repo: make ownership checks optional

Introduce the `GIT_OPT_SET_OWNER_VALIDATION` option, so that users can
disable repository ownership validation.

include/git2/common.h

@@ -225,7 +225,9 @@ typedef enum {
 	GIT_OPT_SET_ODB_PACKED_PRIORITY,
 	GIT_OPT_SET_ODB_LOOSE_PRIORITY,
 	GIT_OPT_GET_EXTENSIONS,
-	GIT_OPT_SET_EXTENSIONS
+	GIT_OPT_SET_EXTENSIONS,
+	GIT_OPT_GET_OWNER_VALIDATION,
+	GIT_OPT_SET_OWNER_VALIDATION
 } git_libgit2_opt_t;
 
 /**
@@ -463,6 +465,14 @@ typedef enum {
  *      > to support repositories with the `noop` extension but does want
  *      > to support repositories with the `newext` extension.
  *
+ *   opts(GIT_OPT_GET_OWNER_VALIDATION, int *enabled)
+ *      > Gets the owner validation setting for repository
+ *      > directories.
+ *
+ *   opts(GIT_OPT_SET_OWNER_VALIDATION, int enabled)
+ *      > Set that repository directories should be owned by the current
+ *      > user. The default is to validate ownership.
+ *
  * @param option Option key
  * @param ... value to set the option
  * @return 0 on success, <0 on failure

src/libgit2/libgit2.c

@@ -406,6 +406,14 @@ int git_libgit2_opts(int key, ...)
 		}
 		break;
 
+	case GIT_OPT_GET_OWNER_VALIDATION:
+		*(va_arg(ap, int *)) = git_repository__validate_ownership;
+		break;
+
+	case GIT_OPT_SET_OWNER_VALIDATION:
+		git_repository__validate_ownership = (va_arg(ap, int) != 0);
+		break;
+
 	default:
 		git_error_set(GIT_ERROR_INVALID, "invalid option key");
 		error = -1;

src/libgit2/repository.c

@@ -39,6 +39,7 @@
 # include "win32/w32_util.h"
 #endif
 
+bool git_repository__validate_ownership = true;
 bool git_repository__fsync_gitdir = false;
 
 static const struct {
@@ -977,7 +978,8 @@ int git_repository_open_ext(
 	 */
 	validation_path = repo->is_bare ? repo->gitdir : repo->workdir;
 
-	if ((error = validate_ownership(validation_path)) < 0)
+	if (git_repository__validate_ownership &&
+	    (error = validate_ownership(validation_path)) < 0)
 		goto cleanup;
 
 cleanup:

src/libgit2/repository.h

@@ -34,6 +34,7 @@
 #define GIT_DIR_SHORTNAME "GIT~1"
 
 extern bool git_repository__fsync_gitdir;
+extern bool git_repository__validate_ownership;
 
 /** Cvar cache identifiers */
 typedef enum {

tests/clar/clar_libgit2.c

@@ -599,6 +599,11 @@ void cl_sandbox_set_search_path_defaults(void)
 	git_str_dispose(&path);
 }
 
+void cl_sandbox_disable_ownership_validation(void)
+{
+	git_libgit2_opts(GIT_OPT_SET_OWNER_VALIDATION, 0);
+}
+
 #ifdef GIT_WIN32
 bool cl_sandbox_supports_8dot3(void)
 {

tests/clar/clar_libgit2.h

@@ -222,6 +222,7 @@ void cl_fake_home(void);
 void cl_fake_home_cleanup(void *);
 
 void cl_sandbox_set_search_path_defaults(void);
+void cl_sandbox_disable_ownership_validation(void);
 
 #ifdef GIT_WIN32
 # define cl_msleep(x) Sleep(x)

tests/clar/main.c

@@ -26,6 +26,7 @@ int main(int argc, char *argv[])
 
 	cl_global_trace_register();
 	cl_sandbox_set_search_path_defaults();
+	cl_sandbox_disable_ownership_validation();
 
 	/* Run the test suite */
 	res = clar_test_run();

tests/libgit2/repo/open.c

@@ -3,11 +3,13 @@
 #include "sysdir.h"
 #include <ctype.h>
 
+static int validate_ownership = 0;
 static git_buf config_path = GIT_BUF_INIT;
 
 void test_repo_open__initialize(void)
 {
 	cl_git_pass(git_libgit2_opts(GIT_OPT_GET_SEARCH_PATH, GIT_CONFIG_LEVEL_GLOBAL, &config_path));
+	cl_git_pass(git_libgit2_opts(GIT_OPT_GET_OWNER_VALIDATION, &validate_ownership));
 }
 
 void test_repo_open__cleanup(void)
@@ -23,6 +25,8 @@ void test_repo_open__cleanup(void)
 
 	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_SEARCH_PATH, GIT_CONFIG_LEVEL_GLOBAL, config_path.ptr));
 	git_buf_dispose(&config_path);
+
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_OWNER_VALIDATION, validate_ownership));
 }
 
 void test_repo_open__bare_empty_repo(void)
@@ -470,6 +474,8 @@ void test_repo_open__validates_dir_ownership(void)
 {
 	git_repository *repo;
 
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_OWNER_VALIDATION, 1));
+
 	cl_fixture_sandbox("empty_standard_repo");
 	cl_git_pass(cl_rename("empty_standard_repo/.gitted", "empty_standard_repo/.git"));
 
@@ -494,6 +500,8 @@ void test_repo_open__can_allowlist_dirs_with_problematic_ownership(void)
 	        config_filename = GIT_STR_INIT,
 	        config_data = GIT_STR_INIT;
 
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_OWNER_VALIDATION, 1));
+
 	cl_fixture_sandbox("empty_standard_repo");
 	cl_git_pass(cl_rename("empty_standard_repo/.gitted", "empty_standard_repo/.git"));
 
@@ -537,6 +545,8 @@ void test_repo_open__can_reset_safe_directory_list(void)
 	        config_filename = GIT_STR_INIT,
 	        config_data = GIT_STR_INIT;
 
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_OWNER_VALIDATION, 1));
+
 	cl_fixture_sandbox("empty_standard_repo");
 	cl_git_pass(cl_rename("empty_standard_repo/.gitted", "empty_standard_repo/.git"));