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Revision 8db1e8743c0f1ed241f6a1b8bf55b6fef07d6751 authored by Johannes Schindelin on 28 March 2024, 18:21:06 UTC, committed by Johannes Schindelin on 19 April 2024, 10:38:23 UTC 
clone: prevent hooks from running during a clone
 
Critical security issues typically combine relatively common
vulnerabilities such as case confusion in file paths with other
weaknesses in order to raise the severity of the attack.

One such weakness that has haunted the Git project in many a
submodule-related CVE is that any hooks that are found are executed
during a clone operation. Examples are the `post-checkout` and
`fsmonitor` hooks.

However, Git's design calls for hooks to be disabled by default, as only
disabled example hooks are copied over from the templates in
`<prefix>/share/git-core/templates/`.

As a defense-in-depth measure, let's prevent those hooks from running.

Obviously, administrators can choose to drop enabled hooks into the
template directory, though, _and_ it is also possible to override
`core.hooksPath`, in which case the new check needs to be disabled.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent 584de0b
Raw File
notes-cache.c 
#include "cache.h"
#include "notes-cache.h"
#include "object-store.h"
#include "repository.h"
#include "commit.h"
#include "refs.h"

static int notes_cache_match_validity(struct repository *r,
				      const char *ref,
				      const char *validity)
{
	struct object_id oid;
	struct commit *commit;
	struct pretty_print_context pretty_ctx;
	struct strbuf msg = STRBUF_INIT;
	int ret;

	if (read_ref(ref, &oid) < 0)
		return 0;

	commit = lookup_commit_reference_gently(r, &oid, 1);
	if (!commit)
		return 0;

	memset(&pretty_ctx, 0, sizeof(pretty_ctx));
	format_commit_message(commit, "%s", &msg, &pretty_ctx);
	strbuf_trim(&msg);

	ret = !strcmp(msg.buf, validity);
	strbuf_release(&msg);

	return ret;
}

void notes_cache_init(struct repository *r, struct notes_cache *c,
		      const char *name, const char *validity)
{
	struct strbuf ref = STRBUF_INIT;
	int flags = NOTES_INIT_WRITABLE;

	memset(c, 0, sizeof(*c));
	c->validity = xstrdup(validity);

	strbuf_addf(&ref, "refs/notes/%s", name);
	if (!notes_cache_match_validity(r, ref.buf, validity))
		flags |= NOTES_INIT_EMPTY;
	init_notes(&c->tree, ref.buf, combine_notes_overwrite, flags);
	strbuf_release(&ref);
}

int notes_cache_write(struct notes_cache *c)
{
	struct object_id tree_oid, commit_oid;

	if (!c || !c->tree.initialized || !c->tree.update_ref ||
	    !*c->tree.update_ref)
		return -1;
	if (!c->tree.dirty)
		return 0;

	if (write_notes_tree(&c->tree, &tree_oid))
		return -1;
	if (commit_tree(c->validity, strlen(c->validity), &tree_oid, NULL,
			&commit_oid, NULL, NULL) < 0)
		return -1;
	if (update_ref("update notes cache", c->tree.update_ref, &commit_oid,
		       NULL, 0, UPDATE_REFS_QUIET_ON_ERR) < 0)
		return -1;

	return 0;
}

char *notes_cache_get(struct notes_cache *c, struct object_id *key_oid,
		      size_t *outsize)
{
	const struct object_id *value_oid;
	enum object_type type;
	char *value;
	unsigned long size;

	value_oid = get_note(&c->tree, key_oid);
	if (!value_oid)
		return NULL;
	value = read_object_file(value_oid, &type, &size);

	*outsize = size;
	return value;
}

int notes_cache_put(struct notes_cache *c, struct object_id *key_oid,
		    const char *data, size_t size)
{
	struct object_id value_oid;

	if (write_object_file(data, size, OBJ_BLOB, &value_oid) < 0)
		return -1;
	return add_note(&c->tree, key_oid, &value_oid, NULL);
}
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