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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 
clone: prevent clashing git dirs when cloning submodule in parallel
 
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
Raw File
help.h 
#ifndef HELP_H
#define HELP_H

#include "string-list.h"
#include "strbuf.h"

struct cmdnames {
	int alloc;
	int cnt;
	struct cmdname {
		size_t len; /* also used for similarity index in help.c */
		char name[FLEX_ARRAY];
	} **names;
};

static inline void mput_char(char c, unsigned int num)
{
	while (num--)
		putchar(c);
}

void list_common_cmds_help(void);
void list_all_cmds_help(int show_external_commands, int show_aliases);
void list_guides_help(void);
void list_user_interfaces_help(void);
void list_developer_interfaces_help(void);

void list_all_main_cmds(struct string_list *list);
void list_all_other_cmds(struct string_list *list);
void list_cmds_by_category(struct string_list *list,
			   const char *category);
void list_cmds_by_config(struct string_list *list);
const char *help_unknown_cmd(const char *cmd);
void load_command_list(const char *prefix,
		       struct cmdnames *main_cmds,
		       struct cmdnames *other_cmds);
void load_builtin_commands(const char *prefix, struct cmdnames *cmds);
void add_cmdname(struct cmdnames *cmds, const char *name, int len);
/* Here we require that excludes is a sorted list. */
void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes);
int is_in_cmdlist(struct cmdnames *cmds, const char *name);
void list_commands(struct cmdnames *main_cmds, struct cmdnames *other_cmds);
void get_version_info(struct strbuf *buf, int show_build_options);

/*
 * call this to die(), when it is suspected that the user mistyped a
 * ref to the command, to give suggested "correct" refs.
 */
NORETURN void help_unknown_ref(const char *ref, const char *cmd, const char *error);

static inline void list_config_item(struct string_list *list,
				    const char *prefix,
				    const char *str)
{
	string_list_append_nodup(list, xstrfmt("%s.%s", prefix, str));
}

#define define_list_config_array(array)					\
void list_config_##array(struct string_list *list, const char *prefix)	\
{									\
	int i;								\
	for (i = 0; i < ARRAY_SIZE(array); i++)				\
		if (array[i])						\
			list_config_item(list, prefix, array[i]);	\
}									\
struct string_list

#define define_list_config_array_extra(array, values)			\
void list_config_##array(struct string_list *list, const char *prefix)	\
{									\
	int i;								\
	static const char *extra[] = values;				\
	for (i = 0; i < ARRAY_SIZE(extra); i++)				\
		list_config_item(list, prefix, extra[i]);		\
	for (i = 0; i < ARRAY_SIZE(array); i++)				\
		if (array[i])						\
			list_config_item(list, prefix, array[i]);	\
}									\
struct string_list

/* These are actually scattered over many C files */
void list_config_advices(struct string_list *list, const char *prefix);
void list_config_color_branch_slots(struct string_list *list, const char *prefix);
void list_config_color_decorate_slots(struct string_list *list, const char *prefix);
void list_config_color_diff_slots(struct string_list *list, const char *prefix);
void list_config_color_grep_slots(struct string_list *list, const char *prefix);
void list_config_color_interactive_slots(struct string_list *list, const char *prefix);
void list_config_color_status_slots(struct string_list *list, const char *prefix);
void list_config_color_sideband_slots(struct string_list *list, const char *prefix);
void list_config_fsck_msg_ids(struct string_list *list, const char *prefix);

#endif /* HELP_H */
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