Revision 9cf85473209ea8ae2b56c13145c4704d12ee1374 authored by Filip Hejsek on 28 January 2024, 04:09:17 UTC, committed by Johannes Schindelin on 17 April 2024, 20:30:01 UTC
While it is expected to have several git dirs within the `.git/modules/` tree, it is important that they do not interfere with each other. For example, if one submodule was called "captain" and another submodule "captain/hooks", their respective git dirs would clash, as they would be located in `.git/modules/captain/` and `.git/modules/captain/hooks/`, respectively, i.e. the latter's files could clash with the actual Git hooks of the former. To prevent these clashes, and in particular to prevent hooks from being written and then executed as part of a recursive clone, we introduced checks as part of the fix for CVE-2019-1387 in a8dee3ca61 (Disallow dubiously-nested submodule git directories, 2019-10-01). It is currently possible to bypass the check for clashing submodule git dirs in two ways: 1. parallel cloning 2. checkout --recurse-submodules Let's check not only before, but also after parallel cloning (and before checking out the submodule), that the git dir is not clashing with another one, otherwise fail. This addresses the parallel cloning issue. As to the parallel checkout issue: It requires quite a few manual steps to create clashing git dirs because Git itself would refuse to initialize the inner one, as demonstrated by the test case. Nevertheless, let's teach the recursive checkout (namely, the `submodule_move_head()` function that is used by the recursive checkout) to be careful to verify that it does not use a clashing git dir, and if it does, disable it (by deleting the `HEAD` file so that subsequent Git calls won't recognize it as a git dir anymore). Note: The parallel cloning test case contains a `cat err` that proved to be highly useful when analyzing the racy nature of the operation (the operation can fail with three different error messages, depending on timing), and was left on purpose to ease future debugging should the need arise. Signed-off-by: Filip Hejsek <filip.hejsek@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent b20c10f
repository.c
/*
* not really _using_ the compat macros, just make sure the_index
* declaration matches the definition in this file.
*/
#define USE_THE_INDEX_VARIABLE
#include "cache.h"
#include "repository.h"
#include "object-store.h"
#include "config.h"
#include "object.h"
#include "lockfile.h"
#include "remote.h"
#include "submodule-config.h"
#include "sparse-index.h"
#include "promisor-remote.h"
/* The main repository */
static struct repository the_repo;
struct repository *the_repository;
struct index_state the_index;
void initialize_the_repository(void)
{
the_repository = &the_repo;
the_repo.index = &the_index;
the_repo.objects = raw_object_store_new();
the_repo.remote_state = remote_state_new();
the_repo.parsed_objects = parsed_object_pool_new();
repo_set_hash_algo(&the_repo, GIT_HASH_SHA1);
}
static void expand_base_dir(char **out, const char *in,
const char *base_dir, const char *def_in)
{
free(*out);
if (in)
*out = xstrdup(in);
else
*out = xstrfmt("%s/%s", base_dir, def_in);
}
static void repo_set_commondir(struct repository *repo,
const char *commondir)
{
struct strbuf sb = STRBUF_INIT;
free(repo->commondir);
if (commondir) {
repo->different_commondir = 1;
repo->commondir = xstrdup(commondir);
return;
}
repo->different_commondir = get_common_dir_noenv(&sb, repo->gitdir);
repo->commondir = strbuf_detach(&sb, NULL);
}
void repo_set_gitdir(struct repository *repo,
const char *root,
const struct set_gitdir_args *o)
{
const char *gitfile = read_gitfile(root);
/*
* repo->gitdir is saved because the caller could pass "root"
* that also points to repo->gitdir. We want to keep it alive
* until after xstrdup(root). Then we can free it.
*/
char *old_gitdir = repo->gitdir;
repo->gitdir = xstrdup(gitfile ? gitfile : root);
free(old_gitdir);
repo_set_commondir(repo, o->commondir);
if (!repo->objects->odb) {
CALLOC_ARRAY(repo->objects->odb, 1);
repo->objects->odb_tail = &repo->objects->odb->next;
}
expand_base_dir(&repo->objects->odb->path, o->object_dir,
repo->commondir, "objects");
repo->objects->odb->disable_ref_updates = o->disable_ref_updates;
free(repo->objects->alternate_db);
repo->objects->alternate_db = xstrdup_or_null(o->alternate_db);
expand_base_dir(&repo->graft_file, o->graft_file,
repo->commondir, "info/grafts");
expand_base_dir(&repo->index_file, o->index_file,
repo->gitdir, "index");
}
void repo_set_hash_algo(struct repository *repo, int hash_algo)
{
repo->hash_algo = &hash_algos[hash_algo];
}
/*
* Attempt to resolve and set the provided 'gitdir' for repository 'repo'.
* Return 0 upon success and a non-zero value upon failure.
*/
static int repo_init_gitdir(struct repository *repo, const char *gitdir)
{
int ret = 0;
int error = 0;
char *abspath = NULL;
const char *resolved_gitdir;
struct set_gitdir_args args = { NULL };
abspath = real_pathdup(gitdir, 0);
if (!abspath) {
ret = -1;
goto out;
}
/* 'gitdir' must reference the gitdir directly */
resolved_gitdir = resolve_gitdir_gently(abspath, &error);
if (!resolved_gitdir) {
ret = -1;
goto out;
}
repo_set_gitdir(repo, resolved_gitdir, &args);
out:
free(abspath);
return ret;
}
void repo_set_worktree(struct repository *repo, const char *path)
{
repo->worktree = real_pathdup(path, 1);
trace2_def_repo(repo);
}
static int read_and_verify_repository_format(struct repository_format *format,
const char *commondir)
{
int ret = 0;
struct strbuf sb = STRBUF_INIT;
strbuf_addf(&sb, "%s/config", commondir);
read_repository_format(format, sb.buf);
strbuf_reset(&sb);
if (verify_repository_format(format, &sb) < 0) {
warning("%s", sb.buf);
ret = -1;
}
strbuf_release(&sb);
return ret;
}
/*
* Initialize 'repo' based on the provided 'gitdir'.
* Return 0 upon success and a non-zero value upon failure.
*/
int repo_init(struct repository *repo,
const char *gitdir,
const char *worktree)
{
struct repository_format format = REPOSITORY_FORMAT_INIT;
memset(repo, 0, sizeof(*repo));
repo->objects = raw_object_store_new();
repo->parsed_objects = parsed_object_pool_new();
repo->remote_state = remote_state_new();
if (repo_init_gitdir(repo, gitdir))
goto error;
if (read_and_verify_repository_format(&format, repo->commondir))
goto error;
repo_set_hash_algo(repo, format.hash_algo);
/* take ownership of format.partial_clone */
repo->repository_format_partial_clone = format.partial_clone;
format.partial_clone = NULL;
if (worktree)
repo_set_worktree(repo, worktree);
clear_repository_format(&format);
return 0;
error:
repo_clear(repo);
return -1;
}
int repo_submodule_init(struct repository *subrepo,
struct repository *superproject,
const char *path,
const struct object_id *treeish_name)
{
struct strbuf gitdir = STRBUF_INIT;
struct strbuf worktree = STRBUF_INIT;
int ret = 0;
strbuf_repo_worktree_path(&gitdir, superproject, "%s/.git", path);
strbuf_repo_worktree_path(&worktree, superproject, "%s", path);
if (repo_init(subrepo, gitdir.buf, worktree.buf)) {
/*
* If initialization fails then it may be due to the submodule
* not being populated in the superproject's worktree. Instead
* we can try to initialize the submodule by finding it's gitdir
* in the superproject's 'modules' directory. In this case the
* submodule would not have a worktree.
*/
const struct submodule *sub =
submodule_from_path(superproject, treeish_name, path);
if (!sub) {
ret = -1;
goto out;
}
strbuf_reset(&gitdir);
submodule_name_to_gitdir(&gitdir, superproject, sub->name);
if (repo_init(subrepo, gitdir.buf, NULL)) {
ret = -1;
goto out;
}
}
subrepo->submodule_prefix = xstrfmt("%s%s/",
superproject->submodule_prefix ?
superproject->submodule_prefix :
"", path);
out:
strbuf_release(&gitdir);
strbuf_release(&worktree);
return ret;
}
static void repo_clear_path_cache(struct repo_path_cache *cache)
{
FREE_AND_NULL(cache->squash_msg);
FREE_AND_NULL(cache->squash_msg);
FREE_AND_NULL(cache->merge_msg);
FREE_AND_NULL(cache->merge_rr);
FREE_AND_NULL(cache->merge_mode);
FREE_AND_NULL(cache->merge_head);
FREE_AND_NULL(cache->merge_autostash);
FREE_AND_NULL(cache->auto_merge);
FREE_AND_NULL(cache->fetch_head);
FREE_AND_NULL(cache->shallow);
}
void repo_clear(struct repository *repo)
{
FREE_AND_NULL(repo->gitdir);
FREE_AND_NULL(repo->commondir);
FREE_AND_NULL(repo->graft_file);
FREE_AND_NULL(repo->index_file);
FREE_AND_NULL(repo->worktree);
FREE_AND_NULL(repo->submodule_prefix);
raw_object_store_clear(repo->objects);
FREE_AND_NULL(repo->objects);
parsed_object_pool_clear(repo->parsed_objects);
FREE_AND_NULL(repo->parsed_objects);
if (repo->config) {
git_configset_clear(repo->config);
FREE_AND_NULL(repo->config);
}
if (repo->submodule_cache) {
submodule_cache_free(repo->submodule_cache);
repo->submodule_cache = NULL;
}
if (repo->index) {
discard_index(repo->index);
if (repo->index != &the_index)
FREE_AND_NULL(repo->index);
}
if (repo->promisor_remote_config) {
promisor_remote_clear(repo->promisor_remote_config);
FREE_AND_NULL(repo->promisor_remote_config);
}
if (repo->remote_state) {
remote_state_clear(repo->remote_state);
FREE_AND_NULL(repo->remote_state);
}
repo_clear_path_cache(&repo->cached_paths);
}
int repo_read_index(struct repository *repo)
{
int res;
if (!repo->index)
CALLOC_ARRAY(repo->index, 1);
/* Complete the double-reference */
if (!repo->index->repo)
repo->index->repo = repo;
else if (repo->index->repo != repo)
BUG("repo's index should point back at itself");
res = read_index_from(repo->index, repo->index_file, repo->gitdir);
prepare_repo_settings(repo);
if (repo->settings.command_requires_full_index)
ensure_full_index(repo->index);
/*
* If sparse checkouts are in use, check whether paths with the
* SKIP_WORKTREE attribute are missing from the worktree; if not,
* clear that attribute for that path.
*/
clear_skip_worktree_from_present_files(repo->index);
return res;
}
int repo_hold_locked_index(struct repository *repo,
struct lock_file *lf,
int flags)
{
if (!repo->index_file)
BUG("the repo hasn't been setup");
return hold_lock_file_for_update(lf, repo->index_file, flags);
}
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