security/tomoyo/file.c

Source file repositories/reference/linux-study-clean/security/tomoyo/file.c

File Facts

System
Linux kernel
Corpus path
security/tomoyo/file.c
Extension
.c
Size
30068 bytes
Lines
1051
Domain
Core OS
Bucket
Security And Isolation
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!tomoyo_get_realpath(&buf, path)) {
			error = -ENOMEM;
			goto out;
		}
		r.obj = &obj;
		if (acc_mode & MAY_READ)
			error = tomoyo_path_permission(&r, TOMOYO_TYPE_READ,
						       &buf);
		if (!error && (acc_mode & MAY_WRITE))
			error = tomoyo_path_permission(&r, (flag & O_APPEND) ?
						       TOMOYO_TYPE_APPEND :
						       TOMOYO_TYPE_WRITE,
						       &buf);
	}
 out:
	kfree(buf.name);
	tomoyo_read_unlock(idx);
	if (r.mode != TOMOYO_CONFIG_ENFORCING)
		error = 0;
	return error;
}

/**
 * tomoyo_path_perm - Check permission for "unlink", "rmdir", "truncate", "symlink", "append", "chroot" and "unmount".
 *
 * @operation: Type of operation.
 * @path:      Pointer to "struct path".
 * @target:    Symlink's target if @operation is TOMOYO_TYPE_SYMLINK,
 *             NULL otherwise.
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_path_perm(const u8 operation, const struct path *path, const char *target)
{
	struct tomoyo_request_info r;
	struct tomoyo_obj_info obj = {
		.path1 = { .mnt = path->mnt, .dentry = path->dentry },
	};
	int error;
	struct tomoyo_path_info buf;
	bool is_enforce;
	struct tomoyo_path_info symlink_target;
	int idx;

	if (tomoyo_init_request_info(&r, NULL, tomoyo_p2mac[operation])
	    == TOMOYO_CONFIG_DISABLED)
		return 0;
	is_enforce = (r.mode == TOMOYO_CONFIG_ENFORCING);
	error = -ENOMEM;
	buf.name = NULL;
	idx = tomoyo_read_lock();
	if (!tomoyo_get_realpath(&buf, path))
		goto out;
	r.obj = &obj;
	switch (operation) {
	case TOMOYO_TYPE_RMDIR:
	case TOMOYO_TYPE_CHROOT:
		tomoyo_add_slash(&buf);
		break;
	case TOMOYO_TYPE_SYMLINK:
		symlink_target.name = tomoyo_encode(target);
		if (!symlink_target.name)
			goto out;
		tomoyo_fill_path_info(&symlink_target);
		obj.symlink_target = &symlink_target;
		break;
	}
	error = tomoyo_path_permission(&r, operation, &buf);
	if (operation == TOMOYO_TYPE_SYMLINK)
		kfree(symlink_target.name);
 out:
	kfree(buf.name);
	tomoyo_read_unlock(idx);
	if (!is_enforce)
		error = 0;
	return error;
}

/**
 * tomoyo_mkdev_perm - Check permission for "mkblock" and "mkchar".
 *
 * @operation: Type of operation. (TOMOYO_TYPE_MKCHAR or TOMOYO_TYPE_MKBLOCK)
 * @path:      Pointer to "struct path".
 * @mode:      Create mode.
 * @dev:       Device number.
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_mkdev_perm(const u8 operation, const struct path *path,
		      const unsigned int mode, unsigned int dev)

Annotation

Implementation Notes