fix(security): harden git_gate.py shell rendering with shlex.quote and name validation

Use shlex.quote() on name and upstream_url in git_gate_render_entrypoint()
so special characters (single quotes, spaces, semicolons) cannot break or
inject into the generated sh script.

Add _GIT_NAME_RE validation in GitEntry.from_repos_entry() to restrict
repo names to [A-Za-z0-9._-]+, making the manifest the first line of
defence and shlex.quote() the belt-and-suspenders backstop.

Closes #155

bot_bottle/git_gate.py

@@ -29,6 +29,7 @@ backend-specific and lives on concrete subclasses (see
 
 from __future__ import annotations
 
+import shlex
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from pathlib import Path
@@ -207,10 +208,7 @@ def git_gate_render_entrypoint(upstreams: tuple[GitGateUpstream, ...]) -> str:
         "mkdir -p /git",
     ]
     for u in upstreams:
-        # Single-quote args so URL/path content (containing : and /)
-        # passes through ash unmangled. Names came through the manifest
-        # validator so they don't contain a single quote.
-        lines.append(f"init_repo '{u.name}' '{u.upstream_url}'")
+        lines.append(f"init_repo {shlex.quote(u.name)} {shlex.quote(u.upstream_url)}")
     lines.extend([
         "",
         "exec git daemon \\",

bot_bottle/manifest.py

@@ -47,6 +47,7 @@ from __future__ import annotations
 
 import ipaddress
 import os
+import re
 from dataclasses import dataclass, field, replace
 from pathlib import Path
 from typing import Mapping, cast
@@ -60,6 +61,12 @@ class ManifestError(Exception):
     """A manifest file (or the manifest tree) is invalid."""
 
 
+# Shell-safe characters for git-gate repo names. Names are embedded in
+# the generated entrypoint shell script (shlex.quote is the primary
+# defence; this regex is belt-and-suspenders and documents intent).
+_GIT_NAME_RE = re.compile(r"^[A-Za-z0-9._-]+$")
+
+
 def _empty_str_dict() -> dict[str, str]:
     return {}
 
@@ -103,6 +110,11 @@ class GitEntry:
             raise ManifestError(
                 f"bottle '{bottle_name}' git-gate.repos has an empty key"
             )
+        if not _GIT_NAME_RE.match(repo_name):
+            raise ManifestError(
+                f"bottle '{bottle_name}' git-gate.repos name {repo_name!r} is invalid; "
+                f"allowed characters: A-Z a-z 0-9 . _ -"
+            )
         label = f"git-gate.repos[{repo_name!r}]"
         d = _as_json_object(raw, f"bottle '{bottle_name}' {label}")
         for k in d:

tests/unit/test_git_gate.py

@@ -76,14 +76,18 @@ class TestEntrypointRender(unittest.TestCase):
         )
         script = git_gate_render_entrypoint(ups)
         self.assertIn("#!/bin/sh", script)
-        self.assertIn(
-            "init_repo 'bot-bottle' "
-            "'ssh://git@gitea.dideric.is:30009/didericis/bot-bottle.git'",
-            script,
+        # shlex.quote leaves safe strings unquoted; verify the call tokens.
+        import shlex as _shlex
+        lines_with_init = [l for l in script.splitlines() if l.startswith("init_repo ")]
+        self.assertEqual(2, len(lines_with_init))
+        self.assertEqual(
+            ["init_repo", "bot-bottle",
+             "ssh://git@gitea.dideric.is:30009/didericis/bot-bottle.git"],
+            _shlex.split(lines_with_init[0]),
         )
-        self.assertIn(
-            "init_repo 'foo' 'ssh://git@github.com/didericis/foo.git'",
-            script,
+        self.assertEqual(
+            ["init_repo", "foo", "ssh://git@github.com/didericis/foo.git"],
+            _shlex.split(lines_with_init[1]),
         )
         # Daemon line is what keeps PID 1 alive.
         self.assertIn("exec git daemon", script)
@@ -108,6 +112,46 @@ class TestEntrypointRender(unittest.TestCase):
         self.assertNotIn("init_repo '", script)
         self.assertIn("exec git daemon", script)
 
+    def test_single_quote_in_upstream_url_is_escaped(self):
+        ups = (GitGateUpstream(
+            name="myrepo",
+            upstream_url="ssh://git@host/path'with'quotes.git",
+            upstream_host="host",
+            upstream_port="22",
+            identity_file="/key",
+            known_host_key="",
+        ),)
+        script = git_gate_render_entrypoint(ups)
+        # The raw single-quoted form would break the shell script;
+        # shlex.quote must produce something safe.
+        self.assertNotIn(
+            "init_repo 'myrepo' 'ssh://git@host/path'with'quotes.git'",
+            script,
+        )
+        self.assertIn("init_repo", script)
+        self.assertIn("path", script)
+
+    def test_space_and_semicolon_in_upstream_url_are_escaped(self):
+        import shlex as _shlex
+        raw_url = "ssh://git@host/path with spaces;evil.git"
+        ups = (GitGateUpstream(
+            name="myrepo",
+            upstream_url=raw_url,
+            upstream_host="host",
+            upstream_port="22",
+            identity_file="/key",
+            known_host_key="",
+        ),)
+        script = git_gate_render_entrypoint(ups)
+        # Skip the function-definition line "init_repo() {"; match the call.
+        line = next(l for l in script.splitlines() if l.startswith("init_repo "))
+        # Re-parsing via shlex must recover exactly the original URL with no
+        # shell injection — three tokens total.
+        tokens = _shlex.split(line)
+        self.assertEqual(3, len(tokens))
+        self.assertEqual("myrepo", tokens[1])
+        self.assertEqual(raw_url, tokens[2])
+
 
 class TestHookRender(unittest.TestCase):
     def test_pre_receive_hook_has_two_phases(self):

tests/unit/test_manifest_git.py

@@ -185,6 +185,51 @@ class TestGitEntryCrossValidation(unittest.TestCase):
                 "agents": {"demo": {"skills": [], "prompt": "", "bottle": "dev"}},
             })
 
+    def test_name_with_single_quote_dies(self):
+        with self.assertRaises(ManifestError):
+            Manifest.from_json_obj(_manifest({
+                "o'reilly": {
+                    "url": "ssh://git@github.com/foo.git",
+                    "identity": "/dev/null",
+                },
+            }))
+
+    def test_name_with_space_dies(self):
+        with self.assertRaises(ManifestError):
+            Manifest.from_json_obj(_manifest({
+                "my repo": {
+                    "url": "ssh://git@github.com/foo.git",
+                    "identity": "/dev/null",
+                },
+            }))
+
+    def test_name_with_semicolon_dies(self):
+        with self.assertRaises(ManifestError):
+            Manifest.from_json_obj(_manifest({
+                "foo;bar": {
+                    "url": "ssh://git@github.com/foo.git",
+                    "identity": "/dev/null",
+                },
+            }))
+
+    def test_name_with_dollar_dies(self):
+        with self.assertRaises(ManifestError):
+            Manifest.from_json_obj(_manifest({
+                "foo$bar": {
+                    "url": "ssh://git@github.com/foo.git",
+                    "identity": "/dev/null",
+                },
+            }))
+
+    def test_valid_name_with_dots_and_hyphens_accepted(self):
+        m = Manifest.from_json_obj(_manifest({
+            "my.repo-name_1": {
+                "url": "ssh://git@github.com/foo.git",
+                "identity": "/dev/null",
+            },
+        }))
+        self.assertEqual("my.repo-name_1", m.bottles["dev"].git[0].Name)
+
     def test_legacy_git_key_dies_with_hint(self):
         msg = ""
         try: