Fix command injection when exporting to httpie

The command generated by `export.clip httpie @focus` or `export.file
httpie @focus /path/to/file` wasn't being properly escaped so it could
contain a malicious command instead of just a simple httpie call.

mitmproxy/addons/export.py

@@ -44,17 +44,21 @@ def curl_command(f: flow.Flow) -> str:
 def httpie_command(f: flow.Flow) -> str:
     raise_if_missing_request(f)
     request = f.request.copy()  # type: ignore
-    data = "http %s " % request.method
+    args = ["http"]
+    args.append(shlex.quote(request.method))
     request.decode(strict=False)
-    data += "%s" % request.url
+    args.append(shlex.quote(request.url))
     for k, v in request.headers.items(multi=True):
-        data += " '%s:%s'" % (k, v)
+        args.append(shlex.quote("%s:%s" % (k, v)))
     if request.content:
-        data += " <<< '%s'" % strutils.bytes_to_escaped_str(
-            request.content,
-            escape_single_quotes=True
-        )
-    return data
+        try:
+            content = strutils.always_str(request.content)
+        except UnicodeDecodeError:
+            # shlex.quote doesn't support a bytes object
+            # see https://github.com/python/cpython/pull/10871
+            raise exceptions.CommandError("Request content must be valid unicode")
+        args += ["<<<", shlex.quote(content)]
+    return ' '.join(args)
 
 
 def raw(f: flow.Flow) -> bytes:

test/mitmproxy/addons/test_export.py

@@ -85,23 +85,40 @@ class TestExportCurlCommand:
 
 class TestExportHttpieCommand:
     def test_get(self, get_request):
-        result = """http GET http://address:22/path?a=foo&a=bar&b=baz 'header:qvalue' 'content-length:0'"""
+        result = """http GET 'http://address:22/path?a=foo&a=bar&b=baz' header:qvalue content-length:0"""
         assert export.httpie_command(get_request) == result
 
     def test_post(self, post_request):
-        result = "http POST http://address:22/path 'content-length:256' <<< '{}'".format(
-            str(bytes(range(256)))[2:-1]
-        )
+        post_request.request.content = b'nobinarysupport'
+        result = "http POST http://address:22/path content-length:15 <<< nobinarysupport"
         assert export.httpie_command(post_request) == result
 
+    def test_fails_with_binary_data(self, post_request):
+        # shlex.quote doesn't support a bytes object
+        # see https://github.com/python/cpython/pull/10871
+        with pytest.raises(exceptions.CommandError):
+            export.httpie_command(post_request)
+
     def test_patch(self, patch_request):
-        result = """http PATCH http://address:22/path?query=param 'header:qvalue' 'content-length:7' <<< 'content'"""
+        result = """http PATCH 'http://address:22/path?query=param' header:qvalue content-length:7 <<< content"""
         assert export.httpie_command(patch_request) == result
 
     def test_tcp(self, tcp_flow):
         with pytest.raises(exceptions.CommandError):
             export.httpie_command(tcp_flow)
 
+    def test_escape_single_quotes_in_body(self):
+        request = tflow.tflow(
+            req=tutils.treq(
+                method=b'POST',
+                headers=(),
+                content=b"'&#"
+            )
+        )
+        command = export.httpie_command(request)
+        assert shlex.split(command)[-2] == '<<<'
+        assert shlex.split(command)[-1] == "'&#"
+
 
 class TestRaw:
     def test_get(self, get_request):