[PATCH 2/2] fetch2: validate striplevel parameter

The striplevel URL parameter is appended to tar_cmd, which is later run
through the shell. Validate it as a decimal count before using it in the
tar arguments.

Signed-off-by: Anders Heimer <[email protected]>
---
 lib/bb/fetch2/__init__.py |  5 ++++-
 lib/bb/tests/fetch.py     | 10 ++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/bb/fetch2/__init__.py b/lib/bb/fetch2/__init__.py
index dc93e64a9..77fc1b15b 100644
--- a/lib/bb/fetch2/__init__.py
+++ b/lib/bb/fetch2/__init__.py
@@ -1545,7 +1545,10 @@ class FetchMethod(object):
         if unpack:
             tar_cmd = 'tar --extract --no-same-owner'
             if 'striplevel' in urldata.parm:
-                tar_cmd += ' --strip-components=%s' %  urldata.parm['striplevel']
+                striplevel = urldata.parm['striplevel']
+                if not striplevel.isdigit():
+                    raise UnpackError("Invalid striplevel parameter: %s" % striplevel, urldata.url)
+                tar_cmd += ' --strip-components=%s' % striplevel
             if file.endswith('.tar'):
                 cmd = '%s -f %s' % (tar_cmd, file)
             elif file.endswith('.tgz') or file.endswith('.tar.gz') or file.endswith('.tar.Z'):
diff --git a/lib/bb/tests/fetch.py b/lib/bb/tests/fetch.py
index bece59e62..5850589e0 100644
--- a/lib/bb/tests/fetch.py
+++ b/lib/bb/tests/fetch.py
@@ -866,6 +866,16 @@ class FetcherLocalTest(FetcherTest):
 
         self.assertIn("does not contain supported data.tar* file", str(context.exception))
 
+    def assertInvalidStriplevel(self, value):
+        with self.assertRaises(bb.fetch2.UnpackError) as context:
+            self.fetchUnpack(['file://archive.tar;subdir=bar;striplevel=%s' % value])
+        self.assertIn("Invalid striplevel parameter", str(context.exception))
+
+    def test_local_striplevel_rejects_invalid_values(self):
+        for value in ("abc", "", "-1", "1\n", "1 2"):
+            with self.subTest(striplevel=repr(value)):
+                self.assertInvalidStriplevel(value)
+
     def dummyGitTest(self, suffix):
         # Create dummy local Git repo
         src_dir = tempfile.mkdtemp(dir=self.tempdir,
-- 
2.34.1