t7423: add tests for symlinked submodule directories

Submodule operations must not follow symlinks in working tree, because
otherwise files might be written to unintended places, leading to
vulnerabilities.

Signed-off-by: Filip Hejsek <[email protected]>
Signed-off-by: Johannes Schindelin <[email protected]>

Author: filip-hejsek

t/t7423-submodule-symlinks.sh

@@ -0,0 +1,66 @@
+#!/bin/sh
+
+test_description='check that submodule operations do not follow symlinks'
+
+. ./test-lib.sh
+
+test_expect_success 'prepare' '
+	git config --global protocol.file.allow always &&
+	test_commit initial &&
+	git init upstream &&
+	test_commit -C upstream upstream submodule_file &&
+	git submodule add ./upstream a/sm &&
+	test_tick &&
+	git commit -m submodule
+'
+
+test_expect_failure SYMLINKS 'git submodule update must not create submodule behind symlink' '
+	rm -rf a b &&
+	mkdir b &&
+	ln -s b a &&
+	test_must_fail git submodule update &&
+	test_path_is_missing b/sm
+'
+
+test_expect_failure SYMLINKS,CASE_INSENSITIVE_FS 'git submodule update must not create submodule behind symlink on case insensitive fs' '
+	rm -rf a b &&
+	mkdir b &&
+	ln -s b A &&
+	test_must_fail git submodule update &&
+	test_path_is_missing b/sm
+'
+
+prepare_symlink_to_repo() {
+	rm -rf a &&
+	mkdir a &&
+	git init a/target &&
+	git -C a/target fetch ../../upstream &&
+	ln -s target a/sm
+}
+
+test_expect_success SYMLINKS 'git restore --recurse-submodules must not be confused by a symlink' '
+	prepare_symlink_to_repo &&
+	test_must_fail git restore --recurse-submodules a/sm &&
+	test_path_is_missing a/sm/submodule_file &&
+	test_path_is_dir a/target/.git &&
+	test_path_is_missing a/target/submodule_file
+'
+
+test_expect_failure SYMLINKS 'git restore --recurse-submodules must not migrate git dir of symlinked repo' '
+	prepare_symlink_to_repo &&
+	rm -rf .git/modules &&
+	test_must_fail git restore --recurse-submodules a/sm &&
+	test_path_is_dir a/target/.git &&
+	test_path_is_missing .git/modules/a/sm &&
+	test_path_is_missing a/target/submodule_file
+'
+
+test_expect_failure SYMLINKS 'git checkout -f --recurse-submodules must not migrate git dir of symlinked repo when removing submodule' '
+	prepare_symlink_to_repo &&
+	rm -rf .git/modules &&
+	test_must_fail git checkout -f --recurse-submodules initial &&
+	test_path_is_dir a/target/.git &&
+	test_path_is_missing .git/modules/a/sm
+'
+
+test_done