CVE-2024-32004 (C, published 2024-05-14T19:15Z)
Description: value: Git is a revision control system. Prior to versions 2.45.1, 2.44.1, 2.43.4, 2.42.2, 2.41.1, 2.40.2, and 2.39.4, an attacker can prepare a local repository in such a way that, when cloned, will execute arbitrary code during the operation. The problem has been patched in versions 2.45.1, 2.44.1, 2.43.4, 2.42.2, 2.41.1, 2.40.2, and 2.39.4. As a workaround, avoid cloning repositories from untrusted sources.
Severity: nan (CVSS v3 base score: )
Weakness: NVD-CWE-noinfo \u2014 Insufficient Information
There is insufficient information about the issue to classify it; details are unkown or unspecified.
Repository: https://github.com/git/git
Files changed:
cache.h
path.c
setup.c
t/t0411-clone-from-partial.sh
Commit message: fetch/clone: detect dubious ownership of local repositories

When cloning from somebody else's repositories, it is possible that,
say, the `upload-pack` command is overridden in the repository that is
about to be cloned, which would then be run in the user's context who
started the clone.

To remind the user that this is a potentially unsafe operation, let's
extend the ownership checks we have already established for regular
gitdir discovery to extend also to local repositories that are about to
be cloned.

This protection extends also to file:// URLs.

The fixes in this commit address CVE-2024-32004.

Note: This commit does not touch the `fetch`/`clone` code directly, but
instead the function used implicitly by both: `enter_repo()`. This
function is also used by `git receive-pack` (i.e. pushes), by `git
upload-archive`, by `git daemon` and by `git http-backend`. In setups
that want to serve repositories owned by different users than the
account running the service, this will require `safe.*` settings to be
configured accordingly.

Also note: there are tiny time windows where a time-of-check-time-of-use
("TOCTOU") race is possible. The real solution to those would be to work
with `fstat()` and `openat()`. However, the latter function is not
available on Windows (and would have to be emulated with rather
expensive low-level `NtCreateFile()` calls), and the changes would be
quite extensive, for my taste too extensive for the little gain given
that embargoed releases need to pay extra attention to avoid introducing
inadvertent bugs.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>


Vulnerable code:
test_expect_failure 'local clone must not fetch from promisor remote and execute script' '
test_expect_failure 'clone from file://... must not fetch from promisor remote and execute script' '
test_expect_failure 'fetch from file://... must not fetch from promisor remote and execute script' '

Fixed code:
/*
 * Check if a repository is safe and die if it is not, by verifying the
 * ownership of the worktree (if any), the git directory, and the gitfile (if
 * any).
 *
 * Exemptions for known-safe repositories can be added via `safe.directory`
 * config settings; for non-bare repositories, their worktree needs to be
 * added, for bare ones their git directory.
 */
void die_upon_dubious_ownership(const char *gitfile, const char *worktree,
				const char *gitdir);

		die_upon_dubious_ownership(gitfile, NULL, used_path.buf);
		die_upon_dubious_ownership(gitfile, NULL, path);
void die_upon_dubious_ownership(const char *gitfile, const char *worktree,
				const char *gitdir)
{
	struct strbuf report = STRBUF_INIT, quoted = STRBUF_INIT;
	const char *path;

	if (ensure_valid_ownership(gitfile, worktree, gitdir, &report))
		return;

	strbuf_complete(&report, '\n');
	path = gitfile ? gitfile : gitdir;
	sq_quote_buf_pretty(&quoted, path);

	die(_("detected dubious ownership in repository at '%s'\n"
	      "%s"
	      "To add an exception for this directory, call:\n"
	      "\n"
	      "\tgit config --global --add safe.directory %s"),
	    path, report.buf, quoted.buf);
}

test_expect_success 'local clone must not fetch from promisor remote and execute script' '
test_expect_success 'clone from file://... must not fetch from promisor remote and execute script' '
test_expect_success 'fetch from file://... must not fetch from promisor remote and execute script' '