Package: mercurial / 4.8.2-1+deb10u1

CVE-2019-3902.patch Patch series | download
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# HG changeset patch
# User Yuya Nishihara <yuya@tcha.org>
# Date 1546951914 -32400
#      Tue Jan 08 21:51:54 2019 +0900
# Branch stable
# Node ID 31286c9282dfa734e9da085649b7ae5a8ba290ad
# Parent  8427fea0401708ba95a27810163c17cee54ed4b0
subrepo: extend path auditing test to include more weird patterns (SEC)

While reviewing patches for the issue 5739, "$foo in repository path
expanded", I realized that subrepo paths can also be cheated. This patch
includes various subrepo paths which are potentially unsafe.

Since an expanded subrepo path isn't audited, this bug allows symlink check
bypass. As a result, a malicious subrepository could be checked out to a
sub tree of e.g. $HOME directory. The good news is that the destination
directory must be empty or nonexistent, so the existing ~/.bashrc wouldn't
be overwritten. See the last part of the tests for details.

# HG changeset patch
# User Yuya Nishihara <yuya@tcha.org>
# Date 1546952865 -32400
#      Tue Jan 08 22:07:45 2019 +0900
# Branch stable
# Node ID 6c10eba6b9cddab020de49fd4fabcb2cadcd85d0
# Parent  31286c9282dfa734e9da085649b7ae5a8ba290ad
subrepo: prohibit variable expansion on creation of hg subrepo (SEC)

It's probably wrong to expand path at localrepo.*repository() layer, but
fixing the layering issue would require careful inspection of call paths.
So, this patch adds add a validation to the subrepo constructor.

os.path.realpath(util.expandpath(root)) is what vfsmod.vfs() would do.

# HG changeset patch
# User Yuya Nishihara <yuya@tcha.org>
# Date 1546953576 -32400
#      Tue Jan 08 22:19:36 2019 +0900
# Branch stable
# Node ID 83377b4b4ae0e9a6b8e579f7b0a693b8cf5c3b10
# Parent  6c10eba6b9cddab020de49fd4fabcb2cadcd85d0
subrepo: reject potentially unsafe subrepo paths (BC) (SEC)

In addition to the previous patch, this prohibits '~', '$nonexistent', etc.
for any subrepo types. I think this is safer, and real-world subrepos wouldn't
use such (local) paths.

--- mercurial.orig/tests/test-audit-subrepo.t
+++ mercurial/tests/test-audit-subrepo.t
@@ -36,6 +36,372 @@
   abort: path 'sub/.hg' is inside nested repo 'sub'
   [255]
 
+Test absolute path
+------------------
+
+on commit:
+
+  $ hg init absolutepath
+  $ cd absolutepath
+  $ hg init sub
+  $ echo '/sub = sub' >> .hgsub
+  $ hg ci -qAm 'add subrepo "/sub"'
+  abort: path contains illegal component: /sub
+  [255]
+
+prepare tampered repo (including the commit above):
+
+  $ hg import --bypass -qm 'add subrepo "/sub"' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > +/sub = sub
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000 /sub
+  > EOF
+  $ cd ..
+
+on clone (and update):
+
+  $ hg clone -q absolutepath absolutepath2
+  abort: path contains illegal component: /sub
+  [255]
+
+Test root path
+--------------
+
+on commit:
+
+  $ hg init rootpath
+  $ cd rootpath
+  $ hg init sub
+  $ echo '/ = sub' >> .hgsub
+  $ hg ci -qAm 'add subrepo "/"'
+  abort: path ends in directory separator: /
+  [255]
+
+prepare tampered repo (including the commit above):
+
+  $ hg import --bypass -qm 'add subrepo "/"' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > +/ = sub
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000 /
+  > EOF
+  $ cd ..
+
+on clone (and update):
+
+  $ hg clone -q rootpath rootpath2
+  abort: path ends in directory separator: /
+  [255]
+
+Test empty path
+---------------
+
+on commit:
+
+  $ hg init emptypath
+  $ cd emptypath
+  $ hg init sub
+  $ echo '= sub' >> .hgsub
+  $ hg ci -qAm 'add subrepo ""'
+  hg: parse error at .hgsub:1: = sub
+  [255]
+
+prepare tampered repo (including the commit above):
+
+  $ hg import --bypass -qm 'add subrepo ""' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > += sub
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000
+  > EOF
+  $ cd ..
+
+on clone (and update):
+
+  $ hg clone -q emptypath emptypath2
+  hg: parse error at .hgsub:1: = sub
+  [255]
+
+Test current path
+-----------------
+
+on commit:
+
+  $ hg init currentpath
+  $ cd currentpath
+  $ hg init sub
+  $ echo '. = sub' >> .hgsub
+  $ hg ci -qAm 'add subrepo "."'
+  abort: subrepo path contains illegal component: .
+  [255]
+
+prepare tampered repo (including the commit above):
+
+  $ hg import --bypass -qm 'add subrepo "."' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > +.= sub
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000 .
+  > EOF
+  $ cd ..
+
+on clone (and update):
+
+  $ hg clone -q currentpath currentpath2
+  abort: subrepo path contains illegal component: .
+  [255]
+
+Test outer path
+---------------
+
+on commit:
+
+  $ mkdir outerpath
+  $ cd outerpath
+  $ hg init main
+  $ cd main
+  $ hg init ../sub
+  $ echo '../sub = ../sub' >> .hgsub
+  $ hg ci -qAm 'add subrepo "../sub"'
+  abort: path contains illegal component: ../sub
+  [255]
+
+prepare tampered repo (including the commit above):
+
+  $ hg import --bypass -qm 'add subrepo "../sub"' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > +../sub = ../sub
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000 ../sub
+  > EOF
+  $ cd ..
+
+on clone (and update):
+
+  $ hg clone -q main main2
+  abort: path contains illegal component: ../sub
+  [255]
+  $ cd ..
+
+Test variable expansion
+-----------------------
+
+Subrepository paths shouldn't be expanded, but we fail to handle them
+properly. Any local repository paths are expanded.
+
+on commit:
+
+  $ mkdir envvar
+  $ cd envvar
+  $ hg init main
+  $ cd main
+  $ hg init sub1
+  $ cat <<'EOF' > sub1/hgrc
+  > [hooks]
+  > log = echo pwned
+  > EOF
+  $ hg -R sub1 ci -qAm 'add sub1 files'
+  $ hg -R sub1 log -r. -T '{node}\n'
+  39eb4b4d3e096527668784893a9280578a8f38b8
+  $ echo '$SUB = sub1' >> .hgsub
+  $ SUB=sub1 hg ci -qAm 'add subrepo "$SUB"'
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+
+prepare tampered repo (including the changes above as two commits):
+
+  $ hg import --bypass -qm 'add subrepo "$SUB"' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > +$SUB = sub1
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000 $SUB
+  > EOF
+  $ hg debugsetparents 0
+  $ hg import --bypass -qm 'update subrepo "$SUB"' - <<'EOF'
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > --- a/.hgsubstate
+  > +++ b/.hgsubstate
+  > @@ -1,1 +1,1 @@
+  > -0000000000000000000000000000000000000000 $SUB
+  > +39eb4b4d3e096527668784893a9280578a8f38b8 $SUB
+  > EOF
+  $ cd ..
+
+on clone (and update) with various substitutions:
+
+  $ hg clone -q main main2
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main2
+
+  $ SUB=sub1 hg clone -q main main3
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main3
+
+  $ SUB=sub2 hg clone -q main main4
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main4
+
+on clone empty subrepo into .hg, then pull (and update), which at least fails:
+
+  $ SUB=.hg hg clone -qr0 main main5
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main5
+  $ test -d main5/.hg/.hg
+  [1]
+  $ SUB=.hg hg -R main5 pull -u
+  pulling from $TESTTMP/envvar/main
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  new changesets 7a2f0e59146f
+  .hgsubstate: untracked file differs
+  abort: untracked files in working directory differ from files in requested revision
+  [255]
+  $ cat main5/.hg/hgrc | grep pwned
+  [1]
+
+on clone (and update) into .hg, which at least fails:
+
+  $ SUB=.hg hg clone -q main main6
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main6
+  $ cat main6/.hg/hgrc | grep pwned
+  [1]
+
+on clone (and update) into .hg/* subdir:
+
+  $ SUB=.hg/foo hg clone -q main main7
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main7
+  $ test -d main7/.hg/.hg
+  [1]
+
+on clone (and update) into outer tree:
+
+  $ SUB=../out-of-tree-write hg clone -q main main8
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main8
+
+on clone (and update) into e.g. $HOME, which doesn't work since subrepo paths
+are concatenated prior to variable expansion:
+
+  $ SUB="$TESTTMP/envvar/fakehome" hg clone -q main main9
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls main9 | wc -l
+  \s*0 (re)
+
+  $ ls
+  main
+  main2
+  main3
+  main4
+  main5
+  main6
+  main7
+  main8
+  main9
+  $ cd ..
+
+Test tilde
+----------
+
+The leading tilde may be expanded to $HOME, but it can be a valid subrepo
+path in theory. However, we want to prohibit it as there might be unsafe
+handling of such paths.
+
+on commit:
+
+  $ hg init tilde
+  $ cd tilde
+  $ hg init './~'
+  $ echo '~ = ~' >> .hgsub
+  $ hg ci -qAm 'add subrepo "~"'
+  abort: subrepo path contains illegal component: ~
+  [255]
+
+prepare tampered repo (including the commit above):
+
+  $ hg import --bypass -qm 'add subrepo "~"' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > +~ = ~
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000 ~
+  > EOF
+  $ cd ..
+
+on clone (and update):
+
+  $ hg clone -q tilde tilde2
+  abort: subrepo path contains illegal component: ~
+  [255]
+
 Test direct symlink traversal
 -----------------------------
 
@@ -130,3 +496,167 @@
   root
 
 #endif
+
+Test symlink traversal by variable expansion
+--------------------------------------------
+
+#if symlink
+
+  $ FAKEHOME="$TESTTMP/envvarsym/fakehome"
+
+on commit:
+
+  $ mkdir envvarsym
+  $ cd envvarsym
+  $ hg init main
+  $ cd main
+  $ ln -s "`echo "$FAKEHOME" | sed 's|\(.\)/.*|\1|'`"
+  $ hg ci -qAm 'add symlink to top-level system directory'
+
+  $ hg init sub1
+  $ echo pwned > sub1/pwned
+  $ hg -R sub1 ci -qAm 'add sub1 files'
+  $ hg -R sub1 log -r. -T '{node}\n'
+  f40c9134ba1b6961e12f250868823f0092fb68a8
+  $ echo '$SUB = sub1' >> .hgsub
+  $ SUB="$FAKEHOME" hg ci -qAm 'add subrepo "$SUB"'
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+
+prepare tampered repo (including the changes above as two commits):
+
+  $ hg import --bypass -qm 'add subrepo "$SUB"' - <<'EOF'
+  > diff --git a/.hgsub b/.hgsub
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsub
+  > @@ -0,0 +1,1 @@
+  > +$SUB = sub1
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > new file mode 100644
+  > --- /dev/null
+  > +++ b/.hgsubstate
+  > @@ -0,0 +1,1 @@
+  > +0000000000000000000000000000000000000000 $SUB
+  > EOF
+  $ hg debugsetparents 1
+  $ hg import --bypass -qm 'update subrepo "$SUB"' - <<'EOF'
+  > diff --git a/.hgsubstate b/.hgsubstate
+  > --- a/.hgsubstate
+  > +++ b/.hgsubstate
+  > @@ -1,1 +1,1 @@
+  > -0000000000000000000000000000000000000000 $SUB
+  > +f40c9134ba1b6961e12f250868823f0092fb68a8 $SUB
+  > EOF
+  $ cd ..
+
+on clone (and update) without fakehome directory:
+
+  $ rm -fR "$FAKEHOME"
+  $ SUB="$FAKEHOME" hg clone -q main main2
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ test -d "$FAKEHOME"
+  [1]
+
+on clone (and update) with empty fakehome directory:
+
+  $ rm -fR "$FAKEHOME"
+  $ mkdir "$FAKEHOME"
+  $ SUB="$FAKEHOME" hg clone -q main main3
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls "$FAKEHOME"
+
+on clone (and update) with non-empty fakehome directory:
+
+  $ rm -fR "$FAKEHOME"
+  $ mkdir "$FAKEHOME"
+  $ touch "$FAKEHOME/a"
+  $ SUB="$FAKEHOME" hg clone -q main main4
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls "$FAKEHOME"
+  a
+
+on clone empty subrepo with non-empty fakehome directory,
+then pull (and update):
+
+  $ rm -fR "$FAKEHOME"
+  $ mkdir "$FAKEHOME"
+  $ touch "$FAKEHOME/a"
+  $ SUB="$FAKEHOME" hg clone -qr1 main main5
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls "$FAKEHOME"
+  a
+  $ test -d "$FAKEHOME/.hg"
+  [1]
+  $ SUB="$FAKEHOME" hg -R main5 pull -u
+  pulling from $TESTTMP/envvarsym/main
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  new changesets * (glob)
+  .hgsubstate: untracked file differs
+  abort: untracked files in working directory differ from files in requested revision
+  [255]
+  $ ls "$FAKEHOME"
+  a
+  $ test -d "$FAKEHOME/.hg"
+  [1]
+
+on clone empty subrepo with hg-managed fakehome directory,
+then pull (and update):
+
+  $ rm -fR "$FAKEHOME"
+  $ hg init "$FAKEHOME"
+  $ touch "$FAKEHOME/a"
+  $ hg -R "$FAKEHOME" ci -qAm 'add fakehome file'
+  $ SUB="$FAKEHOME" hg clone -qr1 main main6
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls "$FAKEHOME"
+  a
+  $ SUB="$FAKEHOME" hg -R main6 pull -u
+  pulling from $TESTTMP/envvarsym/main
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  new changesets * (glob)
+  .hgsubstate: untracked file differs
+  abort: untracked files in working directory differ from files in requested revision
+  [255]
+  $ ls "$FAKEHOME"
+  a
+
+on clone only symlink with hg-managed fakehome directory,
+then pull (and update):
+
+  $ rm -fR "$FAKEHOME"
+  $ hg init "$FAKEHOME"
+  $ touch "$FAKEHOME/a"
+  $ hg -R "$FAKEHOME" ci -qAm 'add fakehome file'
+  $ SUB="$FAKEHOME" hg clone -qr0 main main7
+  $ ls "$FAKEHOME"
+  a
+  $ SUB="$FAKEHOME" hg -R main7 pull -uf
+  pulling from $TESTTMP/envvarsym/main
+  searching for changes
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 3 changes to 2 files
+  new changesets * (glob)
+  abort: subrepo path contains illegal component: $SUB
+  [255]
+  $ ls "$FAKEHOME"
+  a
+
+  $ cd ..
+
+#endif
--- mercurial.orig/mercurial/subrepo.py
+++ mercurial/mercurial/subrepo.py
@@ -115,6 +115,10 @@
                 vfs.unlink(vfs.reljoin(dirname, f))
 
 def _auditsubrepopath(repo, path):
+    # sanity check for potentially unsafe paths such as '~' and '$FOO'
+    if path.startswith('~') or '$' in path or util.expandpath(path) != path:
+        raise error.Abort(_('subrepo path contains illegal component: %s')
+                          % path)
     # auditor doesn't check if the path itself is a symlink
     pathutil.pathauditor(repo.root)(path)
     if repo.wvfs.islink(path):
@@ -403,7 +407,16 @@
         r = ctx.repo()
         root = r.wjoin(path)
         create = allowcreate and not r.wvfs.exists('%s/.hg' % path)
+        # repository constructor does expand variables in path, which is
+        # unsafe since subrepo path might come from untrusted source.
+        if os.path.realpath(util.expandpath(root)) != root:
+            raise error.Abort(_('subrepo path contains illegal component: %s')
+                              % path)
         self._repo = hg.repository(r.baseui, root, create=create)
+        if self._repo.root != root:
+            raise error.ProgrammingError('failed to reject unsafe subrepo '
+                                         'path: %s (expanded to %s)'
+                                         % (root, self._repo.root))
 
         # Propagate the parent's --hidden option
         if r is r.unfiltered():