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
mktag.c
#include "builtin.h"
#include "parse-options.h"
#include "tag.h"
#include "replace-object.h"
#include "object-store.h"
#include "fsck.h"
#include "config.h"
static char const * const builtin_mktag_usage[] = {
"git mktag",
NULL
};
static int option_strict = 1;
static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
static int mktag_fsck_error_func(struct fsck_options *o,
const struct object_id *oid,
enum object_type object_type,
enum fsck_msg_type msg_type,
enum fsck_msg_id msg_id,
const char *message)
{
switch (msg_type) {
case FSCK_WARN:
if (!option_strict) {
fprintf_ln(stderr, _("warning: tag input does not pass fsck: %s"), message);
return 0;
}
/* fallthrough */
case FSCK_ERROR:
/*
* We treat both warnings and errors as errors, things
* like missing "tagger" lines are "only" warnings
* under fsck, we've always considered them an error.
*/
fprintf_ln(stderr, _("error: tag input does not pass fsck: %s"), message);
return 1;
default:
BUG(_("%d (FSCK_IGNORE?) should never trigger this callback"),
msg_type);
}
}
static int verify_object_in_tag(struct object_id *tagged_oid, int *tagged_type)
{
int ret;
enum object_type type;
unsigned long size;
void *buffer;
const struct object_id *repl;
buffer = read_object_file(tagged_oid, &type, &size);
if (!buffer)
die(_("could not read tagged object '%s'"),
oid_to_hex(tagged_oid));
if (type != *tagged_type)
die(_("object '%s' tagged as '%s', but is a '%s' type"),
oid_to_hex(tagged_oid),
type_name(*tagged_type), type_name(type));
repl = lookup_replace_object(the_repository, tagged_oid);
ret = check_object_signature(the_repository, repl, buffer, size,
*tagged_type);
free(buffer);
return ret;
}
int cmd_mktag(int argc, const char **argv, const char *prefix)
{
static struct option builtin_mktag_options[] = {
OPT_BOOL(0, "strict", &option_strict,
N_("enable more strict checking")),
OPT_END(),
};
struct strbuf buf = STRBUF_INIT;
struct object_id tagged_oid;
int tagged_type;
struct object_id result;
argc = parse_options(argc, argv, NULL,
builtin_mktag_options,
builtin_mktag_usage, 0);
if (strbuf_read(&buf, 0, 0) < 0)
die_errno(_("could not read from stdin"));
fsck_options.error_func = mktag_fsck_error_func;
fsck_set_msg_type_from_ids(&fsck_options, FSCK_MSG_EXTRA_HEADER_ENTRY,
FSCK_WARN);
/* config might set fsck.extraHeaderEntry=* again */
git_config(git_fsck_config, &fsck_options);
if (fsck_tag_standalone(NULL, buf.buf, buf.len, &fsck_options,
&tagged_oid, &tagged_type))
die(_("tag on stdin did not pass our strict fsck check"));
if (verify_object_in_tag(&tagged_oid, &tagged_type) < 0)
die(_("tag on stdin did not refer to a valid object"));
if (write_object_file(buf.buf, buf.len, OBJ_TAG, &result) < 0)
die(_("unable to write tag file"));
strbuf_release(&buf);
puts(oid_to_hex(&result));
return 0;
}
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