apply patch relative to the current directory)
  abort: patch failed to apply
  [255]
  $ hg st
  $ shortlog
  o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |
  o  0:07f494440405 test 0 0 - default - adda
  

Test --user, --date and --message

  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg import --bypass --u test2 -d '1 0' -m patch2 ../test.diff
  applying ../test.diff
  $ cat .hg/last-message.txt
  patch2 (no-eol)
  $ shortlog
  o  2:2e127d1da504 test2 1 0 - default - patch2
  |
  | o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |/
  @  0:07f494440405 test 0 0 - default - adda
  
  $ hg rollback
  repository tip rolled back to revision 1 (undo import)

Test --import-branch
(this also tests that editor is not invoked for '--bypass', if the
patch contains the commit message, regardless of '--edit')

  $ HGEDITOR=cat hg import --bypass --import-branch --edit ../test.diff
  applying ../test.diff
  $ shortlog
  o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |
  @  0:07f494440405 test 0 0 - default - adda
  
  $ hg rollback
  repository tip rolled back to revision 1 (undo import)

Test --strip

  $ hg import --bypass --strip 0 - <<EOF
  > # HG changeset patch
  > # User test
  > # Date 0 0
  > # Branch foo
  > # Node ID 4e322f7ce8e3e4203950eac9ece27bf7e45ffa6c
  > # Parent  07f4944404050f47db2e5c5071e0e84e7a27bba9
  > changea
  > 
  > diff -r 07f494440405 -r 4e322f7ce8e3 a
  > --- a	Thu Jan 01 00:00:00 1970 +0000
  > +++ a	Thu Jan 01 00:00:00 1970 +0000
  > @@ -1,1 +1,2 @@
  >  a
  > +a
  > EOF
  applying patch from stdin
  $ hg rollback
  repository tip rolled back to revision 1 (undo import)

Test --strip with --bypass

  $ mkdir -p dir/dir2
  $ echo bb > dir/dir2/b
  $ echo cc > dir/dir2/c
  $ echo d > dir/d
  $ hg ci -Am 'addabcd'
  adding dir/d
  adding dir/dir2/b
  adding dir/dir2/c
  $ shortlog
  @  2:d805bc8236b6 test 0 0 - default - addabcd
  |
  | o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |/
  o  0:07f494440405 test 0 0 - default - adda
  
  $ hg import --bypass --strip 2 --prefix dir/ - <<EOF
  > # HG changeset patch
  > # User test
  > # Date 0 0
  > # Branch foo
  > changeabcd
  > 
  > diff --git a/foo/a b/foo/a
  > new file mode 100644
  > --- /dev/null
  > +++ b/foo/a
  > @@ -0,0 +1 @@
  > +a
  > diff --git a/foo/dir2/b b/foo/dir2/b2
  > rename from foo/dir2/b
  > rename to foo/dir2/b2
  > diff --git a/foo/dir2/c b/foo/dir2/c
  > --- a/foo/dir2/c
  > +++ b/foo/dir2/c
  > @@ -0,0 +1 @@
  > +cc
  > diff --git a/foo/d b/foo/d
  > deleted file mode 100644
  > --- a/foo/d
  > +++ /dev/null
  > @@ -1,1 +0,0 @@
  > -d
  > EOF
  applying patch from stdin

  $ shortlog
  o  3:5bd46886ca3e test 0 0 - default - changeabcd
  |
  @  2:d805bc8236b6 test 0 0 - default - addabcd
  |
  | o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |/
  o  0:07f494440405 test 0 0 - default - adda
  
  $ hg diff --change 3 --git
  diff --git a/dir/a b/dir/a
  new file mode 100644
  --- /dev/null
  +++ b/dir/a
  @@ -0,0 +1,1 @@
  +a
  diff --git a/dir/d b/dir/d
  deleted file mode 100644
  --- a/dir/d
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -d
  diff --git a/dir/dir2/b b/dir/dir2/b2
  rename from dir/dir2/b
  rename to dir/dir2/b2
  diff --git a/dir/dir2/c b/dir/dir2/c
  --- a/dir/dir2/c
  +++ b/dir/dir2/c
  @@ -1,1 +1,2 @@
   cc
  +cc
  $ hg -q --config extensions.strip= strip .

Test unsupported combinations

  $ hg import --bypass --no-commit ../test.diff
  abort: cannot use --no-commit with --bypass
  [255]
  $ hg import --bypass --similarity 50 ../test.diff
  abort: cannot use --similarity with --bypass
  [255]
  $ hg import --exact --prefix dir/ ../test.diff
  abort: cannot use --exact with --prefix
  [255]

Test commit editor
(this also tests that editor is invoked, if the patch doesn't contain
the commit message, regardless of '--edit')

  $ cat > ../test.diff <<EOF
  > diff -r 07f494440405 -r 4e322f7ce8e3 a
  > --- a/a	Thu Jan 01 00:00:00 1970 +0000
  > +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  > @@ -1,1 +1,2 @@
  > -a
  > +b
  > +c
  > EOF
  $ HGEDITOR=cat hg import --bypass ../test.diff
  applying ../test.diff
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: changed a
  abort: empty commit message
  [255]

Test patch.eol is handled
(this also tests that editor is not invoked for '--bypass', if the
commit message is explicitly specified, regardless of '--edit')

  $ $PYTHON -c 'file("a", "wb").write("a\r\n")'
  $ hg ci -m makeacrlf
  $ HGEDITOR=cat hg import -m 'should fail because of eol' --edit --bypass ../test.diff
  applying ../test.diff
  patching file a
  Hunk #1 FAILED at 0
  abort: patch failed to apply
  [255]
  $ hg --config patch.eol=auto import -d '0 0' -m 'test patch.eol' --bypass ../test.diff
  applying ../test.diff
  $ shortlog
  o  3:c606edafba99 test 0 0 - default - test patch.eol
  |
  @  2:872023de769d test 0 0 - default - makeacrlf
  |
  | o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |/
  o  0:07f494440405 test 0 0 - default - adda
  

Test applying multiple patches

  $ hg up -qC 0
  $ echo e > e
  $ hg ci -Am adde
  adding e
  created new head
  $ hg export . > ../patch1.diff
  $ hg up -qC 1
  $ echo f > f
  $ hg ci -Am addf
  adding f
  $ hg export . > ../patch2.diff
  $ cd ..
  $ hg clone -r1 repo-options repo-multi1
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets 07f494440405:4e322f7ce8e3
  updating to branch foo
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo-multi1
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg import --bypass ../patch1.diff ../patch2.diff
  applying ../patch1.diff
  applying ../patch2.diff
  $ shortlog
  o  3:bc8ca3f8a7c4 test 0 0 - default - addf
  |
  o  2:16581080145e test 0 0 - default - adde
  |
  | o  1:4e322f7ce8e3 test 0 0 - foo - changea
  |/
  @  0:07f494440405 test 0 0 - default - adda
  

Test applying multiple patches with --exact

  $ cd ..
  $ hg clone -r1 repo-options repo-multi2
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets 07f494440405:4e322f7ce8e3
  updating to branch foo
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo-multi2
  $ hg import --bypass --exact ../patch1.diff ../patch2.diff
  applying ../patch1.diff
  applying ../patch2.diff
  $ shortlog
  o  3:d60cb8989666 test 0 0 - foo - addf
  |
  | o  2:16581080145e test 0 0 - default - adde
  | |
  @ |  1:4e322f7ce8e3 test 0 0 - foo - changea
  |/
  o  0:07f494440405 test 0 0 - default - adda
  

  $ cd ..

Test avoiding editor invocation at applying the patch with --exact
even if commit message is empty

  $ cd repo-options

  $ echo a >> a
  $ hg commit -m ' '
  $ hg tip -T "{node}\n"
  1b77bc7d1db9f0e7f1716d515b630516ab386c89
  $ hg export -o ../empty-log.diff .
  $ hg update -q -C ".^1"
  $ hg --config extensions.strip= strip -q tip
  $ HGEDITOR=cat hg import --exact --bypass ../empty-log.diff
  applying ../empty-log.diff
  $ hg tip -T "{node}\n"
  1b77bc7d1db9f0e7f1716d515b630516ab386c89

  $ cd ..

#if symlink execbit

Test complicated patch with --exact

  $ hg init repo-exact
  $ cd repo-exact
  $ echo a > a
  $ echo c > c
  $ echo d > d
  $ echo e > e
  $ echo f > f
  $ chmod +x f
  $ ln -s c linkc
  $ hg ci -Am t
  adding a
  adding c
  adding d
  adding e
  adding f
  adding linkc
  $ hg cp a aa1
  $ echo b >> a
  $ echo b > b
  $ hg add b
  $ hg cp a aa2
  $ echo aa >> aa2
  $ chmod +x e
  $ chmod -x f
  $ ln -s a linka
  $ hg rm d
  $ hg rm linkc
  $ hg mv c cc
  $ hg ci -m patch
  $ hg export --git . > ../test.diff
  $ hg up -C null
  0 files updated, 0 files merged, 7 files removed, 0 files unresolved
  $ hg purge
  $ hg st
  $ hg import --bypass --exact ../test.diff
  applying ../test.diff

The patch should have matched the exported revision and generated no additional
data. If not, diff both heads to debug it.

  $ shortlog
  o  1:2978fd5c8aa4 test 0 0 - default - patch
  |
  o  0:a0e19e636a43 test 0 0 - default - t
  
#endif

  $ cd ..