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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diff-no-index.c
/*
* "diff --no-index" support
* Copyright (c) 2007 by Johannes Schindelin
* Copyright (c) 2008 by Junio C Hamano
*/
#include "cache.h"
#include "color.h"
#include "commit.h"
#include "blob.h"
#include "tag.h"
#include "diff.h"
#include "diffcore.h"
#include "revision.h"
#include "log-tree.h"
#include "builtin.h"
#include "parse-options.h"
#include "string-list.h"
#include "dir.h"
static int read_directory_contents(const char *path, struct string_list *list)
{
DIR *dir;
struct dirent *e;
if (!(dir = opendir(path)))
return error("Could not open directory %s", path);
while ((e = readdir_skip_dot_and_dotdot(dir)))
string_list_insert(list, e->d_name);
closedir(dir);
return 0;
}
/*
* This should be "(standard input)" or something, but it will
* probably expose many more breakages in the way no-index code
* is bolted onto the diff callchain.
*/
static const char file_from_standard_input[] = "-";
static int get_mode(const char *path, int *mode)
{
struct stat st;
if (!path || !strcmp(path, "/dev/null"))
*mode = 0;
#ifdef GIT_WINDOWS_NATIVE
else if (!strcasecmp(path, "nul"))
*mode = 0;
#endif
else if (path == file_from_standard_input)
*mode = create_ce_mode(0666);
else if (lstat(path, &st))
return error("Could not access '%s'", path);
else
*mode = st.st_mode;
return 0;
}
static int populate_from_stdin(struct diff_filespec *s)
{
struct strbuf buf = STRBUF_INIT;
size_t size = 0;
if (strbuf_read(&buf, 0, 0) < 0)
return error_errno("error while reading from stdin");
s->should_munmap = 0;
s->data = strbuf_detach(&buf, &size);
s->size = size;
s->should_free = 1;
s->is_stdin = 1;
return 0;
}
static struct diff_filespec *noindex_filespec(const char *name, int mode)
{
struct diff_filespec *s;
if (!name)
name = "/dev/null";
s = alloc_filespec(name);
fill_filespec(s, null_oid(), 0, mode);
if (name == file_from_standard_input)
populate_from_stdin(s);
return s;
}
static int queue_diff(struct diff_options *o,
const char *name1, const char *name2)
{
int mode1 = 0, mode2 = 0;
if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
return -1;
if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2)) {
struct diff_filespec *d1, *d2;
if (S_ISDIR(mode1)) {
/* 2 is file that is created */
d1 = noindex_filespec(NULL, 0);
d2 = noindex_filespec(name2, mode2);
name2 = NULL;
mode2 = 0;
} else {
/* 1 is file that is deleted */
d1 = noindex_filespec(name1, mode1);
d2 = noindex_filespec(NULL, 0);
name1 = NULL;
mode1 = 0;
}
/* emit that file */
diff_queue(&diff_queued_diff, d1, d2);
/* and then let the entire directory be created or deleted */
}
if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
struct strbuf buffer1 = STRBUF_INIT;
struct strbuf buffer2 = STRBUF_INIT;
struct string_list p1 = STRING_LIST_INIT_DUP;
struct string_list p2 = STRING_LIST_INIT_DUP;
int i1, i2, ret = 0;
size_t len1 = 0, len2 = 0;
if (name1 && read_directory_contents(name1, &p1))
return -1;
if (name2 && read_directory_contents(name2, &p2)) {
string_list_clear(&p1, 0);
return -1;
}
if (name1) {
strbuf_addstr(&buffer1, name1);
strbuf_complete(&buffer1, '/');
len1 = buffer1.len;
}
if (name2) {
strbuf_addstr(&buffer2, name2);
strbuf_complete(&buffer2, '/');
len2 = buffer2.len;
}
for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
const char *n1, *n2;
int comp;
strbuf_setlen(&buffer1, len1);
strbuf_setlen(&buffer2, len2);
if (i1 == p1.nr)
comp = 1;
else if (i2 == p2.nr)
comp = -1;
else
comp = strcmp(p1.items[i1].string, p2.items[i2].string);
if (comp > 0)
n1 = NULL;
else {
strbuf_addstr(&buffer1, p1.items[i1++].string);
n1 = buffer1.buf;
}
if (comp < 0)
n2 = NULL;
else {
strbuf_addstr(&buffer2, p2.items[i2++].string);
n2 = buffer2.buf;
}
ret = queue_diff(o, n1, n2);
}
string_list_clear(&p1, 0);
string_list_clear(&p2, 0);
strbuf_release(&buffer1);
strbuf_release(&buffer2);
return ret;
} else {
struct diff_filespec *d1, *d2;
if (o->flags.reverse_diff) {
SWAP(mode1, mode2);
SWAP(name1, name2);
}
d1 = noindex_filespec(name1, mode1);
d2 = noindex_filespec(name2, mode2);
diff_queue(&diff_queued_diff, d1, d2);
return 0;
}
}
/* append basename of F to D */
static void append_basename(struct strbuf *path, const char *dir, const char *file)
{
const char *tail = strrchr(file, '/');
strbuf_addstr(path, dir);
while (path->len && path->buf[path->len - 1] == '/')
path->len--;
strbuf_addch(path, '/');
strbuf_addstr(path, tail ? tail + 1 : file);
}
/*
* DWIM "diff D F" into "diff D/F F" and "diff F D" into "diff F D/F"
* Note that we append the basename of F to D/, so "diff a/b/file D"
* becomes "diff a/b/file D/file", not "diff a/b/file D/a/b/file".
*/
static void fixup_paths(const char **path, struct strbuf *replacement)
{
unsigned int isdir0, isdir1;
if (path[0] == file_from_standard_input ||
path[1] == file_from_standard_input)
return;
isdir0 = is_directory(path[0]);
isdir1 = is_directory(path[1]);
if (isdir0 == isdir1)
return;
if (isdir0) {
append_basename(replacement, path[0], path[1]);
path[0] = replacement->buf;
} else {
append_basename(replacement, path[1], path[0]);
path[1] = replacement->buf;
}
}
static const char * const diff_no_index_usage[] = {
N_("git diff --no-index [<options>] <path> <path>"),
NULL
};
int diff_no_index(struct rev_info *revs,
int implicit_no_index,
int argc, const char **argv)
{
int i, no_index;
int ret = 1;
const char *paths[2];
char *to_free[ARRAY_SIZE(paths)] = { 0 };
struct strbuf replacement = STRBUF_INIT;
const char *prefix = revs->prefix;
struct option no_index_options[] = {
OPT_BOOL_F(0, "no-index", &no_index, "",
PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
OPT_END(),
};
struct option *options;
options = parse_options_concat(no_index_options,
revs->diffopt.parseopts);
argc = parse_options(argc, argv, revs->prefix, options,
diff_no_index_usage, 0);
if (argc != 2) {
if (implicit_no_index)
warning(_("Not a git repository. Use --no-index to "
"compare two paths outside a working tree"));
usage_with_options(diff_no_index_usage, options);
}
FREE_AND_NULL(options);
for (i = 0; i < 2; i++) {
const char *p = argv[i];
if (!strcmp(p, "-"))
/*
* stdin should be spelled as "-"; if you have
* path that is "-", spell it as "./-".
*/
p = file_from_standard_input;
else if (prefix)
p = to_free[i] = prefix_filename(prefix, p);
paths[i] = p;
}
fixup_paths(paths, &replacement);
revs->diffopt.skip_stat_unmatch = 1;
if (!revs->diffopt.output_format)
revs->diffopt.output_format = DIFF_FORMAT_PATCH;
revs->diffopt.flags.no_index = 1;
revs->diffopt.flags.relative_name = 1;
revs->diffopt.prefix = prefix;
revs->max_count = -2;
diff_setup_done(&revs->diffopt);
setup_diff_pager(&revs->diffopt);
revs->diffopt.flags.exit_with_status = 1;
if (queue_diff(&revs->diffopt, paths[0], paths[1]))
goto out;
diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
diffcore_std(&revs->diffopt);
diff_flush(&revs->diffopt);
/*
* The return code for --no-index imitates diff(1):
* 0 = no changes, 1 = changes, else error
*/
ret = diff_result_code(&revs->diffopt, 0);
out:
for (i = 0; i < ARRAY_SIZE(to_free); i++)
free(to_free[i]);
strbuf_release(&replacement);
return ret;
}
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