fix(ssh): keep bulk sync extraction scoped to .hermes

tests/tools/test_ssh_bulk_upload.py

@@ -91,7 +91,7 @@ class TestSSHBulkUpload:
         assert "/home/testuser/.hermes/credentials" in mkdir_str
 
     def test_staging_symlinks_mirror_remote_layout(self, mock_env, tmp_path):
-        """Symlinks in staging dir should mirror the remote path structure."""
+        """Symlinks in staging dir should mirror the .hermes-relative layout."""
         f1 = tmp_path / "local_a.txt"
         f1.write_text("content a")
 
@@ -107,9 +107,7 @@ class TestSSHBulkUpload:
                 c_idx = cmd.index("-C")
                 staging_dir = cmd[c_idx + 1]
                 # Check the symlink exists
-                expected = os.path.join(
+                expected = os.path.join(staging_dir, "skills/my_skill.md")
-                    staging_dir, "home/testuser/.hermes/skills/my_skill.md"
-                )
                 staging_paths.append(expected)
                 assert os.path.islink(expected), f"Expected symlink at {expected}"
                 assert os.readlink(expected) == os.path.abspath(str(f1))
@@ -166,14 +164,42 @@ class TestSSHBulkUpload:
         assert "-" in tar_cmd  # stdout
         assert "-C" in tar_cmd
 
-        # ssh: extract from stdin at /, preserving existing dir modes (#17767)
+        # ssh: extract from stdin at ~/.hermes, preserving existing dir modes (#17767)
         ssh_str = " ".join(ssh_cmd)
         assert "ssh" in ssh_str
         assert "tar xf -" in ssh_str
         assert "--no-overwrite-dir" in ssh_str
-        assert "-C /" in ssh_str
+        assert "-C /home/testuser/.hermes" in ssh_str
         assert "testuser@example.com" in ssh_str
 
+    def test_bulk_upload_never_stages_remote_home_prefix(self, mock_env, tmp_path):
+        """Regression: do not archive /home/<user> path components."""
+        f1 = tmp_path / "nested.txt"
+        f1.write_text("nested")
+        files = [(str(f1), "/home/testuser/.hermes/cache/nested.txt")]
+
+        def capture_tar_cmd(cmd, **kwargs):
+            if cmd[0] == "tar":
+                c_idx = cmd.index("-C")
+                staging_dir = cmd[c_idx + 1]
+                assert not os.path.exists(os.path.join(staging_dir, "home"))
+                expected = os.path.join(staging_dir, "cache/nested.txt")
+                assert os.path.islink(expected)
+
+            mock = MagicMock()
+            mock.stdout = MagicMock()
+            mock.returncode = 0
+            mock.poll.return_value = 0
+            mock.communicate.return_value = (b"", b"")
+            mock.stderr = MagicMock()
+            mock.stderr.read.return_value = b""
+            return mock
+
+        with patch.object(subprocess, "run",
+                          return_value=subprocess.CompletedProcess([], 0)), \
+             patch.object(subprocess, "Popen", side_effect=capture_tar_cmd):
+            mock_env._ssh_bulk_upload(files)
+
     def test_mkdir_failure_raises(self, mock_env, tmp_path):
         """mkdir failure should raise RuntimeError before tar pipe."""
         f1 = tmp_path / "y.txt"

tools/environments/ssh.py

@@ -169,6 +169,7 @@ class SSHEnvironment(BaseEnvironment):
         if not files:
             return
 
+        base = f"{self._remote_home}/.hermes"
         parents = unique_parent_dirs(files)
         if parents:
             cmd = self._build_ssh_command()
@@ -180,7 +181,19 @@ class SSHEnvironment(BaseEnvironment):
         # Symlink staging avoids fragile GNU tar --transform rules.
         with tempfile.TemporaryDirectory(prefix="hermes-ssh-bulk-") as staging:
             for host_path, remote_path in files:
-                staged = os.path.join(staging, remote_path.lstrip("/"))
+                try:
+                    rel_remote = os.path.relpath(remote_path, base)
+                except ValueError as exc:
+                    raise RuntimeError(
+                        f"remote path {remote_path!r} is not under sync base {base!r}"
+                    ) from exc
+
+                if rel_remote == "." or rel_remote.startswith("../"):
+                    raise RuntimeError(
+                        f"remote path {remote_path!r} escapes sync base {base!r}"
+                    )
+
+                staged = os.path.join(staging, rel_remote)
                 os.makedirs(os.path.dirname(staged), exist_ok=True)
                 os.symlink(os.path.abspath(host_path), staged)
 
@@ -190,7 +203,7 @@ class SSHEnvironment(BaseEnvironment):
             # existing directories (e.g. /home/<user>) with the staging
             # directory's mode.  Without this, a umask 002 produces 0775
             # dirs which breaks sshd StrictModes (refuses authorized_keys).
-            ssh_cmd.append("tar xf - --no-overwrite-dir -C /")
+            ssh_cmd.append(f"tar xf - --no-overwrite-dir -C {shlex.quote(base)}")
 
             tar_proc = subprocess.Popen(
                 tar_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE