@matheusbsbs / matheus-bagliano / commits / 0915a5b4cd

Fork 0

set_git_dir: fix crash when used with real_path()

`real_path()` returns result from a shared buffer, inviting subtle reentrance bugs. One of these bugs occur when invoked this way: set_git_dir(real_path(git_dir)) In this case, `real_path()` has reentrance: real_path read_gitfile_gently repo_set_gitdir setup_git_env set_git_dir_1 set_git_dir Later, `set_git_dir()` uses its now-dead parameter: !is_absolute_path(path) Fix this by using a dedicated `strbuf` to hold `strbuf_realpath()`. Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Alexandr Miloslavskiy committed Mar 6, 2020 at 19:03 UTC 0915a5b4cdf00a8c6c755b77b854725a183993b4

5 files changed +23 -14

builtin/init-db.c

+2 -2

@@ -356,12 +356,12 @@ int init_db(const char *git_dir, const char *real_git_dir,

356 if (!exist_ok && !stat(real_git_dir, &st))

357 die(_("%s already exists"), real_git_dir);

358

359 - set_git_dir(real_path(real_git_dir));

359 + set_git_dir(real_git_dir, 1);

360 git_dir = get_git_dir();

361 separate_git_dir(git_dir, original_git_dir);

362 }

363 else {

364 - set_git_dir(real_path(git_dir));

364 + set_git_dir(git_dir, 1);

365 git_dir = get_git_dir();

366 }

367 startup_info->have_repository = 1;

cache.h

+1 -1

@@ -543,7 +543,7 @@ const char *get_git_common_dir(void);

543 char *get_object_directory(void);

544 char *get_index_file(void);

545 char *get_graft_file(struct repository *r);

546 -void set_git_dir(const char *path);

546 +void set_git_dir(const char *path, int make_realpath);

547 int get_common_dir_noenv(struct strbuf *sb, const char *gitdir);

548 int get_common_dir(struct strbuf *sb, const char *gitdir);

549 const char *get_git_namespace(void);

environment.c

+10 -1

@@ -345,11 +345,20 @@ static void update_relative_gitdir(const char *name,

345 free(path);

346 }

347

348 -void set_git_dir(const char *path)

348 +void set_git_dir(const char *path, int make_realpath)

349 {

350 + struct strbuf realpath = STRBUF_INIT;

351 +

352 + if (make_realpath) {

353 + strbuf_realpath(&realpath, path, 1);

354 + path = realpath.buf;

355 + }

356 +

357 set_git_dir_1(path);

358 if (!is_absolute_path(path))

359 chdir_notify_register(NULL, update_relative_gitdir, NULL);

360 +

361 + strbuf_release(&realpath);

362 }

363

364 const char *get_log_output_encoding(void)

path.c

+1 -1

@@ -850,7 +850,7 @@ const char *enter_repo(const char *path, int strict)

850 }

851

852 if (is_git_directory(".")) {

853 - set_git_dir(".");

853 + set_git_dir(".", 0);

854 check_repository_format();

855 return path;

856 }

setup.c

+9 -9

@@ -725,7 +725,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,

725 }

726

727 /* #18, #26 */

728 - set_git_dir(gitdirenv);

728 + set_git_dir(gitdirenv, 0);

729 free(gitfile);

730 return NULL;

731 }

@@ -747,7 +747,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,

747 }

748 else if (!git_env_bool(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, 1)) {

749 /* #16d */

750 - set_git_dir(gitdirenv);

750 + set_git_dir(gitdirenv, 0);

751 free(gitfile);

752 return NULL;

753 }

@@ -759,14 +759,14 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,

759

760 /* both get_git_work_tree() and cwd are already normalized */

761 if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */

762 - set_git_dir(gitdirenv);

762 + set_git_dir(gitdirenv, 0);

763 free(gitfile);

764 return NULL;

765 }

766

767 offset = dir_inside_of(cwd->buf, worktree);

768 if (offset >= 0) { /* cwd inside worktree? */

769 - set_git_dir(real_path(gitdirenv));

769 + set_git_dir(gitdirenv, 1);

770 if (chdir(worktree))

771 die_errno(_("cannot chdir to '%s'"), worktree);

772 strbuf_addch(cwd, '/');

@@ -775,7 +775,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,

775 }

776

777 /* cwd outside worktree */

778 - set_git_dir(gitdirenv);

778 + set_git_dir(gitdirenv, 0);

779 free(gitfile);

780 return NULL;

781 }

@@ -804,7 +804,7 @@ static const char *setup_discovered_git_dir(const char *gitdir,

804

805 /* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */

806 if (is_bare_repository_cfg > 0) {

807 - set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));

807 + set_git_dir(gitdir, (offset != cwd->len));

808 if (chdir(cwd->buf))

809 die_errno(_("cannot come back to cwd"));

810 return NULL;

@@ -813,7 +813,7 @@ static const char *setup_discovered_git_dir(const char *gitdir,

813 /* #0, #1, #5, #8, #9, #12, #13 */

814 set_git_work_tree(".");

815 if (strcmp(gitdir, DEFAULT_GIT_DIR_ENVIRONMENT))

816 - set_git_dir(gitdir);

816 + set_git_dir(gitdir, 0);

817 inside_git_dir = 0;

818 inside_work_tree = 1;

819 if (offset >= cwd->len)

@@ -856,10 +856,10 @@ static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,

856 die_errno(_("cannot come back to cwd"));

857 root_len = offset_1st_component(cwd->buf);

858 strbuf_setlen(cwd, offset > root_len ? offset : root_len);

859 - set_git_dir(cwd->buf);

859 + set_git_dir(cwd->buf, 0);

860 }

861 else

862 - set_git_dir(".");

862 + set_git_dir(".", 0);

863 return NULL;

864 }

865