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>
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hash-object.c
/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
* Copyright (C) Junio C Hamano, 2005
*/
#include "builtin.h"
#include "config.h"
#include "object-store.h"
#include "blob.h"
#include "quote.h"
#include "parse-options.h"
#include "exec-cmd.h"
/*
* This is to create corrupt objects for debugging and as such it
* needs to bypass the data conversion performed by, and the type
* limitation imposed by, index_fd() and its callees.
*/
static int hash_literally(struct object_id *oid, int fd, const char *type, unsigned flags)
{
struct strbuf buf = STRBUF_INIT;
int ret;
if (strbuf_read(&buf, fd, 4096) < 0)
ret = -1;
else
ret = write_object_file_literally(buf.buf, buf.len, type, oid,
flags);
strbuf_release(&buf);
return ret;
}
static void hash_fd(int fd, const char *type, const char *path, unsigned flags,
int literally)
{
struct stat st;
struct object_id oid;
if (fstat(fd, &st) < 0 ||
(literally
? hash_literally(&oid, fd, type, flags)
: index_fd(the_repository->index, &oid, fd, &st,
type_from_string(type), path, flags)))
die((flags & HASH_WRITE_OBJECT)
? "Unable to add %s to database"
: "Unable to hash %s", path);
printf("%s\n", oid_to_hex(&oid));
maybe_flush_or_die(stdout, "hash to stdout");
}
static void hash_object(const char *path, const char *type, const char *vpath,
unsigned flags, int literally)
{
int fd;
fd = xopen(path, O_RDONLY);
hash_fd(fd, type, vpath, flags, literally);
}
static void hash_stdin_paths(const char *type, int no_filters, unsigned flags,
int literally)
{
struct strbuf buf = STRBUF_INIT;
struct strbuf unquoted = STRBUF_INIT;
while (strbuf_getline(&buf, stdin) != EOF) {
if (buf.buf[0] == '"') {
strbuf_reset(&unquoted);
if (unquote_c_style(&unquoted, buf.buf, NULL))
die("line is badly quoted");
strbuf_swap(&buf, &unquoted);
}
hash_object(buf.buf, type, no_filters ? NULL : buf.buf, flags,
literally);
}
strbuf_release(&buf);
strbuf_release(&unquoted);
}
int cmd_hash_object(int argc, const char **argv, const char *prefix)
{
static const char * const hash_object_usage[] = {
N_("git hash-object [-t <type>] [-w] [--path=<file> | --no-filters]\n"
" [--stdin [--literally]] [--] <file>..."),
N_("git hash-object [-t <type>] [-w] --stdin-paths [--no-filters]"),
NULL
};
const char *type = blob_type;
int hashstdin = 0;
int stdin_paths = 0;
int no_filters = 0;
int literally = 0;
int nongit = 0;
unsigned flags = HASH_FORMAT_CHECK;
const char *vpath = NULL;
char *vpath_free = NULL;
const struct option hash_object_options[] = {
OPT_STRING('t', NULL, &type, N_("type"), N_("object type")),
OPT_BIT('w', NULL, &flags, N_("write the object into the object database"),
HASH_WRITE_OBJECT),
OPT_COUNTUP( 0 , "stdin", &hashstdin, N_("read the object from stdin")),
OPT_BOOL( 0 , "stdin-paths", &stdin_paths, N_("read file names from stdin")),
OPT_BOOL( 0 , "no-filters", &no_filters, N_("store file as is without filters")),
OPT_BOOL( 0, "literally", &literally, N_("just hash any random garbage to create corrupt objects for debugging Git")),
OPT_STRING( 0 , "path", &vpath, N_("file"), N_("process file as it were from this path")),
OPT_END()
};
int i;
const char *errstr = NULL;
argc = parse_options(argc, argv, prefix, hash_object_options,
hash_object_usage, 0);
if (flags & HASH_WRITE_OBJECT)
prefix = setup_git_directory();
else
prefix = setup_git_directory_gently(&nongit);
if (vpath && prefix) {
vpath_free = prefix_filename(prefix, vpath);
vpath = vpath_free;
}
git_config(git_default_config, NULL);
if (stdin_paths) {
if (hashstdin)
errstr = "Can't use --stdin-paths with --stdin";
else if (argc)
errstr = "Can't specify files with --stdin-paths";
else if (vpath)
errstr = "Can't use --stdin-paths with --path";
}
else {
if (hashstdin > 1)
errstr = "Multiple --stdin arguments are not supported";
if (vpath && no_filters)
errstr = "Can't use --path with --no-filters";
}
if (errstr) {
error("%s", errstr);
usage_with_options(hash_object_usage, hash_object_options);
}
if (hashstdin)
hash_fd(0, type, vpath, flags, literally);
for (i = 0 ; i < argc; i++) {
const char *arg = argv[i];
char *to_free = NULL;
if (prefix)
arg = to_free = prefix_filename(prefix, arg);
hash_object(arg, type, no_filters ? NULL : vpath ? vpath : arg,
flags, literally);
free(to_free);
}
if (stdin_paths)
hash_stdin_paths(type, no_filters, flags, literally);
free(vpath_free);
return 0;
}
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